SPC AC 310527
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1227 AM CDT Sat Jul 31 2021
Valid 311200Z - 011200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
TENNESSEE AND MIDDLE MISSISSIPPI VALLEY INTO SOUTHERN KANSAS AS WELL
AS WISCONSIN AND THE COASTAL CAROLINAS...
...SUMMARY...
Severe storms with damaging gusts will be possible today, mainly
across a portion of central and southern Missouri into the western
portion of the Tennessee Valley. Other strong storms will be
possible over Wisconsin and the coastal Carolinas.
...Central and southern Missouri into western Tennessee and
Kentucky...
The eastern U.S. synoptic upper trough will amplify today
contributing to a belt of slightly stronger winds aloft over the
middle MS and TN Valley areas. Meanwhile a cold front will move
southward through central into southern KS, while a stationary front
persists from northeast KS to southern MO and western TN. With rich
low-level moisture in place, the atmosphere south of the boundaries
will become moderately unstable with 1500-2500 J/kg MLCAPE likely.
It is probable that an MCS will be in progress across
central/northern MO by 12Z today. Some threat for strong to damaging
wind gusts might still exist, but this activity may weaken as it
continues southeast during the morning. Additional storms are
expected to develop along the trailing outflow boundary/front merger
across central MO and spread southeast into the moderately unstable
warm sector during the afternoon. A belt of up to 35 kt
northwesterly mid-level winds will reside across this region with
modest effective bulk shear supporting mostly multicells. Storms may
evolve into line segments with potential for a few damaging wind
gusts across a portion of southern MO and possibly into western
TN/KY during the afternoon and evening. Considerable uncertainty
remains regarding evolution of morning storms which precludes a
categorical upgrade to SLGT at this time.
...Wisconsin...
A shortwave trough embedded within the broader, amplifying upper
trough will move southeast into the upper Great Lakes during the
afternoon accompanied by a cold front. Up to 1000-1500 J/kg MLCAPE
is expected in the pre-frontal warm sector, but mid-level lapse
rates will remain marginal. Thunderstorms will likely develop along
the cold front and spread southeast through central WI. Northwest
flow aloft with modest vertical shear will support multicells, but
some storms might produce locally strong wind gusts and small hail
before weakening during the evening.
...Coastal Carolinas...
Multicell storms are expected to develop along a stalled front near
the coastal Carolinas within a weakly sheared and moderately
unstable environment during the afternoon. A few of the storms might
produce strong to severe downburst winds before weakening during the
early evening.
..Dial/Moore.. 07/31/2021
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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