563
FXUS63 KARX 231058
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
558 AM CDT WED SEP 23 2026
KEY MESSAGES
- SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH THE END OF THE WEEK
WITH DAYTIME HIGHS IN THE 60S AN OVERNIGHT LOWS FROM THE 40S
TO LOW 50S.
- REMAINING MOSTLY DRY THROUGH THE WEEK WITH HIGHEST
PRECIPITATION CHANCES (40-80%) DECREASING AS THEY SHIFT EAST
SATURDAY NIGHT THROUGH SUNDAY.
DISCUSSION
ISSUED AT 1229 AM CDT WED SEP 23 2026
COOLER & MOSTLY DRY THROUGH FRIDAY:
AN AREA OF CYCLONIC UPPER LEVEL FLOW AND AN ACCOMPANYING
SHORTWAVE TROUGH IS SEEN PROGRESSING EAST THROUGH THE SOUTHERN
GREAT LAKES ON GOES WATER VAPOR IMAGERY LOOPS, ELONGATED BETWEEN
TWO SYNOPTIC AREAS OF ANTICYCLONIC UPPER LEVEL FLOW. EAST LOW
LEVEL WINDS ASSOCIATED WITH THE ANTICYCLONIC FLOW OVER CANADA
WILL CAUSE A PERSISTENTLY COOL AND MOSTLY DRY FORECAST INTO THE
WEEKEND. SUFFICIENT FORCING TO REMOVE THE BACK DOOR COLD FRONT'S
INFLUENCE MAY NOT REACH THE LOCAL FORECAST AREA UNTIL MID NEXT
WEEK.
SPRINKLES WILL BE POSSIBLE LATE THIS AFTERNOON AND EARLY
EVENING FROM ENHANCEMENT OF ACCOMPANYING LOW LEVEL COLD AIR
ADVECTION PRIMARILY EAST OF THE MISSISSIPPI RIVER VALLEY LOCALLY
IN SOUTHWEST WISCONSIN.
WEAKENING PRECIPITATION CHANCES APPROACHING FORECAST AREA THURS &
THIS WEEKEND:
AS THE UPPER LEVEL CYCLONIC FLOW EXITS THROUGH THE END OF THE
WEEK, UNIFICATION OF THE UPPER LEVEL HEIGHTS CAUSES TEMPORARY
AMPLIFICATION OF THE UPPER LEVEL RIDGE OVER THE FORECAST AREA.
RESULTANT DEGRADATION OF INCOMING MID-UPPER LEVEL WAVES AND
ACCOMPANYING POSITIVE VORTICITY ADVECTION REDUCES PRECIPITATION
CHANCES FROM WEST TO EAST AS THEY APPROACH THE LOCAL FORECAST
AREA. INITIAL, LOW (10-15%), PROBABILITIES THURSDAY MORNING
GRAZE WESTERN PERIPHERAL COUNTIES IN SOUTHEAST MINNESOTA
INCREASE FRIDAY NIGHT INTO SATURDAY (50-90%) ONLY TO QUICKLY
DECREASE WHILST ADVECTING EAST THROUGH THE LOCAL FORECAST AREA
(30-60%) ON SATURDAY.
LOW CONFIDENCE LONGER TERM FORECAST:
LONG TERM GLOBAL MODELS DIFFER ON LOCATION OF A NOR'EASTER AND
SYNOPTIC UPPER LEVEL TROUGHING SUFFICIENT TO OVERCOME AND CAUSE
ANTICYCLOLYSIS OVER THE GREAT LAKES, RESPONSIBLE FOR THE
PERSISTENT LOW LEVEL EAST WINDS, THROUGH THE START OF THE NEW
WEEK. EXPECT FURTHER DETAILS IN TIMING AND EXACT LOCATION OF
SYNOPTIC INGREDIENTS TO INCREASE IN CONFIDENCE AS FORECAST HOUR
NEARS, INCREASING LOCAL CONFIDENCE IN PRECIPITATION CHANCES
THROUGH EARLY NEXT WEEK.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 556 AM CDT WED SEP 23 2026
PATCHY MIST/FOG HAS DEVELOPED IN SEVERAL OF THE MISSISSIPPI
RIVER TRIBUTARIES AS WELL AS OVER THE CRANBERRY BOGS ACROSS WEST
CENTRAL WISCONSIN THIS MORNING, BUT SHOULD DISSIPATE AROUND
13-14Z. OTHERWISE, VFR CONDITIONS PREVAIL THROUGHOUT THE DAY
WITH DIURNAL CUMULUS AROUND 3-4KFT EXPECTED TO DEVELOP THIS
AFTERNOON, MAINLY ALONG AND SOUTH OF I-90, AND EAST TO
SOUTHEASTERLY WINDS OF 5-10KT AREAWIDE. CAN'T RULE OUT SOME
STRAY SPRINKLES ACROSS NORTHEAST IOWA/SOUTHWEST WISCONSIN THIS
AFTERNOON (10-20%), BUT IMPACTS ASSOCIATED WITH ANY WOULD BE
MINIMAL. SKY COVER INCREASES TONIGHT WHICH SHOULD HINDER FOG
DEVELOPMENT TOWARDS THE END OF THE TAF PERIOD, BUT THE TYPICAL
FOGGY AREAS OF WISCONSIN MAY BE ABLE TO DEVELOP SOME VISIBILITY
RESTRICTIONS BEFORE THE CLOUDS MOVE IN.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...JAR
AVIATION...FALKINHAM
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