990
ACUS01 KWNS 221627
SWODY1
SPC AC 221625
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1125 AM CDT SUN MAR 22 2026
VALID 221630Z - 231200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS FAR
EASTERN OHIO AND WESTERN/CENTRAL PENNSYLVANIA...
..SUMMARY
SCATTERED SEVERE THUNDERSTORMS APPEAR LIKELY THIS AFTERNOON AND
EVENING ACROSS PARTS OF THE OHIO VALLEY INTO THE MID-ATLANTIC,
PARTICULARLY FROM FAR EASTERN OHIO INTO CENTRAL PENNSYLVANIA. LARGE
TO VERY LARGE HAIL AND DAMAGING WINDS SHOULD BE THE MAIN THREATS,
BUT A TORNADO OR TWO MAY ALSO OCCUR.
..OHIO VALLEY INTO THE MID-ATLANTIC
EARLY-MORNING SOUNDINGS REVEAL A PLUME OF STEEP MID-LEVEL LAPSE
RATES (I.E. GREATER THAN 8 DEG C PER KM FROM 700 TO 500 MB)
EXTENDING FROM THE SOUTHERN PLAINS NORTHEASTWARD INTO THE UPPER OH
VALLEY. THIS PLUME OF STEEPER LAPSE RATES IS LARGELY ORIENTED ALONG
AND WEST OF A COLD FRONT THAT EXTENDS FROM A LOW IN SOUTH-CENTRAL KS
TO ANOTHER LOW IN WESTERN NY. THE AIRMASS PRECEDING THIS FRONT IS
SEASONALLY WARM AND MOIST, WITH TEMPERATURES IN THE 70S AND
DEWPOINTS IN THE 50S ACROSS MUCH OF THE OH VALLEY. THE EXPECTATION
IS FOR CONTINUED AIRMASS MODIFICATION TODAY AS MOISTURE ADVECTS
NORTHEASTWARD. HOWEVER, THIS MOISTENING WILL BE OFFSET BY STRONG
MIXING, WITH DEWPOINTS LIKELY RANGING FROM THE UPPER 50S ACROSS THE
LOWER OH VALLEY INTO THE LOW 50S ACROSS WESTERN/CENTRAL PA. THIS
LOW-LEVEL MOISTURE, COMBINED WITH TEMPERATURES IN THE UPPER 70S/LOW
80S, SHOULD RESULT IN AN EROSION OF SURFACE-BASED CONVECTIVE
INHIBITION AHEAD OF THE FRONT FROM EASTERN OH THROUGH CENTRAL PA.
ADDITIONALLY, GIVEN THE STEEP MID-LEVEL LAPSE RATES IN PLACE, WEAK
INSTABILITY (MLCAPE AROUND 500-1000 J/KG) IS EXPECTED TO DEVELOP
AHEAD OF THE FRONT.
CURRENT EXPECTATIONS ARE FOR ROBUST THUNDERSTORMS TO DEVELOP BY
19-21Z FROM EASTERN OH INTO WESTERN/CENTRAL PA ALONG AND JUST AHEAD
THE FRONT, FORCED BY LOW-LEVEL CONVERGENCE ALONG THE FRONT AND IN
THE VICINITY OF A WEAK SURFACE LOW MOVING ACROSS THE REGION.
AN INITIALLY DISCRETE MODE IS ANTICIPATED, WITH STRONG DEEP-LAYER
SHEAR FAVORING THE DEVELOPMENT OF SUPERCELLS. LONG/STRAIGHT
HODOGRAPHS AND STEEP MID-LEVEL LAPSE RATES SUGGEST THAT LARGE TO
VERY LARGE HAIL (UP TO 1.5-2.5 INCHES IN DIAMETER) IS THE MAIN
THREAT WITH THESE SUPERCELLS. HIGH LCLS AND STEEP LOW-LEVEL LAPSE
RATES ALSO SUPPORT THE POTENTIAL FOR STRONG DOWNBURSTS AS WELL AS
TREND TOWARDS UPSCALE GROWTH AND A MORE LINEAR MODE AS IT MOVES
EAST-SOUTHEASTWARD ACROSS PA THROUGH THE EVENING. PRIMARY SEVERE
THREAT SHOULD TRANSITION FROM HAIL TO DAMAGING GUSTS THROUGHOUT THE
EVENING. GIVEN THE HIGH LCLS AND LIMITED LOW-LEVEL MOISTURE, THE
TORNADO RISK APPEARS LOW, ALTHOUGH NOT ZERO GIVEN THE SUPERCELL MODE
ANTICIPATED.
FARTHER WEST ACROSS THE LOW TO MID OH VALLEY, THUNDERSTORM
INITIATION SHOULD OCCUR A BIT LATER (I.E. CLOSER TO 00Z) AS MODEST
ASCENT ATTENDANT TO A LOW-AMPLITUDE SHORTWAVE TROUGH AUGMENTS
LOW-LEVEL CONVERGENCE ALONG THE FRONT. MUCH OF THIS CONVECTION MAY
TEND TO BECOME ELEVATED ALONG/NORTH OF THE UNDERCUTTING COLD FRONT.
EVEN SO, STEEP MID-LEVEL LAPSE RATES AND STRONG SHEAR WILL SUPPORT A
CONTINUED RISK FOR LARGE HAIL. SOME ISOLATED VERY LARGE HAIL IS
POSSIBLE WITH THE INITIALLY MORE CELLULAR DEVELOPMENT ACROSS
SOUTHERN IL, CENTRAL IN, AND WEST-CENTRAL OH. A TREND TOWARDS MORE
LINEAR STRUCTURES IS EXPECTED WITH TIME, AND WARM/DRY LOW TO
MID-LEVELS COULD STILL SUPPORT SOME STRONG GUSTS DESPITE THE
ELEVATED STORM STRUCTURES.
..MOSIER/WEINMAN.. 03/22/2026
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