880
ACUS02 KWNS 211725
SWODY2
SPC AC 211723
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1223 PM CDT SAT MAR 21 2026
VALID 221200Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE OHIO
VALLEY INTO THE NORTHERN MID ATLANTIC...
..SUMMARY
SCATTERED STRONG TO SEVERE THUNDERSTORMS WITH LARGE HAIL, DAMAGING
WIND GUSTS, AND POSSIBLY SOME TORNADO THREAT ARE EXPECTED ON SUNDAY
AFTERNOON AND EVENING ACROSS PARTS OF THE OHIO VALLEY INTO THE
NORTHERN MID ATLANTIC REGION.
..SYNOPSIS
A MID/UPPER-LEVEL SHORTWAVE TROUGH IS FORECAST TO GRADUALLY AMPLIFY
ON SUNDAY, AS IT MOVES FROM THE NORTHERN PLAINS TOWARDS THE GREAT
LAKES REGION. THIS AMPLIFICATION WILL OCCUR WITHIN A BROADER
WEST-NORTHWESTERLY FLOW REGIME, WITH RELATIVELY STRONG DEEP-LAYER
FLOW EXPECTED TO EVENTUALLY OVERSPREAD THE OHIO VALLEY AND MID
ATLANTIC REGIONS. A COLD FRONT INITIALLY DRAPED FROM THE CENTRAL
PLAINS INTO THE LOWER GREAT LAKES WILL MOVE GENERALLY SOUTHEASTWARD
THROUGH THE PERIOD, AS ONE OR MORE FRONTAL WAVES TRAVERSE THE FRONT
FROM THE MID MS VALLEY INTO THE NORTHEAST AND MID ATLANTIC.
..OHIO VALLEY INTO PARTS OF THE MID ATLANTIC
A PLUME OF RELATIVELY STEEP MIDLEVEL LAPSE RATES WILL EMANATE OUT OF
AN ANOMALOUSLY HOT AND WELL-MIXED REGIME ACROSS THE SOUTHWEST AND
CENTRAL/SOUTHERN PLAINS AND OVERSPREAD PARTS OF THE OHIO VALLEY ON
SUNDAY. WITH FAVORABLE DEEP-LAYER FLOW/SHEAR EXPECTED ACROSS THE
OHIO VALLEY AND MID ATLANTIC, THE PRIMARY UNCERTAINTY REGARDING THE
MAGNITUDE OF BUOYANCY AND POTENTIAL SEVERE THREAT IS LOW-LEVEL
MOISTURE RETURN. THE PARTIALLY MODIFIED NATURE OF RETURNING GULF
MOISTURE AND A TENDENCY FOR STRONG ANTECEDENT HEATING/MIXING
UPSTREAM OF THE OHIO VALLEY MAY CONTINUE TO RESULT IN LESS
AGGRESSIVE MOISTENING COMPARED TO MOST GUIDANCE. HOWEVER, WITH
RELATIVELY COOL MIDLEVEL TEMPERATURES (-14C TO -16C AT 500 MB), EVEN
DEWPOINTS IN THE LOW/MID 50S F WILL RESULT IN MODERATE BUOYANCY
(MLCAPE OF 1000-1500 J/KG) WHERE SUFFICIENT HEATING OCCURS.
THE GREATEST CONFIDENCE IN DIURNAL STORM DEVELOPMENT CURRENTLY
RESIDES WITHIN THE EASTERN PORTION OF THE PRIMARY BUOYANCY PLUME
ACROSS PA AND EASTERN OH, WHERE WEAKER CAPPING AND A MODEST
WARM-ADVECTION REGIME COULD RESULT IN ISOLATED TO WIDELY SCATTERED
SUPERCELL DEVELOPMENT ALONG/AHEAD OF THE FRONT. WEAKER ASCENT WITH
SOUTHWEST EXTENT REDUCES CONFIDENCE IN DEVELOPMENT ACROSS THE LOWER
OHIO VALLEY, THOUGH ISOLATED SUPERCELL DEVELOPMENT CANNOT BE RULED
OUT IN THIS REGION AS WELL. AN INCREASE IN STORM COVERAGE IS
EXPECTED INTO SUNDAY NIGHT AS THE COLD FRONT BEGINS TO SURGE
SOUTHEASTWARD, THOUGH MUCH OF THE NOCTURNAL ACTIVITY MAY TEND TO BE
ANAFRONTAL AND SOMEWHAT ELEVATED.
LARGE HAIL (POTENTIALLY TO THE SIZE OF GOLF BALLS OR LARGER) COULD
ACCOMPANY ANY LONGER-LIVED SUPERCELLS DURING THE AFTERNOON AND
EVENING. THE ENVIRONMENT WILL ALSO BE FAVORABLE FOR DAMAGING-WIND
POTENTIAL, ESPECIALLY WHERE STRONGER DIURNAL HEATING OCCURS, THOUGH
POTENTIAL FOR ORGANIZED CLUSTERING IS UNCERTAIN DUE TO THE EVENTUAL
UNDERCUTTING FRONTAL PASSAGE. ALSO, WHILE FLOW WILL REMAIN RATHER
VEERED, LOW-LEVEL SHEAR/SRH MAY BE SUFFICIENT TO SUPPORT SOME
SUPERCELL TORNADO THREAT, CONDITIONAL UPON SUFFICIENT LOW-LEVEL
MOISTENING. A CORRIDOR OF GREATER TORNADO PROBABILITIES MAY
EVENTUALLY BE NEEDED, IF TRENDS SUPPORT MORE SUBSTANTIAL MOISTURE
RETURN THAN CURRENTLY EXPECTED.
..DEAN.. 03/21/2026
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