Seguimiento general en EEUU

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Ernest
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Re: Seguimiento general en EEUU

Mensajepor Ernest » Mar May 30, 2017 11:15 am

Chuekin escribió:
stormchaserAlberto escribió::shock: :shock: :shock:
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Un poco tarde, pero qué bien que se resaltan en esta imagen (que justo es el atardecer) las ondas de gravedad generadas por la ascendente! Zona de fuerte turbulencia convectiva.


Venía a decir lo mismo, es de libro esta imagen.
Did you want to talk about the weather, or were you just making chitchat?

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stormchaserAlberto
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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Mié May 31, 2017 11:11 am

Otro día más con tiempo severo, pero leve. Hay un 2% de tornados por el noreste. Viento y granizo, los riegos principales.
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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
0744 AM CDT Wed May 31 2017

Valid 311300Z - 011200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
EASTERN NEW YORK INTO CENTRAL NEW ENGLAND...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
KANSAS TO PARTS OF WESTERN MISSOURI...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ELSEWHERE FROM
EASTERN VIRGINIA TO NORTHERN PARTS OF NEW YORK AND NEW ENGLAND...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ELSEWHERE FROM
PORTIONS OF THE CENTRAL HIGH PLAINS TO THE OZARKS...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER SOUTHWEST
TEXAS...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE NORTHERN ROCKIES...

...SUMMARY...
A few severe storms capable of strong, damaging winds and large hail
will be possible from parts of New England southward to the
Mid-Atlantic. Another area of strong/severe storms is expected from
the central High Plains to the Ozarks. Isolated strong to marginally
severe storms will also be possible across southwestern Texas and
the northern Rockies.

...Synopsis...
The general upper-air pattern will be characterized by troughing
from the Gulf of Alaska across the Pacific Coast States, a
high-amplitude ridge from the central/southern Rockies northward to
the western Canadian Arctic islands, and broadly cyclonic flow over
the Upper Midwest, Great Lakes, central/northern Appalachians, and
Northeast. Several low-amplitude shortwave troughs and vorticity
lobes will be embedded within that cyclonic flow.

In the Northwest, a leading shortwave trough, aligned almost
parallel to the flow aloft and containing several embedded vorticity
maxima, is moving northeastward across northern CA and eastern
portions of WA and OR. The southern part of this perturbation will
reach northern ID and northwestern MT late tonight. A
southern-stream shortwave trough -- now evident in moisture-channel
imagery over northwestern MX, will eject northeastward across
southern NM, west TX, and central TX through the period, as another
perturbation digs southeastward across southern CA.

At the surface, the pattern is rather chaotic and mostly devoid of
strong synoptic influences -- more characteristic of later in the
warm season, and dominated by numerous mesoscale and smaller
boundaries. The major exception is a weak surface frontal zone,
analyzed at 11Z from Lake Huron to south-central IL, and eastern
through northwestern KS. Little movement is expected for the
segment of that front over MO and IL, with some northward shift over
northwestern/central KS as heights rise aloft. A weak,
quasistationary, remnant front was drawn from the Delmarva Peninsula
to northern GA, southern MS, and north-central TX. This boundary
will continue to deteriorate through the period.

...Northeast...
Scattered afternoon to early evening thunderstorms with large hail
and damaging gusts are expected, and a tornado cannot be ruled out.
Aloft, relatively cold air aloft (-18 to -20 deg C 500-mb temps, in
the 10th-25th percentile range vs. daily climatology at ALB) will
contribute to steep low/middle-level lapse rates for this area.
Again today, a surface trough and related low-level convergence zone
-- oriented nearly meridionally -- should take shape across the
region. With a nearby theta-e and moist axis heated during the
afternoon beneath that cold midlevel environment, a narrow corridor
of 1000-2000 J/kg MLCAPE should develop and shift eastward across
the outlook area, constrained on the east by Atlantic marine air.
Where sustained convection can stay discrete to semi-discrete,
supercells are possible, given the favorable deep shear (35-45 kt
effective-shear magnitude, locally higher) present amidst the belt
of cyclonic flow aloft. The most favorable forecast CAPE-shear
parameter space still appears to be from the Hudson Valley eastward
across central New England.

...Central Plains to Ozarks...
Multiple rounds of isolated to scattered thunderstorms are possible
through this evening in the general vicinity of the frontal zone,
with outflow/differential-heating boundaries acting as foci south of
the front as well. Sporadic strong/damaging gusts and severe hail
are expected, with the greatest aggregated concentration of
convection and severe potential probable over the 15% hail/wind risk
areas. The most favorable low/middle-level wind profiles and shear
(with isolated supercell organization possible) should be near the
front in the western part of the combined risk area, across the
central High Plains, where strong veering with height is expected
despite modest midlevel flow. Meanwhile the greatest convective
coverage should be from central KS into southwestern MO, where
organized multicells and some clusters and small bows are possible.
A corridor of relatively maximized low-level moisture should advect
into a deepening boundary layer near the frontal zone, with dew
points upper 50s to mid 60s F. Still, well-mixed subcloud layers
are possible in support of gust/hail potential. The air mass will
destabilize through the day as pockets of relatively maximized
surface heating develop in the wake of morning clouds/convection,
contributing to MLCAPE 1000-2000 J/kg, amidst effective-shear
magnitudes 30-40 kt.

....Southwest TX...
Widely scattered to scattered thunderstorms are expected to form
this afternoon into early evening, with isolated severe hail and
gusts possible. This threat will develop as large-scale lift
preceding the ejecting Mexican perturbation moves over a
destabilizing boundary layer characterized by weakening MLCINH,
convective/differential-heating boundaries and orographic forcing
for lift, and surface dew points ranging from the 50s to low 60s F.
Forecast soundings suggest 1500-2000 J/kg MLCAPE is possible where
at least a few hours of direct insolation is available. Concerns
precluding greater probabilities include
1. The lack of substantial midlevel winds (contributing to
disorganized, messy storm structures), and
2. Uncertainties regarding timing of erosion of extensive morning
cloud cover, to permit diabatic destabilization of a boundary layer
stabilized by overnight precip.

...Northern Rockies...
Widely scattered thunderstorms, potentially organizing into small
clusters and gusty arcs, are expected this afternoon. The main
concern is locally damaging wind. As the aforementioned mid/upper
perturbation obliquely approaches, large-scale DCVA/cooling will
spread slowly over this region, concurrent with lift from a related,
weak low-level frontal zone shifting eastward. Those, along with
lower-elevation dew points generally 40s to lower 50s F, and
steepening low-level lapse rates from areas of surface heating, will
support convective development. Deeply mixed boundary layers
beneath 200-500 J/kg MLCAPE, along with momentum transfer from areas
of stronger midlevel winds, will support strong to isolated severe
gust potential with any sustained convection.

..Edwards/Goss.. 05/31/2017

Próxima actualización: 16:30z.
-------------------------------------
Últimas discusiones a mesoescala.
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Mesoscale Discussion 0919
NWS Storm Prediction Center Norman OK
1103 AM CDT Tue May 30 2017

Areas affected...Parts of western and central PA...southwest into
central NY...and southward to the eastern WV Panhandle

Concerning...Severe potential...Watch possible

Valid 301603Z - 301830Z

Probability of Watch Issuance...60 percent

SUMMARY...New thunderstorm development is expected across western PA
into southwest NY and southward some into WV by early afternoon
(around 17Z), with one or more lines of storms and perhaps clusters
spreading east today. Damaging winds and hail will be the primary
severe-weather threats.

DISCUSSION...Trends in satellite imagery indicated ongoing cumulus
formation this morning from the Upper Ohio Valley into WV, toward
central PA and west/southwest NY, as surface heating and low-level
moistening has weakened inhibition. Late morning radar imagery
showed some thunderstorm development within convection along and
parallel to the higher terrain from the eastern WV Panhandle through
central PA to south-central NY. This activity was located within an
area of low-level confluence, and the eastern extent of stronger
instability analyzed over the western PA/Upper Ohio Valley region.

Strengthening west-southwesterly 500-mb winds with the approach of a
MI/IN/OH shortwave trough will support increasing effective bulk
shear for organized storms. In addition, an increase in forcing for
ascent with this trough across the discussion area this afternoon
into the evening will augment ascent along an eastward-moving front
and aforementioned confluence zone to support more robust
convection/thunderstorm development. The degree of instability and
bulk shear suggest damaging winds and hail will be the primary
severe threats. Long, straight hodographs suggest splitting storms
will be possible, while low-level curvature could prove sufficient
for a tornado threat too.

..Peters/Hart.. 05/30/2017

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Mesoscale Discussion 0920
NWS Storm Prediction Center Norman OK
0100 PM CDT Tue May 30 2017

Areas affected...A small part of southeast Louisiana (near and north
of the Gulf of Mexico coast)

Concerning...Severe potential...Watch unlikely

Valid 301800Z - 302030Z

Probability of Watch Issuance...5 percent

SUMMARY...A locally greater, though marginal coverage, tornado risk
exists this afternoon across a small part of southeast Louisiana
from Terrebonne Parish into mainly central portions of Lafourche
Parish and southern St. Mary's Parish. Some potential for this
marginal threat to develop/spread east into portions of Plaquemines
Parish later this afternoon to early evening.

DISCUSSION...Trends in mosaic radar imagery indicated a couple of
periodic and transient low-level rotational couplets with storms
across Terrebonne Parish and central Lafourche Parish. These storms
were located in vicinity of an east-west oriented outflow boundary,
which extended from offshore the north-central gulf coast into far
southeast Louisiana (through central Terrebonne to southern St.
Mary's Parishes). A very moist and unstable environment combined
with vertically veering winds, especially near and north of the
surface boundary, is enhancing the potential for storm rotation and
an attendant, mainly brief, tornado threat. Overall coverage for
the area affected should remain limited this afternoon, precluding
higher severe probabilities in the Day 1 Convective Outlook and a
watch potential.

..Peters/Hart.. 05/30/2017

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Mesoscale Discussion 0921
NWS Storm Prediction Center Norman OK
0303 PM CDT Tue May 30 2017

Areas affected...Central PA into central and parts of eastern NY

Concerning...Severe Thunderstorm Watch 299...

Valid 302003Z - 302200Z

The severe weather threat for Severe Thunderstorm Watch 299
continues.

SUMMARY...Severe-weather threat continues across central
Pennsylvania into mainly central New York, while the northeast part
of WW 299 should maintain a limited severe storm potential, given a
more stable environment. Damaging winds and hail remain the primary
severe-weather risk with the strongest storms.

DISCUSSION...Trends in satellite, surface observations and WSR-88D
VWP data indicated a decidedly veered wind field across western PA
into western NY, with a narrow theta-e axis has shifted east into
central PA to central NY. Mosaic radar imagery showed the ongoing
strong to severe storms were located within this moist and unstable
environment with MLCAPE up to around 500 J/kg. Despite marginal
instability, strong bulk shear will continue to favor organized
storms with damaging winds and hail as the primary threats. The
overall severe-weather threat will remain limited with eastward
extent due to extensive low-level clouds into eastern PA to the
northeast part of WW 299 in eastern NY, where instability is quite
low.

..Peters.. 05/30/2017

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Mesoscale Discussion 0922
NWS Storm Prediction Center Norman OK
0448 PM CDT Tue May 30 2017

Areas affected...portions of the OR/WA Columbia Basin

Concerning...Severe potential...Watch unlikely

Valid 302148Z - 310015Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated small to marginally severe hail and severe gusts
are possible late this afternoon (south) through the late evening
(north).

DISCUSSION...Visible satellite imagery shows a cumulus field across
central OR to the east of a northeast migrating mid-level shortwave
trough forecast to move into central WA tonight. Lightning data and
radar mosaic show isolated storms have developed across
north-central OR within a warm/well-mixed boundary layer (40 degrees
F temperature-dewpoint spreads). Very steep low- to mid-level lapse
rates will favor strong evaporative cooling potential for a couple
of the stronger thunderstorm cores. Strengthening mid-level winds
will act to organize cold pools and a skeletal band of storms may
develop by early evening. If a linear cold pool develops, it is
possible scattered strong to severe gusts may occur on the leading
edge of outflow. Short-term trends will be monitored.

..Smith/Guyer.. 05/30/2017

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Mesoscale Discussion 0923
NWS Storm Prediction Center Norman OK
0456 PM CDT Tue May 30 2017

Areas affected...Northern VA

Concerning...Severe potential...Watch possible

Valid 302156Z - 302300Z

Probability of Watch Issuance...40 percent

SUMMARY...Isolated severe thunderstorms will continue across
northern Virginia into the early evening hours. Large hail will be
the primary threat, though locally damaging winds are possible.

DISCUSSION...Strong boundary-layer heating has contributed to steep
low-level lapse rates west of the wedge front across VA. As a
result, surface-based thunderstorms have developed along the eastern
fringe of this more buoyant air mass and are slowly maturing within
a corridor of favorable low-level convergence. High-res model
guidance has been consistent regarding this development and
supercells are evolving within a strongly sheared and favorably
unstable environment. Latest radar data strongly suggests at least
golf ball sized hail with the supercell over Culpeper/Stafford
Counties. There is increasing concern that this activity will
linger into the evening hours as they propagate southeast along the
wedge front. Hail and wind can be expected with this activity.

..Darrow/Guyer.. 05/30/2017

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Mesoscale Discussion 0924
NWS Storm Prediction Center Norman OK
0558 PM CDT Tue May 30 2017

Areas affected...Eastern KS...Western MO

Concerning...Severe potential...Watch unlikely

Valid 302258Z - 310030Z

Probability of Watch Issuance...5 percent

SUMMARY...An isolated severe wind and hail threat will continue into
early evening before a weakening trend is expected. Watch issuance
is currently not anticipated.

DISCUSSION...A few strong/potentially severe thunderstorms have
recently developed across portions of eastern KS and western MO.
Relatively cool temperatures aloft and steep midlevel lapse rates,
in conjunction with strong diurnal heating, has allowed for
weak-to-moderate instability to develop, with SBCAPE of 750-1500
J/kg in place per recent mesoanalyses. Moderate west-northwesterly
flow aloft is supporting effective shear of 35-45 kts, which will
support at least weakly rotating updrafts, with a corresponding risk
of isolated large hail. Despite weak low-level flow, a localized
damaging wind risk will also exist with strong low-level lapse rates
in place. Brief upscale growth may also support a localized damaging
wind risk in the next 1-2 hours.

With negligible large-scale support and the loss of daytime heating,
storms are expected to diminish in intensity this evening. Given the
relatively limited magnitude and duration of the threat, watch
issuance is not expected.

..Dean/Guyer.. 05/30/2017
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 01, 2017 3:15 pm

Riesgo leve para la costa este de Maine. Es la primera vez que lo veo tan al norte. Viento y granizo, los mayores riesgos.
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% de 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
1053 AM CDT Thu Jun 01 2017

Valid 011630Z - 021200Z

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

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER EASTERN NEW
ENGLAND...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHWEST
TX AND SOUTHEAST NM...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF ID
AND MT...

...SUMMARY...
Isolated strong to severe storms will be possible across parts of
coastal New England this afternoon, as well as from southwest Texas
and over parts of the northern Rockies.

...New England...
Visible satellite imagery shows strong heating occurring over
eastern ME/NH/MA. This is an area with surface dewpoints in the 50s
and cold temperatures aloft. Continued daytime heating will result
in a corridor of sufficient CAPE for scattered strong to severe
thunderstorm activity. Vertical shear profiles are slightly weaker
than yesterday, but still enough to warrant a risk of a few intense
cores capable of hail and damaging winds. The southward extent of
the threat into MA/RI/CT is more uncertain due to expected limited
coverage of storms.

...TX/NM...
Considerable cloud cover is present today over much of TX, limiting
heating/destabilization. However, it appears likely that clouds
will thin sufficiently over parts of southwest TX for the
development of strong instability by late afternoon. Thunderstorms
are expected to form over the higher terrain of southeast NM and far
southwest TX and build eastward through the early evening. A few of
these storms may pose a threat of gusty winds and hail.

...ID/MT...
Water vapor loop shows a shortwave trough over OR. This feature will
move eastward today into parts of ID/MT and promote the development
of scattered showers and thunderstorms. 12Z CAM solutions are in
strong agreement that a cluster of convection will form over the
mountains of central ID and track quickly northeastward into western
MT. Forecast soundings ahead of this activity show sufficient CAPE
and deep-layer shear to promote a risk of hail and damaging wind
gusts. The main uncertainty involves cloud cover and
destabilization. If trends warrant, an upgrade to SLGT might be
needed at 20z.

..Hart/Cook.. 06/01/2017

Próxima actualización: 20:00z.
-------------------------------------
Últimas discusiones a mesoescala.
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Mesoscale Discussion 0925
NWS Storm Prediction Center Norman OK
1100 AM CDT Wed May 31 2017

Areas affected...Extreme southeast Louisiana to Gulf coastal
counties of southeast MS and southwest AL

Concerning...Severe potential...Watch unlikely

Valid 311600Z - 311830Z

Probability of Watch Issuance...5 percent

SUMMARY...A locally greater, though marginal coverage, tornado risk
is possible today across extreme southeast Louisiana into the Gulf
coastal counties in southeast MS and southwest AL. WW issuance is
unlikely due to spatiotemporal limitations in this region, and given
that a somewhat greater potential appears for stronger rotational
couplets to remain offshore as waterspouts.

DISCUSSION...Trends in mosaic reflectivity and velocity data across
extreme southeast LA (primarily including St. Bernard Parish)
indicated a few thunderstorms with periodic, and occasionally
persistent, low-level rotational couplets moving to the
north-northeast toward the islands off of the southeast MS coast
(including Cat Island). General weakening of these couplets
occurred as they tracked closer to the coast, while recent radar
imagery showed these storms have shifted more toward the east, with
additional storms developing near buoy 42040 and tracking toward the
north.

15Z RAP suggested some increase in surface-3 km CAPE today (to
around 100 J/kg) and surface vorticity to be persistent near a weak
west-east oriented boundary located near or just offshore the coast
of southeast MS and southwest AL. Storms developing and/or
interacting with this boundary could have enhanced potential for
low-level rotation, while background vertically veering low-midlevel
winds (per WSR-88D VWP data) also support rotating storms. A very
rich boundary layer (precipitable water around 1.6 inches per 12Z
LIX sounding and mean mixing ratios around 15 g/kg) and moderate
instability should prove favorable for additional storm development
through the afternoon.

..Peters/Hart.. 05/31/2017

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Mesoscale Discussion 0926
NWS Storm Prediction Center Norman OK
1129 AM CDT Wed May 31 2017

Areas affected...Far northeast PA...Eastern NY...VT...NH...Western
ME...Western MA...Northwest CT

Concerning...Severe potential...Watch likely

Valid 311629Z - 311730Z

Probability of Watch Issuance...80 percent

SUMMARY...Thunderstorm coverage is expected to increase over the
next hour or so with the strongest storms capable of hail and
damaging wind gusts. A watch will likely be needed over portions of
the region to cover this threat.

DISCUSSION...Recent visible satellite imagery has shown an increase
in cumulus development across eastern NY, within the area of broadly
confluent surface flow ahead of the approaching shortwave trough.
Forcing for ascent provided by both the modest surface convergence
and the shortwave trough is expected to result in thunderstorm
development during the next hour or two. Low-levels are not
particularly warm or moist but continued daytime heating should
contribute to steep low-level lapse rates and adequate insolation to
remove any remaining convective inhibition. Additionally, cool
mid-level temperatures (i.e. around -19 to -20 deg C at 500 mb) will
result in MLCAPE approaching 1000 J/kg, despite dewpoints in the mid
to upper 50s. Strong mid-level flow will support updraft
organization and hail development within the more robust updrafts.
Quick storm motion and downward momentum transfer of the enhanced
flow aloft could also contribute to some damaging wind gusts. A
watch will likely be needed to address the resulting severe threat.

..Mosier/Hart.. 05/31/2017

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Mesoscale Discussion 0927
NWS Storm Prediction Center Norman OK
1258 PM CDT Wed May 31 2017

Areas affected...VA...southern MD...and southeast WV

Concerning...Severe potential...Watch unlikely

Valid 311758Z - 312030Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated strong to severe storm development will remain
possible this afternoon across southeast WV and perhaps into
southwest VA. Meanwhile, the potential exists for additional storms
to develop with some increase in coverage and intensity by mid-late
after[i]
noon in central and eastern VA to southern MD. Damaging winds
and hail will be the primary severe-weather threats, while forecast
coverage currently suggests WW issuance will be unlikely. However,
convective trends will be monitored for any changes for a greater
severe risk.

DISCUSSION...Satellite imagery indicated a persistent band of
midlevel clouds tracking east across central WV early this
afternoon, with this apparent corridor of forcing for ascent
(attendant to the cloud band) expected to reach central VA around
20Z. Strong surface heating will continue this afternoon,
steepening low-level lapse rates across the discussion area. This
combined with a moist environment extending from southeast VA into
central VA (in vicinity of CHO) to southern MD is resulting in a
moderately unstable air mass (MUCAPE up to 2000 J/kg). New
thunderstorm development should occur with some increase in coverage
by mid-late afternoon across central VA where the air mass is more
moist and unstable, with activity then spreading east. Weak
midlevel lapse rates will tend to temper updraft strength, though
effective bulk shear of 40-50 kt suggests any stronger/sustained
storms could become organized, with isolated damaging winds and some
hail being the primary threats.

..Peters/Hart.. 05/31/2017[/i]

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Mesoscale Discussion 0928
NWS Storm Prediction Center Norman OK
0105 PM CDT Wed May 31 2017

Areas affected...Eastern OH...Western PA...Northern WV

Concerning...Severe potential...Watch unlikely

Valid 311805Z - 311930Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated hail and damaging wind gusts are possible over
the next several hours as thunderstorms move across eastern OH,
western PA, and far northern WV.

DISCUSSION...Storms have developed over the past hour within the
modestly unstable airmass across central OH. Primary forcing for
this increased convection is likely the shortwave trough currently
pivoting through the southwestern periphery of the large upper low
centered over Ontario. Despite relatively scant low-level moisture,
some instability has developed ahead of these storms across central
OH and western PA, largely as a result of cool mid-level
temperatures (around -19 deg C at 500 mb) and modest surface
heating. Unidirectional shear profiles will support fast storm
motion and the potential for a few strong wind gusts with the more
robust updrafts. Additionally, the enhanced flow aloft and resulting
potential updraft organization is supportive of an isolated hail
threat. Limited severe coverage is currently expected, precluding
higher watch probabilities. Even so, convective trends across the
area will be monitored closely.

..Mosier/Hart.. 05/31/2017

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Mesoscale Discussion 0929
NWS Storm Prediction Center Norman OK
0133 PM CDT Wed May 31 2017

Areas affected...Central and Eastern NC

Concerning...Severe potential...Watch unlikely

Valid 311833Z - 312030Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated damaging wind gusts and/or hail are possible over
the next several hours across portions of central and eastern NC.

DISCUSSION...Recent radar imagery showed quick storm development
across central NC over the past hour. Impetus for this development
is likely a fast-moving, low-amplitude shortwave trough embedded
within the enhanced cyclonic flow extending from the TN valley into
the mid-Atlantic. Daytime heating amidst ample low-level moisture
has contributed to modest instability over the region, with recent
mesoanalysis estimating MLCAPE near 1000 J/kg. The stronger
mid-level flow is displaced north of region across the Northeast but
enough mid-level flow (i.e. around 40 kt at 500) and shear (i.e.
effective shear around 40-45 kt) still exists to support rotating
updrafts and modest storm organization. As a result, some hail
and/or damaging wind gusts are possible with the stronger storms.
Limited severe coverage is currently expected to preclude watch
issuance but convective trends across the region will be monitored
closely.

..Mosier/Hart.. 05/31/2017

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Mesoscale Discussion 0930
NWS Storm Prediction Center Norman OK
0145 PM CDT Wed May 31 2017

Areas affected...Eastern KS...Southwest MO

Concerning...Severe Thunderstorm Watch 301...

Valid 311845Z - 311945Z

The severe weather threat for Severe Thunderstorm Watch 301
continues.

SUMMARY...Severe storms will continue to develop across eastern KS
spreading into west-central and southwest MO this afternoon. While
large hail has been, and should continue to be, the primary severe
risk with the northern cluster of storms spreading from eastern KS
into west-central MO, an additional threat for damaging winds can be
expected with storms moving from southeast KS into southwest MO.

DISCUSSION...Objective analyses based on the RAP indicated a
moderately unstable environment has developed along and south of a
surface front which stretched from central MO into central KS this
afternoon. Vertically veering wind profiles with southerly surface
winds in the warm sector and 30-40 kt west-northwesterly winds at
500 mb will continue to result in sufficient effective bulk shear of
35-40 kt across KS into MO. These factors coupled with steep
midlevel lapse rates of 8-8.5 C/km spreading across the discussion
area suggest additional large hail and damaging wind gusts will be
possible. The latter threat will be greatest in southeast KS into
southwest MO where low-level lapse rates are expected to be steeper.

The primary forcing mechanism for the increase in thunderstorm
coverage this afternoon appears to be a midlevel perturbation
tracking through eastern KS at this time per water vapor imagery.
This trough and attendant forcing for ascent will spread into
central and southern MO this afternoon and evening, supporting
additional storm development and severe threat.

..Peters/Hart.. 05/31/2017

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Mesoscale Discussion 0931
NWS Storm Prediction Center Norman OK
0346 PM CDT Wed May 31 2017

Areas affected...East-central and southeast NY...western
CT...western and central MA...southern and eastern VT...NH...and
southwest ME

Concerning...Severe Thunderstorm Watch 300...

Valid 312046Z - 312245Z

The severe weather threat for Severe Thunderstorm Watch 300
continues.

SUMMARY...The severe risk for hail and damaging winds continues late
this afternoon into the evening across east-central and southeast
NY, western CT, western and central MA, southern and eastern VT, NH,
and southwest ME.

DISCUSSION...At 2035Z, mosaic radar imagery showed a broken band of
strong to severe storms extending from northeast VT to east-central
NY to far northeast PA. Objective analyses indicated this activity
will continue to move east through a relatively narrow corridor of
moderate instability and strong effective bulk shear (up to 50 kt)
located across the valid parts of WW 300 to support organized
storms. Hail and damaging winds will remain the primary threats
with any of the stronger/sustained storms into the evening.

..Peters.. 05/31/2017

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Mesoscale Discussion 0932
NWS Storm Prediction Center Norman OK
0634 PM CDT Wed May 31 2017

Areas affected...Northeast PA...Southeast
NY...CT...MA...NH...Western ME

Concerning...Severe Thunderstorm Watch 300...

Valid 312334Z - 010100Z

The severe weather threat for Severe Thunderstorm Watch 300
continues.

SUMMARY...The damaging wind and isolated large hail threat continues
in and near WW 300. Some severe threat may extend downstream of the
watch, but should diminish with eastward extent.

DISCUSSION...At 2330Z, a loosely organized QLCS is ongoing from
southeast NY northeastward into western ME. In addition, a discrete
supercell is ongoing just ahead of the line near Poughkeepsie, NY.
The strongest instability is located across southeast NY into
western CT/MA, with recent mesoanalyses indicating SBCAPE of
500-1250 J/kg. Effective shear of 35-45 kts will continue to support
some organized structures in the short term. The primary threat is
expected to be damaging wind given the primary linear mode, but the
supercell across southeast NY will pose some tornado threat as long
as it remains discrete, with locally backed southeasterly flow
supporting a modest amount of low-level shear/helicity.

As the QLCS advances eastward, it will eventually encounter a cooler
and more stable airmass. This will occur first across portions of
southern ME, where a marginal damaging wind risk may exist
downstream of WW 300, but should diminish with eastward extent.
Further south, there is some potential for a severe threat to extend
east of the watch and local extensions may eventually be needed.

Back to the southwest across northeast PA, a separate line segment
has recently intensified. This will pose some damaging wind risk as
it advances eastward into the southwest portion of WW 300, though it
will encounter an increasingly worked-over environment from earlier
convection.

Finally, some severe threat may extend a small distance south of WW
300 across southeast NY/southwest CT, but the spatiotemporal extent
of this threat appears too limited for new watch issuance.

..Dean.. 05/31/2017

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Mesoscale Discussion 0933
NWS Storm Prediction Center Norman OK
0639 PM CDT Wed May 31 2017

Areas affected...far eastern CO...far southwestern NE...far
northwestern KS

Concerning...Severe potential...Watch possible

Valid 312339Z - 010045Z

Probability of Watch Issuance...40 percent

SUMMARY...A couple of slow-moving supercells capable of large hail
and severe gusts are likely during the early evening.

DISCUSSION...Radar mosaic shows a couple of severe supercells near
the CO/NE/KS tri-state region early this evening. Upslope surface
flow around 20-kt is resulting in effective shear around 40-kt per
KGLD VAD data. Steep low to mid-level lapse rates will support
strong accelerations in the vertical for both hail growth and
precip-laden downdrafts. It seems plausible the strongest storms
may yield a localized significant hail risk (2 inches or greater in
diameter) but generally severe hail and severe gusts are the main
threats with these storms for the next few hours.

..Smith/Thompson.. 05/31/2017

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Mesoscale Discussion 0934
NWS Storm Prediction Center Norman OK
1111 AM CDT Thu Jun 01 2017

Areas affected...Much of Maine...eastern New Hampshire...and eastern
Massachusetts

Concerning...Severe potential...Watch possible

Valid 011611Z - 011830Z

CORRECTED FOR MISSPELLING

Probability of Watch Issuance...40 percent

SUMMARY...A band of convection has developed along an axis near the
western extent of the discussion area. This band should gradually
increase in intensity, with hail and damaging wind gusts becoming
more of a threat as the afternoon progresses. A WW may be needed
(especially in eastern Maine) later this afternoon.

DISCUSSION...Convection has increased along a NNE to SSW band from
near far northern Maine (about 90 W of Caribou) to near Worcester,
Massachusetts. This convection was responsible for a few brief
downpours, small hail, and some lightning. The combination of
cooling temperatures aloft associated with an approaching shortwave
near Lake Ontario and insolation/surface warming will lead to
1000-1500 J/kg MU CAPE developing across the discussion area later
this afternoon. This instability, combined with modest deep shear
profiles and lift associated with the approaching wave will likely
result in the ongoing band of convection increasing with intensity
over time. Hail and damaging wind gusts are the most likely threats
with this activity, and this threat will likely be highest over
eastern Maine. Given the aforementioned factors, a slight risk
(driven by wind and hail probabilities) has been introduced at the
1630Z outlook update and a severe thunderstorm watch may eventually
be needed (particularly for eastern Maine) later in the afternoon.

..Cook/Hart.. 06/01/2017
Dome, dome, dome..The life is a dome

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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Jue Jun 01, 2017 7:01 pm

Aquí va la última actualización del SPC. Continúa el riesgo leve en el este de Maine. Marginal en otras zonas. Viento y granizo, los riesgos más significativos.
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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
0239 PM CDT Thu Jun 01 2017

Valid 012000Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
EASTERN ME...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF NEW ENGLAND...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF ID AND MT...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHWEST TX AND SOUTHEAST NM...

...SUMMARY...
Isolated strong to severe storms will be possible across parts of
coastal New England this afternoon, as well as parts of southwest
Texas into southeast New Mexico, and over parts of the northern
Rockies.

...New England...

The only adjustments made to the ongoing outlook for the 20z update
were across New England. The slight and marginal risk areas were
adjusted eastward to account for increasing inhibition behind the
eastward advancing line of storms now tracking into far eastern ME.


...Idaho/Montana...

Across the northern Rockies, the marginal risk will be left as-is.
Though a few strong to marginally severe storms are possible,
coverage of more intense cells is expected to be rather sparse in
the absence of stronger instability, limiting the overall severe
threat. See MCD 935 for more details.

..Leitman.. 06/01/2017

.PREV DISCUSSION... /ISSUED 1053 AM CDT Thu Jun 01 2017/

...New England...
Visible satellite imagery shows strong heating occurring over
eastern ME/NH/MA. This is an area with surface dewpoints in the 50s
and cold temperatures aloft. Continued daytime heating will result
in a corridor of sufficient CAPE for scattered strong to severe
thunderstorm activity. Vertical shear profiles are slightly weaker
than yesterday, but still enough to warrant a risk of a few intense
cores capable of hail and damaging winds. The southward extent of
the threat into MA/RI/CT is more uncertain due to expected limited
coverage of storms.

...TX/NM...
Considerable cloud cover is present today over much of TX, limiting
heating/destabilization. However, it appears likely that clouds
will thin sufficiently over parts of southwest TX for the
development of strong instability by late afternoon. Thunderstorms
are expected to form over the higher terrain of southeast NM and far
southwest TX and build eastward through the early evening. A few of
these storms may pose a threat of gusty winds and hail.

...ID/MT...
Water vapor loop shows a shortwave trough over OR. This feature will
move eastward today into parts of ID/MT and promote the development
of scattered showers and thunderstorms. 12Z CAM solutions are in
strong agreement that a cluster of convection will form over the
mountains of central ID and track quickly northeastward into western
MT. Forecast soundings ahead of this activity show sufficient CAPE
and deep-layer shear to promote a risk of hail and damaging wind
gusts. The main uncertainty involves cloud cover and
destabilization. If trends warrant, an upgrade to SLGT might be
needed at 20z.

Próxima actualización: 01:00z.
------------------------------------
Últimas discusiones a mesoescala.
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Mesoscale Discussion 0935
NWS Storm Prediction Center Norman OK
0142 PM CDT Thu Jun 01 2017

Areas affected...north central Idaho and southwest through western
Montana

Concerning...Severe potential...Watch unlikely

Valid 011842Z - 012115Z

Probability of Watch Issuance...20 percent

SUMMARY...Widely scattered thunderstorms are expected to continue
developing through north central Idaho into parts of western
Montana. Some of the storms may become capable of producing isolated
downburst winds and hail this afternoon. Due to the anticipated
sparse coverage of any severe events, a watch is not anticipated.

DISCUSSION...Showers and thunderstorms have begun developing over
the mountains of north central ID into western MT. The combination
of pockets of diabatic warming over the higher terrain and
increasing forcing for ascent through a deep layer downstream from a
progressive shortwave trough will continue to promote
destabilization and thunderstorm development in this region. Latest
objective analysis shows a corridor of 500 J/kg MLCAPE, and the 18Z
special sounding from Great Falls indicates steep 700-500 mb lapse
rates and inverted-V profiles evolving in the sfc-600 mb layer.
Moreover, a belt of moderate winds aloft is overspreading this
region in association with the approaching upper trough. This
environment will promote a threat for isolated downburst winds as
storms intensify this afternoon. Due to limited instability and
expected sparse coverage of the more intense storms, a WW will
probably not be needed.

..Dial.. 06/01/2017

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Mesoscale Discussion 0936
NWS Storm Prediction Center Norman OK
0420 PM CDT Thu Jun 01 2017

Areas affected...A small part of southwest Texas

Concerning...Severe potential...Watch unlikely

Valid 012120Z - 012215Z

Probability of Watch Issuance...20 percent

SUMMARY...A bowing segment has organized across Pecos County, Texas
in the past 1-2 hours, with additional trailing activity along an
outflow boundary to it's west/southwest. A WW is not anticipated
for this activity.

DISCUSSION...Storms in southwest Texas have begun to propagate
slowly eastward - particularly across Pecos County, Texas - over the
past hour or so, with additional activity developing westward into
southern Hudspeth County and near the El Paso area. Strong surface
heating within the pre-convective airmass ahead of this linear
complex has fostered moderate to strong destabilization, with recent
objective analyses suggesting up to 4000 J/kg MUCAPE just southeast
of the Pecos County linear segment and somewhat lower instability
values farther to the west. Deep shear is modest in the region,
with 20-25 kt mid-level flow not necessarily supportive of
convective organization, although development of new updrafts along
the leading edge of the slow-moving outflow will aid in some forward
propagation. An isolated hail/wind threat will spread
eastward/southeastward from the current position of the outflow (and
near/ahead of ongoing storms). This threat should be too
sparse/localized for a WW issuance, although convective trends will
be monitored through the afternoon.

..Cook.. 06/01/2017
Dome, dome, dome..The life is a dome

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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Sab Jun 03, 2017 3:13 pm

Riesgo leve para Wisconsin. Marginal para el sur de Texas y el noroeste de los Estados Unidos.
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% de tornados.
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Viento.
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Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1127 AM CDT Sat Jun 03 2017

Valid 031630Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE UPPER
GREAT LAKES REGION...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE UPPER
MISSISSIPPI VALLEY INTO THE GREAT LAKES...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
SOUTH TEXAS...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER THE
NORTHERN INTERMOUNTAIN REGION...

...SUMMARY...
Scattered severe thunderstorms will be possible across portions of
the Upper Great Lakes region this afternoon into tonight, with
isolated strong-to-severe thunderstorms possible from eastern
Washington/northeast Oregon across northern Idaho into northwest
Montana. A small band of locally severe storms could also evolve
later this afternoon and evening across the middle and lower Rio
Grande Valley area of Texas.

...Upper Great Lakes Region...
An upper low over Saskatchewan and Manitoba is forecast to develop
southeastward into northwest Ontario and northern Minnesota through
tonight. This will result in stronger northwest flow aloft
spreading across the upper Mississippi Valley and upper Great Lakes
region. At the surface, a diffuse low will move toward Lake
Superior by tonight as a southward trailing cold front moves across
the Upper Mississippi Valley.

In the wake of morning convection over southeast Wisconsin, visible
imagery shows an area of clearing from Iowa and southern Minnesota
into western/northern Wisconsin and western Upper Michigan. Surface
dew points have increased to 60-65F within this region, and strong
diabatic heating expected within the cloud-free area will contribute
to destabilization with MLCAPE of 1500-2000 J/kg this afternoon.

Model guidance including CAMs indicate convection will develop
along/ahead of the cold front from western Upper Michigan into
northwest Wisconsin during the mid-late afternoon as heating weakens
the cap and mid-level height falls overspread the region from the
northwest. Although stronger winds aloft will remain northwest of
the most favorable low-level thermodynamic environment, modest
veering in the low-mid levels will contribute to sufficient vertical
shear to promote organized multi-cellular convective structures.
Multiple CAMS (NAM Nest, ESRL and NCEP HRRR) all indicate
development of a bowing QLCS moving across parts of Upper Michigan
and northern Wisconsin into the evening, with potential for damaging
wind gusts and occasional hail with stronger storms. This activity
is expected to spread eastward and southeastward through the evening
with potential for severe storms to affect parts central and
possibly southeast Wisconsin after dark. There is more uncertainty
about the primary convective system to maintain intensity as it
crosses northern Lake Michigan and the area of northwest Lower
Michigan will need to be monitored tonight.

Farther to the southwest over the Upper Mississippi Valley, more
limited coverage of convection is expected along/ahead of the cold
front. Large scale ascent will remain weak over the area but
isolated strong-to-severe storms are possible late this afternoon
and evening.

...Parts of South Texas...
Water vapor imagery indicates a slow moving upper vorticity max over
northern Mexico to the immediate south of ELP. Downstream from this
system, strong convection has been occurring over higher terrain
west of the Rio Grande. Strong heating over the lower valley where
weak southeast low-level winds veer to modest westerly flow in the
mid-levels may support a few storms spreading eastward across the
border into parts of southern Texas. Isolated hail and strong wind
gusts will be possible later this afternoon and evening.

...Northern Intermountain Region...
Subtle short-wave impulses within cyclonic/southwesterly flow aloft
will spread across the northwest U.S. today, helping to both steepen
lapse rates and provide a weak source of large-scale ascent. Diurnal
heating/weak destabilization coupled with a deepening mixed layer
will support development of a few showers and -- eventually --
isolated thunderstorms by late afternoon.

With the eastern fringe of stronger mid-level flow to reside atop
this region, a few stronger updrafts could evolve, suggestive of
attendant risk for hail and -- aided by the dry sub-cloud layer --
locally gusty winds. Risk should continue into the evening, with
storms gradually diminishing as the boundary layer stabilizes.

..Weiss/Mosier.. 06/03/2017

Se actualiza a las 20:00z.
------------------------------
Últimas discusiones a mesoescala.
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Mesoscale Discussion 0937
NWS Storm Prediction Center Norman OK
0137 PM CDT Fri Jun 02 2017

Areas affected...Western/Central TX Panhandle

Concerning...Severe potential...Watch unlikely

Valid 021837Z - 022100Z

Probability of Watch Issuance...5 percent

SUMMARY...A couple of landspouts possible through the afternoon.

DISCUSSION...Visible satellite imagery shows a well-defined MCV near
the central TX/NM border with building cumulus to the east of this
feature across the western TX Panhandle. Weak flow aloft and
resulting minimal shear will preclude organized thunderstorm
activity and mostly weak multicellular is anticipated. Even so,
vorticity-rich environment fostered by the presence of the MCV
combined with the presence of steep low-level lapse rates (i.e.
around 7.5 to 8 deg C per km from 0-3 km per the latest
mesoanalysis) and low-level instability (evidenced by 0-3 km MLCAPE
generally greater than 75 J/kg) will result in the potential for a
few brief, non-mesocyclone tornadoes (i.e. landspouts) this
afternoon. Brief and very marginal nature of the threat posed by any
of these landspouts precludes the need for a watch.

..Mosier/Weiss.. 06/02/2017

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Mesoscale Discussion 0938
NWS Storm Prediction Center Norman OK
0203 PM CDT Fri Jun 02 2017

Areas affected...eastern Colorado through western Nebraska

Concerning...Severe potential...Watch unlikely

Valid 021903Z - 022130Z

Probability of Watch Issuance...20 percent

SUMMARY...Storms will likely increase in coverage this afternoon
from eastern CO into portions of western NE posing a risk for
isolated downburst winds and small hail. Overall threat appears too
limited for any WW issuance.

DISCUSSION...Early this afternoon a few showers and thunderstorms
are developing along a lee trough from eastern CO to southwest NE.
Strong diabatic warming is destabilizing the near-surface layer
where dewpoints are in the 40s to low 50s F. Deeply mixed,
inverted-V boundary layers, 500-1000 J/KG MLCAPE, and weakening
convective inhibition should support additional thunderstorm
development this afternoon. Vertical shear is weak with pulse and
multicell storms likely to be the dominant modes, but the
thermodynamic environment will promote a risk for mainly isolated
downburst winds though early evening. In addition, a landspout or
two cannot be ruled out over northeast CO.

..Dial/Weiss.. 06/02/2017

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Mesoscale Discussion 0939
NWS Storm Prediction Center Norman OK
0248 PM CDT Fri Jun 02 2017

Areas affected...Central SD

Concerning...Severe potential...Watch unlikely

Valid 021948Z - 022115Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated damaging wind gusts and hail possible this
afternoon across central SD. Low severe coverage is expected to
preclude the need for a watch.

DISCUSSION...Recent visible satellite imagery shows an increasingly
agitated cu field across central SD. Strengthening updrafts within
this cu field have resulted in lightning over the last 30 mins.
Current surface analysis indicates this development is just ahead of
a pre-frontal trough and within a broad area of pre-frontal
confluence. Overall look of the cu field and recent surface
observations and model soundings suggest this develop is based quite
high, likely over 10kft. Expectation is for the areal extent of this
activity to increase over the next hour or so while moving
north-northeastward. Weak shear will likely preclude anything but
modest storm organization but near dry adiabatic low-level lapse
rates and high storm bases will result in the potential damaging
wind gusts within the strongest storms. Some hail is also possible,
particularly as storms move north-northeastward into a more unstable
airmass across north-central SD. Anticipated severe coverage is
expected to be low, precluding higher watch probabilities, but
convective trends across the area will be monitored closely.

..Mosier/Weiss.. 06/02/2017

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Mesoscale Discussion 0940
NWS Storm Prediction Center Norman OK
0339 PM CDT Fri Jun 02 2017

Areas affected...Central and eastern North Dakota

Concerning...Severe potential...Watch possible

Valid 022039Z - 022245Z

Probability of Watch Issuance...40 percent

SUMMARY...Hail and damaging wind gusts are possible this afternoon
across portions of central and eastern ND.

DISCUSSION...High-based cu continues within the pre-frontal
confluence across central ND. A few stronger updrafts are noted
within the visible imagery and confirmed by recent lightning strikes
and a potentially strong to severe storm in Kidder county. The
airmass across the region is warm, moist, and unstable with recent
surface observations sampling temperatures in the low 90s and
dewpoints in the upper 50s and low 60s and recent mesoanalysis
estimating MLCAPE over 2000 J/kg. This favorable thermodynamic
environment is somewhat tempered by a less-than-optimal kinematic
environment characterized by weak mid-level flow (around 20kt at 500
mb) and weak bulk shear (0-6 km bulk shear less than 25 kt). Even
so, the strong instability and cool temperatures aloft suggest there
is some threat for severe hail. Additionally, high storm bases and
steep low-level lapse rates will foster an environment favorable for
damaging wind gusts. Storms in this area are expected to be slightly
more numerous and stronger than areas farther southwest in central
SD. As a result, convective trends will be monitored closely for
possible watch issuance across portions of central and eastern ND.

..Mosier/Weiss.. 06/02/2017

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Mesoscale Discussion 0941
NWS Storm Prediction Center Norman OK
0549 PM CDT Fri Jun 02 2017

Areas affected...Portions of central/southern MN and northern IA

Concerning...Severe potential...Watch unlikely

Valid 022249Z - 030115Z

Probability of Watch Issuance...5 percent

SUMMARY...Isolated severe thunderstorm potential will exist into the
evening hours from portions of central MN into northern IA, though
Watch issuance will not be needed.

DISCUSSION...Strong surface heating has allowed temperatures to warm
into the lower 90s in many areas west/southwest of a warm front
draped northwest-southeast from west-central MN to north-central IA.
This boundary will continue to advance eastward/northeastward into
the evening hours. Weak warm advection near this boundary, coupled
with diurnally bolstered baroclinic circulations across the
boundary, have promoted widely scattered thunderstorm development --
concentrated across the warm side of the frontal zone. Steep
tropospheric lapse rates are supporting 1000-2000 J/kg of MLCAPE
characterizing convective inflow, despite an overall paucity of
low-level moisture (surface dewpoints in the 50s). Large DCAPE will
support microbursts with an isolated damaging-wind risk, especially
where local cold-pool amalgamation occurs. Severe hail may also
accompany incipient intense updrafts. However, with stronger
effective shear -- and only reaching 20-25 kt -- displaced to the
cool side of the boundary, storms should remain disorganized while
slowly spreading eastward/southeastward into the evening hours.
Isolated severe hail potential may persist well into the evening
hours, as a cross-frontal low-level jet nocturnally strengthens
encouraging some increase in warm advection and elevated convection
potential.

..Cohen/Thompson.. 06/02/2017
Dome, dome, dome..The life is a dome

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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Sab Jun 03, 2017 4:02 pm

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Mesoscale Discussion 0942
NWS Storm Prediction Center Norman OK
0119 PM CDT Sat Jun 03 2017

Areas affected...Portions of Deep South TX

Concerning...Severe potential...Watch unlikely

Valid 031819Z - 031945Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated hail and damaging wind gusts possible this
afternoon across western portions of deep South TX. Watch not
anticipated.

DISCUSSION...Recent KDFX radar imagery has shown a bit more easterly
motion with the ongoing convective line just west of the
international border. A slight increase in overall system speed has
also be noted. At the same time, updraft strength has been largely
maintained with greater than 50 dBZ noted on the 9km CAPPI. The
downstream airmass is warm, moist, and unstable with recent
mesoanalysis estimating the MLCAPE is over 2000 J/kg. This favorable
thermodynamic environment is tempered somewhat by weak flow below
300 mb and resulting weak shear. Additionally, a layer of warm
mid-level temperatures between 850 and 700 mb will result in slower
parcel accelerations and could promote some over weakening of the
ongoing storms. Despite these negative factors, the noted updraft
persistence and strong instability will still result in the likely
perseverance of this convective line into western portions of deep
South Texas. The strong instability supports the potential for hail
(particularly with initial updrafts) and the steep low-level lapse
rates amidst a moist airmass support the threat for damaging
water-loaded downbursts. Isolated and marginal nature of the threat
are expected to preclude the need for a watch but convective trends
will still be monitored closely.

..Mosier/Weiss.. 06/03/2017
Dome, dome, dome..The life is a dome

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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Sab Jun 03, 2017 5:19 pm

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Mesoscale Discussion 0943
NWS Storm Prediction Center Norman OK
0248 PM CDT Sat Jun 03 2017

Areas affected...Portions of upper Michigan and Wisconsin

Concerning...Severe potential...Watch possible

Valid 031948Z - 032045Z

Probability of Watch Issuance...60 percent

SUMMARY...Thunderstorms will increase in coverage this afternoon,
with a few storms having the potential for damaging winds and a few
instances of large hail. Convective trends are being monitored for
potential watch issuance.

DISCUSSION...Gradually increasing forcing for ascent associated with
a passing shortwave trough is yielding isolated convective
development this afternoon across western upper Michigan. Visible
satellite data also indicate growing cumulus underneath mid/upper
clouds over portions of western Wisconsin, aided by weak surface
convergence along/ahead of a cold front. To the south of ongoing
cloud cover, temperatures have warmed into the lower/mid 80s, with
dew points in the lower/mid 60s, yielding upwards of 1000-1500 J/kg
of MLCAPE. Recent KDLH VWP data indicate adequate deep-layer shear,
characterized by relatively straight hodographs. As such, storm
splits and small bowing segments may evolve, with a deepening
boundary layer enhancing the potential for damaging wind gusts.
Additionally, a few instances of large hail will be possible.
Convective trends are being monitored for potential watch issuance.

..Picca/Weiss.. 06/03/2017
Dome, dome, dome..The life is a dome

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stormchaserAlberto
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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Sab Jun 03, 2017 5:36 pm

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URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 304
NWS Storm Prediction Center Norman OK
315 PM CDT Sat Jun 3 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Western and Central Upper Michigan
North Central and Northeast Wisconsin
Lake Michigan

* Effective this Saturday afternoon and evening from 315 PM until
1000 PM CDT.

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

SUMMARY...Thunderstorm developing over western upper Michigan and
north central Wisconsin are expected to intensify as they move
east-southeastward into the evening hours. Damaging wind gusts and
hail will be possible with stronger storms.

The severe thunderstorm watch area is approximately along and 60
statute miles either side of a line from 30 miles northwest of
Rhinelander WI to 15 miles southeast of Escanaba MI. 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.

&&

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 450. Mean storm motion vector
27025.

...Weiss
Dome, dome, dome..The life is a dome

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stormchaserAlberto
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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Sab Jun 03, 2017 9:18 pm

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Mesoscale Discussion 0944
NWS Storm Prediction Center Norman OK
0558 PM CDT Sat Jun 03 2017

Areas affected...Portions of eastern Upper MI...western Lower
MI...and eastern/central WI

Concerning...Severe Thunderstorm Watch 304...

Valid 032258Z - 040030Z

The severe weather threat for Severe Thunderstorm Watch 304
continues.

SUMMARY...An isolated damaging wind/large hail threat continues
across mainly southern portions of WW 304. Downstream watch issuance
into western Lower MI is unlikely.

DISCUSSION...As of 2250Z, a small cluster of thunderstorms is moving
southeastward along an instability gradient across eastern Upper MI
and northeastern WI. This cluster has produced isolated damaging
wind gusts over the past few hours, and it should remain capable of
isolated strong to locally damaging winds and perhaps marginally
severe hail over the next several hours. VWP from KMQT shows a
veering/strengthening wind profile with height, and 30-35 of
effective bulk shear will continue to promote some storm
organization with the ongoing convective cluster. Farther to the
southwest (across central WI), mid-level flow is weaker per VWP from
KARX, and thunderstorms have remained less organized. An isolated
severe risk should continue across mainly the southern half of WW
304 as storms move southeastward. Downstream watch issuance into
western Lower MI appears unlikely owing to an increasingly hostile
thermodynamic environment with eastward extent.

..Gleason.. 06/03/2017
Dome, dome, dome..The life is a dome

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Re: Seguimiento general en EEUU

Mensajepor stormchaserAlberto » Dom Jun 04, 2017 4:49 pm

Nuevo día de riesgos marginales a leves en zonas del nordeste y noroeste de los Estados Unidos y al sur de Texas. No hay probabiliades de tornados, así que, el granizo y el viento, son las estrellas del día.
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Granizo.
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Discusión.
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Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0231 PM CDT Sun Jun 04 2017

Valid 042000Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
NORTHERN OH INTO WEST-CENTRAL PA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
EASTERN OR INTO WESTERN MT...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE GREAT
LAKES VICINITY...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE NORTHERN ROCKIES...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH
TX...

...SUMMARY...
Scattered strong to isolated severe thunderstorms with damaging
winds and hail are possible across portions of the Lower Great Lakes
region and vicinity, and across the northern Rockies and parts of
the Pacific Northwest, mainly this afternoon into the evening. A few
strong storms also could occur across parts of southern Texas.

...Great Lakes...
The marginal and slight risk areas have been trimmed further on the
east side to remove all of western NY and much of PA. Ongoing rain
and cloud cover has prevented stronger heating and destabilization
of the boundary layer and hence, any appreciable severe threat.
Additional modifications were made to the WI/MI portion of the
marginal risk area based on latest surface observations and hi-res
guidance. Isolated convection could still pose a gusty wind and
small hail threat into the evening across that area.

...Eastern Oregon to western Montana...

Only minor changes have been made on the northwest side of the
marginal risk area across parts of northern ID into far northwest MT
where cloud cover, showers and cool temperatures exist. Otherwise,
forecast remains unchanged from previous outlook.

...South Texas...

No changes have been made, ongoing forecast remains on track.

..Leitman.. 06/04/2017

.PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Jun 04 2017/

...Great Lakes...
Bands of showers and thunderstorms continue at midday from
northern/eastern OH into parts of PA/NY. Precipitation and related
cloud cover will tend to limit appreciable destabilization where
vertical shear is otherwise expected to be stronger across the lower
Great Lakes vicinity and Upper OH River Valley. Even so, a degree of
heating/destabilization in the wake of the early-day convection will
allow for the possibility of redevelopment later today near and
ahead of a southeastward-moving front. Isolated strong to severe
thunderstorms may develop at least as far west as north-central
portions of IL/IN within a regime of weak low/mid-tropospheric
winds. While effective shear magnitudes will generally only be 25-30
kt at most across IL/IN, moderate buoyancy and steep low-level lapse
rates could yield some pulse-type hail risk aside from
severe-caliber wind gusts through early evening. Any stronger
thunderstorms that develop across the region should gradually wane
in intensity this evening.

Farther north, a separate corridor of isolated strong/locally severe
thunderstorm development may occur this afternoon across parts of
WI/MI in close proximity to the upper vort max and near a weak
surface trough. While the boundary layer will tend to dry/mix during
the day, adequate moisture and buoyancy in the presence of
relatively steep lapse rates and moderate vertical shear could yield
a few storms capable of strong and gusty winds and/or marginally
severe hail this afternoon into early evening.

...Eastern Oregon to western Montana...
As the upper system advances inland, an increase in both upper level
winds and large-scale ascent is forecast to overspread the risk
area, concurrent with the slow eastward advance of a cold front.
Diurnal heating beneath cooling mid-level temperatures will support
modest high-based CAPE development, fueling development of afternoon
showers and scattered thunderstorms. Sufficient vertical shear will
exist for convective organization, while the rather deep mixed-layer
that will diurnally evolve should foster potential for locally
damaging winds with stronger storms. Marginally severe hail will
also be possible, particularly with any longer-lived updraft which
can acquire mid-level rotation. The severe risk may persist into
mid-evening, though gradually diminishing with time after sunset as
the boundary layer cools.

...South Texas...
A vort max will spread southward and somewhat weaken on the western
periphery of a weak/slow-moving upper low centered across north/east
TX. On the western periphery of a slow-moving MCS along the upper TX
coast into southern LA, relatively weak capping and residual
outflows/differential heating should contribute to the redevelopment
of at least isolated thunderstorms across South TX this afternoon.
Moderate buoyancy and adequate vertical shear, which is expected to
stronger with southward extent across Deep South TX, could allow for
isolated instances of hail/wind this afternoon into evening.

Próxima actualización: 01:00z.
------------------------------------------------------
Última discusión a mesoescala.
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Mesoscale Discussion 0945
NWS Storm Prediction Center Norman OK
0215 PM CDT Sun Jun 04 2017

Areas affected...Portions of North Carolina and far southern
Virginia

Concerning...Severe potential...Watch unlikely

Valid 041915Z - 042045Z

Probability of Watch Issuance...5 percent

SUMMARY...A few strong to briefly severe storms may be capable of
gusty downburst winds producing localized damage this afternoon.
However, a watch does not appear warranted.

DISCUSSION...Clusters of thunderstorms have developed this
afternoon, aided by a weak impulse along the northern periphery of
mid-level ridging. Regional VWP data depict relatively weak flow
within the lower/middle troposphere, with winds generally 15-20 kt
or less. As such, overall storm organization should remain quite
limited. However, a very warm/moist boundary layer, combined with
some residual dry mid-level air (observed in 12Z GSO/RNK soundings),
is fostering an environment capable of occasional strong downburst
winds. Mesoanalysis data indicate a corridor of upwards of 1000 J/kg
of DCAPE ahead of a cluster of storms over central NC; therefore,
localized damaging gusts appear possible through early evening. This
threat will be further enhanced if merging storms can develop
organized trailing precipitation regions, although this seems
somewhat uncertain with stronger anvil-layer flow present.
Regardless, despite the threat for a few damaging gusts,
disorganized storm structures will preclude the need for a watch.

..Picca/Guyer.. 06/04/2017
Dome, dome, dome..The life is a dome


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