710
FXUS63 KARX 020645
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
145 AM CDT WED SEP 2 2026
KEY MESSAGES
- SEVERE STORMS EXPECTED NEAR THE INTERSTATE 90 CORRIDOR
OVERNIGHT. THE MAIN THREAT IS DAMAGING WINDS.
- SEVERAL MESOSCALE CONVECTIVE COMPLEXES WILL AFFECT THE AREA
NIGHTLY THROUGH THE UPCOMING WEEKEND. THE ONE ON THURSDAY
NIGHT MIGHT PRODUCE DAMAGING WINDS.
DISCUSSION
ISSUED AT 145 AM CDT TUE SEP 2 2026
OVERNIGHT: STRONG TO SEVERE STORMS
AS THE 30 TO 40 KNOT 850 MB NOCTURNAL JET GRADUALLY VEERS FROM
SOUTHWEST TO WEST OVERNIGHT, THE A SEVERE THUNDERSTORM COMPLEX
WILL GRADUALLY TURN AND MOVE ALONG THE INTERSTATE 90 CORRIDOR.
AS THE COLD POOL CONTINUES TO COALESCE, THIS COMPLEX WILL BECOME
A PROGRESSIVE LINEAR MESOSCALE CONVECTIVE COMPLEX. THE BIGGEST
QUESTION AT THIS TIME WILL BE WHEN WILL THIS EASTWARD TURN
OCCURS. IF THIS OCCURS TOO LATE (BETWEEN 2 AND 4 AM), THIS
SYSTEM WILL HAVE LESS DOWNDRAFT CAPE AND MORE CONVECTIVE
INHIBITION (CIN) TO CONTEND WITH AS IT MOVES FURTHER EAST. IN
THIS SCENARIO, THE WINDS WOULD REMAIN ALOFT AND THE SYSTEM WOULD
RAPIDLY WEAKEN AS IT MOVES AWAY FROM THE BETTER INSTABILITY. IF
THIS SYSTEM TURNS EAST BY 2 AM, THE CIN WOULD BE LESS THAN 50
J/KG AND THE DOWNDRAFT CAPE WOULD BE AROUND 1000 J/KG. UNDER
THIS SCENARIO, THERE WILL BE A POSSIBILITY FOR NARROW BAND OF
STRONG TO SEVERE WINDS (40-65 MPH) ON THE SOUTHERN EDGE OF
BOWING COMPLEX. THE WIND THREAT WOULD BE 1 TO 2 COUNTIES WIDE IN
SOUTHEAST MINNESOTA AND ALONG AND NORTH OF I-90 IN WESTERN
WISCONSIN. THERE MIGHT ALSO BE A BRIEF QLCS TORNADO THREAT NEAR
THE MINNESOTA AND IOWA CORRIDOR. AT THIS TIME, SCENARIO LOOKS
MORE LIKELY.
FURTHER EAST, THERE IS A QUASI-STATIONARY BOUNDARY STATIONED
ALONG THE I-90 CORRIDOR. STORM PARAMETERS OF MLCAPE AHEAD OF THE
TROUGH ARE BETWEEN 1500 AND 2500 J/KG WITH SUFFICIENT DEEP
LAYER SHEAR (0-6KM) OF 45 TO 55 KNOTS. THE EXPECTATION IS THAT
THESE STORMS WILL GROW UPSCALE AND MERGE INTO THE MCC. SOUNDINGS
SUGGEST THAT THESE ELEVATED STORMS WILL OCCASIONALLY SPLIT WITH
THE LEFT MOVERS BEING FAVORED TO PRODUCE LARGE (HAIL UP TO GOLF
BALL) AS THEY MOVE NORTHEAST AT 40 TO 45 KNOTS.
TODAY: SCATTERED STORMS CONTINUE
THE QUASI-STATIONARY BOUNDARY WILL REMAIN NEAR AND SOUTH OF THE
I-90 CORRIDOR. WITH 0-1 KM MOST-UNSTABLE CAPES OF 2500 TO 3500
J/KG AND 30-40 KNOT 0-6 KM SHEAR, THERE WILL BE THE POSSIBILITY
OF SCATTERED STRONG TO SEVERE STORMS.
HIGH TEMPERATURES WILL RANGE FROM THE UPPER 70S TO MID-80S NORTH
OF INTERSTATE 94 AND FROM THE MID-80S TO LOWER 90S ELSEWHERE.
TONIGHT AND THURSDAY MORNING: ANOTHER THUNDERSTORM COMPLEX
ANOTHER MESOSCALE CONVECTIVE COMPLEX WILL DEVELOP ACROSS
NORTHWEST MINNESOTA THIS EVENING ON A NOSE OF A 25-30 KNOT
850 MB JET. AS THIS NOCTURNAL JET GRADUALLY VEERS OVERNIGHT,
THIS COMPLEX IS EXPECTED TO SHIFT EAST AND THEN SOUTHEAST. WITH
WEAKENING 0-6 KM SHEAR OVERNIGHT, NOT EXPECTING ANY SEVERE
ORGANIZED SEVERE WEATHER.
LOW TEMPERATURES WILL RANGE FROM THE UPPER 50S TO MID-60S NORTH
OF INTERSTATE 94 AND FROM THE MID-60S TO LOWER 70S.
THURSDAY NIGHT INTO FRIDAY MORNING: ANOTHER THUNDERSTORM COMPLEX
SHOWERS AND STORMS WILL DEVELOP AHEAD OF A SHORTWAVE TROUGH LATE
THURSDAY AFTERNOON AND EVENING OVER NORTHEAST SOUTH DAKOTA AND
CENTRAL AND NORTHWEST MINNESOTA. AS THESE COLD POOLS COALESCE,
A THUNDERSTORM COMPLEX WILL GRADUALLY DEVELOP. OVER TIME AS THE
LOW LEVEL JET VEERS AND THE COLD POOL GROWS LARGE, THIS WILL
LIKELY BECOME A RATHER PROGRESSIVE LINEAR MESOSCALE CONVECTIVE
COMPLEX WHICH WILL MOVE SOUTHEAST THROUGH THE UPPER MISSISSIPPI
RIVER VALLEY. THE MAIN SEVERE WEATHER THREAT WILL BE DAMAGING
WINDS.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 145 AM CDT TUE SEP 2 2026
SEVERAL ROUNDS OF STORMS WILL AFFECT THE TAF SITES OVERNIGHT. A
FEW OF THESE STORMS MAY BECOME SEVERE THROUGH 02.08Z FOR KRST
AND THROUGH 02.10Z FOR KLSE. THE MAIN THREAT WILL BE DAMAGING
WINDS.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...CECAVA/BOYNE
AVIATION...BOYNE
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