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ACUS01 KWNS 201614

SWODY1

SPC AC 201612



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1112 AM CDT Sat Apr 20 2024



Valid 201630Z - 211200Z



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

TO SOUTHERN TEXAS AS WELL AS THE SOUTHERN GULF STATES INTO THE

SOUTHEAST...



...SUMMARY...

Marginally severe storms capable of strong wind gusts and hail will

be possible mainly this afternoon/evening across portions of central

and south Texas, and from southern Mississippi to southern North

Carolina.



...Synopsis...

Mid-morning radar mosaics show a broad swath of elevated convection

ongoing across the southern Plains ahead of an approaching

upper-level wave. While a few instances of gusty winds and/or

sub-severe hail will be possible with this activity, a slightly more

robust severe threat will be focused along a surface cold front

recently analyzed from the southern Appalachians to southern TX.

Surface high pressure is expected to build east into the Plains/MS

Valley through the day, which will nudge the cold front slowly

southward over the next 24 hours. Isolated to scattered

thunderstorms are expected to develop along this boundary by

mid-afternoon with a few strong/severe storms possible. 



...Southern Gulf states to the Southeast...

Mostly clear to partly cloud skies are noted along and ahead of the

cold front from SC into southern AL/MS. Diurnal warming of a

modestly moist air mass should yield MLCAPE values upwards of 1000

J/kg by early to mid-afternoon. Despite minimal inhibition, weak

forcing for ascent along the front should support isolated to widely

scattered thunderstorms. Storm motions largely along the boundary

should support initial cells growing upscale into clusters through

the afternoon/evening. While low to mid-level winds are modest,

30-40 knot flow aloft may support sufficient deep-layer shear for a

few more organized cells/clusters with an attendant hail risk.

Damaging outflow gusts are also possible - especially across areas

where surface temperatures can warm into the mid/upper 80s by peak

heating. Based on 16 UTC observations, this appears most likely to

occur across parts of GA into the Carolinas.



...Southern Texas...

Two clusters of thunderstorms appear possible this afternoon and

evening across southern Texas. Elevated convection developing along

the western fringe of the synoptic front across the Big Bend region

of TX should gradually become surface-based as storms migrate east

into an increasingly buoyant air mass. Thunderstorms should also be

focused along a more subtle boundary noted along the TX Coastal

Plain in recent surface analyses. Across both regions, sufficient

deep-layer shear should be in place to support a few organized

cells, but mean storm motions and deep-layer shear vectors largely

along the initiating boundaries should favor convective clusters

with an attendant hail/wind risk. A low-end tornado threat may

materialize along the boundary along the Coastal Plain where

low-level flow should remain backed to the south/southeast, yielding

effective SRH values between 100-150 m2/s2. However, given the

potential for upscale growth, this threat is expected to be fairly

limited.



..Moore.. 04/20/2024



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