U.S. Severe Weather Forecast (Previsión convectiva)

día tres

acus01 kwns 250532 
Storm Prediction Center ac 250531 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1131 PM CST Sat Feb 24 2018 

Valid 251200z - 261200z 

..there is a marginal risk of severe thunderstorms across parts of 
the central Gulf Coast Sunday night... 

General thunderstorms are expected mainly from Texas eastward along 
the central Gulf Coast on Sunday. A few storms may be capable of 
localized wind damage or a brief/weak tornado, mainly across 
southern Louisiana into the far western Florida Panhandle overnight. 

An intense, negatively tilted shortwave trough will move from the 
Midwest across the Great Lakes during the day, with strong 
southwesterly flow aloft remaining over much of the eastern half of 
the Continental U.S.. a secondary, lower-amplitude wave will move from The Four 
Corners to the plains during the day, and across the Ohio Valley 
overnight. At the surface, low pressure will continue northward from 
Lake Superior across Ontario. An occluding front will extend south 
into New York and PA, with a cold front roughly from the Appalachians to 
the central Gulf and southeast Texas during the afternoon. 

Upper 60s f dewpoints will exist ahead of the Gulf of Mexico portion 
of the front, which will continue a southward drift for much of the 
day. As the secondary wave moves into the plains, southerly 
low-level flow will increase, allowing for warm/moist advection and 
a retreat of the front from southern la into the western Florida 

Elsewhere, showers and perhaps a few weak thunderstorms are expected 
across Alabama into Georgia during the day, but there will be little to 
support severe or organized storms. 

..central Gulf Coast region... 
While a few showers and storms are expected along the 
southward-moving cold front early in the day, these are not expected 
to be severe. Additional elevated showers and storms are expected 
over much of eastern Texas into central la, perhaps producing small 
hail at best. Overnight, southerly 850 mb flow should increase to 
around 30 kt, resulting in lift and a slow northward shift of the 
boundary. Up to 1000 j/kg MUCAPE is forecast to move into la, with 
up to 500 j/kg farther east along the coast. Most of the lift will 
be north of the front, but the very moist air mass should allow for 
surface based storms. Sufficient low-level shear supportive of 
modest rotation will exist, and a brief/weak tornado or strong wind 
gust cannot be ruled out. 

.Jewell/leitman.. 02/25/2018 


Mesoscale Discussion

acus11 kwns 250600 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 250600 

Mesoscale discussion 0098 
National Weather Service Storm Prediction Center Norman OK 
1200 am CST sun Feb 25 2018 

Areas affected...Texas coastal plain 

Concerning...severe potential...watch unlikely 

Valid 250600z - 250730z 

Probability of watch issuance...5 percent 

Summary...some thunderstorm activity developing across the region 
could become fairly strong through the 2-4 am CST time frame. 
Overall, though, the severe weather potential seems limited, and a 
watch is not currently anticipated. 

Discussion...scattered thunderstorm development is underway near and 
ahead of the weak surface front advancing into the Texas coastal 
plain. This is being aided by forcing for ascent associated with 
another low-amplitude short wave impulse crossing the lower Rio 
Grande Valley, within the subtropical westerlies. Although 
southerly low-level flow across the region is generally modest, with 
speeds up to 30 kt generally confined to Upper Texas coastal areas, 
deep layer shear is strong. With layers of modestly steep lower/mid 
tropospheric lapse rates contributing to cape up to around 1000 j/kg 
(for moist boundary layer parcels with dew points in the upper 60s 
to near 70), some of these storms could be accompanied by some risk 
for severe hail into the 07-09z time frame. Eventually, upscale 
convective growth is possible along and just ahead of the front. As 
this occurs, the risk for hail probably will decrease, but a few 
locally strong wind gusts may accompany developing outflow. 

.Kerr/grams.. 02/25/2018 

..please see www.Spc.NOAA.Gov for graphic product... 


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