116
ACUS01 KWNS 211626
SWODY1
SPC AC 211625
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1125 AM CDT TUE OCT 21 2025
VALID 211630Z - 221200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE SOUTHERN GREAT LAKES...
..SUMMARY
ISOLATED STRONG TO LOCALLY SEVERE GUSTS ARE POSSIBLE THIS AFTERNOON
OVER PARTS OF THE SOUTHERN GREAT LAKES.
..SYNOPSIS
MORNING WATER-VAPOR LOOP AND UPPER-AIR DATA INDICATE A MIDLEVEL LOW
TRACKING EAST-SOUTHEASTWARD OVER THE UPPER MIDWEST -- ACCOMPANIED BY
COLD 500-MB TEMPERATURES (AROUND -28C). THIS FEATURE WILL CONTINUE
EASTWARD ACROSS THE GREAT LAKES THROUGH THE PERIOD, WHILE A COLD
FRONT MOVES FROM THE UPPER OH VALLEY TO THE ATLANTIC COAST. WITHIN
THE BASE OF THE MIDLEVEL LOW, AN EMBEDDED VORTICITIY MAXIMUM WILL
MOVE ACROSS THE LOWER GREAT LAKES THROUGH THE AFTERNOON, WHILE A
RELATED SURFACE FRONT/WIND SHIFT OVERSPREADS IN, OH, AND LOWER MI.
..SOUTHERN GREAT LAKES
IN THE WAKE OF A WEAKENING BAND OF SHOWERS ALONG THE DEPARTING FRONT
OVER THE UPPER OH VALLEY, MOSTLY CLEAR SKIES WILL PROMOTE
BOUNDARY-LAYER HEATING/STEEPENING LOW-LEVEL LAPSE RATES (SHALLOW
INVERTED-V PROFILES) BENEATH THE MIDLEVEL COLD POCKET -- YIELDING
MARGINAL DESTABILIZATION ACROSS PARTS OF NORTHERN OH AND SOUTHEAST
LOWER MI. AS WIDELY SCATTERED CONVECTION ALONG THE SECONDARY SURFACE
FRONT/WIND SHIFT SPREADS/DEVELOPS INTO THIS ENVIRONMENT, A MODEST
UPTICK IN UPDRAFT INTENSITY IS POSSIBLE THIS AFTERNOON. GIVEN STRONG
DEEP-LAYER FLOW FLANKING THE MIDLEVEL LOW, ISOLATED STRONG-LOCALLY
SEVERE CONVECTIVELY ENHANCED WIND GUSTS (45-60 MPH) WILL BE POSSIBLE
DURING THE LATE AFTERNOON INTO EARLY EVENING TIME FRAME. SMALL HAIL
WILL ALSO BE POSSIBLE WITH ANY SHALLOW CELLULAR CONVECTION.
..CENTRAL GULF COAST VICINITY
A WARM, MOIST, AND UNCAPPED AIR MASS AHEAD OF THE TAIL-END OF THE
COLD FRONT WILL SUPPORT ISOLATED THUNDERSTORMS ACROSS PARTS OF EAST
TX INTO SOUTHERN LA THIS AFTERNOON. WHILE MODERATE SURFACE-BASED
BUOYANCY AND AROUND 25 KT OF EFFECTIVE SHEAR COULD PROMOTE A COUPLE
STRONG STORMS ALONG THE FRONT, WARM TEMPERATURES ALOFT AND MINIMAL
LARGE-SCALE FORCING FOR ASCENT SHOULD GENERALLY LIMIT UPWARD
ACCELERATIONS IN UPDRAFTS.
..WEINMAN/SUPINIE.. 10/21/2025
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