987
ACUS03 KWNS 311934
SWODY3
SPC AC 311933
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0233 PM CDT MON AUG 31 2026
VALID 021200Z - 031200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM LOWER
MICHIGAN SOUTHEASTWARD TOWARD THE MID ATLANTIC...
..SUMMARY
SEVERE STORMS WITH WIND AND HAIL RISK ARE EXPECTED FROM THE LOWER
GREAT LAKES TO THE MID-ATLANTIC ON WEDNESDAY. A FEW SEVERE STORMS
MAY ALSO OCCUR OVER PARTS OF MONTANA.
..LOWER GREAT LAKES TO MID ATLANTIC
AN UPPER RIDGE WILL HOLD OVER THE TN VALLEY TO APPALACHIANS, WHILE
AN UPPER LOW DRIFTS EAST INTO QUEBEC. IN BETWEEN, MODERATE
WESTERLIES ALOFT WILL EXIST, SUPPORTING FAVORABLE DEEP-LAYER SHEAR
AND AREAS OF STORM ORGANIZATION.
AT THE SURFACE, A WEAK SURFACE TROUGH SHOULD EXTEND ROUGHLY FROM
LOWER MI INTO NY, WITH UPPER 60S TO NEAR 70 F DEWPOINTS TO THE
SOUTH. THE WESTERLY LOW-LEVEL WINDS WILL SUPPORT AIR MASS RECOVERY
BEHIND ANY EARLY/DYING MORNING ACTIVITY, WITH AFTERNOON
REDEVELOPMENT EXPECTED FROM LOWER MI INTO NY. CORRIDORS OF DAMAGING
WINDS ARE MOST LIKELY AS STORMS MOVE RAPIDLY SOUTHEASTWARD.
DEEP-LAYER SHEAR MAY ALSO FAVOR LARGE HAIL WITH THE MORE CELLULAR
ACTIVITY. LOW-LEVEL SHEAR MAY FAVOR A FEW SUPERCELLS ACROSS EASTERN
NY/PA/NJ/DELMARVA, AND THEREFORE A BRIEF TORNADO OR TWO CANNOT BE
RULED OUT ASSUMING STORM MODE REMAINS DISCRETE AS THEY MOVE EAST
INTO THE BETTER SHEAR ENVIRONMENT.
..WESTERN TO NORTHERN MT
A POTENT SHORTWAVE TROUGH IS FORECAST TO MOVE OUT OF THE GREAT BASIN
AND ACROSS ID AND MT WEDNESDAY, WITH SUBSTANTIAL COOLING ALOFT. LOW
PRESSURE IS FORECAST TO DEVELOP INTO WEST-CENTRAL MT, WITH A
PROMINENT COLD FRONT MOVING ACROSS THE ENTIRE STATE INTO THURSDAY
MORNING.
STRONG SURFACE HEATING AHEAD OF THE FRONT COMBINED WITH COOLING
ALOFT WILL RESULT IN STEEP LAPSE RATES THROUGH A DEEP LAYER, AIDING
DESTABILIZATION DESPITE LIMITED MOISTURE. STORMS THAT DEVELOP NEAR
THE FRONT DURING THE AFTERNOON ARE THUS LIKELY TO PRODUCE STRONG TO
LOCALLY SEVERE GUSTS. MARGINALLY SEVERE HAIL MAY ALSO OCCUR. FARTHER
EAST, INCREASING SOUTHEAST LOW-LEVEL WINDS WILL BRING A PLUME OF
INSTABILITY INTO EASTERN MT AS WELL, WHICH MAY SUPPORT CELLS CAPABLE
OF HAIL THROUGH THE EVENING.
..NE...SD...MN...IA
PREDICTABILITY IS LOW, BUT ISOLATED STRONG TO SEVERE STORMS CANNOT
BE RULED OUT DURING THE LATE AFTERNOON AND EVENING, AS WINDS
INCREASE OUT OF THE SOUTH AHEAD OF THE NORTHERN ROCKIES WAVE. AREAS
OF MODERATE INSTABILITY WILL REMAIN OVER THE REGION WITH
SOUTHEASTERLY SURFACE WINDS AND MID TO UPPER 60S F DEWPOINTS. PEAK
HEATING WILL LEAD TO AN UNCAPPED AIR MASS ACROSS CENTRAL SD AND NE,
WITH LIFT INCREASING INTO THE EVENING AS A LOW-LEVEL JET DEVELOPS.
MODELS ARE IN DISAGREEMENT WITH THE MOST LIKELY AREA FOR
DEVELOPMENT, BUT SEVERE PROBABILITIES MAY BE ADDED LATER FROM NE
INTO MN.
..JEWELL.. 08/31/2026
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