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ACUS01 KWNS 071637

SWODY1

SPC AC 071636



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1136 AM CDT Tue May 07 2024



Valid 071630Z - 081200Z



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

INDIANA...WESTERN AND CENTRAL OHIO...AND NORTHERN KENTUCKY...



...SUMMARY...

Scattered severe thunderstorms are expected across the southern

Great Lakes and Ohio Valley this afternoon and evening.  A few

tornadoes (some strong), large to very large hail, and

severe/damaging winds all appear possible.



...Southern Great Lakes/Ohio Valley and vicinity...

Considerable uncertainty remains for this forecast due largely in

part to an ongoing broken squall line moving east across KY/IN/Lake

Michigan and the related influences for airmass destabilization in

its wake.  However, clearing skies in the MCS' wake will result in a

seemingly sufficient period of heating during the afternoon. 

Water-vapor imagery shows the deep-layer cyclone centered over the

northern Great Plains.  A mid-level speed max rotating through the

base of the larger-scale trough will move from the mid MS Valley

late this morning into the southern Great Lakes by early evening. 

Rapid strengthening of southwesterly 500-mb flow is forecast over

northern IL into the northern half of IN through the mid-late

afternoon.  As an effective warm frontal zone becomes draped across

the southern Great Lakes/OH Valley regions, curved low-level

hodographs beneath a lengthening of the mid and upper part of the

hodograph will support a supercell risk.  It seems most probable

based on morning model guidance that storms will initially develop

across central/northern IL and move northeast into northern IN. 

Isolated to scattered storms are forecast to eventually develop this

afternoon across parts of the OH Valley in association with

warm/moist-air advection---although considerable uncertainty remains

regarding this scenario.  The stronger storms (i.e., supercells)

will be potentially capable of a large to very large hail threat, in

addition to several tornadoes (perhaps a few which may be strong).  



...Arklatex to north-central and south-central TX...

Not much change in the forecast thinking across the Mid South

southwestward into parts of TX.  Isolated severe thunderstorms are

possible during mid/late afternoon.  Damaging gusts and large hail

would be the main concerns.  The threat over the area is conditional

-- more due to weak lift than thermodynamic considerations.  Surface

dewpoints commonly in the 70s F will underlie a deep troposphere and

enough middle-level lapse rates for MLCAPE in the 3500-4500 J/kg

range.  Weak low-level winds will constrain hodograph size and

boundary- layer shear.  However, enough mid/upper flow remains to

support around 45-55 kt effective-shear magnitudes, yielding a

conditional supercell environment.  In the absence of meaningful

large-scale support, and with shallower overall lift near the

front/dryline, convective coverage over this region is more in

question and likely isolated.  Additional convection may form

overnight in a warm-advection plume near and southeast of the front,

across parts of the Mid-South to Arklatex regions.  Marginal hail

and isolated damaging gusts would be the main concerns.



...Southeast KS late tonight...

A strengthening LLJ and associated warm-air advection will be

focused over the northeast OK/southeast KS region late tonight. 

Forecast soundings show large MUCAPE amidst strong deep-layer shear.

Large hail may accompany a stronger storm or two that manages to

develop/become sustained during the 08-12z period.



..Smith/Jewell.. 05/07/2024



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