167
ACUS02 KWNS 251730
SWODY2
SPC AC 251729
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1229 PM CDT THU JUN 25 2026
VALID 261200Z - 271200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF FAR
EASTERN MISSOURI...SOUTHERN ILLINOIS INTO SOUTHERN INDIANA...AND
NORTHWESTERN KENTUCKY...
..SUMMARY
ISOLATED SEVERE STORMS WILL BE POSSIBLE ACROSS THE HIGH PLAINS,
SOUTHERN KANSAS AND NORTHERN OKLAHOMA, AND INTO THE OHIO VALLEY ON
FRIDAY. ADDITIONAL SEVERE STORMS CAPABLE OF DAMAGING WIND AND
ISOLATED LARGE HAIL WILL ALSO BE POSSIBLE ACROSS PORTIONS OF THE
NORTHEAST.
..SYNOPSIS
A MID-LEVEL TROUGH ACROSS THE NORTHERN PACIFIC WILL DEEPEN AND BEGIN
TO SHIFT INLAND ACROSS THE WESTERN US ON FRIDAY. HEIGHT RISES WILL
BEGIN AS RIDGING BUILDS IN ACROSS THE CENTRAL/NORTHERN PLAINS.
BETWEEN THESE FEATURES, STRONG SOUTHWESTERLY FLOW ALOFT WILL
OVERSPREAD THE NORTHERN ROCKIES, WITH RESULTING LEE CYCLOGENESIS
OCCURRING ACROSS MONTANA/NORTHERN WYOMING. FURTHER EAST, A SHORTWAVE
TROUGH WILL MOVE ACROSS THE MIDDLE MISSISSIPPI VALLEY/OHIO VALLEY,
WITH A SURFACE LOW POSSIBLY DEEPENING AND MOVING NORTHEAST FROM
TEXAS INTO THE MIDDLE MISSISSIPPI/OHIO VALLEY. ACROSS THE
NORTHEASTERN US, A BELT OF STRENGTHENING MID-LEVEL FLOW WILL SHIFT
THROUGH THE BROADER MID-LEVEL TROUGH AS A SURFACE LOW SHIFTS INTO
QUEBEC. A BROAD COLD FRONT WILL EXTEND FROM THE NORTHEASTERN SURFACE
LOW BACK INTO THE MISSISSIPPI VALLEY AND CENTRAL/SOUTHERN PLAINS.
..HIGH PLAINS
INCREASING MID-LEVEL ASCENT AND SURFACE LOW DEVELOPMENT WILL SUPPORT
SCATTERED THUNDERSTORM DEVELOPMENT ACROSS THE HIGH TERRAIN FROM
EASTERN MONTANA SOUTH INTO WYOMING AND COLORADO. HEIGHT RISES ACROSS
THE CENTRAL/NORTHERN PLAINS MAY INHIBIT COVERAGE A BIT WITH EASTWARD
EXTENT. WEAK TO MODERATE INSTABILITY IS PROGGED BY THE AFTERNOON
ALONG WITH STEEP LOW TO MID-LEVEL LAPSE RATES. DEEP LAYER SHEAR WILL
BE STRONGEST ACROSS EASTERN MONTANA, WEAKENING INTO
WYOMING/COLORADO. GIVEN MODEST SHEAR, POTENTIAL FOR A MIXED MODE OF
SUPERCELLS AND MULTI-CELL CLUSTERS CAPABLE OF DAMAGING WINDS AND
LARGE HAIL.
..CENTRAL/SOUTHERN PLAINS TO THE OHIO VALLEY
A BROAD AREA OF SHOWERS/THUNDERSTORM ACTIVITY IS LIKELY TO BE
ONGOING NEAR THE START OF THE PERIOD FROM THE MID MISSISSIPPI VALLEY
INTO THE GREAT LAKES REGION. THE FOCUS FOR AFTERNOON REDEVELOPMENT
ACROSS PORTIONS OF EASTERN MISSOURI INTO SOUTHERN ILLINOIS/INDIANA
WILL LIKELY BE WHERE THE RESIDUAL OUTFLOW/DIFFERENTIAL HEATING
BOUNDARY INTERSECTS THE SURFACE COLD FRONT BY THE AFTERNOON.
GUIDANCE SUGGESTS THAT THOUGH CLOUD COVER MAY LINGER, AIR MASS
RECOVERY THROUGH FILTERED HEATING WILL LEAD TO MODERATE INSTABILITY
BY THE AFTERNOON. RECENT TRENDS IN 06Z ECMWF GUIDANCE HAS COME INTO
SOMEWHAT BETTER AGREEMENT WITH THE NAM, WHICH WAS AN OUTLIER IN THE
00Z GUIDANCE, SUGGESTING THAT A SURFACE LOW MAY DEEPEN ACROSS
SOUTHERN ILLINOIS/INDIANA BY THE AFTERNOON. THIS WOULD RESULT IN
MUCH STRONGER LOW-LEVEL JET RESPONSE ACROSS THE REGION AND POTENTIAL
FOR AN INCREASE IN TORNADO POTENTIAL. SOME LIMITING FACTORS MAY BE
THE RELATIVELY WEAK MID-LEVEL FLOW AND STORM MODE. NONETHELESS,
TORNADO PROBABILITIES WERE INCREASED TO 5% TO ACCOUNT FOR SOME
POTENTIAL FOR A TORNADO OR TWO. THE MAIN THREATS WILL LIKELY BE
DAMAGING WIND AND HAIL WITH SUPERCELLS AND MULTI-CELL CLUSTERS
DEVELOPING NEAR AND AHEAD OF THE FRONT BY THE AFTERNOON.
ADDITIONAL THUNDERSTORM DEVELOPMENT IS LIKELY ALONG THE FRONT SOUTH
AND WESTWARD INTO PORTIONS OF THE SOUTHERN PLAINS. FORCING FOR
ASCENT WILL BE WEAKER TO THE WEST, BUT SUFFICIENT DEEP LAYER SHEAR
FOR A FEW ORGANIZED STORMS WILL BE IN PLACE NEAR THE FRONTAL ZONE
AMID MODERATE TO STRONG INSTABILITY. THESE STORMS WILL POSE
POTENTIAL FOR DAMAGING WIND AND HAIL ALSO.
..NORTHEAST
A BELT OF STRONG MID-LEVEL WESTERLY FLOW WILL OVERSPREAD THE
NORTHEAST IN THE WAKE OF MORNING CONVECTION. WHILE IT REMAINS
UNCERTAIN HOW MUCH DESTABILIZATION CAN OCCUR BEHIND THE MORNING
ACTIVITY, IT DOES APPEAR THAT ADDITIONAL THUNDERSTORMS ARE LIKELY
TO DEVELOP BY THE AFTERNOON. GIVEN STRONG DEEP LAYER SHEAR PROFILES
AMID STRENGTHENING UPPER-LEVEL FLOW, THESE STORMS WILL POSE SOME
POTENTIAL FOR DAMAGING WIND AND FEW INSTANCES OF LARGE HAIL.
..THORNTON.. 06/25/2026
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