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ACUS02 KWNS 171718

SWODY2

SPC AC 171716



Day 2 Convective Outlook  

NWS Storm Prediction Center Norman OK

1216 PM CDT Wed Apr 17 2024



Valid 181200Z - 191200Z



...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF

EASTERN MISSOURI INTO SOUTHERN ILLINOIS...EXTREME SOUTHWEST

INDIANA...FAR SOUTHWESTERN KENTUCKY...FAR NORTHWESTERN TENNESSEE...



...SUMMARY...

Strong to severe storms capable of several damaging gusts, large

hail, and perhaps a couple tornadoes, are likely tomorrow (Thursday)

from parts of the lower Ohio Valley into the southern Plains.



...Synopsis...

Mainly zonal flow aloft will overspread the CONUS tomorrow

(Thursday) as a mid-level trough traverses the northern Plains. In

response, a gradually weakening surface low will move from the

central Plains toward the OH Valley as a surface cold front sags

southward from the OH Valley to central TX through the day. Ample

low-level moisture, overspread by cooler temperatures aloft, along

with adequate deep-layer vertical wind shear, will precede the

surface cold front and support a risk for severe thunderstorms by

afternoon. Strong to severe thunderstorms will initiate off of the

cold front by afternoon from the OH Valley into TX, with all severe

hazards possible.



...MO into portions of the OH Valley...

A surface low will be traversing central MO/IL during the late

morning/afternoon hours, with thunderstorm development likely

underway along the cold front at the start of the period. As the

surface low continues to drift northeast, with the cold front

drifting southeast, diurnal heating will destabilize the warm sector

over the mid MS Valley, where an increase in convective coverage and

intensity is expected. Here, surface temperatures will peak into the

upper 70s to low 80s F amid mid 60s F dewpoints. 7-8 C/km mid-level

lapse rates will overspread a deepening/mixing boundary layer,

boosting SBCAPE into the 2000-3000 J/kg range. Deep-layer shear will

not be overly strong, but modest mid-level flow and associated

speed/directional shear will support low-level hodographs of modest

curvature and limited mid-level elongation. This shear/buoyancy

profile will support multicells (accompanied by wind and hail)

rapidly growing upscale into a mature MCS by afternoon. Given a

preceding mixed boundary layer, the MCS should efficiently produce

damaging gusts, warranting the introduction of Category 3/Enhanced

risk probabilities. Given modest low-level hodograph curvature,

embedded mesovortices may develop near the apex of any bowing

segments, perhaps accompanied by a QLCS tornado risk. 



...Portions of northern into central TX...

Robust thunderstorm development should take place along/ahead of the

southeastward-sagging cold front by afternoon peak heating. These

storms will develop atop a well-mixed boundary layer, with 3000+

J/kg SBCAPE expected to precede the storms given steep mid-level

lapse rates overspreading upper 60s F surface dewpoints. Multicell

thunderstorms, accompanied by a severe hail/wind risk, are expected

given 30 kts of effective bulk shear and short hodographs over

northern TX. Farther southwest into central TX though, locally

stronger mid-level flow may support longer mid-level hodographs and

9+ C/km mid-level lapse rates. These steeper lapse rates should

result in deep, wide CAPE profiles, with a couple instances of 2+

inch diameter hail possible, especially if more persistent updrafts

can develop.



..Squitieri.. 04/17/2024



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