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ACUS01 KWNS 231227

SWODY1

SPC AC 231226



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0726 AM CDT Tue Apr 23 2024



Valid 231300Z - 241200Z



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS

AFTERNOON/EVENING ACROSS NORTHWEST TX...



...SUMMARY...

Isolated severe thunderstorms capable of producing large hail (2+

inch diameter) and gusts to 65 mph will be possible this afternoon

and evening across northwest Texas. Additional strong storms

producing hail up to 1 inch diameter and gusts up to 60 mph are

possible from southeast Wisconsin and northern Illinois into Lower

Michigan.



...Northwest TX area this afternoon/evening...

No appreciable changes to the prior outlook.  In the wake of a

midlevel trough crossing the Great Lakes, a surface cold front will

move southward across KS/OK today, eventually stalling by tonight

across southeast OK and northwest TX.  There will be sufficient

cross-Rockies flow aloft for lee cyclogenesis across eastern NM and

adjacent west central TX, which will maintain southerly low-level

flow and northward advection of a modifying western Gulf air mass

into the frontal zone by mid-late afternoon.  Strong surface heating

along the west edge of the returning moisture will result in a

sharpening dryline by late afternoon, with a dryline/front triple

point likely just off the Caprock.  Isolated thunderstorm

development will be most probable near the triple point after 21z,

and convection will subsequently move southeastward before weakening

by late evening.  The storm environment will be characterized by

moderate buoyancy (MLCAPE of 1500-2000 J/kg), steep midlevel lapse

rates near 9 C/km, and sufficient deep-layer shear for supercells. 

Isolated very large hail of 2-2.5 inches in diameter will be the

main threat, along with a few 55-65 mph outflow gusts.



...Northern IL/southeast WI/Lower MI late this afternoon/evening...

Only minor changes to the MRGL risk area in lower MI.  A midlevel

trough over the upper MS Valley this morning will continue

east-southeastward over the Great Lakes by Wednesday morning.  An

associated surface trough will likewise move southeastward, and this

trough will be preceded by a band of rain with minimal buoyancy. 

Behind the rain band, surface heating with steepening low-level

lapse rates and cooling midlevel temperatures will support weak

surface-based buoyancy just ahead of a secondary frontal surge. 

Some low-topped convection will be possible in this zone late this

afternoon through late evening from northern IL/southeast WI into

lower MI.  The storms could pose a marginal hail/wind threat.



..Thompson/Kerr.. 04/23/2024



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