586
ACUS03 KWNS 180731
SWODY3
SPC AC 180730
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CDT WED JUN 18 2025
VALID 201200Z - 211200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
NORTHERN PLAINS INTO THE UPPER MIDWEST/GREAT LAKES...
..SUMMARY
SEVERE THUNDERSTORMS MAY DEVELOP FRIDAY INTO FRIDAY NIGHT ACROSS
PARTS OF THE NORTHERN PLAINS AND UPPER MIDWEST.
..SYNOPSIS
AN UPPER-LEVEL RIDGE IS FORECAST TO AMPLIFY ON FRIDAY FROM THE
SOUTHERN PLAINS INTO PARTS OF THE MS/OH VALLEYS, AS A SEASONABLY
DEEP MID/UPPER-LEVEL TROUGH MOVES GRADUALLY EASTWARD OVER THE WEST.
RICH LOW-LEVEL MOISTURE WILL CONTINUE TO STREAM NORTHWARD TO THE
EAST OF A DEEPENING LEE SURFACE CYCLONE ACROSS THE NORTHERN HIGH
PLAINS. MULTIPLE SHORTWAVES MAY EMANATE OUT OF THE WESTERN TROUGH
AND TRAVERSE THE PERIPHERY OF THE BUILDING RIDGE FROM THE NORTHERN
ROCKIES/PLAINS INTO THE UPPER MIDWEST AND PARTS OF GREAT LAKES.
..NORTHERN GREAT PLAINS INTO THE UPPER MIDWEST/GREAT LAKES
UNCERTAINTY REMAINS HIGH REGARDING THE DETAILS OF CONVECTIVE
EVOLUTION FRIDAY INTO FRIDAY NIGHT, BUT POTENTIAL FOR SEVERE STORM
DEVELOPMENT WITHIN A RELATIVELY VOLATILE ENVIRONMENT REMAINS
EVIDENT.
TO THE EAST OF THE HIGH PLAINS CYCLONE AND TRAILING SURFACE TROUGH,
AND ALONG/SOUTH OF AN EFFECTIVE WARM FRONT, STRONG TO EXTREME
BUOYANCY WILL DEVELOP FRIDAY AFTERNOON ACROSS PARTS OF THE
CENTRAL/NORTHERN PLAINS INTO THE UPPER MIDWEST. DETAILS OF DIURNAL
STORM DEVELOPMENT (IF ANY) WITHIN THIS REGIME REMAIN UNCLEAR.
WARMING TEMPERATURES ALOFT MAY TEND TO SUPPRESS DEVELOPMENT ACROSS
THE WARM SECTOR, BUT SHORTWAVES EMANATING OUT OF THE WESTERN
MID/UPPER-LEVEL TROUGH MAY AID IN DEVELOPMENT OF AN ISOLATED
SUPERCELL OR TWO NEAR THE SURFACE TROUGH/DRYLINE AND/OR EFFECTIVE
WARM FRONT. ANY SURFACE-BASED DEVELOPMENT WITHIN THIS REGIME COULD
POSE A THREAT FOR ALL SEVERE HAZARDS.
A SOMEWHAT MORE LIKELY SCENARIO IS FOR STORMS TO EXPAND IN COVERAGE
NEAR/NORTH OF THE WARM FRONT DURING THE EVENING, IN RESPONSE TO A
STRENGTHENING LOW-LEVEL JET AND RELATED WARM-ADVECTION REGIME. LARGE
TO EXTREME BUOYANCY AND FAVORABLE DEEP-LAYER SHEAR WILL SUPPORT
ORGANIZED CONVECTION, WITH UPSCALE GROWTH INTO A POTENTIALLY INTENSE
MCS POSSIBLE WITH TIME. AT THIS TIME, THE MOST LIKELY MCS CORRIDOR
APPEARS TO BE SOMEWHERE FROM EASTERN ND INTO CENTRAL/NORTHERN MN,
NORTHERN WI, AND UPPER MI, THOUGH UNCERTAINTY REMAINS HIGH DUE TO
VARYING GUIDANCE SOLUTIONS REGARDING THE LOCATION OF THE WARM FRONT
AND EVOLUTION OF THE LOW-LEVEL JET.
DESPITE THE REMAINING UNCERTAINTY, A SLIGHT RISK HAS BEEN ADDED
GIVEN THE CONDITIONAL POTENTIAL FOR SIGNIFICANT SEVERE WEATHER. SOME
ADJUSTMENTS TO THIS AREA WILL LIKELY BE NEEDED WITH TIME, ALONG WITH
POSSIBLE UPGRADES.
..MONTANA
LOW-LEVEL EASTERLY FLOW WILL TRANSPORT MODEST MOISTURE INTO PARTS OF
CENTRAL/WESTERN MT DURING THE DAY ON FRIDAY. INCREASINGLY DIFLUENT
UPPER-LEVEL FLOW ASSOCIATED WITH THE DEEP WESTERN TROUGH WILL
SUPPORT DEVELOPMENT OF SCATTERED TO NUMEROUS THUNDERSTORMS THROUGH
THE DAY INTO FRIDAY NIGHT. ELONGATED HODOGRAPHS WILL SUPPORT
ORGANIZED STORMS, WITH A THREAT OF AT LEAST ISOLATED HAIL AND STRONG
TO SEVERE GUSTS WITH INITIAL CONVECTION OVER WESTERN MT. ONE OR MORE
CLUSTERS MAY MOVE INTO CENTRAL AND NORTHEAST MT BY EVENING, WITH A
CONTINUED THREAT OF SEVERE GUSTS AND HAIL. DEPENDING ON TRENDS
REGARDING DESTABILIZATION, GREATER SEVERE PROBABILITIES MAY
EVENTUALLY BE NEEDED.
..LOWER GREAT LAKES INTO THE NORTHEAST
MODEST LOW-LEVEL MOISTENING IS POSSIBLE DURING THE DAY ON FRIDAY
FROM THE LOWER GREAT LAKES INTO THE NORTHEAST, WITHIN A DEVELOPING
NORTHWESTERLY FLOW REGIME IN THE WAKE OF A DEPARTING MID/UPPER-LEVEL
TROUGH. WHILE WIND PROFILES MAY BECOME SOMEWHAT FAVORABLE FOR
ORGANIZED CONVECTION, RELATIVELY COOL POST-FRONTAL CONDITIONS AND
GENERALLY WEAK MIDLEVEL LAPSE RATES WILL TEND TO LIMIT
DESTABILIZATION, AND ANY FOCI FOR ROBUST STORM DEVELOPMENT ARE NOT
CLEAR AT THIS TIME.
..DEAN.. 06/18/2025
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