851
ACUS02 KWNS 301747
SWODY2
SPC AC 301745
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1245 PM CDT TUE JUN 30 2026
VALID 011200Z - 021200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN
MINNESOTA INTO PARTS OF NORTHERN/CENTRAL WISCONSIN AND NORTHERN
LOWER MICHIGAN...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHEAST AND THE CENTRAL HIGH PLAINS...
..SUMMARY
SCATTERED SEVERE STORMS WILL AGAIN BE POSSIBLE ACROSS THE UPPER
MIDWEST/GREAT LAKES WEDNESDAY INTO WEDNESDAY NIGHT. DAMAGING WIND
GUSTS (SOME TO 80 MPH) ARE EXPECTED, IN ADDITION TO ISOLATED LARGE
TO VERY LARGE HAIL AND A FEW TORNADOES. ADDITIONAL SEVERE STORMS,
POSING MAINLY A DAMAGING WIND RISK, ARE POSSIBLE ACROSS PARTS OF THE
NORTHEAST AND THE CENTRAL HIGH PLAINS.
..SYNOPSIS
AN UPPER SHORTWAVE TROUGH WILL MOVE ACROSS THE UPPER MIDWEST AND
GREAT LAKES WEDNESDAY, EVENTUALLY FLATTENING THE UPPER RIDGE OVER
THE NORTHEAST LATE IN THE PERIOD. WITH THIS SHORTWAVE, A BAND OF
ENHANCED MID/UPPER-LEVEL SOUTHWESTERLY FLOW WILL OVERSPREAD THE
UPPER MIDWEST AND GREAT LAKES. A QUASI-STATIONARY SURFACE BOUNDARY
WILL EXTEND FROM EASTERN SD NORTHEAST TOWARD LAKE SUPERIOR. ALONG
AND SOUTH OF THIS BOUNDARY WILL BE A FOCUS FOR POTENTIALLY MULTIPLE
ROUNDS OF SEVERE THUNDERSTORMS WEDNESDAY AND WEDNESDAY NIGHT ACROSS
THE UPPER MS VALLEY/GREAT LAKES. ADDITIONAL STRONG TO SEVERE STORMS
ARE EXPECTED ACROSS THE NORTHEAST, THE SOUTH, THE CENTRAL/SOUTHERN
HIGH PLAINS, AND PORTIONS OF MONTANA.
..UPPER MIDWEST/GREAT LAKES VICINITY
A SOMEWHAT SIMILAR PATTERN COMPARED TO PREVIOUS DAYS IS EXPECTED ON
WEDNESDAY. HOWEVER, THE UPPER TROUGH MOVING ACROSS THE REGION WILL
BE A BIT STRONG AS THE UPPER LOW OVER THE CANADIAN PRAIRIES FINALLY
BECOMES MORE PROGRESSIVE. A BELT OF 50-70 KT SOUTHWESTERLY FLOW
BETWEEN 700-500 MB IS NOTED IN VARIOUS FORECAST GUIDANCE, SUPPORTING
40+ KT EFFECTIVE SHEAR MAGNITUDES AND SUPERCELL WIND PROFILES. THE
BOUNDARY LAYER CONTINUES TO BE VERY MOIST, WITH DEWPOINTS IN THE MID
60S TO MID 70S PRESENT BENEATH MODESTLY STEEP MIDLEVEL LAPSE RATES,
RESULTING IN STRONG TO EXTREME BUOYANCY.
CONVECTION MAY BE ONGOING EARLY IN THE PERIOD NEAR SOUTHERN MN,
THOUGH WHERE EXACTLY THESE STORMS ARE LOCATED DEPENDS ON CONVECTIVE
EVOLUTION IN THE CURRENT DAY 1/TUESDAY PERIOD. THIS CONVECTION COULD
BE SEVERE WITH A RISK FOR DAMAGING WINDS AND HAIL. IT IS POSSIBLE
THIS ACTIVITY COULD DEVELOP EAST/NORTHEAST ALONG THE SURFACE
BOUNDARY AND INTENSIFY THROUGH THE MORNING/AFTERNOON AS IT MOVES
ACROSS WI AND POSE A SEVERE RISK OF DAMAGING WINDS. OR, IT COULD
WEAKEN AND ADDITIONAL SEVERE STORMS COULD DEVELOP NEAR THE SURFACE
BOUNDARY ACROSS WI/NORTHERN MI DURING THE DAY. ANOTHER ROUND OF
CONVECTION IS EXPECTED TO DEVELOP DURING THE EVENING ACROSS SOUTHERN
MN. THIS ACTIVITY COULD INITIALLY BE SUPERCELLS, WITH AN
ACCOMPANYING ALL-HAZARDS SEVERE RISK. HOWEVER, STORMS ARE EXPECTED
TO QUICKLY GROW UPSCALE INTO A BOWING MCS, MOVING EAST/NORTHEAST
THROUGH THE NIGHTTIME HOURS ACROSS WI/MI.
WHILE EXACT CONVECTIVE EVOLUTION IS UNCERTAIN, IT DOES APPEAR THAT
MORE THAN ONE ROUND OF SEVERE STORMS IS POSSIBLE ACROSS THE REGION
ON WEDNESDAY. SWATHS OF DAMAGING WINDS (SOME TO NEAR 80 MPH) APPEAR
LIKELY. ISOLATED LARGE TO VERY LARGE HAIL ALSO IS POSSIBLE,
ESPECIALLY IF ANY SUPERCELL STORM MODE CAN PERSIST. A FEW TORNADOES
ALSO WILL BE POSSIBLE.
..NORTHEAST
ENHANCED WEST/NORTHWESTERLY FLOW WILL CONTINUE ON WEDNESDAY ACROSS
THE REGION. ANOTHER DAY OF VERY MOIST AND HOT CONDITIONS IS
EXPECTED, SUPPORTING A CORRIDOR OF STRONG TO EXTREME BUOYANCY.
THUNDERSTORM CLUSTERS POSING A DAMAGING WIND AND ISOLATED HAIL RISK
WILL BE POSSIBLE DURING THE AFTERNOON. MORE ORGANIZED CONVECTION IS
EXPECTED TO SWEEP ACROSS THE REGION DURING THE EVENING/OVERNIGHT
HOURS AS THE UPPER RIDGE BREAKS DOWN WITH THE APPROACH OF AN UPPER
SHORTWAVE TROUGH OVER THE UPPER GREAT LAKES. ORGANIZED CONVECTION
OVER ONTARIO/QUEBEC WILL LIKELY MOVE EAST/SOUTHEAST DURING THE
NIGHTTIME HOURS AND POSE A RISK FOR DAMAGING WIND GUSTS.
..CENTRAL/SOUTHERN HIGH PLAINS
CONVECTION IS EXPECTED TO DEVELOP ALONG A SURFACE DRYLINE WEDNESDAY
AFTERNOON/EVENING. VERTICALLY VEERING WIND PROFILES WILL INCREASE
SOUTHWESTERLY FLOW ALOFT WILL SUPPORT TRANSIENT SUPERCELL STRUCTURES
INITIALLY. FORECAST HODOGRAPHS SHOW 25 KT EFFECTIVE SHEAR MAGNITUDES
AMID LONG/STRAIGHT HODOGRAPHS. STRONG/SEVERE OUTFLOW WINDS WILL BE
POSSIBLE, ALONG WITH ISOLATED HAIL. SUFFICIENT CLUSTERING/OUTFLOW
CONSOLIDATION MAY OCCUR, SUPPORTING GREATER WIND POTENTIAL,
PARTICULARLY ACROSS THE WESTERN KS VICINITY.
..LOWER MS/TN VALLEYS VICINITY
A SIMILAR PATTERN WILL EXIST ACROSS THE REGION ON WEDNESDAY ON THE
SOUTHERN PERIPHERY OF THE UPPER ANTICYCLONE OVER THE EASTERN U.S.
FORECAST GUIDANCE ONCE AGAIN DEPICTS MODEST MIDLEVEL
EAST/NORTHEASTERLY FLOW PROVIDING SUPPORT FOR 20-25 KT EFFECTIVE
SHEAR MAGNITUDES. THUNDERSTORM CLUSTERS WILL DEVELOP DURING THE
AFTERNOON WITHIN THE THETA-E AXIS. THE VERY MOIST AND ABUNDANTLY
UNSTABLE AIRMASS WILL SUPPORT A WET MICROBURST RISK. IF SUFFICIENT
CLUSTERING OCCURS, SOME POTENTIAL FOR FORWARD PROPAGATING CONVECTION
WILL EXIST, WHICH COULD INCREASE DAMAGING WIND POTENTIAL THROUGH
EARLY EVENING.
..MT
AN UPPER TROUGH OVER THE WESTERN U.S. WILL BRING MODESTLY ENHANCED
SOUTHWESTERLY MID/UPPER FLOW ACROSS PORTIONS OF THE NORTHERN ROCKIES
WEDNESDAY AFTERNOON/EVENING. A PLUME OF STEEPER MIDLEVEL LAPSE RATES
WILL GRADUALLY SPREAD NORTHEAST FROM THE GREAT BASIN INTO PARTS OF
SOUTHWEST/CENTRAL MT ATOP MODEST LOW-LEVEL MOISTURE. THIS WILL
SUPPORT 500-1000 J/KG MLCAPE. STEEP LOW-LEVEL LAPSE RATES AND
SUFFICIENT VERTICAL SHEAR FOR ORGANIZED CELLS/CLUSTERS WILL RESULT
IN A RISK FOR ISOLATED STRONG TO SEVERE WIND GUSTS.
..LEITMAN.. 06/30/2026
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