U.S. Severe Weather Forecast (Convective Outlook)

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acus01 kwns 251953 
swody1 
Storm Prediction Center ac 251951 


Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0151 PM CST sun Feb 25 2018 


Valid 252000z - 261200z 


..there is a marginal risk of severe thunderstorms from southeast 
Texas to the central Gulf Coast... 


... 
A few storms capable of producing hail, localized wind damage or a 
brief/weak tornado are possible across parts of Texas today, and 
then across the central Gulf Coast region tonight. 


... 
Thunderstorms continue to form atop a surface stable layer over 
southeast Texas this afternoon. Favorable effective shear, evidenced 
by recent kewx/khgx vwp data and near-term forecast soundings, will 
maintain a marginal hail threat into this evening. Indeed, mrms 
cappi and mid-level rotational products suggest occasional updraft 
organization. Additionally, an isolated storm or two may continue to 
pose a hail threat across the central Gulf Coast overnight. 


In terms of the wind/tornado threat, with the glancing influence of 
a mid-level impulse over the Southern Plains and Mississippi Valley, 
some weak/brief poleward surface Theta-E advection is anticipated, 
likely returning a maritime air mass to parts of the central Gulf 
Coast. In turn, despite the earlier passage of a composite 
outflow/cold front, adequate surface destabilization may occur 
across coastal areas for a marginal wind/tornado threat overnight, 
and only minor adjustments have been made to the ongoing outlook. 


.Picca.. 02/25/2018 


Previous discussion... /issued 1010 am CST sun Feb 25 2018/ 


..TX today... 
Clusters of thunderstorms are affecting parts of central and 
southeast Texas this morning, ahead of a mid-level shortwave trough and 
in region of low-level warm advection. Continued re-development in 
this area will likely persist trough the afternoon, with sufficient 
elevated cape and deep-layer shear to promote rotating cells capable 
of hail. The risk of organized severe storms appears marginal. 


..western/middle Gulf Coast tonight... 
Later tonight, the low-level air mass is forecast to slowly recover 
along the immediate Gulf Coast from southern la into the Florida 
Panhandle. Most 12z model guidance is consistent in the development 
of thunderstorms tonight along/north of the retreating warm front 
over la. These storms will track eastward in vicinity of the 
boundary and move across parts of MS/al/FL. While the overall 
severe threat appears low, there is some risk of locally 
gusty/damaging winds or a brief tornado. 


$$ 

Mesoscale Discussion


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acus11 kwns 250600 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 250600 
laz000-txz000-250730- 


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... 


Attention...WFO...lch...hgx...crp...ewx... 


Latitude...Lon 29389792 29819689 30329548 30699453 30749369 29739370 
29199540 28219685 28179780 29389792