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ACUS01 KWNS 200545

SWODY1

SPC AC 200543



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1243 AM CDT Sat Apr 20 2024



Valid 201200Z - 211200Z



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

OF CENTRAL/SOUTH TEXAS AND ACROSS PARTS OF THE SOUTHEASTERN US...



...SUMMARY...

Marginally severe storms capable of strong wind gusts and hail will

be possible across portions of central and south Texas, and during

the afternoon from southern Mississippi/Alabama across parts of

Georgia and into southern South Carolina.



...Texas...



Southern stream remains active early this morning.  One weak

mid-level disturbance is advancing east across the lower Rio Grande

Valley, while a second more significant short-wave trough is located

upstream over the lower CO River Valley/Baja region. This feature is

forecast to progress into west TX by 21/00z, then deamplify as it

approaches the upper TX Coast late in the period. Large-scale

pattern favors surface ridging across the middle of the country and

a dominant high pressure will remain wedged deep against the higher

terrain of the Rockies. With time the leading edge of this air mass

will surge into the lower Rio Grande Valley with the surface front

expected to move off the lower TX Coast by 21/12z.



Early in the period, low-level warm advection will focus along a

corridor arcing from the Edwards Plateau into the Red River region

of north TX/southern OK. Elevated convection will be common at the

start of the period. Considerable amount of elevated convection will

likely persist north of the front through the period, gradually

sagging south as the short wave approaches and the front advances

into lower latitudes. Forecast soundings do not exhibit very steep

low-level lapse rates along/near the front and this should limit

surface-based convection through the period. Most storms are

expected to develop north of the boundary. Even so, some risk for

hail/wind will be noted with thunderstorm clusters. If frontal

convection can develop there is an outside chance for a brief

tornado with surface-based supercells.



...Southeast...



Surface front is forecast to be draped across the Carolinas-central

GA-southern AL/MS early in the period. This boundary will move

little during the day and will serve as the main focus for

convective development as boundary layer temperatures warm and

low-level lapse rates steepen. Forecast soundings suggest convective

temperatures will be breached by early afternoon and scattered

thunderstorms are expected to develop. Early-morning water-vapor

imagery suggests the weak short-wave trough over deep south TX may

contribute to convection along/near this boundary later today. If

so, some clustering is possible given the large-scale assistance. At

this time locally damaging winds appear to be the primary risk.



..Darrow/Weinman.. 04/20/2024



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