Seguimiento general en EEUU

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stormchaserAlberto
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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Dom Jun 11, 2017 6:47 pm

Se bajó a leve ahora el riesgo. Se disminuyeron también las probabilidades de viento destructivo.
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% de tornados.
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Viento.
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Granizo.
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Discusión.
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Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Sun Jun 11 2017

Valid 112000Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF
NORTHERN LOWER MICHIGAN AND THE UPPER PENINSULA OF MICHIGAN...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST
WYOMING TO NORTHERN COLORADO...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
NORTHERN ROCKIES TO THE GREAT LAKES...

...SUMMARY...
Severe storms with a threat for mainly damaging wind will continue
across the remainder of the upper peninsula of Michigan into the
northern part of lower Michigan this afternoon. Otherwise, Isolated
strong-severe storms remain possible across parts of southeast
Wyoming/northern Colorado, and the northern Great Basin as well as
farther east into the central plains and upper Mississippi Valley
this afternoon and evening.

...Northern Wisconsin, northern lower Michigan and the eastern
portion of upper Michigan...

Threat for damaging wind will continue this afternoon into early
evening as squall line continues through this region.

Elsewhere...an east-west band of storms will persist over northern
Wisconsin into early evening within zone of isentropic ascent
resulting from the southwesterly low-level jet interacting with
trailing outflow boundary. These storms are elevated well north of
the outflow boundary with heavy rain the main threat, though a small
risk for marginally severe hail also exists.

...Northern Rockies through southeast Wyoming and northern
Colorado...

Satellite trends suggest storms will develop over the higher terrain
and spread north and northeast. High based storms with inverted-V
profiles will support a risk for isolated downburst winds. Strong
surface - 6 km AGL shear will also promote a few rotating updrafts.
Updrafts may be somewhat more robust from southeast WY into northern
CO where richer low-level moisture has advected westward within the
evolving upslope regime.

...Nebraska through northern Iowa and southern Minnesota...

Will maintain marginal risk category in this region. Strong
instability has developed (3000+ J/kg MLCAPE) where a warm elevated
mixed layer has advected above the moist axis in vicinity of stalled
boundary. However, only shallow frontal convergence and weak forcing
for ascent aloft associated with a building ridge, along with strong
convective inhibition resulting from the elevated mixed layer will
probably limit storm coverage. Any storms developing in this regime
will be capable of producing downburst winds and large hail.

..Dial.. 06/11/2017

.PREV DISCUSSION... /ISSUED 1136 AM CDT Sun Jun 11 2017/

...Synopsis...
An upper low over the northern California coast will move slowly
east towards the Great Basin through tonight. A belt of stronger
mid-level flow will extend across the central/northern Rockies and
from the northern Plains/Upper Midwest into New England. A surface
warm front extends along the southern periphery of the stronger
mid-level flow from low pressure over southeast South Dakota across
central Wisconsin, with a trailing cold front from the low into
northeast Colorado. A surface trough/dryline extends south through
eastern Colorado into far west Texas.

...Upper Midwest/northern Great Lakes into central Plains...
A well-developed bowing MCS continues to move east-northeast at
around 50 kts with a history of wind damage/measured severe gusts
and large hail. In the short-term this MCS is likely to track along
the instability gradient as the warm front slowly lifts north across
central/northern Wisconsin and the Upper Peninsula of Michigan aided
by 40-45 kt 850 mb inflow. Severe wind and hail will remain primary
threats, with a tornado risk associated with QLCS circulations.
Severe storms may also develop in advance of the MCS associated with
low-level warm advection, with supercell structures possible given
ample effective shear and buoyancy. Isolated strong/severe storms
are expected to expected to redevelop later this afternoon west of
the MCS along the composite frontal boundary as afternoon
heating/destabilization takes place within a favorably sheared
environment. Isolated occurrences of large hail and damaging winds
will be possible.

...Front Range of northeast Colorado/southeast Wyoming...
An increasingly moist upslope/post-frontal flow regime will become
established by this afternoon across southeast WY and northeast CO.
The more likely area for isolated severe storm development will be
near the east slope of the Laramie Range southward into northern CO.
Within an environment characterized by MLCAPE of 1000-1500 j/kg and
around 40 kts of deep-layer shear, storms that do form will develop
supercell structures capable of isolated large hail.

...Northern Nevada/southern Idaho into western Wyoming this
afternoon...
A closed mid-level low over northern California will move slowly
eastward to northern Nevada by tonight. Downstream from the low,
upper divergence in the exit region of the cyclonically curved jet
will combine with daytime heating to support at least widely
scattered thunderstorm development. Low-level moisture and buoyancy
will remain limited, though steep low-level lapse rates and
substantial deep-layer southerly shear could support isolated storms
with gusty outflow winds.

Próxima actualización: 01:00z.
----------------------------------------------
Últimas discusiones a mesoescala.
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Mesoscale Discussion 0988
NWS Storm Prediction Center Norman OK
0246 PM CDT Sun Jun 11 2017

Areas affected...Eastern Upper Michigan into northern Lower

Concerning...Severe Thunderstorm Watch 314...

Valid 111946Z - 112145Z

The severe weather threat for Severe Thunderstorm Watch 314
continues.

SUMMARY...A threat of damaging winds continues across the watch
area.

DISCUSSION...A long-lived convective system is now crossing over
northern Lake Michigan, with sporadic cellular development just
ahead of it near the northern coast. This line of storms has a long
history of producing wind damage.

While instability levels decrease to the east, surface observations
and satellite imagery show warming continues across much of Lower
Michigan, with temperatures rising into the mid 80s along with weak
pressure falls. In addition, southerly low-level flow continues to
increase ahead of the MCS. Therefore, while the line may not be as
strong as it was previously, conditions may prove sufficient for a
continued localized damaging wind threat.

..Jewell.. 06/11/2017

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Mesoscale Discussion 0989
NWS Storm Prediction Center Norman OK
0349 PM CDT Sun Jun 11 2017

Areas affected...North Central CO...Southeast WY

Concerning...Severe potential...Watch possible

Valid 112049Z - 112315Z

Probability of Watch Issuance...40 percent

SUMMARY...Isolated thunderstorms are expected to develop this
afternoon along the front range and foothills of north-central CO
and southeast WY. The strongest cells may produce large hail. A
watch may be considered.

DISCUSSION...Water vapor loop shows a mid-level shortwave trough
moving across NM and western CO. Mid to high level lift in advance
of this feature is spreading across the Rockies and is approaching
the front range region. Meanwhile, northerly post-frontal surface
winds over much of eastern CO have maintained near-50 dewpoints
across the region. Forecast soundings modified for observed
conditions suggest over 1000 J/kg of MLCAPE and only a weak cap
along the foothills and adjacent plains. Vertical shear is also
moderately strong, with effective shear values of 35-45 knots.

Present indications are that scattered showers and isolated
thunderstorms will form over the foothills this afternoon and spread
into the adjacent counties of CO. A few of the storms may become
supercellular with large hail being a concern. Consensus of CAM
solutions suggests that coverage of severe storms may be quite
sparse. Therefore it is uncertain whether a watch will be needed
for this scenario.

..Hart/Bunting.. 06/11/2017
Dome, dome, dome..The life is a dome

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stormchaserAlberto
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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Dom Jun 11, 2017 9:22 pm

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Mesoscale Discussion 0990
NWS Storm Prediction Center Norman OK
0620 PM CDT Sun Jun 11 2017

Areas affected...Southeast MN...central and northern WI...and part
of southern Upper MI

Concerning...Severe potential...Watch possible

Valid 112320Z - 120145Z

Probability of Watch Issuance...40 percent

SUMMARY...Thunderstorms will continue to develop this evening across
parts of southeast MN into west-central WI, with hail and strong
wind gusts being the primary threats. The wind threat will be
greatest if storm mergers/cold pool formation occurs and activity
spreads to the south/southeast. A conditional tornado threat cannot
be ruled out in vicinity of a west-east stationary/warm front
extending from Goodhue/Wabasha Counties MN to Marathon/Wood Counties
WI.

DISCUSSION...Strong southerly low-level flow and clearing skies
across southeast MN into west-central/central WI in the wake of the
early day MCS (that was currently moving east of northern Lower MI)
has resulted in sufficient theta-e advection across southeast MN
through WI for robust destabilization. Objective analyses indicated
mixed-layer CAPE of 2000-2500 J/kg extending from southern MN to
central WI, situated in vicinity of an outflow-reinforced baroclinic
zone and 1000-1500 J/kg of MUCAPE extending into northern WI near a
southwest to east-northeast oriented outflow boundary. Meanwhile,
modified 12Z DVN/16Z GRB soundings for southeast MN/western WI
surface observations suggested mixed-layer CAPE close to 3000 J/kg.
In addition to ongoing storms across northern WI, storms were also
developing attendant to an eastward-moving northeast-southwest
oriented outflow that extended from Barron County WI to southern
Goodhue County MN to Kossuth County IA at 2305Z.

Strong 850-700-mb layer warm advection across southeast MN and much
of central and northern WI will support additional strong to severe
storms this evening, with the available instability and strong bulk
shear supporting both hail and strong wind gusts. A concern for a
tornado threat exists in vicinity of the west-east oriented
baroclinic zone, extending from Goodhue/Wabasha Counties MN to
central WI (eastward to Marathon/Wood Counties), where low-level
shear is maximized (effective SRH of 300-400 m2/s2 per objective
analyses). Storms interacting with this boundary should have the
greatest conditional probability for a tornado to form.

..Peters/Edwards.. 06/11/2017
Dome, dome, dome..The life is a dome

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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Lun Jun 12, 2017 12:56 pm

Interesante día el de hoy, con riesgo MODERADO para el sudeste de Wyoming, noroeste de Nebraska y el sudoeste de Dakota del Sur. Tornado y granizo, riesgos principales.
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Viento.
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Granizo.
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Discusión.
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Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0731 AM CDT Mon Jun 12 2017

Valid 121300Z - 131200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING FOR EASTERN WY...NORTHWESTERN NE...AND
SOUTHWESTERN SD...

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
MODERATE RISK AREA...FROM NORTHEASTERN CO TO NORTHEASTERN WY AND
WESTERN SD...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN
ROCKIES TO THE MIDDLE MO VALLEY AND WI...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
NORTHERN ROCKIES TO LOWER MI...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
ACROSS PARTS OF ME...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING FOR PARTS OF WEST TX...

...SUMMARY...
Severe thunderstorms with tornadoes, very large hail, and damaging
winds are likely this afternoon into tonight across the
north-central High Plains. Other severe thunderstorms are expected
from parts of the northern Rockies to the Upper Midwest, as well as
across Maine and west Texas this afternoon into evening.

...Central/northern High Plains this afternoon into tonight...
On the southeastern periphery of the closed low over NV, a 70+ kt
midlevel jet streak will eject northeastward to the northern High
Plains tonight. A related lee cyclone will deepen across northeast
CO by this evening, before translating to central NE/SD by the end
of this forecast period. Initial boundary-layer dewpoints in the
low 60s will spread northwestward from northeast CO into eastern WY
today as low-level upslope flow strengthens in response to lee
cyclogenesis. Daytime heating within this upslope regime, beneath
steep midlevel lapse rates, will drive moderate-strong buoyancy
(MLCAPE of 2000-3000 J/kg) and weakening convective inhibition by
mid afternoon. A special NSSL sounding from Cheyenne WY at 12z
revealed a 100-mb mean mixing ratio of 12.5 g/kg and only a weak
cap.

Thunderstorm development appears likely by early-mid afternoon from
just northeast of the lee cyclone in CO northward to the east slopes
of the Laramie and Big Horn ranges. As buoyancy increases through
the afternoon, both deep-layer and low-level shear (i.e., hodograph
length and curvature) will also increase, resulting in a favorable
environment for tornadic supercells. The initially discrete
supercells will pose a threat for isolated strong tornadoes and very
large hail, while eventual mergers/upscale growth will result in an
increasing damaging-wind threat as storms spread from WY into SD.

...Northern Rockies this afternoon/evening...
A gradual increase in low-level moisture will occur today as far
west as southwestern MT. Convection is expected to form over the
high terrain by early-mid afternoon and spread northward, as
large-scale ascent increases in advance of the ejecting midlevel low
now over NV. Weak-moderate buoyancy and substantial deep-layer
southerly shear will support a threat of organized/supercell storms
capable of producing isolated large hail and damaging gusts.

...Mid MO Valley to the Great Lakes through tonight...
Isolated strong/severe storms have formed this morning in
eastern/southeastern NE in a zone of low-level warm advection on the
nose of the steepest midlevel lapse rates. Though the low-level jet
will weaken some later this morning and the ongoing storms could
likewise weaken, lingering outflow boundaries could also provide
some focus for additional storm development this afternoon.
Otherwise, scattered thunderstorm development is expected on the
synoptic front farther to the north, from southeastern SD eastward
near the IA/MN border. One or more thunderstorm clusters could pose
a large hail/damaging wind threat along this corridor. A couple of
tornadoes with more discrete storms will also be possible, given the
narrow corridor of somewhat enhanced vertical shear along the
boundary. Weaker buoyancy and vertical shear suggest that the
severe-storm threat will diminish with eastward extent into Lower
MI.

...Maine today...
A series of remnant/subtle MCVs will move from the Great Lakes to
Maine today and potentially help focus storm initiation.
Boundary-layer dewpoints in the 60s and surface heating in cloud
breaks will drive potentially moderate buoyancy this afternoon, and
deep-layer unidirectional wind profiles with substantial speed shear
could support some storm organization/supercell structures. The
strongest storms may produce isolated large hail and/or damaging
gusts.

...West TX this afternoon/evening...
Strong surface heating/mixing on the west edge of the richer
low-level moisture should support at least widely-scattered
thunderstorm development late this afternoon from parts of the
Trans-Pecos to the Caprock. Moderate buoyancy, a deep mixed
boundary layer, and modest deep-layer vertical shear could support a
few marginal supercells capable of producing some hail/wind.

..Thompson.. 06/12/2017

Próxima actualización: 16:30z.
--------------------------------------------------------------
Últimas discusiones a mesoescala.
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Mesoscale Discussion 0991
NWS Storm Prediction Center Norman OK
0939 PM CDT Sun Jun 11 2017

Areas affected...North-central and northeastern WI...and
south-central Upper MI

Concerning...Severe Thunderstorm Watch 315...

Valid 120239Z - 120445Z

The severe weather threat for Severe Thunderstorm Watch 315
continues.

SUMMARY...Potential for damaging winds and hail persists across
north-central into northeast WI, and in south-central Upper MI this
evening. Additional strong to severe storms were developing across
west-central WI (in the wake of the outflow attendant to the
north-central and northeast WI storms) and should pose primarily a
hail threat with the stronger updrafts. Thus, western parts of WW
315 should not be canceled from this watch until these more recent
storms advance to the east.

DISCUSSION...Particular concern in the short-term consists of a
damaging wind threat with bowing lines of storms advancing eastward
from southern Forest to northern Marathon Counties WI (per regional
radar imagery). Recent trends indicated these bows were moving to
the east at 45-50 kt, and should reach Menominee County MI after
03Z, and Oconto/Marinette Counties WI between 03-04Z. The damaging
wind threat should eventually decrease as the boundary layer
stabilizes/surface-based inhibition strengthens with the continued
trend of cooling surface temperatures. However, in the short term
(until 03Z), the present forward speed of 45-50 kt may tend to
offset the near-surface stabilization for a continued damaging-wind
threat.

Otherwise, the presence of strong warm-air advection per a 40-45 kt
south-southwesterly low-level jet into the ongoing complex of storms
in central WI to central Upper MI should sustain thunderstorm
development into the overnight. Moderate instability and the
available effective shear suggests hail will become the predominant
severe threat once the damaging wind risk diminishes later this
evening.

..Peters.. 06/12/2017

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Mesoscale Discussion 0992
NWS Storm Prediction Center Norman OK
1159 PM CDT Sun Jun 11 2017

Areas affected...North-central and northeast WI into southern Upper
MI

Concerning...Severe Thunderstorm Watch 315...

Valid 120459Z - 120630Z

The severe weather threat for Severe Thunderstorm Watch 315
continues.

SUMMARY...Hail cannot be ruled out with any of the remaining
stronger storms across the north-central and northeast WI into
south-central Upper MI portions of WW 315. However, recent trends
in radar imagery suggest the overall severe-weather threat should
diminish overnight and this watch could be canceled prior to the 08Z
expiration.

DISCUSSION...Radar imagery and surface observations showed an
outflow boundary, attendant to storms that are now moving eastward
through far northern Lake Michigan, extended southwest through
southern Door County to northern Waupaca County to southern Marathon
County. A veered/southwesterly 40-45 kt low-level jet extending
into north-central and northeast WI overnight will maintain a
warm-air advection regime to support additional thunderstorms, given
the presence of moderate elevated instability. Given most of the
storms are elevated north of the convective outflow boundary and
surface-based inhibition has strengthened through the evening, the
damaging-wind threat is greatly reduced, while hail could still
occur with any remaining stronger updrafts. However, this latter
potential is also diminishing as indicated by recent weakening
trends in MRMS MESH data.

..Peters.. 06/12/2017
Dome, dome, dome..The life is a dome

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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Lun Jun 12, 2017 8:24 pm

Nueva actualización del SPC. No hay grandes cambios. Lo único, es que han puesto en riesgo leve al norte de Maine, noreste de los Estados Unidos. Tornado y granizo, los riesgos principales sobre el área bajo riesgo MODERADO.
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Viento.
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Granizo.
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Discusión.
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Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Mon Jun 12 2017

Valid 122000Z - 131200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
SOUTHEAST WY...THE NE PANHANDLE...AND SOUTHEAST SD...

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
WY...CO...NE...AND SD...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EXTENDING FROM
SOUTHERN MT INTO CENTRAL/SOUTHERN WI...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
ME...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
NORTHERN ROCKIES INTO THE GREAT LAKES REGION...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
WEST TX...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
ME...

...SUMMARY...
Severe thunderstorms with tornadoes, very large hail, and damaging
winds are likely this afternoon into tonight across the
north-central High Plains. Other severe thunderstorms are expected
from parts of the northern Rockies to the Upper Midwest, as well as
across Maine and west Texas this afternoon into evening.

...20Z Update...
Little changes needed to the ongoing forecast. Latest observational
trends/guidance continue to suggest that a relatively rapid increase
of intense surface-based thunderstorms will occur over the next few
hours across the northern CO into WY Front Range and adjacent High
Plains, with considerable towering cu and incipient thunderstorm
development at 20Z spanning areas from west of Boulder/Fort Collins
CO north-northwestward to areas near/west of Laramie/Casper WY, with
other towering cu farther east across southeast WY roughly near the
I-80 corridor. All indications are that supercells capable of large
hail and tornadoes, some of which may be strong, are likely
especially with the Moderate Risk corridor as storms spread
northeastward through the early evening hours.

Elsewhere, a cluster of storms are likely to continue to pose a
damaging wind/severe hail risk from southeast MN into central WI
this afternoon in close proximity of a roughly west/east-oriented
front where moderate buoyancy/effective shear are collocated. These
storms should reach eastern WI by late afternoon/early evening and
there is some possibility a severe risk could even continue into
lower MI.

..Guyer.. 06/12/2017

.PREV DISCUSSION... /ISSUED 1122 AM CDT Mon Jun 12 2017/

...Northern High Plains...
An upper low is centered over NV this morning, with a progressive
shortwave trough rotating through the base of the low and into UT.
Lift and mid-level cooling ahead of this feature is expected to
promote thunderstorm development over parts of the northern Rockies
and High Plains this afternoon and evening. East-southeasterly
low-level winds over southeast WY and northeast CO have transported
rich boundary-layer moisture back to the foothills, where daytime
heating and approaching trough will likely result in first
initiation of thunderstorms. Forecast soundings in this area show
very steep lapse rates and large CAPE values, as well as favorable
low-level and deep-layer vertical shear. Discrete supercells will
be likely as activity moves off the higher terrain and into the
adjacent High Plains. Parameters appear quite favorable for very
large hail and tornadoes with these storms. Strong tornadoes are
possible today. This evening, several CAM solutions suggest an
upscale evolution to one or more bowing complexes as storms move
into western NE/SD.

...NE/IA/MN/WI...
Scattered strong/severe thunderstorms are ongoing this morning over
parts of southeast SD and southwest MN. This activity is in
proximity to a surface boundary that extends eastward into southern
WI. Given the strong heating and destabilization occurring along
the boundary, it appears likely that this activity will persist
through much of the day and build eastward along the front. Large
hail and damaging winds will be possible in this corridor. Models
hint at the development of a bowing MCS this evening, affecting
parts of IA/WI.

...MT/WY...
To the northwest of the primary severe concern today (southeast WY),
there will be a risk of severe storms capable of large hail and
damaging winds into parts of western MT and northern WY.
Thunderstorms may form through the afternoon over parts of eastern
ID and central WY, and build northward into MT during the evening.
Large hail and gusty/damaging winds will be possible in the
strongest cells.

...Maine...
Strong heating is occurring today over much of ME, with fast
westerly flow aloft and dewpoints in the 60s. A consensus of 12z
model guidance shows considerable coverage of afternoon
thunderstorms in this region. Forecast soundings show moderate CAPE
values and sufficient deep-layer shear to support a few rotating
storms. Hail will be the main threat in the stronger cells, but
gusty outflow winds will also be possible.

..TX..
A few high-based thunderstorms capable of gusty winds and hail will
be possible this afternoon over parts of west TX, in a corridor of
strong CAPE and steep low-level lapse rates. This threat should be
focused in the 23-03z period.

Próxima actualización: 01:00z.
----------------------------------------------------------------------
Watchs vigentes. Hay un PDS por tornado.
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URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 316
NWS Storm Prediction Center Norman OK
1150 AM CDT Mon Jun 12 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Northern Iowa
Southern Minnesota

* Effective this Monday morning and evening from 1150 AM until
700 PM CDT.

* Primary threats include...
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
Scattered damaging wind gusts to 70 mph possible

SUMMARY...Thunderstorms are expected to move into the watch area
from the west, as well as develop along a boundary extending across
the region. Large hail and damaging winds will be possible in the
strongest cells.

The severe thunderstorm watch area is approximately along and 45
statute miles north and south of a line from 25 miles west of
Fairmont MN to 10 miles south of La Crosse WI. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU6).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
27030.

...Hart

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URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 317
NWS Storm Prediction Center Norman OK
110 PM MDT Mon Jun 12 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of
Northeast Colorado
Western Nebraska Panhandle
Southeast Wyoming

* Effective this Monday afternoon and evening from 110 PM until
800 PM MDT.

...THIS IS A PARTICULARLY DANGEROUS SITUATION...

* Primary threats include...
Several tornadoes and a few intense tornadoes likely
Widespread large hail expected with scattered very large hail
events to 4 inches in diameter likely
Isolated significant damaging wind gusts to 75 mph possible

SUMMARY...Isolated intense supercell thunderstorms are expected to
develop across the watch area this afternoon. Giant hail and strong
tornadoes will be possible in the most intense storms.

The tornado watch area is approximately along and 60 statute miles
east and west of a line from 50 miles north northeast of Douglas WY
to 55 miles southeast of Fort Collins CO. For a complete depiction
of the watch see the associated watch outline update (WOUS64 KWNS
WOU7).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 316...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 4 inches. Extreme turbulence and surface wind
gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 24030.

...Hart

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URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 318
NWS Storm Prediction Center Norman OK
245 PM MDT Mon Jun 12 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
South Central Montana
Northern Wyoming

* Effective this Monday afternoon and evening from 245 PM until
1000 PM MDT.

* Primary threats include...
Scattered large hail likely with isolated very large hail events
to 2 inches in diameter possible
Scattered damaging wind gusts to 70 mph possible
A tornado or two possible

SUMMARY...Scattered strong to severe thunderstorms are expected to
develop and spread across the watch area this afternoon and evening.
Large hail and damaging winds will be possible in the strongest
cells, along with the potential of an isolated tornado.

The severe thunderstorm watch area is approximately along and 80
statute miles north and south of a line from 15 miles north
northwest of Livingston MT to 55 miles north northeast of Casper WY.
For a complete depiction of the watch see the associated watch
outline update (WOUS64 KWNS WOU8).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 316...WW 317...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 400. Mean storm motion vector
21035.

...Hart

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URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 319
NWS Storm Prediction Center Norman OK
435 PM CDT Mon Jun 12 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Central, southern and eastern Wisconsin
Lake Michigan

* Effective this Monday afternoon from 435 PM until Midnight CDT.

* Primary threats include...
Isolated damaging wind gusts to 70 mph possible
Isolated large hail events to 1.5 inches in diameter possible
A tornado or two possible

SUMMARY...Bowing clusters of thunderstorms are expected to move
eastward into and across the watch area through this evening,
offering occasional damaging gusts and isolated large hail. The
threat may extend eastward as far as western Lake Michigan early
tonight.

The severe thunderstorm watch area is approximately along and 75
statute miles north and south of a line from 25 miles south
southwest of Camp Douglas WI to 50 miles southeast of Manitowoc WI.
For a complete depiction of the watch see the associated watch
outline update (WOUS64 KWNS WOU9).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 316...WW 317...WW 318...

AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
27035.

...Edwards

-------------------------------------
Últimas discusiones a mesoescala.
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Mesoscale Discussion 0993
NWS Storm Prediction Center Norman OK
1128 AM CDT Mon Jun 12 2017

Areas affected...Southeast South Dakota...southern
Minnesota...northern Iowa

Concerning...Severe potential...Watch likely

Valid 121628Z - 121800Z

Probability of Watch Issuance...80 percent

SUMMARY...Thunderstorms are expected to increase in coverage and
intensity through the afternoon hours. Large hail and potentially
damaging winds will be the primary threats and a watch is possible
by 18z.

DISCUSSION...A cluster of thunderstorms occasionally producing large
hail was located over southeast South Dakota and southwest Minnesota
at 1615z. The storms have thus far been slightly elevated to the
north of a quasi-stationary frontal boundary that extends from
central Nebraska northeast along the Minnesota/Iowa border and into
central/southern Wisconsin. Temperatures continue to warm to the
south of the front, and with the nose of a plume of steep mid-level
lapse rates across the area, strong surfaced-based instability will
develop this afternoon. Visible satellite imagery reveals
increasing cumulus field development along the front as CINH erodes,
and thunderstorms are likely to increase in coverage/intensity over
the next few hours within the discussion area. In the presence of
effective shear generally ranging between 30 and 40 kts, supercells
and clusters of severe storms will be possible with large hail and
damaging winds. Where cold pools can congeal, a more concentrated
damaging wind threat may develop with east/southeast-moving bowing
segments. Some tornado risk will exist given the favorable low-level
SRH near the boundary with the more discrete storms that develop.

Given the expected increase in storm coverage and severe potential,
a watch is likely prior to 1730z for the eastern two-thirds of the
discussion area.

..Bunting/Hart.. 06/12/2017

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Mesoscale Discussion 0994
NWS Storm Prediction Center Norman OK
1223 PM CDT Mon Jun 12 2017

Areas affected...eastern Idaho...northwestern Wyoming...southwestern
Montana

Concerning...Severe potential...Watch possible

Valid 121723Z - 122000Z

Probability of Watch Issuance...40 percent

SUMMARY...Isolated instances of severe hail and gusty winds will be
possible with thunderstorms this afternoon across eastern Idaho
initially, then spreading northward and eastward into adjacent
portions of Montana and Wyoming. Trends will continue to be
monitored for the necessity of a severe thunderstorm watch.

DISCUSSION...Mid-level ascent ahead of the closed upper-level low
over northeastern Nevada has encouraged early thunderstorm
initiation over portions of eastern Idaho this morning. Diurnal
heating in cloud-free areas to the north and east of these initial
thunderstorms will allow for destabilization with MLCAPE values
approaching 1000 J/kg later this afternoon. Given effective bulk
shear values around 40 knots, organized and sustained updrafts will
be possible in the strongest storms resulting in a risk of severe
hail and damaging winds. Thunderstorm intensity and coverage trends
will continue to be monitored into the afternoon hours for the
possibility of a severe thunderstorm watch.

..Jirak/Hart.. 06/12/2017

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Mesoscale Discussion 0995
NWS Storm Prediction Center Norman OK
1229 PM CDT Mon Jun 12 2017

Areas affected...Portions of eastern Wyoming...northeast
Colorado...western Nebraska and southwest South Dakota

Concerning...Severe potential...Tornado Watch likely

Valid 121729Z - 121930Z

Probability of Watch Issuance...95 percent

SUMMARY...Potentially rapid development of severe thunderstorms
including supercells is expected by early-mid afternoon. Tornadoes,
some potentially strong, along with very large hail and damaging
winds will be possible. A Tornado Watch will be issued by early
afternoon.

DISCUSSION...Surface observational trends show a very moist upslope
low-level flow across the discussion area at 17z with surface dew
points in the mid 50s-lower 60s. Breaks in cloud cover are allowing
for steady diurnal heating and moderate/strong surfaced-based
buoyancy is expected to be in place by early-mid afternoon. Latest
visible imagery depicts a few towering cumulus clouds along the west
edge of the deeper moisture across central Wyoming, and thunderstorm
development will become likely over the next couple of hours with
continued heating/low-level upslope flow and large-scale ascent in
advance of an upper low over Nevada. Strengthening mid-level flow
will result in deep-layer shear of 50-60 kts across the area,
favoring supercell structures as the initial storm mode. Very steep
mid-level lapse rates will be favorable for very large hail, and
increasing low-level winds with time will result in long hodographs
with substantial low-level curvature/low-level SRH. Given this
setup, strong tornadoes will be possible this afternoon.

Given recent observational trends, a Tornado Watch will be needed
early this afternoon.

..Bunting/Hart.. 06/12/2017

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Mesoscale Discussion 0996
NWS Storm Prediction Center Norman OK
0222 PM CDT Mon Jun 12 2017

Areas affected...Portions of southern Minnesota and northern Iowa

Concerning...Severe Thunderstorm Watch 316...

Valid 121922Z - 122115Z

The severe weather threat for Severe Thunderstorm Watch 316
continues.

SUMMARY...The threat for damaging winds and isolated large hail will
continue across the watch area. With time, the risk for damaging
winds in particular may develop east of the current watch area.

DISCUSSION...A loosely organized cluster of severe storms was
located over southeast Minnesota at 1915z, with a recent history of
measured severe gusts and radar indications of marginally severe
hail. The storms have been moving northeast near and just north of a
quasi-stationary surface boundary which extends east across portions
of southern/central Wisconsin. An increase in stratiform
precipitation to the west of the cluster suggests that a developing
cold pool may result in a transition to a more focused damaging wind
risk as this convective system begins to move east along the
instability gradient the remainder of this afternoon/early evening.
In addition, any storm development along the boundary to the east of
the convective system would also have severe potential given strong
surface-based buoyancy and 35-40 kts of westerly deep-layer shear.

Across western portions of the watch area, the aforementioned region
of stratiform precipitation/resultant destabilization has diminished
the severe risk.

..Bunting.. 06/12/2017

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Mesoscale Discussion 0997
NWS Storm Prediction Center Norman OK
0229 PM CDT Mon Jun 12 2017

Areas affected...Maine

Concerning...Severe potential...Watch possible

Valid 121929Z - 122130Z

Probability of Watch Issuance...40 percent

SUMMARY...Isolated-to-scattered thunderstorms are expected to
develop in the next couple of hours across Maine. The strongest
storms will be capable of producing severe hail and damaging winds.
A severe thunderstorm watch is possible if coverage of severe storms
appears sufficient.

DISCUSSION...The focus for convective initiation is ill-defined
across Maine this afternoon though a few west-southwest to
east-northeast bands of towering cumulus have become apparent in
visible satellite imagery. The northern-most of the cloud bands,
which may be aided by a weak mid-level impulse, across northern
Maine extending westward into eastern Quebec appears the most likely
to generate deep convection. With surface dew points in the mid-60s
F, there should be sufficient instability (MLCAPE values over 1000
J/kg) to get organized updrafts given the more-than-sufficient
effective bulk shear (i.e., around 50 knots). The most likely
severe hazards will be damaging wind gusts and severe hail.
Convective trends will continue to be monitored, especially the
overall coverage of thunderstorms, regarding the need for a severe
thunderstorm watch.

..Jirak/Hart.. 06/12/2017

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Mesoscale Discussion 0998
NWS Storm Prediction Center Norman OK
0317 PM CDT Mon Jun 12 2017

Areas affected...northern Wyoming and southern Montana

Concerning...Severe potential...Watch likely

Valid 122017Z - 122145Z

Probability of Watch Issuance...80 percent

SUMMARY...Thunderstorms are beginning to form over central Wyoming.
Coverage and intensity of storms are expected to increase throughout
the afternoon hours, as they spread northward over time. Large hail
and damaging winds will be the primary severe weather threats from
the strongest storms, likely requiring a watch.

DISCUSSION...Strong insolation has led to destabilization across
central and northern Wyoming in advance of an upper-level low over
northeastern Nevada. As the upper-low approaches the area,
mid-level ascent will favor increasing storm coverage and intensity.
With low 50s F dewpoint temperatures holding across much of the
region, MLCAPE values will approach 1000 J/kg. The instability
coupled with effective deep-layer shear around 50 knots will be more
than sufficient to support rotating updrafts. Large hail and
damaging winds will be the primary severe weather hazards. Severe
storm coverage is expected to be sufficient to require a watch.

..Jirak/Hart.. 06/12/2017

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Mesoscale Discussion 0999
NWS Storm Prediction Center Norman OK
0351 PM CDT Mon Jun 12 2017

Areas affected...Portions of west Texas

Concerning...Severe potential...Watch unlikely

Valid 122051Z - 122245Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated strong/severe thunderstorms will be capable of
damaging gusts late this afternoon into early evening. The threat is
expected to be isolated and a watch is not anticipated.

DISCUSSION...Strong diurnal heating in the vicinity of a diffuse
dryline has resulted in weak-moderate surface based instability and
very steep low-level lapse rates. Latest visible satellite and
radar data show towering cumulus across the Texas South Plains and
far west Texas with an isolated thunderstorm west of Fort Stockton.
Despite weak mid-level southwesterly flow of 15-20 kts, southeast
low-level flow is contributing to effective shear averaging 25-35
kts. Isolated high-based thunderstorms will continue to develop
through early evening and the strongest storms will be capable of
damaging gusts. Sufficient shear is in place for some risk for large
hail, especially over southern portions of the discussion area.
Overall coverage is expected to remain isolated and a watch is not
anticipated.

..Bunting/Hart.. 06/12/2017

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Mesoscale Discussion 1000
NWS Storm Prediction Center Norman OK
0548 PM CDT Mon Jun 12 2017

Areas affected...North-central Lower Michigan

Concerning...Severe potential...Watch unlikely

Valid 122248Z - 130115Z

Probability of Watch Issuance...20 percent

SUMMARY...Storms advancing east from central WI may pose a risk for
producing severe weather into west-central and perhaps central Lower
MI by mid-late evening. Watch potential will continue to be
monitored for this region, though current likelihood for issuance is
low.

DISCUSSION...Late afternoon/early evening surface analyses showed a
boundary extending from south-central WI across the middle portion
of Lake Michigan into west-central Lower MI (Mason and Manistee
Counties), then east-northeast near KHTL to Alcona County MI.
Despite clouds across much of north-central and central Lower MI, a
corridor of surface dew points in the upper 60s to 70 F in vicinity
of the boundary and some late-day heating in west-central Lower MI
is resulting in mixed-layer CAPE of at least 1000 J/kg.

Meanwhile, if the ongoing bowing line of storms moving east at 35-40
kt across south-central WI maintains this forward speed, it will
reach west-central Lower MI around 02Z. Uncertainty exists with the
effect the pre-bow storms have on the forward speed of the bow and
its potential to reach parts of Lower MI prior to boundary-layer
stabilization with the loss of daytime heating. Any storms that can
move across Lake Michigan will move into at least a moderately
unstable environment through mid evening with effective bulk shear
strengthening as westerly midlevel winds increase. Last several
runs of the HRRR suggest storms will move across north-central Lower
MI from 02/03Z through 07Z.

..Peters/Edwards.. 06/12/2017

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Mesoscale Discussion 1001
NWS Storm Prediction Center Norman OK
0605 PM CDT Mon Jun 12 2017

Areas affected...Portions of eastern WY...southwestern SD...western
NE...and northeastern CO

Concerning...Tornado Watch 317...

Valid 122305Z - 130030Z

The severe weather threat for Tornado Watch 317 continues.

SUMMARY...All severe hazards, including strong tornadoes, large to
giant hail, and damaging winds will continue with multiple
supercells across Particularly Dangerous Situation Tornado Watch
317. A downstream watch into western/central NE and southern SD will
be needed within the next several hours.

DISCUSSION...At least 3 supercells are ongoing as of 23Z across far
southeastern WY/northeastern CO into far western NE. With a very
favorable thermodynamic and kinematic environment characterized by
MLCAPE of 2000-3500 J/kg and effective bulk shear of 50-60 kt, these
supercells have produced over a dozen reports of significant hail (2
inch in diameter or greater) over the past few hours, with several
reports of hail greater than 4 inches. At least 2 tornadoes have
also occurred. The airmass downstream of ongoing convection will
easily support continued significant severe hail, along with a risk
for tornadoes and damaging winds through this evening. Strong
tornadoes will continue to be a possibility with any discrete
supercell across far southeastern WY, northeastern CO, and western
NE for the next few hours given a strongly veering and strengthening
wind profile with height. Of note, 0-1 km SRH is around 300 m2/s2
per recent VWP from KCYS, and 0-3 SRH is around 500 m2/s2.

A southerly low-level jet will strengthen to around 40-50 kt across
western/central NE into southern SD this evening/tonight, and all
severe hazards will remain possible into this evening across these
areas. Evolution from discrete supercells into one or more bowing
line segments appears likely to occur at some point later this
evening in tandem with the increasing low-level jet, which would
likely increase the threat for damaging winds with eastward extent.
In addition, large hail and a few tornadoes should continue to be a
threat with any supercell embedded within the line(s). A downstream
watch in western/central NE and southern SD will be needed within
the next several hours.

..Gleason.. 06/12/2017
Dome, dome, dome..The life is a dome

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stormchaserAlberto
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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Lun Jun 12, 2017 11:09 pm

Ya pasó lo mejorcito. Bajaron un toque el riesgo.
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% de tornados.
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Viento.
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Granizo.
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Discusión.
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Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0803 PM CDT Mon Jun 12 2017

Valid 130100Z - 131200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL/NORTHERN HIGH PLAINS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN
MONTANA TO THE NORTHERN PLAINS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHEASTERN
WISCONSIN TO LOWER MICHIGAN...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
NORTHERN ROCKIES TO LOWER MICHIGAN...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WEST TEXAS...

...SUMMARY...
Severe thunderstorms capable of large hail, damaging winds, and a
few tornadoes will remain possible across parts of the
northern/central High Plains this evening into tonight. Elsewhere, a
few severe storms remain possible over northern Wyoming into
southern Montana, as well as across portions of the Midwest.

...High Plains...
Scattered strong to severe storms continue to evolve across the
region this evening, with multiple reports of very large hail,
tornadoes, and damaging winds over the last several hours. As a
low-level jet continues to strengthen over the next several hours,
severe cells should grow upscale, trending towards one or more
bowing segments across portions of northwestern Nebraska and far
southern South Dakota later this evening. Dry mid-level air and
residual boundary-layer moisture (e.g., surface dew points in the
upper 60s to near 70 across northern Nebraska/southern South Dakota)
will support ample downdraft momentum, likely resulting in one or
more localized swaths of wind damage spreading northeast. Despite
the expected/ongoing mode transition, strong storm-relative inflow
(and considerable veering of winds with height) may continue to
favor a few tornadoes in any residual supercell structures or
line-embedded circulations. Additionally, embedded mesocyclones will
continue to offer a threat of large hail, some of which could be
over two inches in diameter this evening.

...Northern Wyoming into Montana...
Several clusters of severe storms continue to spread northward
across the region this evening, along and ahead of a bent-back front
over the region. While an expanding precipitation shield and some
upscale growth will likely result in a slow downward trend in the
severe threat, sufficient boundary-layer moisture and ample
effective shear will maintain a threat for large hail, damaging
winds, and a couple tornadoes before more substantial weakening
occurs.

...Upper Great Lakes...
A mesoscale convective system is pushing across southern/eastern
Wisconsin this evening, making steady progress towards Lake
Michigan. While some uncertainty remains regarding the potential for
severe-wind gusts downstream (due to gradually increasing convective
inhibition), a hot, well-mixed boundary-layer, characterized by
surface dew points in the 60s, may maintain a potential for pockets
of damaging winds as the line reaches Lower Michigan. As such,
15-percent wind probabilities are expanded eastward.

..Picca.. 06/13/2017

Próxima actualización: 06:00z.
------------------------------------
Watchs vigentes.
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URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 320
NWS Storm Prediction Center Norman OK
535 PM MDT Mon Jun 12 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of
Northwestern Nebraska
Western and southern South Dakota
Northeastern Wyoming

* Effective this Monday afternoon and Tuesday morning from 535 PM
until 200 AM MDT.

* Primary threats include...
A few tornadoes possible
Scattered damaging winds and isolated significant gusts to 80
mph possible
Scattered large hail and isolated very large hail events to 4
inches in diameter possible

SUMMARY...Supercells should move into the watch area from the
southwest, offering a threat for tornadoes and large to giant hail.
Activity should evolve into one or two complexes of storms with an
increasing risk of severe wind later this evening into tonight,
across the Badlands/Black Hills region and points northeast from
there.

The tornado watch area is approximately along and 100 statute miles
east and west of a line from 90 miles northwest of Rapid City SD to
55 miles southwest of Valentine NE. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU0).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 316...WW 317...WW
318...WW 319...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 4 inches. Extreme turbulence and surface wind
gusts to 70 knots. A few cumulonimbi with maximum tops to 550. Mean
storm motion vector 22035.

...Edwards

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URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 321
NWS Storm Prediction Center Norman OK
905 PM EDT Mon Jun 12 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Central Lower Michigan
Lake Huron
Lake Michigan

* Effective this Monday night and Tuesday morning from 905 PM
until 400 AM EDT.

* Primary threats include...
Isolated damaging wind gusts to 70 mph possible

SUMMARY...A well-developed, occasionally severe, bowing arc of
thunderstorms in eastern Wisconsin may survive its trek across a
shallow/stable marine layer of Lake Michigan and pose a threat of
damaging wind in Lower Michigan.

The severe thunderstorm watch area is approximately along and 70
statute miles north and south of a line from 45 miles southwest of
Manistee MI to 5 miles north northeast of Bad Axe MI. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU1).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 317...WW 318...WW
319...WW 320...

AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few
cumulonimbi with maximum tops to 450. Mean storm motion vector
27035.

...Edwards

-------------------------------------------------
Últimas discusiones a mesoescala.
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Mesoscale Discussion 1002
NWS Storm Prediction Center Norman OK
0638 PM CDT Mon Jun 12 2017

Areas affected...Portions of central...southern and eastern WI

Concerning...Severe Thunderstorm Watch 316...319...

Valid 122338Z - 130145Z

The severe weather threat for Severe Thunderstorm Watch 316, 319
continues.

SUMMARY...Severe threat for damaging winds and hail persists across
WW 319 this evening, while these threats have moved east of WW 316
(allowing this latter watch to be canceled early).

DISCUSSION...Mosaic radar imagery showed an ongoing bow advancing to
the east at 35-40 kt across south-central toward eastern WI, with
the bow currently extending from western Waupaca County to Waushara
and Green Lake Counties at the bow apex to Sauk County. From the
apex of the bow, a surface boundary extended eastward to Sheboygan
County and across the middle portion of Lake Michigan. The
environment downstream from the bow remains moderately unstable with
effective bulk shear of 40-50 kt oriented parallel to the surface
boundary. These factors suggest a continued forward propagation of
the bow with damaging winds being the primary threat along the bow
path. Meanwhile, additional strong to severe storm development
remains possible with northward extent (across the WI counties of
Marathon to Oconto) where sufficient instability and strong bulk
shear favor storm organization with a hail and damaging wind threat.

..Peters.. 06/12/2017

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Mesoscale Discussion 1003
NWS Storm Prediction Center Norman OK
0700 PM CDT Mon Jun 12 2017

Areas affected...Portions of southern MT and northern/central WY

Concerning...Severe Thunderstorm Watch 318...

Valid 130000Z - 130130Z

The severe weather threat for Severe Thunderstorm Watch 318
continues.

SUMMARY...An isolated threat for large hail and damaging winds
continues across WW 318. A tornado or two also remains possible
mainly across southern/eastern portions of the Watch.

DISCUSSION...Convection has increased in coverage and intensity
across northern/central WY over the past several hours as an upper
low moves northeastward across the northern Great Basin. Strong mid
to upper-level winds are contributing to generally 40-50 kt of
effective bulk shear in/near the Severe Thunderstorm Watch. Although
low-level moisture is more limited across this region (mid/upper 40s
to mid 50s dewpoints) compared to southeastern WY, steep mid-level
lapse rates overlying this sufficient moisture and diurnal heating
have resulted in MLCAPE of 500-1500 J/kg. Multiple supercell
structures have been observed per KRIW and KBLX radars, and isolated
large hail and damaging winds will continue to be a threat through
the evening hours as storms move northward into southern MT. A
tornado or two will also remain possible, particularly across the
Bighorn Basin and vicinity. Across this area, slightly greater
low-level moisture (dewpoints in the low to mid 50s) is allowing for
lower LCL heights, and a supercell over Johnson County WY has
recently produced a tornado (as of 2342Z), along with 2+ inch hail.
Diurnal cooling later this evening will act to reduce available
instability to maintain storm intensity, and the overall severe
threat should slowly lessen over the next few hours.

..Gleason.. 06/13/2017

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Mesoscale Discussion 1004
NWS Storm Prediction Center Norman OK
0902 PM CDT Mon Jun 12 2017

Areas affected...Portions of western/central NE...northeastern into
east-central WY...and western/central SD

Concerning...Tornado Watch 317...320...

Valid 130202Z - 130300Z

The severe weather threat for Tornado Watch 317, 320 continues.

SUMMARY...A threat for a few tornadoes and scattered large
hail/damaging winds continues across valid portions of WW 317/320.
Parts of WW 317 have been locally extended in time until 03Z based
on latest radar trends.

DISCUSSION...Two semi-discrete supercells continue across western NE
as of 02Z. The southernmost storm has had multiple tornado and large
hail reports associated with it over the past several hours. A
strongly unstable airmass into central NE/southern SD, where MLCAPE
ranges from 2500-3500 J/kg per 01Z mesoanalysis, will very likely
support continued severe-caliber storms into the late evening.
Strong effective bulk shear values of 50-60+ kt owing to a
northeastward- moving upper low over the northern Great Basin will
also contribute to robust updraft organization, with all severe
hazards remaining possible. A short-term (next hour or two) tornado
threat should be maximized across parts of western NE into far
southwestern SD with the previously mentioned semi-discrete
supercells. Across this area, strongly veering/strengthening
low-level winds are contributing to a relative maximum in effective
SRH values (300-500+ m2/s2).

Additional convection has recently formed along northern portions of
the Laramie Mountains in east-central WY, and this activity may also
pose some severe risk, although instability is weaker with northward
extent. Current expectations are still for ongoing storms to grow
upscale into one or more bowing line segments as they move into
north-central NE and western/central SD later this evening. If this
were to occur, then damaging winds would likely become the primary
severe threat.

..Gleason.. 06/13/2017
Dome, dome, dome..The life is a dome

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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Mar Jun 13, 2017 10:35 am

Otro día de tiempo severo, aunque no tan marginal como ayer. Persiste riesgo para tornados, vientos potencialmente destructivos y granizo de variados tamaños.
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Viento.
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Granizo.
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Discusión.
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Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0748 AM CDT Tue Jun 13 2017

Valid 131300Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING FROM THE RED RIVER VALLEY OF THE NORTH TO THE MID
MO VALLEY...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM ND/MN ACROSS
THE CENTRAL PLAINS TO WEST TX...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
PLAINS SLIGHT RISK...AND EXTENDING EASTWARD ACROSS THE LOWER GREAT
LAKES TO SOUTHERN NEW ENGLAND...

...SUMMARY...
Severe thunderstorms, capable of large hail, damaging winds, and a
few tornadoes, will be possible across the northern Plains and upper
Mississippi Valley this afternoon and evening. Farther south across
the central/southern Plains, a few severe storms, primarily capable
of large hail and damaging winds, are expected through the evening
hours. Isolated strong/marginally severe storms will also be
possible across the Northeast.

...Synopsis...
A closed midlevel low over northwestern WY, and a trailing shortwave
trough through the Four Corners, will eject northeastward across the
central/northern Plains through tonight. An associated surface
cyclone along the SD/NE border will develop north-northeastward to
southeastern ND by this evening, in advance of the midlevel trough.
In the wake of morning convection and related outflow across
west-central MN and northeast SD, the surface warm front will move
northward with the cyclone to southeastern ND and west-central MN
this afternoon. A cold front will move slowly eastward across
central SD/NE, while a lee trough will extend southward across
western KS and west TX. These boundaries will provide the primary
foci for severe thunderstorm development through early tonight.

...Red River Valley of the north to the middle MO Valley...
The convection/outflow in SD is a few counties farther south than
most convection-allowing guidance as of 12z, though northward
recovery should begin by late morning. The stronger midlevel height
falls and winds will approach the mid MO and Red River Valleys this
afternoon into this evening, when thunderstorm development is likely
from the warm front southward along the cold front. Potentially
strong buoyancy (MLCAPE at or above 3000 J/kg) is expected in the
surface warm sector with temperatures in the 80s and dewpoints of
68-72 F, beneath 8-9 C/km midlevel lapse rates. Deep-layer vertical
shear will increase from west to east through the afternoon near the
dryline, while low-level shear will be maximized near and north of
the warm front. The tornado threat will be relatively greater where
semi-discrete storms form and interact with the warm front this
afternoon/evening. Farther south, large hail and damaging winds
will be the main threats as cells/clusters form along the dryline
and tend to grow upscale into line segments given deep-layer
shear/flow largely parallel to the boundary.

...TX Panhandle and South Plains area late this afternoon...
Though the stronger forcing for ascent will pass north of this area,
strong surface heating/deep mixing will support scattered
thunderstorm development along the dryline this afternoon near the
Caprock, and storms will persist into this evening. Moderate-strong
buoyancy and effective bulk shear in excess of 40 kt will support
splitting supercells capable of producing isolated very large hail
and severe outflow gusts, mainly from 21-01z.

..Thompson/Mosier.. 06/13/2017

Próxima actualización: 16:30z
--------------------------------------
Últimas discusiones a mesoescala.
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Mesoscale Discussion 1005
NWS Storm Prediction Center Norman OK
0930 PM CDT Mon Jun 12 2017

Areas affected...Far eastern WI into central and northern Lower MI

Concerning...Severe Thunderstorm Watch 321...

Valid 130230Z - 130400Z

The severe weather threat for Severe Thunderstorm Watch 321
continues.

SUMMARY...Severe-weather threat (primarily damaging winds) has
exited the land areas of WW 319 in eastern WI, with the storms
moving across middle portions of Lake Michigan. Potential continues
for storms to be capable of producing strong wind gusts as they
spread across Lake Michigan, reaching the eastern shore of Lake
Michigan between 0230-03Z, and then advancing inland across Lower MI
late this evening/early overnight.

DISCUSSION...Trends in mosaic radar imagery indicated the strongest
and most persistent portion of the eastward-moving band of storms
was located over the open waters of the north-central to central
portions of Lake Michigan (or from 45 NE KMTW to 35 WSW KMBL) at
0210Z. The storm motion is toward the east-northeast at 35-40 kt
and should reach the eastern shore of Lake Michigan by 0230-03Z in
the MI counties of Mason, Manistee, and Benzie. Although objective
analyses indicated ongoing boundary-layer stabilization with an
increase in surface-based inhibition/weakening surface-3-km lapse
rates, the strength of the cold pool could prove sufficient to
support stronger wind gusts reaching the surface. This potential
should be further aided by an increase in MUCAPE (per objective
analyses) of 1500-2000 J/kg, as a plume of steep midlevel lapse
rates spreads across into Lower MI, sustaining the band of storms.

..Peters.. 06/13/2017

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Mesoscale Discussion 1006
NWS Storm Prediction Center Norman OK
1114 PM CDT Mon Jun 12 2017

Areas affected...Western...central and northern SD and northwest NE

Concerning...Tornado Watch 320...

Valid 130414Z - 130545Z

The severe weather threat for Tornado Watch 320 continues.

SUMMARY...All severe hazards remain possible with the storms moving
northeast through northwest NE and southwest SD. Meanwhile, a
bowing line has recently formed in the SD counties of Jackson and
Bennett. This bowing line and at least one additional bowing line
expected to form in southwest SD overnight will pose a threat for
damaging winds across parts of central and northern SD, where a new
WW will be coordinated soon. Additional storms may form in
northeast SD ahead of the lead bow with a threat for hail and strong
wind gusts.

DISCUSSION...CAPE/shear parameter space including strong effective
SRH remains favorable for discrete/semi-discrete supercells with an
attendant tornado threat across the valid portions of WW 320 in
northwest NE to western SD. Mosaic radar imagery indicated the
recent development of a bow in Jackson and Bennett Counties SD, with
this bow tracking toward the northeast. Last several runs of the
HRRR continued to suggest upscale development of one or two bows
tracking from southwest to central and northern SD through the
overnight.

This downstream environment was supporting of sustained bow
structures as strengthening southerly low-level winds result in
further poleward theta-e advection across SD. This combined with
forcing for ascent with height falls ahead of the
northeastward-moving Great Basin upper low will support storm
development through tonight.

..Peters/Edwards.. 06/13/2017

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Mesoscale Discussion 1007
NWS Storm Prediction Center Norman OK
1158 PM CDT Mon Jun 12 2017

Areas affected...Northeast Lower Michigan

Concerning...Severe Thunderstorm Watch 321...

Valid 130458Z - 130630Z

The severe weather threat for Severe Thunderstorm Watch 321
continues.

SUMMARY...The severe-weather threat continues across northeast Lower
Michigan as a band of storms advances to the east at 40 kt. The
severe-weather threat has ended across the northwest part of WW 321
as storms have moved into northeast Lower Michigan, while farther
south a more stable environment precluded storms in central parts of
Lower Michigan.

DISCUSSION...At 0445Z, mosaic radar imagery indicated a short band
of storms advancing east across northeast Lower Michigan at 40 kt,
with this activity expected to move east of the Lake Huron shore
around 06Z. These storms will move along an instability gradient
posing a continued threat for strong/damaging wind gusts.

..Peters.. 06/13/2017

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Mesoscale Discussion 1008
NWS Storm Prediction Center Norman OK
0233 AM CDT Tue Jun 13 2017

Areas affected...northeast and north-central SD...southeast ND

Concerning...Severe Thunderstorm Watch 322...

Valid 130733Z - 130830Z

The severe weather threat for Severe Thunderstorm Watch 322
continues.

SUMMARY...Widespread 50-70 mph gusts are likely for at least the
next couple of hours. The need for a new severe thunderstorm watch
into southeastern ND is unlikely but a watch extension-in-area (EXA)
could be used for the northeastern-most counties in SD if severe
gusts are still occurring as the squall line moves through Spink and
Brown counties.

DISCUSSION...Radar mosaic shows a severe squall line moving
northeast at 50 kt on the apex of a bowing segment moving into
southwestern Faulk county as of 0730Z. Surface observations on
either end of the squall line recorded severe gusts (KMBG 51 kt at
0653Z; KPIR 62 kt at 0619Z). Expecting the potential for severe
gusts to remain high, especially ahead of the bowing segment moving
northeast towards Aberdeen with radar velocities from KABR
indicating an intense rear-inflow jet (75-85 kt at 5,000 ft). 07Z
surface data shows pressure falls are occurring (2mb/2hr) ahead of
the line in northeast SD. The steep mid-level lapse rate
environment will remain very supportive of squall line longevity and
expecting widespread 50-70 mph gusts with localized gusts with the
bowing segment in the 60-85 mph range.

..Smith.. 06/13/2017
Dome, dome, dome..The life is a dome

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Re: Seguimiento general en EEUU

Mensajepor Santi » Mar Jun 13, 2017 10:44 pm

Impresionante caída de granizo en Grand Island, Nebraska (USA) hace instantes. Tornado reciente en Morris, Minnesota. Día movido..

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Aficionado a la meteorología

MetRA - Meteorología de la República Argentina
http://metra-noticias.blogspot.com.ar/

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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Mar Jun 13, 2017 11:31 pm

Última actualización del SPC.
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Viento.
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Granizo.
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Discusión.
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Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0755 PM CDT Tue Jun 13 2017

Valid 140100Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE MID
MISSOURI VALLEY AND UPPER MISSISSIPPI VALLEY...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE PLAINS STATES...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
SLIGHT RISK ACROSS THE CENTRAL US...

...SUMMARY...
Severe thunderstorms will continue east across the upper Mississippi
Valley this evening, with an attendant threat of damaging winds,
large hail, and a few tornadoes. These storms will progress east
across Minnesota overnight, with the threat transitioning to mainly
damaging winds. Isolated/widely scattered severe storms, capable of
large hail and damaging winds, will remain possible this evening
over the southern/central Plains, as well.

...Upper Midwest...
With the steady approach of the western U.S. trough, numerous severe
thunderstorms continue to evolve across the region at present. Two
regimes of severe thunderstorms have emerged: 1) An evolving QLCS
approaching the South Dakota/Minnesota border and 2) a cluster of
storms with embedded mesocyclones over west-central Minnesota. The
first area will likely continue to accelerate eastward, pushing into
a moist/unstable environment over southern/central Minnesota this
evening. The main threat with this activity will likely be damaging
winds, with some potential for a couple tornadoes closer to the warm
front, where storm-relative helicity is maximized. Amplifying
warm-air advection associated with a strengthening low-level jet is
fostering the second area of convection farther east along the front
(over west-central Minnesota). Rich boundary-layer moisture and
backed low-level flow will maintain an environment supporting a
couple tornadoes for the next couple of hours. Over time, these
storms will be consumed by the eastward-advancing QLCS, such that
the main severe threat transitions to damaging winds across the
region through tonight.

...Southern/Central Plains...
Thunderstorms have blossomed along the dryline this evening,
stretching from eastern Nebraska to west Texas. Steep lapse rates
and adequate effective shear values will maintain a threat of
supercells capable of large hail and damaging winds through the late
evening hours. However, with stronger large-scale ascent removed to
the north, storms will encounter increasing convective inhibition as
they progress east, resulting in a downward trend in the severe
threat through the early overnight hours.

..Picca.. 06/14/2017

Próxima actualización: 06:00z.
-----------------------------------------------------------
Watchs vigentes.
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URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 324
NWS Storm Prediction Center Norman OK
340 PM CDT Tue Jun 13 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Southwest Kansas
Western Oklahoma
Texas Panhandle

* Effective this Tuesday afternoon and evening from 340 PM until
1100 PM CDT.

* Primary threats include...
Widespread large hail expected with isolated very large hail
events to 4 inches in diameter likely
Scattered damaging winds likely with isolated significant gusts
to 75 mph possible
A tornado or two possible

SUMMARY...Thunderstorms are expected to rapidly develop this
afternoon over the watch area, posing a risk of large hail and
damaging wind gusts. Isolated giant hail reports are possible in
the most intense storms.

The severe thunderstorm watch area is approximately along and 55
statute miles east and west of a line from 45 miles northeast of
Dodge City KS to 50 miles south southeast of Lubbock TX. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU4).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 323...

AVIATION...A few severe thunderstorms with hail surface and aloft to
4 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
24030.

...Hart

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URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 325
NWS Storm Prediction Center Norman OK
525 PM CDT Tue Jun 13 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Extreme western Iowa
North-central Kansas
Eastern Nebraska

* Effective this Tuesday afternoon and Wednesday morning from 525
PM until 100 AM CDT.

* Primary threats include...
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
Isolated damaging wind gusts to 70 mph possible
A tornado or two possible

SUMMARY...Multiple episodes of thunderstorms are expected to affect
the watch area through this evening, moving rapidly northeastward
through a favorably moist and unstable air mass. Damaging winds and
hail are likely, and even with likely clustered mode by that time, a
tornado cannot be ruled out in the relatively moist air mass of
eastern Nebraska.

The severe thunderstorm watch area is approximately along and 60
statute miles either side of a line from 35 miles south of Russell
KS to 30 miles northeast of Norfolk NE. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU5).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 323...WW 324...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 600. Mean storm motion vector
22035.

...Edwards

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URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 326
NWS Storm Prediction Center Norman OK
555 PM CDT Tue Jun 13 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Northwestern Minnesota
Eastern North Dakota

* Effective this Tuesday afternoon and Wednesday morning from 555
PM until 100 AM CDT.

* Primary threats include...
Scattered large hail and isolated very large hail events to 2.5
inches in diameter possible
Scattered damaging wind gusts to 70 mph possible
A tornado or two possible

SUMMARY...Severe-thunderstorm potential is increasing across the
watch area, north of a surface warm front and northeast of a surface
low, as the air mass at and especially above the surface continues
to destabilize. The main risks will be damaging wind and large hail
from activity emerging out of South Dakota, with an arching band or
complex of storms likely to evolve and sweep northeastward. A
tornado or two cannot be ruled out near the southern end of the
watch, closer to that warm front.

The severe thunderstorm watch area is approximately along and 90
statute miles east and west of a line from 75 miles south southeast
of Jamestown ND to 15 miles west northwest of Warroad MN. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU6).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 323...WW 324...WW 325...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
23035.

...Edwards

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URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 327
NWS Storm Prediction Center Norman OK
700 PM CDT Tue Jun 13 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of
Northwestern Iowa
Central and southwestern Minnesota
Extreme northeastern Nebraska
Southeastern South Dakota

* Effective this Tuesday night and Wednesday morning from 700 PM
until 200 AM CDT.

* Primary threats include...
A couple tornadoes possible
Scattered damaging wind gusts to 70 mph possible
Isolated very large hail events to 2.5 inches in diameter
possible

SUMMARY...In addition to an existing isolated supercell along the
warm front in western Minnesota, a band of thunderstorms (with
embedded supercells and potential QLCS circulations forming) will
move northeastward into the watch area over the next few hours. The
tornado potential will be relatively maximized near that warm front,
while damaging gusts and sporadic hail are expected throughout the
convective regime.

The tornado watch area is approximately along and 60 statute miles
east and west of a line from 45 miles southeast of Yankton SD to 40
miles northeast of Alexandria MN. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU7).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 323...WW 324...WW
325...WW 326...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 2.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean
storm motion vector 24035.

...Edwards

-------------------------------------
Últimas discusiones a mesoescala.
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Mesoscale Discussion 1009
NWS Storm Prediction Center Norman OK
1118 AM CDT Tue Jun 13 2017

Areas affected...Portions of OH/IN/KY/WV/VA/MD/PA

Concerning...Severe potential...Watch unlikely

Valid 131618Z - 131845Z

Probability of Watch Issuance...5 percent

SUMMARY...An isolated damaging wind risk could accompany the
strongest storms across portions of the lower Great Lakes and
middle/upper Ohio Valley region through the afternoon. Watch
issuance will not be needed.

DISCUSSION...Subtle low-level confluence per surface observations
and plan-view depictions of 1-km-above-ground flow per VAD wind
profiles, amid a very weakly capped and moist boundary layer, are
already supporting isolated to scattered thunderstorm development.
The Wilmington and Pittsburgh 12Z soundings sampled around 13.0-14.5
g/kg mean mixing ratios, highlighting the ample moisture
contributing to appreciable buoyancy, with diurnal heating
supporting MLCAPE upwards of 2000 J/kg. Where convective overturning
has not already been abundant, insolation continues to contribute to
steepening low-level lapse rates, allowing MLCAPE, as well as DCAPE,
to increase. As such, convection should experience an overall
increase in coverage/intensity into the afternoon, with the
potential for isolated damaging wind gusts.

Given around 1000 J/kg of DCAPE indicated by the aforementioned
soundings suggesting the potential for strong convective outflow
(with further diurnal gains in DCAPE ongoing), and given moderate
midlevel lapse rates implying some enhancement to convective-scale
upward accelerations, isolated strong to damaging wind gusts will be
possible through the afternoon -- especially with cell mergers and
local outflow amalgamation and as cells collapse. However, deep
shear is very weak -- with midlevel wind speeds generally 15 kt or
less. As such, convective organization will be greatly lacking,
which should limit severe coverage.

..Cohen/Hart.. 06/13/2017

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Mesoscale Discussion 1010
NWS Storm Prediction Center Norman OK
0125 PM CDT Tue Jun 13 2017

Areas affected...Portions of southern New England...southeast
NY...northern NJ

Concerning...Severe potential...Watch possible

Valid 131825Z - 132100Z

Probability of Watch Issuance...40 percent

SUMMARY...The area is being monitored for some severe thunderstorm
potential through the afternoon and into the evening. Uncertainty
exists regarding the anticipated severe coverage, though the
issuance of a Severe Thunderstorm Watch will be possible across
portions of the region.

DISCUSSION...Temperatures have warmed into the lower 90s from
northern NJ and southeast NY and across southern New England, while
the dewpoints have held in the middle/upper 60s. This is
contributing to 1500-2000 J/kg of MLCAPE with little capping.
Meanwhile, along the periphery of subtle midlevel speed maxima
crossing northern NY into adjacent New England, and along subtle
confluence axes farther south from northeast PA to southern New
England, ascent has been sufficient to support initial towering
cumulus and isolated thunderstorm development.

Thunderstorms will likely increase in number and intensity during
the next few hours as diurnal heating continues. A mix of weak
supercell structures, and loosely organized convective clusters, may
eventually evolve and spread eastward. This will be supported by
sufficient deep shear aided by 25-30 kt westerly winds around 4-5 km
above ground indicated by the Albany VAD wind profile.

Present indications are that severe coverage could be lacking, owing
to the lack of stronger deep ascent/shear overlapping with the
moderate buoyancy. However, with at least isolated to widely
scattered severe hail/wind possible -- especially as convection
develops into southern New England -- Watch issuance will be
possible.

..Cohen/Hart.. 06/13/2017

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Mesoscale Discussion 1011
NWS Storm Prediction Center Norman OK
0209 PM CDT Tue Jun 13 2017

Areas affected...Portions of southwest TX

Concerning...Severe potential...Watch possible

Valid 131909Z - 132145Z

Probability of Watch Issuance...40 percent

SUMMARY...The area is being monitored for some severe thunderstorm
risk developing this afternoon and continuing into the evening.
Watch issuance will be possible.

DISCUSSION...Diurnally enhanced orographic circulations are
encouraging towering cumulus development over the Davis Mountains
and other southwest Texas mountains, on the east edges of nearly
dry-adiabatic lapse rates in the lowest 3 km above ground. This
initial convection should deepen, evolving into a couple of isolated
storms. Meanwhile, a dryline continues to sharpen from near the
southeast NM/southwest TX border southward to the international
border. This dryline will be a focused zone for additional,
possible, isolated thunderstorm development into the late afternoon
hours. However, stronger forcing for ascent, attendant to a midlevel
speed maximum advancing from the southern Rockies to the adjacent
Plains, will reside north of the area.

Nevertheless, sufficient deep shear peripheral to the speed
maximum -- e.g., effective shear of 25-35 kt -- may support a few
sustained/organized cells (possible supercells) with severe
hail/wind possible. Storm motion will be somewhat erratic, with a
general slow eastward/southeastward spread of convection east of the
dryline into the evening hours. Upward convective-scale
accelerations will be bolstered by 8.0-8.5 C/km lapse rates
overlying a relatively moist boundary layer east of the dryline,
characterized by lower/middle 60s dewpoints. This is supporting
upwards of 2500 J/kg of MLCAPE. Very isolated instances of
significant severe hail could occur. However, overall storm coverage
may be lacking, owing to the lack of stronger deep ascent.
Regardless, convective and environmental trends will continue to be
monitored.

..Cohen/Hart.. 06/13/2017

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Mesoscale Discussion 1012
NWS Storm Prediction Center Norman OK
0225 PM CDT Tue Jun 13 2017

Areas affected...Portions of northern IL and northwest IN

Concerning...Severe potential...Watch unlikely

Valid 131925Z - 132200Z

Probability of Watch Issuance...5 percent

SUMMARY...Isolated severe-thunderstorm potential will exist into the
early evening hours. Watch issuance will not be needed.

DISCUSSION...Low-level ascent along a composite outflow/lake-breeze
boundary is supporting increasingly agitated cumulus fields and
isolated thunderstorm development from north-central IL into
northwest IN. Strong diurnal heating south of this boundary
continues, with temperatures having warmed into the lower/middle 90s
amid dewpoints in the upper 60s to lower 70s, supporting 1500-2500
J/kg of MLCAPE and little capping. A few robust convective cores
capable of isolated severe hail/wind may occur into early evening.
However, with this activity approximately aligned with a
larger-scale ridge aloft associated with a dearth of deep ascent and
paucity of ambient tropospheric flow/vertical shear, organized
convection and greater coverage of severe storms are not expected.

..Cohen/Hart.. 06/13/2017

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Mesoscale Discussion 1013
NWS Storm Prediction Center Norman OK
0232 PM CDT Tue Jun 13 2017

Areas affected...North-central Nebraksa...East-central South
Dakota...Southeast North Dakota

Concerning...Severe potential...Watch likely

Valid 131932Z - 132030Z

Probability of Watch Issuance...95 percent

SUMMARY...A severe threat is likely to develop this afternoon from
central Nebraska north northeastward into southeastern North Dakota
and west-central Minnesota. Large hail and wind damage will be
possible after cells initiate but a tornado threat should also
develop as cells mature. A weather watch will likely be needed
across the region by 20Z.

DISCUSSION...The latest surface analysis shows a 999 mb low over
north-central Nebraska with a cold front extending
south-southwestward from the low. Surface winds are backed across
much of eastern South Dakota where low-level moisture is maximized
with surface dewpoints in the lower to mid 70s F. This is
contributing to a pocket of strong instability in eastern South
Dakota and northeastern Nebraska where the RAP is estimating MLCAPE
values in the 3000 to 4000 J/kg range. In addition, water vapor
imagery shows a shortwave trough over the central and northern
Rockies. A vorticity maxima associated with the shortwave trough is
analyzed by the RAP across western Nebraska. As this feature moves
across the central and northern Plains this afternoon, large-scale
ascent will support the development of numerous thunderstorms along
the cold front and to the northeast of the surface low into
southeastern North Dakota and west-central Minnesota.

Forecast soundings along this corridor show favorable wind profiles
for supercells with strong speed shear in the low to mid-levels with
0-6 km shear forecast to be in the 35 to 45 kt range. This combined
with very steep mid-level lapse rates exceeding 8.5 C/km across
parts of the MCD area will be favorable for large hail with
supercells. Hailstones of greater than 2 inches in diameter will be
possible within the strongest cores. Cells that do not form into
supercells may still be severe with a threat for hail and wind
damage. As the low-level jet increases in strength late this
afternoon and as the storms become mature, a tornado threat will
also be possible across the MCD area. The most favorable area for
tornado development could be across northeastern South Dakota,
southeastern North Dakota and west-central Minnesota.

..Broyles/Hart.. 06/13/2017

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Mesoscale Discussion 1014
NWS Storm Prediction Center Norman OK
0314 PM CDT Tue Jun 13 2017

Areas affected...Portions of the TX/OK Panhandles...TX South
Plains...and western OK

Concerning...Severe potential...Watch likely

Valid 132014Z - 132245Z

Probability of Watch Issuance...95 percent

SUMMARY...Severe thunderstorm development will likely occur in the
21-22Z time frame, and a Severe Thunderstorm Watch will be likely.
Significant severe hail will be possible.

DISCUSSION...High-based cumulus development continues in proximity
to diurnal-heating bolstered dryline circulations from the central
OK Panhandle to western/central parts of the TX Panhandle and South
Plains. As MLCINH accompanying a warm elevated mixed layer continues
to erode, thunderstorm development will be likely in the 21-22Z time
frame, with activity spreading east-northeastward into the evening
hours east of the sharpening dryline. East of the dryline, surface
dewpoints have held in the lower/middle 60s beneath 8-9 C/km
midlevel lapse rates, yielding SBCAPE locally upwards of 3000-4000
J/kg. Furthermore, with 35-45 kt of effective shear -- enhanced by a
vertically veering wind profile and in proximity to a midlevel speed
maximum crossing the area per water vapor imagery -- sustained
supercells with significant severe hail will be likely. Some risk
for giant hail (4-inch hail) cannot be ruled out. Into the late
afternoon hours and the evening, strengthening convective outflow
with merging outflows may support isolated to widely scattered
severe wind gusts, as convection spreads into western OK. Given the
substantial buoyancy, and increase in effective SRH early this
evening coincident with the incipient stages of nocturnal decoupling
of the boundary layer, a tornado could also occur.

..Cohen/Hart.. 06/13/2017

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Mesoscale Discussion 1015
NWS Storm Prediction Center Norman OK
0346 PM CDT Tue Jun 13 2017

Areas affected...ofk

Concerning...Severe potential...Watch likely

Valid 132046Z - 132315Z

Probability of Watch Issuance...80 percent

SUMMARY...A severe threat is expected to develop late this afternoon
from southern Nebraska northeastward into far southeastern South
Dakota and northwest Iowa. An isolated tornado threat along with a
potential for large hail and wind damage will be possible as cells
initiate and increase in coverage over the next couple of hours.
Weather watch issuance will likely be needed.

DISCUSSION...The latest surface analysis shows a 999 mb low over
central Nebraska with a moist airmass in place to the east of the
low. Surface dewpoints are in the mid 60s to lower 70s F across
southern and eastern Nebraska into western Iowa. This is
contributing to a corridor of strong instability with MLCAPE values
estimated by the RAP to be in the 2000 to 4000 J/kg range across the
MCD area. In addition, a belt of strong low-level flow is analyzed
by the RAP across eastern Nebraska extending north-northeastward
into far southeastern North Dakota and northwestern Iowa. As this
feature strengthens over the next few hours, new surface-based cells
are forecast to initiate from near Norfolk south-southwestward to
near Grand Island. Forecast soundings across this area late this
afternoon show moderate deep-layer shear with some directional shear
in the low-levels. This is creating 0-6 km shear in the 30 to 40 kt
range according to the RAP which will support supercell development.
The shear along with strong instability and steep low to mid-level
lapse will be favorable for large hail and wind damage with
supercells and short line segments. Hail greater than 2 inches in
diameter along with a tornado threat may accompany the more dominant
supercells.

..Broyles/Hart.. 06/13/2017

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Mesoscale Discussion 1016
NWS Storm Prediction Center Norman OK
0349 PM CDT Tue Jun 13 2017

Areas affected...Portions of Kansas

Concerning...Severe potential...Watch possible

Valid 132049Z - 132315Z

Probability of Watch Issuance...40 percent

SUMMARY...Isolated to widely scattered thunderstorms with a severe
hail/wind risk may develop in the 2130-0000Z time frame and continue
into the evening. The area is being monitored for possible Severe
Thunderstorm Watch issuance.

DISCUSSION...The air mass east of a composite surface trough/dryline
analyzed from the Hill City KS area southward to near Dodge City KS
and farther south into the OK/TX Panhandles continues to undergo
strong destabilization, owing to widespread insolation amid surface
dewpoints holding in the lower/middle 60s. Diabatic-surface-heating-
bolstered baroclinic circulations along the aforementioned composite
boundary may support isolated to widely scattered surface-based
convective initiation in the 2130-0000Z time frame, as lapse rates
are approaching dry adiabatic in the lowest 3 km above ground west
of this feature. The severe risk could also spread into the region
from recently issued Watch 324 into the evening hours. Storm
development may also be aided by modest large-scale ascent/midlevel
cooling accompanying the southern extension of a speed maximum
crossing the area, as implied by water vapor imagery.

With 8.5-9.5 C/km midlevel lapse rates overlying the aforementioned
moisture, SBCAPE of 3000-4000 J/kg will support robust upward
convective-scale accelerations. Meanwhile, effective shear of 25-35
kt could support organized convective structures, with possible
supercells. Forecast hodographs across the region are modestly long
in the mid/high levels, with geometries of either straight or with
one or two inflections. Resultant, storm-scale, upward perturbation
pressure gradient forces could favor both left and right members of
supercell splits, along with small convective clusters following
potential mergers of initial cells. In addition to severe hail,
amalgamating cold pools amid 1000-1700 J/kg of DCAPE may foster
isolated to widely scattered severe wind gusts.

Given the modest magnitude of large-scale ascent and somewhat modest
deep shear magnitude, severe coverage may be limited, but may be
sufficient for Severe Thunderstorm Watch issuance by this evening.
Convective and environmental trends will continue to be monitored.

..Cohen/Hart.. 06/13/2017

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Mesoscale Discussion 1017
NWS Storm Prediction Center Norman OK
0543 PM CDT Tue Jun 13 2017

Areas affected...Northeast Nebraska...eastern South Dakota...western
Minnesota...eastern North Dakota

Concerning...Tornado Watch 323...

Valid 132243Z - 140045Z

The severe weather threat for Tornado Watch 323 continues.

SUMMARY...A threat of very large hail and a few tornadoes persists
across the watch area. Severe storms are expected to eventually
develop or spread into surrounding areas to the north and east this
evening.

DISCUSSION...Surface observations, visible satellite imagery and
radar show a warm front extending from Spink county SD eastward
across central MN. Numerous supercells extend southward along the
surface trough, with strongest storm near the low in Spink county
which is also near the warm front. Radar continues to show very
large hail in most of these cells, and brief tornadoes will also
remain possible given sufficient low-level shear and a moist air
mass.

To the east, an isolated cell was noted along the warm front across
west central MN, where temperatures were approaching 90 F. A brief
tornado is not out of the question with this activity, if it can
remain rooted in the higher theta-e air south of the front.
Otherwise, hail is possible as it continues to lift northward.

Farther north into eastern ND, surface temperatures are largely in
the low 70s F, but some gradual warming is expected. However, the
boundary layer is expected to remain cool with rather poor 0-3 km
lapse rates. Thus, severe thunderstorms capable of hail appear the
most likely threat there, with new activity that forms due to warm
advection, and, as cells west of the main surface trough continue
north.

..Jewell.. 06/13/2017

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Mesoscale Discussion 1018
NWS Storm Prediction Center Norman OK
0558 PM CDT Tue Jun 13 2017

Areas affected...Portions of north-central and northeastern MT

Concerning...Severe potential...Watch unlikely

Valid 132258Z - 140100Z

Probability of Watch Issuance...5 percent

SUMMARY...An isolated and marginal risk for hail and strong/gusty
winds will exist through the evening hours. Watch issuance is not
expected.

DISCUSSION...22Z surface analysis indicates a 998 mb low in the
vicinity of Miles City MT. A narrow east-west corridor of limited
low-level moisture and surface heating across northeastern into
north-central MT has allowed weak to locally moderate instability to
develop. An upper low evident on water-vapor satellite imagery over
central MT will continue northeastward this evening, and strong
mid-level southerly to southeasterly winds, particularly across
northeastern MT, are supporting generally 30-40 kt of effective bulk
shear. Some isolated instances of marginally severe hail and
strong/gusty winds will be possible with any thunderstorm in this
environment for the next several hours. Already weak instability
should further lessen with the loss of daytime heating later this
evening. The overall severe threat will very likely remain too
isolated/marginal for watch issuance.

..Gleason/Edwards.. 06/13/2017

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Mesoscale Discussion 1019
NWS Storm Prediction Center Norman OK
0630 PM CDT Tue Jun 13 2017

Areas affected...Portions of the eastern TX/OK Panhandles into
northwest TX...western OK...and southwestern KS

Concerning...Severe Thunderstorm Watch 324...

Valid 132330Z - 140100Z

The severe weather threat for Severe Thunderstorm Watch 324
continues.

SUMMARY...1 to 4 inch diameter hail will continue to be the main
threat with supercells across WW 324. This significant severe-hail
threat should continue into western OK and southwestern KS for the
next several hours.

DISCUSSION...Impressive radar signatures depict multiple ongoing
supercells as of 2330Z across the eastern TX/OK Panhandles, moving
east-northeastward with time. In particular, a supercell moving from
northern Hall into Collingsworth/Childress Counties in TX has had a
consistent MRMS max hail estimate of 2.5-4 inches for the last 30
minutes or so. Multiple large hail reports of 1-2.5 inches have been
received with these thunderstorms so far, and a very favorable
thermodynamic environment characterized by 2000-3000 J/kg MLCAPE
will easily support a continued threat for large hail as convection
develops into western OK and southwestern KS over the next several
hours. In addition to the threat for large to giant hail, strong to
locally damaging winds should remain possible. A tornado or two also
cannot be ruled out in the next hour or two with any right-moving
supercell as a strengthening southerly low-level jet elongates the
hodograph at low-levels, thereby increasing effective SRH into the
250-300 m2/s2 range. By 02Z and later, increasing convective
inhibition will likely act to weaken any remaining storms.

..Gleason.. 06/13/2017

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Mesoscale Discussion 1020
NWS Storm Prediction Center Norman OK
0748 PM CDT Tue Jun 13 2017

Areas affected...Portions of central KS...south-central into eastern
NE...and far west-central IA

Concerning...Severe Thunderstorm Watch 325...

Valid 140048Z - 140215Z

The severe weather threat for Severe Thunderstorm Watch 325
continues.

SUMMARY...Thunderstorms that have erupted along a dryline will
continue to pose a threat for scattered large hail and damaging
winds through the remainder of the evening as they move
east-northeastward across WW 325.

DISCUSSION...A line of storms quickly developed along a dryline
across south-central NE from 2330Z to 0045Z, with embedded
supcercells producing multiple reports of large hail, some greater
than 2 inches in diameter. This ongoing convection will develop
eastward into eastern NE and more of north-central KS over the next
several hours, where a very unstable airmass (MLCAPE around 3250
J/kg per 00Z Omaha NE sounding) will prove more than adequate to
maintain current severe-caliber storm intensities. Recent radar
trends from the KOAX radar suggest a bowing segment may be forming
across eastern NE, with strong 70+ kt inbound velocities noted
around 7000 ft AGL. Scattered damaging winds will likely become the
main threat across most of WW 325 though the remainder of the
evening as this line of storms moves east-northeastward with time,
although large hail will continue to be possible with any embedded
supercell.

..Gleason.. 06/14/2017

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Mesoscale Discussion 1021
NWS Storm Prediction Center Norman OK
0834 PM CDT Tue Jun 13 2017

Areas affected...Eastern South Dakota into Minnesota... northwest
Iowa...eastern North Dakota

Concerning...Tornado Watch 326...327...

Valid 140134Z - 140230Z

The severe weather threat for Tornado Watch 326, 327 continues.

SUMMARY...Damaging winds, hail, and brief tornadoes continue to be
possible across the watch area.

DISCUSSION...The bulk of the storm activity has now consolidated
into a QLCS, from southeast ND into eastern SD and far northeast NE.
A very moist and unstable air mass remains ahead of these storms
along and south of the warm front which exists across central MN.
The air mass is also unstable in an elevated sense north of the
boundary, with 40-50 kt 850 mb flow present.

The northern portion of the QLCS is a bit more favorably oriented
relative to the deep-layer shear, and radar shows areas of rotation
along the gust front. Strong to severe wind gusts and/or brief and
likely weak tornadoes remain possible.

To the south, outflow appears to be surging well ahead of the main
storm cores, but recent radar trends show an increasing hail threat,
from near the Sioux Falls area southward into Nebraska. The 00Z OAX
sounding shows a very unstable profile supportive of large hail.

Severe storms are expected to persist across the watch area for a
few more hours. To the east of the watch, convective inhibition
increases, and may result in weakening storms. Therefore, it is
unclear if a new watch will be needed.

..Jewell.. 06/14/2017

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Mesoscale Discussion 1022
NWS Storm Prediction Center Norman OK
0855 PM CDT Tue Jun 13 2017

Areas affected...Portions of the eastern TX/OK Panhandles into
northwestern TX...western OK...and southwestern KS

Concerning...Severe Thunderstorm Watch 324...

Valid 140155Z - 140300Z

The severe weather threat for Severe Thunderstorm Watch 324
continues.

SUMMARY...Isolated large hail and strong/gusty winds remain possible
in the short term with ongoing storms. Overall severe threat should
continue to diminish this evening.

DISCUSSION...Widely spaced supercells persist mainly across eastern
portions of WW 324. Radar trends over the past hour have shown a
general weakening trend to convection, which is likely related to
increasing convective inhibition due to the loss of daytime heating
(reference 00Z sounding from Norman OK modified for current surface
observations). While isolated instances of large hail and perhaps
strong/gusty winds may still occur with the more robust cores over
the next hour or so, current expectations are for a continued
decrease in storm intensity and the overall severe threat through
03Z.

..Gleason.. 06/14/2017
Dome, dome, dome..The life is a dome

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stormchaserAlberto
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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Mié Jun 14, 2017 10:43 pm

Convective outlook para esta noche y madrugada. Sólo riesgo leve. Viento y granizo, los riesgos más signficativos.
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% de vientos destructivos.
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Granizo.
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Discusión.
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Day 1 Convective Outlook RESENT 1
NWS Storm Prediction Center Norman OK
0800 PM CDT Wed Jun 14 2017

Valid 150100Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM WEST TEXAS
NORTHEASTWARD INTO THE LOWER MISSOURI AND OHIO VALLEYS...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
THE GREAT LAKES TO MID MISSISSIPPI VALLEY REGION...ACROSS THE
CAROLINAS...AND OVER MUCH OF WEST TEXAS...

...SUMMARY...
Scattered severe storms capable of large hail and damaging winds
will persist over a narrow zone of west Texas. Widely-spaced storms
capable of hail or wind are possible through tonight across parts of
Oklahoma into southeast Kansas. More numerous storms with wind
threat and heavy rain should persist over much of Missouri and
southern Illinois.

...Much of MO into southern IL through tonight...
A very moist air mass remains in place across the region, evident in
00Z soundings and surface observations with dewpoints in the 70s F.
An MCS currently exists over northeast MO into western IL, and this
system is expected to develop in a general southerly direction this
evening and overnight. Sporadic areas of severe winds will be
possible, with marginal hail only expected with any cellular
activity that may develop ahead of the main outflow.

...West Texas...
A few clusters of severe thunderstorms are currently ongoing,
comprised of both supercells producing very large hail and surging
outflows with damaging winds measured in the Odessa area. These
storms should persist for a few more hours until the uncapped warm
sector becomes overturned. The straight-line hodographs are
supporting a few left splits as well, and some of these cells could
affect northwest TX into southwest OK later this evening.

...Western OK into southeast KS...
Strong heating all day led to a narrow zone of uncapped air mass
along a retreating dryline, from near Wichita KS into western OK.
Widely-spaced thunderstorms currently exist, but lift is lacking
given a capping inversion in place. Still, 00Z soundings show a very
moist, and relatively deep boundary layer, with steep lapse rates
above. This suggests that any cells that can survive past sunset may
persist in an isolated manner, moving in a generally southward
direction with hail and/or wind threat.

..Jewell.. 06/15/2017

Próxima actualización: 06:00z.
-----------------------------------------------------------
Watchs vigentes.
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URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 329
NWS Storm Prediction Center Norman OK
105 PM CDT Wed Jun 14 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Central Illinois
Central Missouri

* Effective this Wednesday afternoon and evening from 105 PM
until 800 PM CDT.

* Primary threats include...
Scattered damaging wind gusts to 70 mph possible
Scattered large hail events to 1.5 inches in diameter possible

SUMMARY...Scattered strong to severe thunderstorms will affect the
watch area this afternoon and evening, posing a risk of hail and
damaging winds in the most intense storms.

The severe thunderstorm watch area is approximately along and 85
statute miles north and south of a line from 40 miles west of Knob
Noster MO to 40 miles east of Mattoon IL. For a complete depiction
of the watch see the associated watch outline update (WOUS64 KWNS
WOU9).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 328...

AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
24030.

...Hart

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URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 331
NWS Storm Prediction Center Norman OK
600 PM CDT Wed Jun 14 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Southwest Oklahoma
West/southwest Texas

* Effective this Wednesday night from 600 PM until Midnight CDT.

* Primary threats include...
Isolated very large hail events to 3 inches in diameter possible
Isolated damaging wind gusts to 70 mph possible

SUMMARY...Isolated strong to severe thunderstorms are expected to
develop near a dryline within a hot and relatively moist/unstable
environment. A few supercells capable of large hail and
severe-caliber wind gusts are expected this evening.

The severe thunderstorm watch area is approximately along and 55
statute miles east and west of a line from 35 miles north northwest
of Altus OK to 70 miles south southwest of Midland TX. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU1).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 328...WW 329...WW 330...

AVIATION...A few severe thunderstorms with hail surface and aloft to
3 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
29020.

...Guyer

---------------------------------------------------------
Últimas discusiones a mesoescala.
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Mesoscale Discussion 1023
NWS Storm Prediction Center Norman OK
0936 PM CDT Tue Jun 13 2017

Areas affected...Portions of north-central KS into eastern
NE...western/central IA...and far northwestern MO

Concerning...Severe Thunderstorm Watch 325...

Valid 140236Z - 140330Z

The severe weather threat for Severe Thunderstorm Watch 325
continues.

SUMMARY...Damaging winds and large hail will continue to be the main
threats with ongoing storms across WW 325. A downstream watch into
more of IA appears unlikely at this time.

DISCUSSION...A bowing line of convection has produced numerous
measured 60-75 mph wind gusts as it has moved across eastern NE over
the past several hours. Recent radar imagery from KOAX depicts
outflow surging ahead of this line of storms as it approaches and
crosses the NE/IA state line. Instability remains favorable for
maintenance of this line for the next hour or so, as MLCAPE of
2500-3000 J/kg resides immediately downstream. However, increasing
convective inhibition noted on 02Z mesoanalysis into western/central
IA should act to weaken ongoing convection as it moves eastward.
While isolated damaging winds may occur for a brief period to the
east of the WW 325, downstream watch issuance into more of
western/central IA is unlikely at this time. Farther to the
southwest across south-central NE and north-central IA, a cluster of
supercells persists in producing large hail of 1-1.5 inches in
diameter. This activity may continue for several more hours given a
favorable thermodynamic and kinematic environment.

..Gleason.. 06/14/2017

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Mesoscale Discussion 1024
NWS Storm Prediction Center Norman OK
1206 PM CDT Wed Jun 14 2017

Areas affected...Eastern Iowa...South-central Wisconsin...Northwest
Illinois...Far Northeast Missouri

Concerning...Severe potential...Watch possible

Valid 141706Z - 141930Z

Probability of Watch Issuance...60 percent

SUMMARY...An isolated severe threat is expected to develop this
afternoon across parts of the mid to upper Mississippi Valley. The
stronger thunderstorms could have a potential for isolated large
hail and wind damage. Weather watch issuance may be needed across
the region as storms intensify and increase in coverage.

DISCUSSION...The latest surface analysis shows a very moist airmass
in place across much of the mid to upper Mississippi Valley. Surface
dewpoints are maximized into the lower to mid 70s F from central
Missouri northward into western Illinois and southern Wisconsin.
Surface temperatures have warmed into the 85 to 90 F range along the
moist corridor which is contributing to moderate instability. The
RAP is estimating MLCAPE values in the 2000 to 3000 J/kg range. In
addition, the WSR-88D VWPs at Davenport, IA and Lincoln, IL show
unidirectional wind profiles with some speed shear from just above
the surface into the mid-levels. This is resulting in about 30 kt of
0-6 km shear which will support an isolated severe threat this
afternoon. Although deep-layer shear appears marginal for
supercells, organized multicell clusters should be accompanied by
storms that could produce isolated large hail and wind damage.

..Broyles/Hart.. 06/14/2017

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Mesoscale Discussion 1025
NWS Storm Prediction Center Norman OK
1217 PM CDT Wed Jun 14 2017

Areas affected...Portions of VA/NC/SC/TN/GA

Concerning...Severe potential...Watch unlikely

Valid 141717Z - 141945Z

Probability of Watch Issuance...5 percent

SUMMARY...Thunderstorm coverage will increase into the afternoon
hours, with the risk for a few strong storms capable of locally
damaging wind gusts. Convection will lack organization, and Watch
issuance will not be needed.

DISCUSSION...A broad area of partly cloudy to mostly sunny skies is
permitting sufficient insolation amid a favorably moist boundary
layer -- e.g. surface dewpoints in the middle 60s to lower 70s --
for increasing thunderstorm potential this afternoon. This will
occur over a broad region from the central and southern Appalachians
eastward across the Piedmont to the coastal plain where capping is
minimal.

Initial storm development may tend to be focused in the following
regimes:
(1) Diurnally enhanced orographic ascent over the higher terrain /
Appalachians,
(2) An axis of weak convergence across north-central VA,
(3) Ascent preceding a weak, eastward-moving MCV across southeast
VA,
(4) A west-east frontal zone from northeast GA through northern SC
into southeast NC where cumulus fields are swelling, and
(5) Along sea-breeze boundaries closer to the coast.

Scattered thunderstorm coverage is anticipated, with storms slowly
moving southward to eastward into the early evening hours. However,
water vapor imagery does not depict any particularly salient
midlevel perturbations enhancing deep ascent, though slightly
cyclonic flow aloft and a related modestly tightened midlevel height
gradient are supporting around 10-15 kt of 500-mb flow. This may be
sufficient for a few loosely organized multicell clusters to evolve
as cells merge, though the character of convection should be lacking
any appreciable organization.

Nevertheless, steepening low-level lapse rates will contribute to a
few substantively robust convective cores, with downdrafts enhanced
by water-loading processes associated with PW around 1.50-1.75
inches. Isolated damaging wind gusts could accompany the most
intense convection through the afternoon and into the early evening,
before nocturnal gains in boundary-layer static stability occur.

..Cohen/Hart.. 06/14/2017

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Mesoscale Discussion 1026
NWS Storm Prediction Center Norman OK
1240 PM CDT Wed Jun 14 2017

Areas affected...Missouri...South-central Illinois

Concerning...Severe potential...Watch possible

Valid 141740Z - 142015Z

Probability of Watch Issuance...60 percent

SUMMARY...A severe threat is expected to develop across parts of the
mid Mississippi Valley this afternoon. Isolated large hail and wind
damage should be the primary threats. Weather watch issuance may be
needed across the MCD area.

DISCUSSION...The latest surface analysis shows a very moist airmass
in place across the mid Mississippi Valley with surface dewpoints
mostly in the lower to mid 70s F. This is contributing to strong
instability from central Missouri eastward into south-central
Illinois where the RAP is estimating MLCAPE from 2500 to 3500 J/kg.
As instability continues to slowly increase over the next hour or
two, a severe threat is expected to develop. The WSR-88D VWP at St.
Louis, MO shows a unidirectional wind profile above the surface with
speed shear in the low to mid-levels. This along with steep
low-level lapse rates should be favorable for wind damage with the
more organized multicell clusters or line segments. Isolated large
hail could also accompany the stronger thunderstorms.

..Broyles/Hart.. 06/14/2017

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Mesoscale Discussion 1027
NWS Storm Prediction Center Norman OK
1244 PM CDT Wed Jun 14 2017

Areas affected...Portions of eastern IL...IN...northern KY

Concerning...Severe potential...Watch possible

Valid 141744Z - 142015Z

Probability of Watch Issuance...40 percent

SUMMARY...The area is being monitored for some increase in severe
potential this afternoon. While Watch issuance is not likely, there
is some possibility for the issuance of a Severe Thunderstorm Watch
this afternoon -- especially if the risk for a more organized
convective cluster with damaging-wind potential were to become
apparent.

DISCUSSION...The air mass continues to destabilize southwest of a
convectively enhanced surface boundary analyzed from northern
Indiana to northern KY. With temperatures on the warm side of this
boundary rising into the upper 80s to lower 90s amid dewpoints in
the lower 70s, MLCAPE around 2000-3000 J/kg exists with little
capping. Thunderstorm coverage will increase across the area during
the next few hours -- initially focused around the aforementioned
boundary with additional development to its southwest. Storms
farther west may also spread into the region later this afternoon.

The lack of any salient midlevel impulses, and effective shear
magnitudes under 25 kt, detract confidence in an organized
convective risk evolving. However, with PW around 1.6-1.7 inches,
water-loading and related enhanced downdrafts will have a tendency
to support strong outflow winds. The potential for localized
convective upscale growth associated with substantial thunderstorm
coverage exists. While not immediately apparent, if a more organized
convective cluster/cold pool were to evolve, a more concentrated
area of damaging-wind potential could exist. Otherwise, isolated
damaging wind gusts and marginally severe hail will be possible
through the early evening hours owing to the appreciable buoyancy.

..Cohen/Hart.. 06/14/2017

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Mesoscale Discussion 1028
NWS Storm Prediction Center Norman OK
0120 PM CDT Wed Jun 14 2017

Areas affected...Portions of OH/PA/WV/VA/KY/MD

Concerning...Severe potential...Watch unlikely

Valid 141820Z - 142045Z

Probability of Watch Issuance...5 percent

SUMMARY...The risk for strong storms is increasing this afternoon,
and isolated damaging wind gusts could occur. Watch issuance will
not be needed.

DISCUSSION...Amid a moist and uncapped boundary layer, with
dewpoints in the middle 60s to around 70F, thunderstorms will
increase in number and intensity through the afternoon hours, as
diabatic surface-layer heating continues. A diffuse, arching surface
boundary from central PA to the Lake Erie shore between Erie PA and
Cleveland OH will serve as both an eastern extent, and perhaps
general zone, of thunderstorm activity. Otherwise, the lake breeze
boundary, orographic circulations, an MCV tracking eastward into
northwest OH, and baroclinic circulations on the eastern edge of
multi-layered clouds from western/central OH into eastern KY --
augmented by outflow -- will all serve as focused zones of storm
intensification during the next few hours across the region.

Thunderstorms will slowly move eastward to southward through the
early evening hours before weakening. Until then, PW around
1.50-1.75 inches suggests that water-loading processes could support
strong outflow winds as convection deepens amid 1000-2500 J/kg of
MUCAPE. Weak deep shear will greatly limit convective organization,
while midlevel lapse rates remain modest. These factors will
substantially limit the severe risk. Regardless, isolated damaging
wind gusts could occur.

..Cohen/Hart.. 06/14/2017

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Mesoscale Discussion 1029
NWS Storm Prediction Center Norman OK
0157 PM CDT Wed Jun 14 2017

Areas affected...A small part of southwest TX

Concerning...Severe potential...Watch possible

Valid 141857Z - 142130Z

Probability of Watch Issuance...40 percent

SUMMARY...The risk for at least isolated severe thunderstorms is
increasing across a small part of southwest TX. While there is some
uncertainty regarding anticipated severe coverage, the issuance of a
Severe Thunderstorm Watch will be possible.

DISCUSSION...Visible satellite trends suggest towering cumulus over
the Davis Mountains, where orographic circulations -- bolstered by
strong insolation and steepening low-level lapse rates on the west
edge of a north-south moisture gradient -- are ongoing. Surrounding
areas of higher terrain, along with baroclinic circulations along
the moisture-gradient zone, may also be foci for subsequent
convective development. Convection will likely deepen into isolated
thunderstorm activity in this regime during the next couple of
hours, and then slowly drift eastward to southward through the
evening hours. As this activity ingests increasingly buoyant inflow
near/east of the moisture gradient -- characterized by 1500-3000
J/kg of MLCAPE -- it will likely intensify with severe hail/wind
potential increasing. The presence of 25-40 kt of effective shear
could support supercell structures, with 7.5-8.5 C/km midlevel lapse
rates bolstering updraft accelerations. Isolated significant severe
hail could occur. However, water vapor imagery implies a dearth of
deep ascent over the area, which suggests that storm coverage may be
quite isolated. If the potential for more appreciable severe
coverage were to increase, prospects for Watch issuance would also
increase.

..Cohen/Hart.. 06/14/2017

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Mesoscale Discussion 1030
NWS Storm Prediction Center Norman OK
0302 PM CDT Wed Jun 14 2017

Areas affected...Southwest Lower Michigan...Northern Indiana...Far
Northeast Illinois

Concerning...Severe potential...Watch possible

Valid 142002Z - 142200Z

Probability of Watch Issuance...40 percent

SUMMARY...An isolated severe threat is expected to develop across
parts of southwest Lower Michigan, northern Indiana and far
northeast Illinois. Isolated large hail and wind damage will be
possible across the MCD area and weather watch issuance may be
needed.

DISCUSSION...The latest surface analysis shows a moist airmass
extending northward from the Ohio Valley into the southern Great
Lakes where surface dewpoints are generally in the upper 60s and
lower 70s F. This is contributing to moderate instability with
MLCAPE values estimated to be in the 1500 to 2500 J/kg range.
Instability will continue to increase across the southern Great
Lakes over the next hour or two. In addition, forecast soundings
across southwestern Lower Michigan and northern Indiana show
directional shear in the low to mid-levels with some speed shear in
the mid-levels. This is creating enough deep-layer shear for
organized severe multicells. As storms move into southwestern Lower
Michigan and northern Indiana from the west, isolated large hail and
wind damage will be possible with the stronger cells.

..Broyles/Hart.. 06/14/2017

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Mesoscale Discussion 1031
NWS Storm Prediction Center Norman OK
0333 PM CDT Wed Jun 14 2017

Areas affected...West Texas...Far Southwest Oklahoma

Concerning...Severe potential...Watch possible

Valid 142033Z - 142300Z

Probability of Watch Issuance...60 percent

SUMMARY...A severe threat may develop across parts of west Texas and
far southwest Oklahoma late this afternoon. Large hail and wind
damage will be possible as cells initiate and increase in coverage.
Weather watch may be needed once it becomes more certain where and
when cells will initiate.

DISCUSSION...The latest surface analysis shows a moist airmass in
place across much of Texas with surface dewpoints in west-central
Texas generally in the 60s F. This combined with very hot surface
temperatures in the mid to upper 90s F has resulted in strong
instability. The RAP is estimating MLCAPE in the 2000 to 3500 J/kg
range across the MCD area. In addition, regional WSR-88D VWPs at
Lubbock, TX and Frederick, OK show directional and speed shear in
the low to mid-levels which is resulting in 30 to 40 kt of 0-6 km
shear. With the strong instability in place, the amount of shear
should be sufficient for supercell formation. Convection is
forecast to initiate and increase in coverage late this afternoon
into early this evening. The latest HRRR seems reasonable which
initiates cells by 23Z from near Lubbock south-southwestward to near
Midland. This activity should spread southeastward into areas along
the eastern edge of the Caprock and into the Low Rolling Plains
where a threat for large hail and wind damage will be possible.

..Broyles/Hart.. 06/14/2017

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Mesoscale Discussion 1032
NWS Storm Prediction Center Norman OK
0337 PM CDT Wed Jun 14 2017

Areas affected...Portions of eastern/southern
KS...northern/western/central OK

Concerning...Severe potential...Watch possible

Valid 142037Z - 142300Z

Probability of Watch Issuance...40 percent

SUMMARY...The area is being monitored for severe-thunderstorm
potential into the evening hours. Prospects for sustained deep
convection with severe hail/wind potential are presently unclear,
but the conditional potential will exist, and Severe Thunderstorm
Watch issuance may eventually become necessary.

DISCUSSION...Amid a moist boundary layer characterized by surface
dewpoints in the middle 60s to lower 70s, diabatic surface-layer
heating has contributed to strong diurnal gains in buoyancy.
Modifications to the 17Z Lamont OK sounding for ongoing surface
conditions suggest 2500-4000 J/kg of MLCAPE across the region, with
substantial erosion to MLCINH accompanying the base of a
moist-boundary-layer-overlying EML. In fact, visible satellite
imagery is suggesting slight agitation to cumulus fields across
south-central and central KS -- i.e., near a northeast-southwest-
oriented surface front marking the west edge of the strongest
buoyancy. This boundary extends from its intersection with a
diffuse, frontolytic, west-east outflow boundary near/north of the
Topeka KS area southwestward into east-central parts of the TX
Panhandle area. Baroclinic circulations along the front and decaying
outflow boundary could be foci for surface-based convective
development during the next several hours.

However, the severe risk is conditional on surface-based convective
initiation and sustenance. Surface observations suggest only weakly
convergent wind fields accompanying the aforementioned boundaries.
Furthermore, notable midlevel drying in the wake of a shortwave
trough is evident per water vapor imagery, with ongoing midlevel
height rises. This reflects air with a history of subsidence, which
may be associated with thermodynamic conditions proving hostile for
sustained storm development -- i.e. both associated with localized
boosts in static stability in the thermal profile aloft and abundant
dry-air-entrainment potential with incipient updrafts.

If convection were to develop (perhaps following repeated and
spatially focused pulsations of shallow convective plumes), the
aforementioned substantial buoyancy may facilitate the development
of vigorous updrafts. Moreover, with 25-40 kt of effective shear,
southward- to southeastward-moving supercells and multicell clusters
could evolve through the evening hours. Severe hail/wind would be
the primary concerns with this activity. Also, the overlap of
pre-existing vertical vorticity and substantive low-level buoyancy
on either side of the outflow boundary could foster very low tornado
potential in northeast KS. Some heat-burst potential may accompany
decaying convection later this evening (accompanied by strong
surface winds and rapid warming/drying of the boundary layer) --
especially in OK where midlevel lapse rates will be steepest in
association with the largest DCAPE.

Again, any severe risk is highly conditional, and prospects for
sustained storm formation -- if any -- are highly unclear. If it
were to appear a sustained severe risk were to eventually evolve,
Watch issuance may possibly become necessary.

..Cohen/Hart.. 06/14/2017

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Mesoscale Discussion 1033
NWS Storm Prediction Center Norman OK
0459 PM CDT Wed Jun 14 2017

Areas affected...Portions of far eastern Wisconsin...northeast
Illinois...and lower Michigan

Concerning...Severe Thunderstorm Watch 328...330...

Valid 142159Z - 142330Z

The severe weather threat for Severe Thunderstorm Watch 328, 330
continues.

SUMMARY...Several clusters of strong/severe storms will continue
east across Watches 328 and 330 this evening. Storms currently
crossing Lake Michigan may pose a threat of locally gusty winds and
marginally severe hail across parts of Lower Michigan. However,
downstream watch issuance is not currently expected.

DISCUSSION...Numerous strong/severe storms have evolved eastward
across Watches 328 and 330 this afternoon, driven largely by merged
cold pools and advancing outflow boundaries. In pockets where the
air mass has not been convectively overturned, a warm/moist boundary
layer will maintain a threat of strong/damaging winds and marginally
severe hail. However, as storms progress east, they will become
increasingly displaced from stronger mid-level flow (and related
deep-layer shear) to the west. In turn, as storms reach western
Lower Michigan, they will probably have weakened sufficiently to
preclude downstream watch issuance. Nonetheless, MLCAPE around
1000-1500 J/kg may encourage a few loosely organized cores capable
of gusty winds and marginally severe hail this evening. Convective
trends will be monitored, however, in case storms exhibit greater
overall organization than is currently expected.

..Picca.. 06/14/2017

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Mesoscale Discussion 1034
NWS Storm Prediction Center Norman OK
0531 PM CDT Wed Jun 14 2017

Areas affected...Portions of central Indiana

Concerning...Severe potential...Watch unlikely

Valid 142231Z - 142330Z

Probability of Watch Issuance...20 percent

SUMMARY...Storms may strengthen for a brief period of time over the
next 30 minutes or so; however, the relatively short-lived nature of
the strengthening will likely preclude watch issuance.

DISCUSSION...Visible satellite and regional radar data exhibit
multiple outflow boundaries across central Indiana early this
evening, with an expected merger of these boundaries over Boone,
Hendricks, and Morgan counties in the near term. Rich boundary layer
moisture and temperatures in the 80s to lower 90s have contributed
to around 1000-1500 J/kg of MLCAPE. Surface convergence from the
colliding boundaries may yield a local uptick in convective
intensity (resulting in gusty winds and marginally severe hail) as
forced updrafts utilize the aforementioned buoyancy. However, the
small spatial/temporal scale of the threat should preclude watch
issuance.

..Picca/Guyer.. 06/14/2017

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Mesoscale Discussion 1035
NWS Storm Prediction Center Norman OK
0611 PM CDT Wed Jun 14 2017

Areas affected...Portions of Missouri and southern Illinois

Concerning...Severe Thunderstorm Watch 329...

Valid 142311Z - 150015Z

The severe weather threat for Severe Thunderstorm Watch 329
continues.

SUMMARY...A cluster of thunderstorms across northeastern Missouri
and western Illinois will likely progress southeast over the next
few hours, with an attendant threat of gusty, damaging winds and
perhaps marginally severe hail. Farther southwest, confidence in
thunderstorm development over the next few hours has decreased.
However, storms may develop across far western portions of the watch
later this evening.

DISCUSSION...Strong/severe thunderstorms continue to evolve near the
Mississippi River this afternoon, aided by large-scale ascent from a
weak passing impulse. Ongoing convective development and merging
cold pools may yield a stronger southeastward push of convection
over the next few hours, with an attendant threat of damaging winds
and severe hail. Farther southwest, satellite trends suggest
convective initiation appears less probable, as the cumulus field
has thinned on the backside of the aforementioned shortwave trough.
Therefore, the potential for severe convection across much of the
SGF CWA may be waning. Across northwestern portions of the watch,
cumulus development has remained a little more robust and high-res
guidance suggests more vigorous convection may develop later this
evening across western Kansas and northwest Missouri, perhaps in
response to a weak upstream impulse. As such convective trends will
be monitored here for potential new watch issuance.

..Picca.. 06/14/2017

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Mesoscale Discussion 1036
NWS Storm Prediction Center Norman OK
0756 PM CDT Wed Jun 14 2017

Areas affected...Portions of west/northwest TX into southwestern OK

Concerning...Severe Thunderstorm Watch 331...

Valid 150056Z - 150230Z

The severe weather threat for Severe Thunderstorm Watch 331
continues.

SUMMARY...An isolated large hail and damaging wind threat continues
across WW 331 this evening.

DISCUSSION...Isolated thunderstorms initiated across west TX this
afternoon along a dryline, and quickly became severe with strong
instability and sufficient deep-layer shear present across this
region. Subsequent evolution of thunderstorms over the past several
hours has tended towards several splitting supercells and small
bowing clusters. One such cluster moved across the Midland/Odessa TX
area, producing measured 64 mph winds and 1.5-2 inch diameter hail.
00Z sounding from Midland TX shows strong MLCAPE around 2250 J/kg,
which will easily support ongoing thunderstorms. Although a weakness
in the mid-level flow is noted around 700 mb, strengthening winds
from 600 mb to the tropopause is supporting around 45 kt of 0-6 km
shear. Ongoing multicell clusters and isolated supercells will
continue to pose a large hail and damaging wind threat for at least
the next several hours. By late evening, increasing convective
inhibition owing to the loss of daytime heating should result in the
weakening of ongoing convection. The severe threat across northern
portions of WW 331 remains conditional, and recent visible satellite
imagery indicates a general lessening of the cumulus field with
northeastward extent (into southwestern OK). Still, a left-split
supercell over Kent County TX as of 0055Z may pose an isolated
severe threat as it moves northeastward.

..Gleason.. 06/15/2017
Dome, dome, dome..The life is a dome

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stormchaserAlberto
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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Jue Jun 15, 2017 10:49 am

Otro día más de tiempo severo y van.. Un poco más al sur ya de los días anteriores. Viento y granizo, los riesgos más significativos. Sólo un 2% de probabilidades de tornados en una porción de Kansas.
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% de vientos destructivos.
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Granizo.
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Discusión.
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Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0748 AM CDT Thu Jun 15 2017

Valid 151300Z - 161200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
INTO EARLY TONIGHT FROM CENTRAL KANSAS TO NORTHERN OKLAHOMA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
ENHANCED RISK AREA FOR PARTS OF THE CENTRAL PLAINS TO NORTHWEST
TEXAS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
ACROSS CENTRAL AND NORTHERN MISSISSIPPI/ALABAMA AND VICINITY...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN A BROAD AREA
FROM THE OHIO VALLEY TO THE SOUTHEAST...

...SUMMARY...
Severe thunderstorms with damaging winds and large hail, some
significant, are expected this afternoon into tonight from central
Kansas into northern Oklahoma, while more isolated severe storms
should form farther southwest into parts of northwest Texas.
Widely-scattered severe storms with damaging winds will be possible
this afternoon across parts of Mississippi and Alabama, though more
isolated damaging gusts could occur over a broad area from the upper
Ohio Valley to the Southeast.

...Central/southern Plains through tonight...
A surface boundary and associated moisture gradient has drifted
northwestward into central KS, while a lingering dryline extends
south-southwestward across the southern High Plains. Surface
heating and a moist boundary layer (low 70s F dewpoints) beneath
steep midlevel lapse rates will result in strong buoyancy this
afternoon from central KS southward into OK and west TX.
Thunderstorm development is likely this afternoon along the boundary
in KS, especially where the residual outflow across eastern KS
intersects the moisture gradient. Deep-layer vertical shear will be
sufficient for some supercell structures initially, with very large
hail possible. Upscale growth into one or more clusters also
appears likely by this evening, and the storms will subsequently
move southeastward into reservoir of strong buoyancy across OK and
southeastern KS. Damaging winds, some significant, will become the
primary threat with the expected MCS by late afternoon/evening,
which could persist well into the overnight hours.

Farther southwest, scattered thunderstorms are expected along the
dryline this afternoon in conjunction with strong surface
heating/deep mixing. Similar to the previous couple of days,
splitting supercells with large hail will be the main threat this
afternoon/evening.

...Mid South and TN Valley this afternoon...
Ongoing convective clusters across southern MO/northern AR into KY
will continue to move southeastward and weaken through the morning
across northern AR and TN. However, the outflow generated by the
storms could move across much northeastern AR and western/middle TN
by about midday, and reach northern MS and northwestern AL by early
afternoon. Storm coverage is somewhat in question, but renewed
thunderstorm development is possible by early-mid afternoon along
the residual outflow boundary and/or differential heating zones
resulting from this morning convection. Vertical shear will be
weak, but thermodynamic profiles will favor a threat for downbursts
with isolated damaging winds.

..Thompson.. 06/15/2017

Próxima actualización: 16:30z.
--------------------------------------------
Última discusión a mesoescala.
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Mesoscale Discussion 1037
NWS Storm Prediction Center Norman OK
0954 PM CDT Wed Jun 14 2017

Areas affected...Portions of eastern Kansas and northern/central
Missouri

Concerning...Severe potential...Watch possible

Valid 150254Z - 150430Z

Probability of Watch Issuance...40 percent

SUMMARY...Thunderstorms re-developing across northern Missouri and
eastern Kansas this evening may pose the potential for a few
damaging gusts and instances of large hail. Trends are being
monitored for possible watch issuance.

DISCUSSION...Isolated/widely scattered thunderstorms have developed
west of a decaying MCS this evening, and a couple of these cells
possess relatively deep cores, with 9-km CAPPI reflectivity upwards
of 50 dBZ or so. The 00Z TOP sounding sampled an uncapped
environment characterized by rich boundary-layer moisture and steep
mid-level lapse rates. While nocturnal cooling has decreased
mixed-layer CAPE somewhat, modified soundings still suggest upwards
of 3000 J/kg and little inhibition is present. In turn, weak
large-scale forcing for ascent should be sufficient to maintain
developing convection into early tonight. Deep-layer shear is
relatively weak, but thermodynamic profiles would support a few
damaging gusts and perhaps large hail in association with stronger,
organized updrafts. Therefore, trends are being monitored for
continued robust development, which would necessitate watch
issuance.

..Picca/Guyer.. 06/15/2017
Dome, dome, dome..The life is a dome


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