237
FXUS63 KARX 240500
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1200 AM CDT THU SEP 24 2026
KEY MESSAGES
- THE POTENTIAL FOR RAIN LATER THIS AFTERNOON AND TONIGHT HAS
INCREASED RAPIDLY FROM PREVIOUS FORECASTS--NOW UP TO A 40-70%
CHANCE--THOUGH RAINFALL AMOUNTS LOOK TO BE LIGHT WITH ONLY A
10-20% CHANCE OF >0.25" WEST OF THE MISSISSIPPI RIVER.
- THE POTENTIAL FOR RAIN LINGERS INTO FRIDAY AND SATURDAY WEST
OF THE MISSISSIPPI RIVER (20-50% CHANCE). AMOUNTS LOOK LIGHT
AS WELL AND THE SHOWERS MORE SCATTERED IN NATURE.
- THE END OF THE WEEKEND AND START OF NEXT WEEK IS SHAPING UP TO
BE DRY BEFORE ANOTHER STRETCH OF WETTER WEATHER PUSHES THROUGH
TUESDAY INTO MIDWEEK.
- LITTLE CHANGE IN TEMPERATURES INTO NEXT WEEK WITH READINGS
RUNNING SLIGHTLY BELOW SEASONAL NORMS.
DISCUSSION
ISSUED AT 1200 AM CDT THU SEP 24 2026
THIS AFTERNOON - TONIGHT: RAPIDLY INCREASING RAINFALL POTENTIAL
THE ONE BIG CHANGE TO THE NEAR-TERM FORECAST HAS BEEN A RAPID
INCREASE IN THE PROBABILITIES FOR LIGHT TO MODERATE RAINFALL
SPREADING EASTWARD FROM CENTRAL MN AFTER NOON, REACHING THE
MISSISSIPPI RIVER TOWARDS SUNSET AND LINGERING FOR MANY LOCALES
THROUGH THE NIGHT INTO FRIDAY.
A SMALL EASTWARD WOBBLE OF THE LOWER TROPOSPHERIC RIDGE AXIS IS
ALL IT TOOK FOR THE EASTWARD EXTENT OF THE RAIN SHIELD TO SHIFT
FROM THE I-35 CORRIDOR TO NOW WESTERN AND CENTRAL WI. THE
SIGNAL IN THE SHORT AND MEDIUM RANGE ENSEMBLES
(LREF/EPS/GEFS/HREF) IS NEARLY UNANIMOUS IN THERE BEING RAIN
WEST OF THE MISSISSIPPI RIVER, WITH THE NUMBER OF DRY MEMBERS
INCREASING AS ONE HEADS FURTHER EAST. WHILE THE RAINFALL
PROBABILITIES ARE QUITE HIGH, THE INTRUSION OF DRY AIR FROM
850-700-MB WILL LIMIT RAINFALL AMOUNTS WITH THE PROBABILITIES
FOR >0.25" WEST OF THE MISSISSIPPI RIVER ONLY 10-20% AND LESS
THAN 10% ELSEWHERE.
FRIDAY - SATURDAY
WEAK 290K ISENTROPIC ASCENT AND BROAD LOWER TROPOSPHERIC
CONFLUENCE LOOK TO KEEP THE RISK FOR SHOWERS GOING WEST OF THE
MISSISSIPPI RIVER THROUGH FRIDAY--AGAIN WITH MINIMAL RAINFALL
AMOUNTS. HOW THE RAIN ON SATURDAY UNFOLDS IS OF SOMEWHAT LESSER
CONFIDENCE WITH THERE LIKELY BEING A SHARP CUTOFF IN THE
EASTWARD EXTENT OF THE RAIN BETWEEN I-35 AND THE MISSISSIPPI
RIVER--EXACTLY WHERE IS TO BE DETERMINED. ONCE AGAIN, IN THE
ABSENCE OF DEEP MOISTURE OR LIFT, RAINFALL AMOUNTS SHOULD BE
MINIMAL WITH A 20-50% CHANCE OF >0.25" AND 10-20% CHANCE OF
>0.50" WEST OF THE MISSISSIPPI RIVER. UPPER TROPOSPHERIC RIDGING
BUILDS TO THE WEST FOR SUNDAY AND MONDAY, BRINGING A REPRIEVE
FROM THE LIGHT RAIN TO START THE NEW WEEK.
TUESDAY - WEDNESDAY: NEXT WIDESPREAD RAIN RISK
A LONGWAVE TROUGH WILL MOVE EAST THROUGH THE MID- AND UPPER
MISSISSIPPI RIVER VALLEY. THIS WILL BRING RAIN INTO THE REGION.
THERE ARE SOME MODELS THAT BRING TROPICAL MOISTURE NORTHWARD
INTO THE REGION. MEANWHILE, OTHER MODELS SHOW THAT THIS PLUME OF
TROPICAL MOISTURE WILL BE SOUTHEAST OF THE AREA.
HIGH TEMPERATURES WILL BE IN THE MID- TO UPPER 60S. LOW
TEMPERATURES WILL RANGE FROM THE MID-40S TO MID-50S.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 612 PM CDT WED SEP 23 2026
AS THE NOCTURNAL INVERSION DEVELOPS TONIGHT, LIGHT WINDS WILL
REMAIN NEAR THE SURFACE. THIS WILL RESULT IN THE DEVELOPMENT OF
SOME IFR/MVFR FOG IN SOUTHWEST AND WEST-CENTRAL WISCONSIN
BETWEEN 23.06Z AND 23.15Z.
SHOWERS WILL MOVE INTO PARTS OF NORTHEAST IOWA AND SOUTHEAST
MINNESOTA AFTER 24.21Z. THESE SHOWERS WILL BE MAINLY WEST OF
HIGHWAY 52. NO VISIBILITY OR CEILING ISSUES ARE EXPECTED.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...SKOW/BOYNE
AVIATION...BOYNE
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page