247
ACUS01 KWNS 112002
SWODY1
SPC AC 112000
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0300 PM CDT FRI SEP 11 2026
VALID 112000Z - 121200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
MIDWEST...
..SUMMARY
SCATTERED SEVERE THUNDERSTORMS CAPABLE OF PRODUCING LARGE HAIL,
(SOME 2+ INCHES), DAMAGING WINDS, AND A COUPLE OF TORNADOES ARE
EXPECTED LATE THIS AFTERNOON AND TONIGHT ACROSS PARTS OF THE UPPER
MIDWEST. THUNDERSTORM DEVELOPMENT IS MORE UNCERTAIN FARTHER SOUTH
INTO THE CENTRAL PLAINS, WHERE A RISK FOR LARGE HAIL AND SEVERE
GUSTS MAY EXIST LATE THIS AFTERNOON INTO THE EVENING.
..20Z UPDATE
THE ONGOING FORECAST REMAINS MOSTLY ON TRACK WITH MOST AREAS
REMAINING UNCHANGED. GIVEN THE SIGNAL FOR THE COLD FRONT TO PUSH
INTO NORTHERN KANSAS BY EARLY SATURDAY MORNING, ALONG WITH AT LEAST
A MODEST LOW-LEVEL JET, MARGINAL WIND/HAIL PROBABILITIES HAVE BEEN
EXTENDED INTO MORE OF CENTRAL KANSAS FOR THE CONDITIONAL POTENTIAL
OF SEVERE STORMS OVERNIGHT.
..WENDT.. 09/11/2026
PREV DISCUSSION
/ISSUED 1127 AM CDT FRI SEP 11 2026/
..UPPER MIDWEST/CENTRAL PLAINS
AN EASTWARD-PROGRESSIVE BELT OF QUASI-ZONAL WESTERLIES EXISTS OVER
THE NORTHERN HALF OF THE CONUS, TO THE SOUTH OF UPPER TROUGHING OVER
THE CANADIAN PRAIRIES/CENTRAL CANADA, AND THE EAST OF THE AMPLIFYING
UPPER TROUGH OFF THE COASTAL PACIFIC NORTHWEST. WEAK FRONTAL WAVE
DEVELOPMENT WILL OCCUR FROM EASTERN SOUTH DAKOTA INTO MINNESOTA AS A
COLD FRONT SPREADS EASTWARD, WITH THE FRONT EVENTUALLY OVERTAKING A
PRE-FRONTAL TROUGH/DRYLINE ACROSS THE CENTRAL PLAINS.
A NARROW CORRIDOR OF 60S F SURFACE DEWPOINTS ARE IN PLACE AHEAD OF
THE COLD FRONT/DRYLINE, WITH DIURNAL HEATING AIDING MODERATE
DESTABILIZATION ALONG WITH STEEPENED MID-LEVEL LAPSE RATES. MINIMAL
MLCIN IS EXPECTED ALONG/AHEAD OF THE FRONT IN FAR NORTHEAST SOUTH
DAKOTA/WESTERN MINNESOTA INTO/JUST AFTER PEAKING HEATING. CONVECTIVE
DEVELOPMENT APPEARS LIKELY IN THIS TIME FRAME ACROSS THIS REGION,
ESPECIALLY ACROSS MINNESOTA, OWING TO SUFFICIENT LOW-LEVEL
CONVERGENCE ALONG THE FRONT COUPLED WITH FORCING FOR ASCENT
ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH.
STRONGLY VEERING AND GRADUALLY STRENGTHENING WINDS WITH HEIGHT
THROUGH LOW/MID-LEVELS, AND 35-45 KT OF DEEP-LAYER SHEAR WILL EASILY
SUPPORT ORGANIZED CONVECTION. INITIAL SUPERCELLS SHOULD POSE A
THREAT FOR LARGE HAIL (ISOLATED 2+ INCHES POSSIBLE), BUT CONVECTIVE
MODE WILL PROBABLY TREND TOWARDS CLUSTERING FAIRLY QUICKLY GIVEN THE
PRESENCE OF THE COLD FRONT AND STRENGTHENING LOW-LEVEL JET THIS
EVENING. ANY SUPERCELLS THAT CAN REMAIN AT LEAST SEMI-DISCRETE INTO
THE EARLY EVENING MAY ALSO HAVE A TORNADO THREAT WITH GREATER
LOW-LEVEL SHEAR FORECAST IN THIS TIME FRAME. SCATTERED
SEVERE/DAMAGING WINDS SHOULD OCCUR WITH ANY CLUSTERS OR BOWING LINE
SEGMENTS THAT CAN DEVELOP AND SPREAD EASTWARD THROUGH THE EVENING.
HOWEVER, THE WIND THREAT WILL LIKELY WANE WITH EASTWARD EXTENT
ACROSS MINNESOTA INTO WESTERN WISCONSIN BY LATE THIS EVENING GIVEN
THE NARROW ZONE OF DESTABILIZATION FORECAST.
FARTHER SOUTHWEST, CONVECTIVE INITIATION AND OVERALL THUNDERSTORM
COVERAGE FROM SOUTHEAST SOUTH DAKOTA/SOUTHWEST MINNESOTA
SOUTHWESTWARD INTO NEBRASKA AND NORTHERN KANSAS ARE MORE UNCERTAIN
AND PROBABLY MORE LIMITED/CONDITIONAL LATE THIS AFTERNOON AND
EVENING, AS THE BETTER FORCING FOR ASCENT WITH THE SHORTWAVE TROUGH
WILL REMAIN REGIONALLY FOCUSED TO THE NORTH. STILL, A FAVORABLE
THERMODYNAMIC ENVIRONMENT AND SUFFICIENT (25-35 KT) DEEP-LAYER SHEAR
WOULD CONDITIONALLY SUPPORT SEVERE HAIL/WIND WITH ANY THUNDERSTORMS
THAT CAN DEVELOP AND BE SUSTAINED.
..MID-SOUTH/TENNESSEE VALLEY/CAROLINAS AND VIRGINIA
MULTIPLE CONVECTIVELY AUGMENTED MID-LEVEL PERTURBATIONS REMAIN
EVIDENT AT MIDDAY IN SATELLITE/RADAR IMAGERY, INCLUDING OVER THE
OZARKS AS WELL AS THE MIDDLE GULF COAST IN VICINITY OF SOUTHERN
ALABAMA. A STALLED SURFACE FRONT EXTENDING FROM THE ARKLATEX
EAST-NORTHEASTWARD INTO THE TENNESSEE VALLEY AND VIRGINIA WILL
PROVIDE A FOCUS FOR THUNDERSTORMS. GENERALLY SPEAKING, EXPECTATIONS
ARE FOR GENERALLY DISORGANIZED/PULSE-TYPE CONVECTION TO POSE A
THREAT FOR OCCASIONAL DAMAGING WINDS AS DIURNAL HEATING DESTABILIZES
THE BOUNDARY LAYER AND STEEPENS LOW-LEVEL LAPSE RATES. HOWEVER, A
MODEST ENHANCEMENT TO MID-LEVEL FLOW ACROSS PARTS OF THE MID-SOUTH
(25 KT MID-LEVELS PER LITTLE ROCK AR WSR-88D VWP), AS WELL AS
VIRGINIA, COULD PROMOTE A COUPLE OF LOOSELY ORGANIZED CLUSTERS WITH
A BIT MORE OF A FOCUSED DAMAGING WIND THREAT.
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