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ACUS01 KWNS 020601

SWODY1

SPC AC 020600



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0100 AM CDT Tue Apr 02 2024



Valid 021200Z - 031200Z



...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS THE OHIO

VALLEY...



...SUMMARY...

A potentially substantial severe weather outbreak -- possibly

including a few significant/long-track tornadoes -- is anticipated

this afternoon and evening, with the highest probability centered

over the Ohio Valley.  Severe risk exists as far south as the Gulf

Coast, and as far east as western portions of Virginia and the

Carolinas.



...Discussion...



Strong northern-stream upper low, currently located over southern

MB, is forecast to drop south across MN into northern IL late in the

period. This evolution is driven in part by a 500mb speed max that

will translate across the central Plains, increasing to near 100kt

over eastern KS/OK by 03/12z. Intense 12hr midlevel height falls are

forecast across much of the Great Lakes, OH/TN Valley, and the

northern Gulf States, where values in excess of 200m are expected

during the latter half of the period. Synoptic front that is

currently draped across the OH Valley will be encouraged to

gradually advance north due to the digging trough; however, an

extensive corridor of convection currently extends across the MS

Valley into the OH valley, which is maintaining cool boundary-layer

conditions north of I-70.



Latest water-vapor imagery suggests a southern-stream short-wave

trough is progressing across eastern KS/eastern OK. This feature

will progress downstream and likely aid early-day thunderstorm

development near the confluence of the MS/OH Rivers. Seasonally high

PW airmass currently extends across northern AR/southern MO into

southern IL. NAM forecast sounding for JBR at 15z exhibits 60kt

surface-6km bulk shear with SBCAPE on the order of 1500 J/kg.

Discrete supercells may evolve ahead of this feature then

spread/develop northeast across southern IN/KY into OH. Some

uncertainty exists across northern OH/IN regarding destabilization.

It's not entirely clear if ongoing convection will allow the warm

front to lift appreciably north of its current position. However,

large-scale pattern is quite dynamic and favors surface low

deepening over southern Lake MI during the latter half of the

pattern. NAM struggles to reflect this scenario, thus weaker

instability is forecast at higher latitudes. Tornadoes, damaging

winds, and large hail are expected with supercells that evolve

across the warm sector. Some tornadoes may be long-lived and strong.





Farther south, a bimodal severe threat may ultimately evolve with a

secondary corridor of more concentrated severe across portions of

the northern Gulf States. 500mb speed max is forecast to eject

across northern Mexico into TX by 03/00z. This feature will

intensify as it translates across LA into eastern TN by the end of

the period. There is some concern that severe probabilities may need

to be increased across this region to account for this low-latitude

speed max during the evening/overnight hours. Strong shear will

support supercells along with a threat for tornadoes, damaging

winds, and hail.



..Darrow/Bentley.. 04/02/2024



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