####018003291####
ACUS02 KWNS 201716

SWODY2

SPC AC 201714



Day 2 Convective Outlook  

NWS Storm Prediction Center Norman OK

1214 PM CDT Wed Mar 20 2024



Valid 211200Z - 221200Z



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

SOUTH-CENTRAL TEXAS TO THE MIDDLE AND UPPER TEXAS COAST...



...SUMMARY...

Isolated severe thunderstorms capable of producing mainly large hail

are expected across portions of northwest, central and coastal

Texas, into coastal Louisiana on Thursday. Some locations may see

multiple rounds of thunderstorm activity from the morning through

evening.



...Texas/Louisiana...



An upper low and attendant trough over northern Mexico and the

southern Rockies is forecast to develop eastward across the Southern

Plains on Thursday. A weak lead shortwave impulse within the

sub-tropic jet oriented across south TX into the western Gulf

Thursday morning will support early convection via warm advection

across parts of the Middle/Upper Texas Coast vicinity. This activity

will spread east across the northwest Gulf and the LA coast through

the day. 



Favorable vertical shear across the region will support organized

convection. Initial isolated strong to severe supercells are

possible, evolving into a cluster with time as convection moves into

the Gulf/LA coast by late morning/early afternoon. Steep midlevel

lapse rates and elongated/straight hodographs above around 2-3 km,

amid a deep layer of elevated instability (MUCAPE around 1500 J/kg)

suggest large hail potential. Some of this activity may remain

elevated depending on degree of low-level destabilization, which

remains uncertain given likely cloud cover and ongoing

showers/thunderstorms at the beginning of the period. This may

modulate damaging wind and/or tornado potential with this first

round of thunderstorm activity, but large hail would still be

possible even with elevated, more discrete/cellular convection.



Additional convection is likely to develop across Oklahoma into

central TX by late afternoon/early evening as the upper trough

ejects eastward and stronger large-scale ascent overspreads the

region. This second round of convection will shift east through the

overnight hours toward east TX/western LA, though severe potential

will be focused from northwest TX south to the Hill Country and the

Middle/Upper TX Coast.



Favorable vertical shear across the region, especially with

southward extent toward the Hill Country, will support organized

convection. Weak capping in the 850-700 mb layer is noted in

forecast soundings across parts of the region. This may limit a more

intense/higher coverage severe episode during the evening, though

even elevated convection will pose a large hail risk. Initial cells

developing into one or more clusters with time are expected.

Boundary-layer moisture will remain limited with northward extent

across central into northern TX, with surface dewpoints generally in

the 50s F. Nevertheless, MUCAPE around 500-750 J/kg (northwest TX)

to 1000-1500 J/kg (Hill Country to the coast) will be sufficient for

isolated severe storms capable of producing large hail and locally

strong gusts.



..Leitman.. 03/20/2024



$$