El tiempo en NORTEAMÉRICA

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stormchaserAlberto
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Registrado: Jue Feb 20, 2014 2:34 am
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Re: Seguimiento general en EEUU

Mensaje por stormchaserAlberto »

El mismo sistema que provoco tiempo severo ayer entre Oklahoma y Texas, ya puso rumbo al este y va a afectar a zonas del sur de los Estados Unidos.
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% de tornado.
Spoiler
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% de vientos de hasta 50 kt o mayores a 25 millas de un punto.
Spoiler
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% de granizos de entre una o dos pulgadas de diametro a 25 millas de un punto.
Spoiler
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Discusion:
Spoiler
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 AM CDT Mon Mar 27 2017

Valid 271300Z - 281200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MID-SOUTH TO
CENTRAL KY/MIDDLE TN...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LOWER OH VALLEY TO
CENTRAL MS/AL...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS MIDDLE OH VALLEY
TO LOWER MS VALLEY...

...SUMMARY...
Scattered to numerous severe thunderstorms are expected across the
Lower Mississippi and Ohio Valleys into the Tennessee Valley this
afternoon and evening. Very large hail, damaging winds, and a couple
tornadoes will be possible.

...Synopsis...
A shortwave trough along the KS/MO border will move east to the
Cumberland Plateau by early Tuesday. Attendant surface cyclone will
track from the Ozark Plateau into the Middle OH Valley, weakening
late in the period. A cold front will shift east across the
Mid-South this afternoon with trailing portion stalling tonight over
the Lower MS Valley.

...Lower MS/OH and TN Valleys...
Two storm clusters are ongoing across southern IL/western KY and
separately over northwest AR. The 27/00Z WRF-NSSL and HRW-ARW appear
to have the best reflection of these clusters compared to other
CAMs. The eastern cluster should slow destabilization north of the
OH River today where surface dew points are predominately in the 40s
as of 12Z. Meanwhile, low-level moisture will continue to advect
northeast ahead of the northwest AR cluster into the Mid-South
within a broad 30-40 kt LLJ. This should result in a plume of lower
60s surface dew points nosing towards the MS/OH River confluence,
with middle 60s maintained across the Lower MS Valley. The
increasing moisture coupled with diurnal destabilization will likely
result in MLCAPE of 1000-2000 J/kg developing by mid afternoon.
Low-level WAA ahead of the AR cluster in conjunction with
convergence along the impinging cold front should serve as a focus
for increasing afternoon storm development.

With effective shear magnitudes of 35-45 kt, several supercells are
anticipated, especially with southern extent in the open warm
sector. Large hail, a couple tornadoes, and isolated damaging winds
are most probable with this activity centered on the Mid-South. Some
of the hail may be significantly severe owing to steep mid-level
lapse rates sampled by 12Z Jackson, Shreveport, and Little Rock
RAOBs. A few of these supercells will likely organize into one or
more east-moving line segments axis, with damaging winds becoming
the predominant hazard towards middle TN/central KY/northwest AL.

Farther south into central portions of MS/AL, weak 500-mb height
falls during the day coupled with heating and weakening convective
inhibition should result in at least isolated storms developing
within confluence bands in the absence of any well-defined boundary.
A risk for hail and wind damage should accompany the stronger
storms.

..Grams/Gleason.. 03/27/2017
Se actualiza de vuelta a las 16:30z.
Deberíamos de dejar de decirle aguanieve a cualquier llovizna :mrgreen:
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CORIMET
Mensajes: 2319
Registrado: Dom Jul 28, 2013 8:34 pm
Ubicación: Ramos Mejía/Villa Luzuriaga. Bs As, Argentina

Re: Seguimiento general en EEUU

Mensaje por CORIMET »

Cazatormentas terminaron a las piñas en una estación de gas. Esto habla de la competencia yankee por las tormentas y quién caza algo decente.. ¿Se acuerdan del enfrentamiento en Twister? Bueno, así lo tuvimos ayer! Los tuvo que parar la policía.. uno de los afectados fue Derek Smith.
Imagen
Villa Luzuriaga-Ramos Mejía [GBA OESTE]| Buenos Aires, Argentina
https://www.wunderground.com/dashboard/pws/ILAMAT12
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stormchaserAlberto
Mensajes: 9308
Registrado: Jue Feb 20, 2014 2:34 am
Ubicación: Río Tercero,Córdoba.

Re: Seguimiento general en EEUU

Mensaje por stormchaserAlberto »

Vengo un poco atrasado, asi que paso a dejarles los ultimos watches y mesoscale discussions.
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Spoiler
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 89
NWS Storm Prediction Center Norman OK
1205 PM CDT Mon Mar 27 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Eastern Arkansas
Western Kentucky
Missouri Bootheel
Northern Mississippi
Western Tennessee

* Effective this Monday afternoon and evening from 1205 PM until
800 PM 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 thunderstorms will continue to develop within an
increase moist and unstable air mass across the region. Mostly
linear bands of severe thunderstorms will spread east-northeastward
across northwest Tennessee into west-central Kentucky, while more
isolated storms are expected across northern Mississippi into
west-central Tennessee. Large hail and damaging winds can be
expected, and at least some tornado risk could gradually increase
through the afternoon.

The severe thunderstorm watch area is approximately along and 70
statute miles east and west of a line from 30 miles south southwest
of Oxford MS to 50 miles north northwest of Fort Campbell KY. 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.

&&

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 500. Mean storm motion vector
25030.

...Guyer
Imagen
Spoiler
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 90
NWS Storm Prediction Center Norman OK
155 PM CDT Mon Mar 27 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Northern and central Alabama
Far southeast Arkansas
Far northeast Louisiana
Central Mississippi

* Effective this Monday afternoon and evening from 155 PM until
900 PM 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 thunderstorms will continue to increase from
northeast Louisiana and central Mississippi into western and
northern Alabama. Steep lapse rates and moderate vertical shear will
support the potential for well-organized storms including supercells
capable of large hail, damaging winds and possibly a tornado (mainly
across northern Alabama).

The severe thunderstorm watch area is approximately along and 60
statute miles north and south of a line from 30 miles northeast of
Gadsden AL to 50 miles south southwest of Greenville MS. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU0).

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 89...

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 500. Mean storm motion vector
24030.

...Guyer
Imagen
Spoiler
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 91
NWS Storm Prediction Center Norman OK
225 PM CDT Mon Mar 27 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Far southern Indiana
Central Kentucky
Middle Tennessee

* Effective this Monday afternoon and evening from 225 PM until
1000 PM 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...Within a moderately moist and unstable environment,
multiple corridors of severe thunderstorms including some supercells
will continue to move east-northeastward across the region through
the late afternoon and evening hours.

The severe thunderstorm watch area is approximately along and 60
statute miles east and west of a line from 40 miles northeast of
Louisville KY to 80 miles south of Nashville TN. 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 89...WW 90...

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 500. Mean storm motion vector
24035.

...Guyer
Imagen
Spoiler
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 92
NWS Storm Prediction Center Norman OK
600 PM EDT Mon Mar 27 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
Northwestern Georgia
Eastern Kentucky
Eastern Tennessee
Extreme western Virginia

* Effective this Monday evening from 600 PM until 1100 PM EDT.

* Primary threats include...
Scattered damaging wind gusts to 70 mph possible
Isolated large hail events to 1 inch in diameter possible

SUMMARY...Clusters of strong/severe thunderstorms will spread
eastward from northern Alabama, middle Tennessee and central
Kentucky, and new storms will form over the next few hours across
eastern Tennessee/Kentucky. The strongest storms will be capable of
producing damaging winds and isolated large hail before convection
begins to weaken after sunset.

The severe thunderstorm watch area is approximately along and 40
statute miles east and west of a line from 55 miles north of Jackson
KY to 45 miles south of Chattanooga TN. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU2).

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 89...WW 90...WW 91...

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
24030.

...Thompson
Imagen
Spoiler
Mesoscale Discussion 0342
NWS Storm Prediction Center Norman OK
1126 AM CDT Mon Mar 27 2017

Areas affected...Northeast Arkansas...Far Southeast
Missouri...western and central Tennessee...southwestern and
south-central Kentucky

Concerning...Severe potential...Watch possible

Valid 271626Z - 271900Z

Probability of Watch Issuance...60 percent

SUMMARY...A severe threat appears likely to develop by early
afternoon across parts of the mid Mississippi Valley extending
eastward into south-central Kentucky and middle Tennessee. As cells
gradually intensify, wind damage and isolated large hail will be
possible. WW issuance will may be needed by 18Z across the region.

DISCUSSION...The latest surface analysis shows a surface low in
southwest Missouri with a cold front located southwestward from the
low. A warm front extends eastward from the surface low across
southern Illinois and west-central Kentucky. A line of thunderstorms
is ongoing in northeastern Arkansas located along a gradient of
low-level moisture oriented from west southwest to east northeast.
Moderate instability appears likely to develop along this corridor
over the next few hours. The line of storms is also located just
ahead of a shortwave trough on the southeast side of a pronounced
vorticity max. As the shortwave trough moves eastward, strong
large-scale ascent and continued surface heating will provide
support for a gradually increase in convective coverage.

In addition, the RAP is analyzing a mid-level jet from northwest
Mississippi extending northeastward into western Kentucky. This
feature is helping to create moderate deep-layer shear profiles with
0-6 km shear in the 35 to 40 kt range as evidenced by the Paducah
and Nashville WSR-88D VWPs. The wind shear environment should be
favorable for severe thunderstorm development with bowing line
segments and supercells both possible. The current thinking is that
the line of storms in northeast Arkansas will gradually expand in
length from north to south. The line should obtain a severe threat
by early afternoon as it moves across northwest Tennessee and
western Kentucky. Additional thunderstorms with a wind damage and
isolated large hail threat may develop ahead of the line from
northern Mississippi into western and middle Tennessee.

..Broyles.. 03/27/2017
Imagen
Spoiler
Mesoscale Discussion 0343
NWS Storm Prediction Center Norman OK
1212 PM CDT Mon Mar 27 2017

Areas affected...Northern/Central MS...Far northeast LA

Concerning...Severe potential...Watch possible

Valid 271712Z - 271915Z

Probability of Watch Issuance...40 percent

SUMMARY...Thunderstorm coverage is expected to increase over the
next several hours. Some severe is possible and trends will be
monitored for possible watch issuance.

DISCUSSION...Moisture continues to advect northward across the
region ahead of the approaching shortwave trough. Current surface
observations reveal low 60 dewpoints as far north as southern
portions of western TN with mid-60s dewpoints reaching into central
MS. 12Z sounding sampled steep mid-level lapse rates (i.e. 7.8 deg C
per km between 700-500 mb at JAN) advecting into the region. These
steep lapse rates atop gradually improving low-level moisture will
support at least moderate instability. Recent mesoanalysis already
suggests MLCAPE at or greater than 1500 J per kg for much of the
region. Modifying the 12Z JAN sounding with current conditions
validates the mesoanalysis estimates and also suggest little
convective inhibition remains. As such, thunderstorm coverage is
expected to increase as forcing for ascent provided by both
low-level confluence and shortwave trough increases.

Strong mid-level flow also exists across the region (i.e. 500 mb
flow around 40 to 50 kt), which will help organize any thunderstorms
that do develop. Given the steep lapse rates and strong mid-level
flow, the primary severe threat appears to be hail and damaging wind
gusts. The tornado threat will be mitigated somewhat by gradually
veering low-level flow and generally modest surface winds. However,
an isolated tornado threat may exist, particularly if storms
interact with any mesoscale boundaries and/or if locally backed
surface winds exist. Trends across the area will be monitored for
possible watch issuance later this afternoon.

..Mosier/Guyer.. 03/27/2017
Imagen
Spoiler
Mesoscale Discussion 0344
NWS Storm Prediction Center Norman OK
0149 PM CDT Mon Mar 27 2017

Areas affected...Central/Northern AL

Concerning...Severe potential...Watch likely

Valid 271849Z - 271945Z

Probability of Watch Issuance...80 percent

SUMMARY...Thunderstorm coverage will continue to increase across the
region, with some severe hail and damaging wind gusts possible. A
watch will be issued to cover the attendant severe threat.

DISCUSSION...Thunderstorms have quickly developed near BHM in an
area where cloudiness stunted boundary-layer mixing and dewpoints
have remained in the mid 60s. Based on recent VAD data, 1-2km flow
is a bit weaker here than areas farther west but 5-6 km flow remains
strong. Resulting bulk shear is favorable for organization within
the strongest updrafts, which, when coupled with the favorable
thermodynamic environment, will support the potential for some
severe hail. Damaging wind gusts are also possible. A tornado or two
cannot be completely ruled out given the somewhat backed surface
winds across portions of east-central and northeast AL but the
weakening 1-2 km winds should mitigate a higher tornado threat. A
watch will be issued across portions of the region to cover the
resulting severe threat.

..Mosier/Guyer.. 03/27/2017
Imagen
Spoiler
Mesoscale Discussion 0345
NWS Storm Prediction Center Norman OK
0158 PM CDT Mon Mar 27 2017

Areas affected...Middle Tennessee...Western and Central
Kentucky...Far Southern Indiana

Concerning...Severe potential...Watch likely

Valid 271858Z - 272100Z

Probability of Watch Issuance...80 percent

SUMMARY...A severe threat is likely to develop across west-central
Kentucky and middle Tennessee over the next couple of hours. Wind
damage and isolated large hail will accompany the stronger
thunderstorms as cells move northeastward out of WW 89. New WW
issuance is probable across parts of central Kentucky and middle
Tennessee by 20Z.

DISCUSSION...The latest radar imagery shows several clusters of
strong to severe thunderstorms ongoing from northern Mississippi
northward across western Tennessee into southwestern Kentucky. These
storm clusters are located along the leading edge of large-scale
ascent associated with a shortwave trough moving into the mid
Mississippi Valley. At the surface, a corridor of low-level moisture
is present across middle Tennessee extending northward into
west-central Kentucky where surface dewpoints are in the upper 50s
to near 60 F. Due to surface heating, moderate instability is now in
place over the southern two-thirds of the MCD area with MLCAPE
values estimated at 1000 to 1500 J/kg by the RAP. In addition to the
instability, moderate deep-layer shear is present with the Nashville
WSR-88D VWP showing 40 kt of 0-6 km shear and the Louisville WSR-88D
VWP up to almost 45 kt. This shear environment should support severe
storm development. Cells that remain discrete will have the
opportunity to become supercells and should be accompanied by large
hail and wind damage. A tornado or two will be possible with
supercells especially across middle Tennessee where more instability
is present and low-level shear is adequate for low-level storm
rotation. Cell clusters that can organize into short line-segments
should be favored for a wind damage threat but hail could also occur
with the more intense parts of the line.

..Broyles.. 03/27/2017
Imagen
Spoiler
Mesoscale Discussion 0346
NWS Storm Prediction Center Norman OK
0333 PM CDT Mon Mar 27 2017

Areas affected...Far northeast LA...central MS...northern/central
AL...far northwest GA...far southeast TN

Concerning...Severe Thunderstorm Watch 90...

Valid 272033Z - 272200Z

The severe weather threat for Severe Thunderstorm Watch 90
continues.

SUMMARY...Threat for hail and damaging winds is expected to persist
for the next several hours across WW 90.

DISCUSSION...Numerous thunderstorms are ongoing in a corridor from
far northeast LA northeastward into far northwest GA. The overall
environment in this region is characterized by modest low-level
moisture (i.e. dewpoints in mid 50s to low 60s) and moderate shear
(effective bulk shear around 40 kt). Thunderstorm activity across
northeast AL/northwest GA continues to move northeastward/northward
towards southeast TN where cloudiness inhibited heating a bit and
temperatures are still in the mid 70s. Less favorable mid-level
lapse rates and low-level moisture also exist here, suggesting the
ongoing activity will gradually weaken. Although some isolated
severe will still be possible, current thinking is that a watch will
not be needed across this region as a result of this activity.
However, there is a chance the more organized line across middle TN
reaches this area with some increasing severe threat possible as a
result.

Farther southwest (across far northeast LA and central MS), strong
to severe multicells with a few supercells will continue to move
northeastward. Primary severe threat with this activity continues to
be hail, although damaging wind gusts are also possible. Tornado
threat remains low, owing primarily to the veered surface winds and
weakening low-level flow.

..Mosier.. 03/27/2017
Imagen
Spoiler
Mesoscale Discussion 0347
NWS Storm Prediction Center Norman OK
0339 PM CDT Mon Mar 27 2017

Areas affected...Northeast Arkansas...Northern Mississippi...Western
Tennessee...Western Kentucky

Concerning...Severe Thunderstorm Watch 89...

Valid 272039Z - 272245Z

The severe weather threat for Severe Thunderstorm Watch 89
continues.

SUMMARY...The severe threat across WW 89 is expected to continue
into the early evening. Wind damage and isolated large hail will be
the primary threats with the stronger thunderstorms.

DISCUSSION...The latest surface analysis shows a 1008 mb surface low
over far southwestern Kentucky with a cold front extending
southwestward across northeast Arkansas. Thunderstorms have
developed along the front and further east along a corridor of
low-level moisture extending north northeastward across western
Tennessee. Surface dewpoints in western Tennessee are in the lower
60s F which is contributing to moderate instability with MLCAPE
values estimated in the 1000 to 1500 J/kg range. In addition to the
instability, strong large-scale ascent will provide support for
continued convective development across WW 89 late this afternoon
into this evening. Moderate deep-layer shear profiles and steep
lapse rates will be favorable for storm rotation and isolated large
hail within the strongest cores. Wind damage will also be possible
with short line segments along the front and further to the east
across the warm sector. Cells may eventually consolidate into a
cluster, moving eastward across west-central Tennessee and perhaps
far northeastern Mississippi.

..Broyles.. 03/27/2017
Imagen
Spoiler
Mesoscale Discussion 0348
NWS Storm Prediction Center Norman OK
0443 PM CDT Mon Mar 27 2017

Areas affected...Central/eastern KY...Middle/eastern TN...Far
northern AL...Far northeast GA

Concerning...Severe Thunderstorm Watch 91...

Valid 272143Z - 272315Z

The severe weather threat for Severe Thunderstorm Watch 91
continues.

SUMMARY...Threat for damaging wind gusts and hail will persist
across central and eastern portions of WW 91 for the next few hours.
Trends will also be monitored for downstream watch issuance across
eastern KY/TN and far northwest GA.

DISCUSSION...Convective line stretching from near HNB (in far
southern IN) southward across central KY and middle TN and into
northwest AL is expected to continue moving eastward/northeastward
over the next few hours. The downstream airmass is generally cooler
and has less low-level moisture and, as a result, less overall
instability. However, the line is well-organized and the bulk shear
is expected to remain relatively constant for the next several
hours. Some increase in the low-level flow is possible around 00Z.
Near-severe gusts have been measured at several sites as the line
moved through, most recently at MQY in middle TN, which measured a
gust of 42 kt. The ongoing severe threat will persist across WW 91
for the next few hours, with some threat possible downstream in
eastern KY/TN and far northwest GA. Additionally, the cluster of
storms well ahead of the line in eastern KY could pose an isolated
hail and damaging wind threat. Trends will be monitored for possible
watch issuance in these areas downstream from the current watch.

..Mosier.. 03/27/2017
Deberíamos de dejar de decirle aguanieve a cualquier llovizna :mrgreen:
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stormchaserAlberto
Mensajes: 9308
Registrado: Jue Feb 20, 2014 2:34 am
Ubicación: Río Tercero,Córdoba.

Re: Seguimiento general en EEUU

Mensaje por stormchaserAlberto »

Imagen
Spoiler
Mesoscale Discussion 0349
NWS Storm Prediction Center Norman OK
0559 PM CDT Mon Mar 27 2017

Areas affected...Parts of western/middle Tennessee and adjacent
areas

Concerning...Severe Thunderstorm Watch 89...91...

Valid 272259Z - 280030Z

The severe weather threat for Severe Thunderstorm Watch 89, 91
continues.

SUMMARY...The risk mainly for severe hail and strong surface gusts
is expected to continue with storms overspreading middle Tennessee
into/through the 7-10 pm CDT time frame.

DISCUSSION...In the wake of generally weakening, loosely organized
convective development now spreading toward the central/southern
Appalachians, an area of enhanced low-level warm advection is
maintaining vigorous thunderstorm activity near/east of the
Interstate 40 corridor of western into middle Tennessee. Forcing
associated with the remnants of a compact mid-level closed low
likely is augmenting ascent and associated convection, which is
expected to continue to spread eastward across middle Tennessee
into/through the 00-03Z time frame.

Inflow of relatively moist low-level air into the vicinity of this
activity, beneath a lingering area of steep mid-level lapse rates is
probably contributing to moderately large CAPE. This may be mostly
based above a relatively stable surface-based air mass, but, in the
presence of strong vertical shear, supercells will remain possible,
with upscale growth into a small organizing convective system
possible through mid/late evening. While an additional isolated
tornado may not be out of the question, the risk for severe hail and
strong surface gusts seems more prominent.

..Kerr.. 03/27/2017
Deberíamos de dejar de decirle aguanieve a cualquier llovizna :mrgreen:
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jotape
Mensajes: 2803
Registrado: Jue Ene 10, 2013 12:59 am
Ubicación: Bernal, Buenos Aires

Re: Seguimiento general en EEUU

Mensaje por jotape »

Che... en los próximos premios Gustfront hay que nominar a Alberto para esta categoría eh! Linda seguidilla de días con riesgo severo hay...
ImagenImagenImagen
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Lucas de Zárate
Mensajes: 7589
Registrado: Lun Jul 13, 2009 8:38 pm
Ubicación: Zárate, Bs As

Re: Seguimiento general en EEUU

Mensaje por Lucas de Zárate »

Cuantos mapas!! Fotos y videos ni ahi no?
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stormchaserAlberto
Mensajes: 9308
Registrado: Jue Feb 20, 2014 2:34 am
Ubicación: Río Tercero,Córdoba.

Re: Seguimiento general en EEUU

Mensaje por stormchaserAlberto »

Otro riesgo moderado.
Imagen
% de tornados.
Spoiler
Imagen
% de vientos.
Spoiler
Imagen
% de granizo.
Spoiler
Imagen
Discusion:
Spoiler
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0754 AM CDT Tue Mar 28 2017

Valid 281300Z - 291200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS NORTHWEST TX AND
FAR SOUTHWEST OK...

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTRAL OK TO
THE EDWARDS PLATEAU...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF OK/TX...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF
SOUTHERN GREAT PLAINS...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS VA/NC...

...SUMMARY...
Numerous severe storms are expected across the southern Great
Plains, mainly after 2 pm CDT into tonight. Very large hail,
tornadoes, and damaging winds will be possible.

...Synopsis...
Vigorous shortwave trough over eastern AZ will shift east and reach
the southern High Plains by early Wednesday. Surface cyclone over
the Permian Basin will move northeast into northwest TX and become
quasi-stationary. By late afternoon, a bulging dryline will sharpen
to the south of this cyclone. A Pacific cold front will overtake the
dryline in west Texas this evening and sweep east into central Texas
overnight. A warm front will advance across northern TX and should
arc from the cyclone across the Red River into eastern OK by 00Z.

...Southern Great Plains...
Rich gulf moisture characterized by mean mixing ratios to 14 g/kg
per 12Z Del Rio, Corpus Christi, and Lake Charles RAOBs has become
prevalent in the broadening warm sector over central/south TX. While
diurnal mixing may yield pockets of lower dew points over
central/east TX, a plume of lower to middle 60s surface dew points
will be sustained along the dryline and warm front. Beneath a stout
EML with very steep lapse rates to 9 degree C/km from 700-500 mb per
12Z Del Rio RAOB, moderate to large buoyancy is expected ahead of
the dryline. MLCAPE should reach 1500-3000 J/kg across the Edwards
Plateau and Big Country. The leading edge of 50-kt 500-mb
south-southwesterlies will spread east over this instability axis by
late afternoon, yielding an environment favorable for supercells.

While elevated storms will increase over the Texas Panhandle through
midday, surface-based storms should develop towards mid-afternoon
near the surface cyclone. Scattered storms will form farther south
along the dryline late afternoon, with WAA-driven storms possible
farther east over north-central TX. Initially discrete supercell
mode should favor very large hail and localized severe wind gusts.
Relatively high confidence in the coverage and location of storms
warrants an upgrade to a hail-driven moderate risk from the Big
Country into southwest OK. A few tornadic storms appear probable in
this similar corridor. However, the temporal overlap of discrete
cells with enlarging hodographs may be relatively short in the open
warm sector. Low-level hodographs will be quite enlarged along the
warm front, but should be coincident with modest low-level lapse
rates and predominant cluster to linear mode. As such, an upgrade to
15 percent tornado probabilities does not appeared warranted this
outlook.

As storms mature, upscale growth into lines with embedded bowing
segments is expected due to both the strong large-scale ascent and
meridional flow aloft generally paralleling the dryline. These
linear bands should accelerate northeast into southern/central
Oklahoma during the evening, with attendant risks for damaging
winds, hail, and a couple tornadoes.

Farther south over the Edwards Plateau, initially isolated to widely
scattered late afternoon/early evening storms should become
widespread in coverage during mid-late evening as the Pacific front
merges with the dryline. This should result in a predominant risk of
large hail transitioning quickly to strong to severe wind gusts. An
extensive squall line will likely evolve east overnight with an
isolated severe risk spreading into central TX.

...VA/NC...
A dampening shortwave impulse over WV will shift off the VA/NC coast
by mid-evening. Ongoing showers and isolated storms will subdue
destabilization early in the diurnal heating cycle. However, by late
afternoon, widely scattered storms should develop ahead of the
impulse. Increased veering of the wind profile with height should
foster mainly discrete cells, some of which should weakly rotate.
Isolated severe hail and damaging wind appear possible.

..Grams/Dial.. 03/28/2017
Se actualiza a las 16:30z.
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stormchaserAlberto
Mensajes: 9308
Registrado: Jue Feb 20, 2014 2:34 am
Ubicación: Río Tercero,Córdoba.

Re: Seguimiento general en EEUU

Mensaje por stormchaserAlberto »

Nuevamente, me quede atras en los mesoscale discussions y en los watches, asi que los voy a ir dejando 1 por 1.
Imagen
Spoiler
Mesoscale Discussion 0350
NWS Storm Prediction Center Norman OK
0930 AM CDT Tue Mar 28 2017

Areas affected...Texas Panhandle...West Texas

Concerning...Severe potential...Watch unlikely

Valid 281430Z - 281700Z

Probability of Watch Issuance...20 percent

SUMMARY...A threat for hail will continue this morning as storms
develop across the Texas Panhandle southward into west Texas. The
storms across this area will remain elevated and WW issuance is not
expected.

DISCUSSION...The latest radar imagery shows several elevated
thunderstorms oriented from south to north across the western Texas
Panhandle. These storms are located along the western edge of the
stronger low-level flow and along the eastern edge of a band of
large-scale ascent associated with an upper-level low in the Four
Corners region. As moisture advection continues across the Texas
Panhandle and large-scale ascent increases from the west,
thunderstorm coverage should gradually expand over the next few
hours. The convection is developing in a moderately unstable
environment with forecast soundings showing MUCAPE in the 1500 to
2500 J/kg range. Most of the instability is located above 700 mb
where winds are generally from south to south southwest. Some speed
shear is evident from 700 to 500 mb which along with steep mid-level
lapse rates will support a marginal hail threat. The hail threat
should continue in the western Texas Panhandle but should gradually
expand eastward over the next 2 to 3 hours as new cells initiate and
move northward across the central and eastern Texas Panhandle. Other
elevated thunderstorms may also develop southward across west Texas.

..Broyles/Guyer.. 03/28/2017
Imagen
Spoiler
Mesoscale Discussion 0351
NWS Storm Prediction Center Norman OK
1223 PM CDT Tue Mar 28 2017

Areas affected...West Texas

Concerning...Severe potential...Watch likely

Valid 281723Z - 281830Z

Probability of Watch Issuance...80 percent

SUMMARY...A severe threat will continue to develop across west Texas
over the next hour. Isolated large hail and wind damage will be the
primary threats. WW issuance will likely be needed by 18Z.

DISCUSSION...The latest surface analysis shows 1001 mb low over far
southeastern New Mexico with a corridor of low-level moisture
extending northward across west-central Texas to near the vicinity
of Lubbock. Surface dewpoints along this corridor are in the upper
50s and lower 60s F and the RAP is analyzing moderate instability
with MLCAPE values from 1000 to 2000 J/kg. In addition, water vapor
imagery shows a band of strong large-scale ascent associated with an
upper-level low in the Desert Southwest. This band of ascent will
move across west Texas over the next few hours providing support for
strong to severe thunderstorm development. The instability combined
with strong deep-layer shear with 0-6 km shear near 55 kt on the
Lubbock WSR-88D-VWP will be favorable for storm rotation with
isolated large hail and possibly supercell development. The latest
HRRR develops a band of surface-based storms near Lubbock and moves
this convection northward eventually reaching the southern Texas
Panhandle later this afternoon. This is the corridor where WW
issuance is likely.

..Broyles/Guyer.. 03/28/2017
Imagen
Spoiler
Mesoscale Discussion 0352
NWS Storm Prediction Center Norman OK
1258 PM CDT Tue Mar 28 2017

Areas affected...Central and eastern Virginia and North Carolina

Concerning...Severe potential...Watch unlikely

Valid 281758Z - 282030Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated strong to marginally severe storms capable of
hail are possible this afternoon mainly across southeast Virginia
into eastern North Carolina.

DISCUSSION...Surface heating beneath cool midlevel temperatures in
association with a shortwave trough has led to around 1000 J/kg
MUCAPE across central VA and NC. Visible satellite imagery shows
widespread cumulus development, with a few weak thunderstorms over
western VA aided by the higher terrain. Farther east, a relative
cool pockets was noted over eastern NC due to ongoing showers,
however, these will eventually move offshore with warmer air
returning from the west.

With time, further heating will erode any remaining CIN, allowing at
least isolated thunderstorms to form across the entire area. Little
focus exists given a broad/weak surface low, however, the best area
may be over southeastern VA and central to northeastern NC in a few
hours, as the instability axis shifts into that area, and where
low-level convergence will exist for a longer duration as winds
generally veer with time, from west to east. A cell or two could
exhibit supercell characteristics at times, but the main threat
should be hail as winds in the low-levels will be weak.

..Jewell/Guyer.. 03/28/2017
Imagen
Spoiler
Mesoscale Discussion 0353
NWS Storm Prediction Center Norman OK
0125 PM CDT Tue Mar 28 2017

Areas affected...Pecos River Valley

Concerning...Severe potential...Watch likely

Valid 281825Z - 282000Z

Probability of Watch Issuance...80 percent

SUMMARY...A severe threat is expected to develop this afternoon
across the Pecos River Valley. Isolated large hail and a few
damaging wind gusts will be possible as cells initiate and increase
in intensity mainly after 19Z. WW issuance may be needed.

DISCUSSION...The latest surface analysis shows a 1001 mb low over
far southeast New Mexico with a dryline located just to the
southeast of the low from near Midland/Odessa southward to the
Mexican border. Surface dewpoints to the east of the dryline are in
the lower to mid 60s F and the RAP is analyzing moderate instability
with MLCAPE estimated from 2000 to 2500 J/kg. As surface heating
continues this afternoon and as a band of large-scale ascent moves
in from the west (evident on water vapor imagery), convective
initiation should continue to take place along the dryline through
early to mid afternoon.

In addition to the instability, regional WSR-88D VWPs have strong
deep-layer shear profiles with directional shear in the lowest 2 km
and ample speed shear above that. This combined with steep mid-level
lapse rates should support supercell development accompanied with
isolated large hail. A few damaging wind gusts will also be
possible. Convective development may eventually take place in the
vicinity of San Angelo later this afternoon with a convective
cluster moving north northeastward into the southern section of the
Low Rolling Plains.

..Broyles/Guyer.. 03/28/2017
Imagen
Spoiler
Mesoscale Discussion 0354
NWS Storm Prediction Center Norman OK
0150 PM CDT Tue Mar 28 2017

Areas affected...Eastern New Mexico

Concerning...Severe potential...Watch unlikely

Valid 281850Z - 282115Z

Probability of Watch Issuance...20 percent

SUMMARY...An isolated severe threat may develop across eastern New
Mexico this afternoon. A threat for hail and a few strong wind gusts
will be possible. WW issuance is not expected due to the marginal
nature of the threat.

DISCUSSION...The latest surface analysis shows a 1000 mb low in far
southeastern New Mexico with an inverted surface trough extending
north northwestward across eastern New Mexico. Thunderstorms are
developing in the vicinity of Santa Rosa, New Mexico just to the
west of the surface trough where low-level convergence appears to be
maximized. This combined with strong large-scale ascent downstream
from an upper-level low in the Desert Southwest will help storm
coverage to increase across eastern New Mexico this afternoon. The
environment is characterized by strong deep-layer shear (evident on
the Tucumcari WSR-88D VWP), steep lapse rates and enough instability
for a marginal severe threat. Hail and isolated damaging wind gusts
will be possible with the stronger cores over the next two to three
hours. Instability appears weak enough to keep the threat marginal.
For that reason, WW issuance will probably not be needed.

..Broyles.. 03/28/2017
Imagen
Spoiler
Mesoscale Discussion 0355
NWS Storm Prediction Center Norman OK
0244 PM CDT Tue Mar 28 2017

Areas affected...Northwest Texas into southwest Oklahoma

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

Valid 281944Z - 282215Z

Probability of Watch Issuance...95 percent

SUMMARY...Ongoing severe thunderstorms as well as new development
are expected to spread across much of northwestern Texas and into
southwestern Oklahoma through evening, with a threat of tornadoes,
wind and hail. A new tornado watch is likely.

DISCUSSION...A broken line of supercells currently extends from just
east of Lubbock toward Midland along a dryline. To the east into the
Abilene area, visible satellite shows deepening boundary layer
cumulus where heating is occurring. Just to the north, stable billow
clouds were noted which also corresponds to an area of
backed/easterly surface winds.

Models continue to suggest a large cluster of cells developing ahead
of the western line of storms by about 21Z. These cells would then
spread northeastward.

All modes of severe appear possible in this situation. Cellular
activity may become supercellular with a tornado threat as the
boundary layer shear will be increasing this evening. However,
magnitude of storm interaction is unknown at this time, which could
have a negative impact on tornado potential. Even so, a merging
cluster could still result in one or more severe bows containing
damaging wind and hail.

..Jewell/Guyer.. 03/28/2017
Imagen
Spoiler
Mesoscale Discussion 0356
NWS Storm Prediction Center Norman OK
0244 PM CDT Tue Mar 28 2017

Areas affected...Northwest Texas...Eastern Texas Panhandle...Western
Oklahoma

Concerning...Severe Thunderstorm Watch 93...

Valid 281944Z - 282145Z

The severe weather threat for Severe Thunderstorm Watch 93
continues.

SUMMARY...The severe threat located across the central part of WW 93
is expected to continue late this afternoon and should spread
eastward across the remainder of the Texas Panhandle. A threat for
large hail and wind damage will exist with the stronger
thunderstorms with the threat affecting western Oklahoma later this
afternoon. A potential for tornadoes may also develop in the
southeastern part of WW 93. WW issuance may be needed across parts
of western Oklahoma by 21Z.

DISCUSSION...The latest radar imagery shows a line of strong
thunderstorms extending from south to north across the central Texas
Panhandle with another line to the east of Lubbock. This activity is
located along the western edge of a 30 to 45 kt low-level jet which
has increased in strength over the last few hours. This combined
with lift associated with a band of large-scale ascent moving
eastward across the southern high Plains should aide a gradual ramp
up in storm intensity late this afternoon. The environment ahead of
this convection is characterized by moderate instability, steep
mid-level lapse rates and strong deep-layer shear (as evidenced on
several regional WSR-88D VWPs). This should support supercell
development especially across the southeastern part of WW 93 near a
warm front in the vicinity of Childress and southeastward across
northwest Texas. As cells interact with the warm front later this
afternoon, a tornado threat and potential for isolated very large
hail will also be possible. This threat may extend eastward into
parts of far southwestern Oklahoma along the Red River. Further
north across much of west-central and northwestern Oklahoma, the
storms should remain elevated but isolated large hail and a few
damaging wind gusts will be possible.

..Broyles.. 03/28/2017
Imagen
Spoiler
Mesoscale Discussion 0357
NWS Storm Prediction Center Norman OK
0531 PM CDT Tue Mar 28 2017

Areas affected...Parts of nwrn Texas and adjacent southwestern
Oklahoma

Concerning...Tornado Watch 95...

Valid 282231Z - 290000Z

The severe weather threat for Tornado Watch 95 continues.

SUMMARY...The risk for potentially damaging surface gusts appears
likely to increase in association with an evolving mesoscale
convective system by 7-9 pm CDT. Tornado potential will probably
maximize in this time frame as well, mainly in the isolated discrete
supercells.

DISCUSSION...Vigorous convective development appears to be in the
process of consolidation/growing upscale between Childress and
Abilene, aided by forcing for ascent associated with modest
low/mid-level warm advection beneath difluent/divergent upper flow.
Additional discrete storm development continues to the south and
east of this activity, near and southwest of Abilene, in the
presence of a moist, weakly capped boundary layer that appears
characterized by CAPE up to 2000 J/kg.

Low-level hodographs still appear somewhat modest in size, but are
expected to substantively enlarge between now and 00-02Z, with
southerly 850 mb flow forecast to strengthen in excess of 50 kt. As
this occurs, and the evolving convective system and nearby
supercells tend to develop north/northeastward, the risk for strong
surface gusts is expected to increase across parts of northwest
texas into southwestern Oklahoma.

Despite some weakness in the high-level flow/length of deep layer
hodographs, the environment still appears conducive to the risk for
tornadoes. This probably will remain most prominent with the
discrete supercells, and the threat may maximize in the 00-02Z time
frame, within areas near/between Wichita Falls and Mineral Wells Tx.

..Kerr.. 03/28/2017
Imagen
Spoiler
Mesoscale Discussion 0358
NWS Storm Prediction Center Norman OK
0604 PM CDT Tue Mar 28 2017

Areas affected...Portions of central TX to the Edwards Plateau

Concerning...Severe potential...Watch possible

Valid 282304Z - 290100Z

Probability of Watch Issuance...40 percent

SUMMARY...Significant severe potential will exist with an evolving
supercell west-northwest of the Del Rio area. Otherwise, areas
across the Edwards Plateau to central TX are being monitored for
possible Watch issuance.

DISCUSSION...Low-level inflow and a midlevel mesocyclone continue to
intensify with a supercell storm around 55-60 nautical miles
west-northwest of the DFX RDA. This cell has remained anchored to a
subtle northeast-southwest-oriented boundary representing
differential mixing (moister air and shallower boundary layer to the
east). As the midlevel mesocyclone continues to organize and the
cell advances east-northeast, it will encounter surface dewpoints in
the upper 60s supporting MLCAPE around 2000-2500 J/kg per the DRT
21Z sounding. With around 50 kt of effective shear, and backed
surface winds enhancing low-level SRH and inflow, the risk for
significantly severe hail will exist as the cell eventually advances
east of the Rio Grande River in the next hour or so. While low-level
hodographs are relatively small, the backed surface winds and some
increase in low-level shear related to an approaching midlevel wave,
could support some uptick in the tornado potential.

Otherwise, weak convection is beginning to develop along subtle
north-south confluence axes northeastward across central TX. This
activity lies within the open warm sector, where adequately moist
boundary layer conditions and related low LFCs may support continued
deepening of convection. This may especially be the case later this
evening as stronger deep ascent approaches the area. While it is
unclear whether more robust convection were to evolve from this zone
of weak warm advection, there will be conditional severe potential.
Severe hail/wind would be the primary concerns with potential
supercell clusters in the moderately sheared environment, though the
strengthening low-level mass response could foster some increase in
tornado potential into the evening hours with more discrete
convection.

..Cohen/Thompson.. 03/28/2017
Imagen
Spoiler
Mesoscale Discussion 0359
NWS Storm Prediction Center Norman OK
0630 PM CDT Tue Mar 28 2017

Areas affected...Portions of southwest TX

Concerning...Severe Thunderstorm Watch 94...

Valid 282330Z - 290100Z

The severe weather threat for Severe Thunderstorm Watch 94
continues.

SUMMARY...The risk for severe storms continues across Watch 94.

DISCUSSION...The leading edge of strong ascent (marked by a shield
of midlevel clouds from high-based convection over the Trans-Pecos
region) will continue overtaking the western extent of Gulf moisture
within the next few hours. A line of strong to severe storms will
likely develop from parts of the Permian Basin vicinity to the Rio
Grande River vicinity, along a Pacific front overtaking a dryline
analyzed from Howard County to Brewster Country. East of the
dryline, moderate to strong instability amid 40-60 kt of effective
shear will support robust updrafts capable of severe winds and large
hail. Sufficient line-orthogonal low-level shear -- intensifying
into the evening hours -- may support line-embedded meso-vortices
yielding pockets of enhanced wind damage. A few supercell storms may
evolve ahead of the developing line across eastern parts of the
Permian Basin, capable of severe hail and wind.

..Cohen.. 03/28/2017
Imagen
Spoiler
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 93
NWS Storm Prediction Center Norman OK
1250 PM CDT Tue Mar 28 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
West and northwest Texas

* Effective this Tuesday afternoon and evening from 1250 PM until
900 PM CDT.

* Primary threats include...
Scattered large hail likely with isolated very large hail events
to 2.5 inches in diameter possible
A tornado or two possible

SUMMARY...Storms will continue to increase and steadily spread
north-northeastward across the Texas South Plains and Texas
Panhandle this afternoon. Large hail will be the primary risk,
especially northward into the Texas Panhandle where storms will be
increasingly elevated. An increasing surface-based severe risk later
this afternoon may result in an increasing tornado risk across parts
of the region including the Texas South Plains and Low Rolling
Plains, such that a new/replacement Tornado Watch would be needed
across these areas.

The severe thunderstorm watch area is approximately along and 70
statute miles east and west of a line from 55 miles north of Borger
TX to 55 miles south southeast of Lubbock TX. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU3).

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
2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
20030.

...Guyer
Imagen
Spoiler
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 94
NWS Storm Prediction Center Norman OK
150 PM CDT Tue Mar 28 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of
West-central and southwest Texas

* Effective this Tuesday afternoon and evening from 150 PM until
1000 PM CDT.

* Primary threats include...
Scattered large hail likely with isolated very large hail events
to 3.5 inches in diameter possible

SUMMARY...As the air mass continues to strongly destabilize this
afternoon, strong shear will support increasing potential for
supercells near and just east of the dryline across
west-central/southwest Texas. Very large hail is the main risk. The
number of storms should increase across the region later this
evening with a more widespread severe hail and wind threat evolving,
even beyond the currently scheduled Watch expiration time.

The severe thunderstorm watch area is approximately along and 60
statute miles east and west of a line from 60 miles northwest of
Abilene TX to 55 miles east southeast of Dryden 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 93...

AVIATION...A few severe thunderstorms with hail surface and aloft to
3.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
24030.

...Guyer
Imagen
Spoiler
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 95
NWS Storm Prediction Center Norman OK
335 PM CDT Tue Mar 28 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of
Southwest and south-central Oklahoma
western North Texas

* Effective this Tuesday afternoon and evening from 335 PM until
1100 PM CDT.

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

SUMMARY...As a warm front continues to spread northward and
low-level moisture continues to increase, the potential for
tornadoes should increase in addition to increasing risks for large
hail and damaging winds across western North Texas into southwest
and eventually south-central Oklahoma. These will be initially via
semi-discrete supercells, with a more linear mode and widespread
damaging wind risk later this evening.

The tornado watch area is approximately along and 80 statute miles
east and west of a line from 30 miles north northwest of Fort Sill
OK to 35 miles west of Brownwood TX. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU5).

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 93...WW 94...

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 500. Mean
storm motion vector 21030.

...Guyer
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stormchaserAlberto
Mensajes: 9308
Registrado: Jue Feb 20, 2014 2:34 am
Ubicación: Río Tercero,Córdoba.

Re: Seguimiento general en EEUU

Mensaje por stormchaserAlberto »

Imagen
Spoiler
Mesoscale Discussion 0360
NWS Storm Prediction Center Norman OK
0745 PM CDT Tue Mar 28 2017

Areas affected...Portions of the TX Panhandle/South Plains

Concerning...Severe Thunderstorm Watch 93...

Valid 290045Z - 290145Z

The severe weather threat for Severe Thunderstorm Watch 93
continues.

SUMMARY...While an isolated marginal severe risk continues across
remaining-valid portions of Watch 93, additional Watch issuance is
unlikely.

DISCUSSION...Convection has intensified along an eastward-advancing
Pacific cold front; which has merged with a southwestward-moving,
convectively reinforced boundary -- across southwestern parts of the
TX Panhandle and the western TX South Plains. Steep midlevel lapse
rates sampled by NM/west TX 00Z soundings suggest that a few robust
convective cores will be possible during the next few hours.
However, inflow for this activity will remain rooted above the
stable surface layer, while elevated CAPE layers erode owing to the
influx of cooler low-level air from the north/northeast. As a
result, convection may weaken as it advances farther east,
particularly while exhibiting a cluster-type mode (as opposed to
discrete supercells). While a few instances of small to marginally
severe hail may occur -- aided by 45-60 kt of effective shear --
additional Watch issuance is unlikely.

..Cohen.. 03/29/2017
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stormchaserAlberto
Mensajes: 9308
Registrado: Jue Feb 20, 2014 2:34 am
Ubicación: Río Tercero,Córdoba.

Re: Seguimiento general en EEUU

Mensaje por stormchaserAlberto »

Imagen
Spoiler
Mesoscale Discussion 0361
NWS Storm Prediction Center Norman OK
0758 PM CDT Tue Mar 28 2017

Areas affected...Parts of western and central Oklahoma

Concerning...Severe potential...Watch possible

Valid 290058Z - 290230Z

Probability of Watch Issuance...40 percent

SUMMARY...It is not clear that an additional severe weather watch is
needed north and east of tornado watch 95, at least in the near
term. However, there probably is at least some risk for occasional
surface gusts at least approaching severe limits with convection
overspreading the region this evening.

DISCUSSION...Lead area of large-scale forcing for ascent, primarily
associated with low/mid-level warm advection beneath divergent upper
flow, appears likely to continue overspreading much of western and
central Oklahoma through 03-06Z, before weakening. As it does, an
evolving cluster of storms will follow suit, with strongest activity
expected to spread across/east of the Interstate-44 corridor,
through at least portions of the Oklahoma City metropolitan area.

North of the Red River, surface dew points continue to slowly
increase on easterly low-level flow, but boundary layer based
instability remains generally weak, and instability based within
higher moisture content above the boundary layer remains relatively
modest (based on 00Z OKC sounding). Even with heavy precipitation
loading contributing to downward momentum transfer (in the presence
of 40+ kt southwesterly mean environmental flow) the potential for
surface gusts in excess of 50 kt remains unclear.

..Kerr/Kerr.. 03/29/2017
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