423
ACUS03 KWNS 200731
SWODY3
SPC AC 200730
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CDT FRI JUN 20 2025
VALID 221200Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL NE
INTO NORTHWEST IA...THE EASTERN DAKOTAS...AND WESTERN/CENTRAL MN...
..SUMMARY
SEVERE THUNDERSTORMS MAY DEVELOP ON SUNDAY FROM PARTS OF THE CENTRAL
AND NORTHERN PLAINS INTO THE UPPER MIDWEST.
..SYNOPSIS
A MID/UPPER-LEVEL SHORTWAVE TROUGH AND ATTENDANT JET MAXIMUM ARE
FORECAST TO MOVE FROM THE CENTRAL ROCKIES TOWARDS THE NORTHERN GREAT
PLAINS ON SUNDAY. A SURFACE LOW WILL MOVE FROM NE/SD NORTHEAST
TOWARD LAKE SUPERIOR, AS A TRAILING COLD FRONT MOVES THROUGH PARTS
OF THE NORTHERN/CENTRAL PLAINS. DOWNSTREAM, AN UPPER RIDGE WILL
AMPLIFY FURTHER ACROSS THE EASTERN CONUS THROUGH THE DAY, AS A
SHORTWAVE TROUGH INITIALLY OVER NEW ENGLAND MOVES OFFSHORE.
..GREAT PLAINS INTO THE UPPER MIDWEST
STRONG TO EXTREME INSTABILITY IS AGAIN FORECAST TO DEVELOP
ALONG/AHEAD OF THE COLD FRONT ACROSS PARTS OF THE CENTRAL/NORTHERN
PLAINS INTO THE UPPER MIDWEST. GUIDANCE GENERALLY SUGGESTS THAT
STRONGER ASCENT AND DEEP-LAYER FLOW ASSOCIATED WITH THE EJECTING
MID/UPPER-LEVEL SHORTWAVE TROUGH MAY LAG BEHIND THE FRONT, RESULTING
IN SOME UNCERTAINTY REGARDING THE MAGNITUDE AND COVERAGE OF THE
SEVERE THREAT. HOWEVER, STRONG DIURNAL HEATING WILL SUPPORT
POTENTIAL FOR STORM DEVELOPMENT IN THE VICINITY OF THE FRONT, AND
ALSO SOUTHWARD ALONG A SURFACE TROUGH INTO THE CENTRAL AND PERHAPS
SOUTHERN HIGH PLAINS.
GIVEN THE MAGNITUDE OF INSTABILITY, DEEP-LAYER SHEAR WILL BE
SUFFICIENT FOR SOME STORM ORGANIZATION, WITH A FEW STRONG CELLS OR
CLUSTERS POSSIBLE. A SLIGHT RISK HAS BEEN ADDED FROM CENTRAL NE INTO
MN, WHERE CONFIDENCE IS CURRENTLY GREATEST IN DEVELOPMENT OF WIDELY
SCATTERED STRONG TO SEVERE STORMS DURING THE AFTERNOON AND EVENING.
CONVECTION MAY PERSIST INTO LATE SUNDAY NIGHT, WITH AN ISOLATED
SEVERE THREAT SPREADING GRADUALLY EASTWARD.
ISOLATED SEVERE STORMS WILL ALSO BE POSSIBLE WITHIN THE POST-FRONTAL
REGIME ACROSS THE CENTRAL/NORTHERN HIGH PLAINS, THOUGH GUIDANCE
VARIES REGARDING THE MAGNITUDE OF MUCAPE IN THIS REGION. HIGH-BASED
STORMS MAY DEVELOP INTO PARTS OF THE SOUTHERN HIGH PLAINS, WITH A
THREAT OF ISOLATED STRONG TO SEVERE GUSTS.
..PARTS OF THE NORTHEAST/NEW ENGLAND
GUIDANCE VARIES SUBSTANTIALLY REGARDING THE STRENGTH/TIMING OF THE
SHORTWAVE TROUGH AND RELATED FLOW FIELDS THAT WILL MOVE ACROSS NEW
ENGLAND SUNDAY MORNING. DEPENDING ON THE STRENGTH OF THE SYSTEM AND
THE EVOLUTION OF CONVECTION ON D2/SATURDAY, THERE IS SOME POTENTIAL
FOR ISOLATED STRONG TO SEVERE STORMS SUNDAY ACROSS THE REGION, GIVEN
THE PRESENCE OF INCREASING BUOYANCY AND FAVORABLE DEEP-LAYER SHEAR.
A SLOWER SYSTEM COULD RESULT IN A MORE ROBUST DIURNAL THREAT, WHILE
A FASTER SYSTEM MAY CONFINE THE PRIMARY THREAT TO THE MORNING.
..DEAN.. 06/20/2025
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