109
ACUS01 KWNS 111624
SWODY1
SPC AC 111622
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1122 AM CDT THU JUN 11 2026
VALID 111630Z - 121200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTHERN ILLINOIS...FAR EASTERN IOWA...AND FAR SOUTHERN WISCONSIN...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-ATLANTIC AND CENTRAL APPALACHIANS...
..SUMMARY
WIDESPREAD SEVERE THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND
EVENING ACROSS PARTS OF THE MIDWEST AND GREAT LAKES REGION,
INCLUDING FAR EASTERN IOWA, NORTHERN MISSOURI, NORTHERN/CENTRAL
ILLINOIS, SOUTHERN WISCONSIN, LOWER MICHIGAN, AND NORTHERN INDIANA.
THIS INCLUDES THE POTENTIAL FOR WIDESPREAD/INTENSE DAMAGING WINDS
(SOME 75+ MPH), LARGE HAIL, AND SEVERAL TORNADOES, SOME OF WHICH MAY
BE STRONG TO INTENSE.
..MIDWEST/GREAT LAKES
AN ACTIVE AND IMPACTFUL SEVERE WEATHER EVENT IS STILL EXPECTED
ACROSS PARTS OF THE MIDWEST GREAT LAKES LATER THIS AFTERNOON AND
EVENING. ONGOING BOWING CLUSTER ACROSS SOUTHEAST IA/NORTHWEST
IL/SOUTHWEST WI AND VICINITY MAY CONTINUE TO POSE AT LEAST SOME
SEVERE WIND AND EMBEDDED QLCS TORNADO THREAT AS IT CONTINUES
EAST-NORTHEASTWARD ACROSS PARTS OF THE MIDWEST THIS AFTERNOON. THERE
IS STILL AIRMASS RECOVERY UNDERWAY AHEAD OF THIS ACTIVITY,
ESPECIALLY INTO CENTRAL/NORTHERN IL, NORTHERN IN, AND PARTS OF
SOUTHERN LOWER MI WHERE STRONG HEATING IS OCCURRING. ENHANCED
MID-LEVEL WEST-SOUTHWESTERLY WINDS ASSOCIATED WITH A POTENT
SHORTWAVE TROUGH OVER THE NORTHERN PLAINS/UPPER MIDWEST WILL
OVERSPREAD THE DEVELOPING WARM SECTOR THIS AFTERNOON, AND SUPPORT
ORGANIZED SEVERE POTENTIAL, INCLUDING THE POSSIBILITY OF MULTIPLE
TORNADIC SUPERCELLS AND WIDESPREAD SEVERE/DAMAGING WINDS.
EVEN SO, GREATER THAN USUAL UNCERTAINTY EXISTS REGARDING
REDEVELOPMENT LATER TODAY ON THE SOUTHERN/WESTERN FLANK OF ONGOING
CONVECTION ACROSS NORTHERN IL INTO NORTHEAST MO AND VICINITY. A
GRADUAL INCREASE IN BOTH LOW-LEVEL AND DEEP-LAYER SHEAR IS
ANTICIPATED ACROSS THIS AREA AS A 30-40+ KT SOUTHERLY LOW-LEVEL JET
DEVELOPS EASTWARD IN TANDEM WITH THE EASTWARD-EJECTING SHORTWAVE
TROUGH AND MID-LEVEL JET. A MIX OF SUPERCELLS AND BOWING SEGMENTS
APPEARS PROBABLE AS RENEWED THUNDERSTORMS DEVELOP ALONG/AHEAD OF THE
SURFACE COLD FRONT THIS AFTERNOON IN A STRONGLY UNSTABLE AND RATHER
FAVORABLY SHEARED ENVIRONMENT. IF AT LEAST SEMI-DISCRETE SUPERCELL
STRUCTURES CAN BE MAINTAINED, THEN POTENTIAL EXISTS FOR SEVERAL
TORNADOES, AND MULTIPLE STRONG TO INTENSE TORNADOES (EF-2/3+) GIVEN
THE ENHANCED LOW-LEVEL SHEAR. ISOLATED LARGE TO VERY LARGE HAIL MAY
ALSO OCCUR WITH ANY SUSTAINED SUPERCELLS.
OTHERWISE, NUMEROUS TO POTENTIALLY WIDESPREAD SEVERE/DAMAGING WINDS
ALSO APPEAR LIKELY THROUGH THE PERIOD ACROSS PARTS OF
NORTHERN/CENTRAL IL INTO SOUTHERN LOWER MI AND NORTHERN IN. BOTH THE
ONGOING CLUSTER AND EVENTUAL UPSCALE GROWTH OF CONVECTION THAT
DEVELOPS THIS AFTERNOON WILL LIKELY PRODUCE SEVERE/DAMAGING WINDS,
SOME OF WHICH COULD BE SIGNIFICANT (75+ MPH). THE NORTHERN EXTENT OF
THE SEVERE RISK INTO WI AND NORTHERN LOWER MI REMAINS UNCERTAIN, BUT
AT LEAST SOME WIND AND/OR TORNADO THREAT WILL LIKELY CONTINUE WITH
EASTWARD EXTENT INTO THE SOUTHERN GREAT LAKES AND NORTHERN IN THIS
EVENING.
..EASTERN KANSAS/SOUTHERN MISSOURI INTO THE SOUTHERN PLAINS
ADDITIONAL THUNDERSTORMS WILL LIKELY DEVELOP THIS AFTERNOON AND
EVENING ALONG THE TRAILING COLD FRONT INTO PORTIONS OF EASTERN
KS/SOUTHERN MO INTO THE SOUTHERN PLAINS. STRONGER DEEP-LAYER SHEAR
IS FORECAST TO LAG BEHIND/TO THE NORTH OF THE COLD FRONT. STILL,
AROUND 20-30 KT OF EFFECTIVE BULK SHEAR AND MODERATE TO STRONG
INSTABILITY WILL SUPPORT MARGINAL SUPERCELL STRUCTURES AND LOOSELY
ORGANIZED MULTICELLS CAPABLE OF PRODUCING BOTH LARGE HAIL AND
DAMAGING WINDS. A LARGE COMPONENT OF BOUNDARY-PARALLEL SHEAR WILL
LIKELY LEAD TO CLUSTERING AND MESSY CONVECTIVE MODES THROUGH THE
EVENING BEFORE THUNDERSTORMS GRADUALLY WEAKEN WITH THE LOSS OF
DAYTIME HEATING.
..MID-ATLANTIC/CENTRAL APPALACHIANS
RECENT VISIBLE SATELLITE IMAGERY ACROSS MUCH OF THE MID-ATLANTIC AND
CENTRAL APPALACHIANS SHOWS MOSTLY SUNNY TO PARTLY CLOUDY CONDITIONS,
WITH AMPLE LOW-LEVEL MOISTURE PRESENT PER LATEST SURFACE
OBSERVATIONS AND AREA 12Z OBSERVED SOUNDINGS. LARGE-SCALE ASCENT
ASSOCIATED WITH MULTIPLE LOW-AMPLITUDE MID-LEVEL SHORTWAVE TROUGHS
WILL LIKELY SUPPORT THE DEVELOPMENT OF WIDELY SCATTERED
THUNDERSTORMS BY AFTERNOON ACROSS PARTS OF THE MID-ATLANTIC INTO THE
CENTRAL APPALACHIANS. THOUGH DEEP-LAYER SHEAR IS FORECAST TO REMAIN
MODEST, MODERATE TO STRONG INSTABILITY WILL EXIST WITH CONTINUED
DIURNAL HEATING THIS AFTERNOON. THIS WILL SUPPORT STRONGER UPDRAFTS
CAPABLE OF SCATTERED SEVERE/DAMAGING WINDS AND PERHAPS ISOLATED
HAIL. MULTIPLE CLUSTERS SHOULD EVENTUALLY EMERGE, WITH POTENTIAL FOR
ORGANIZING ALONG OUTFLOW/COLD POOLS, AND MORE FOCUSED CORRIDORS OF
DAMAGING WINDS POSSIBLE ACROSS PARTS OF THE I-95 CORRIDOR FROM
NORTHERN VA TO EASTERN PA AND NJ.
..GLEASON/FLOURNOY.. 06/11/2026
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