408
FXUS63 KARX 270544
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1244 AM CDT SUN SEP 27 2026
KEY MESSAGES
- ISOLATED LIGHT SHOWERS CONTINUE THROUGH THE MORNING HOURS,
MAINLY WEST OF THE MISSISSIPPI RIVER.
- DRIER CONDITIONS ARE EXPECTED TONIGHT THROUGH MONDAY BEFORE
RAIN CHANCES RETURN TUESDAY THROUGH THE REST OF THE WEEK.
- TEMPERATURES WILL REMAIN SEASONAL IN THE 60S TO 70S.
DISCUSSION
ISSUED AT 1243 AM CDT SUN SEP 27 2026
TODAY - TUESDAY: ON AND OFF CHANCES FOR RAIN, DRY PERIODS
A WEAK UPPER LEVEL SHORTWAVE TROUGH OVERHEAD IS INTERACTING
WITH RELATIVELY DEEP MOISTURE WEST OF THE MISSISSIPPI RIVER
CREATING SOME ISOLATED LIGHT SHOWERS. ADDITIONAL DEVELOPMENT IS
EXPECTED THROUGH THE EARLY MORNING HOURS AS ADDITIONAL MID-LEVEL
MOISTURE MAKES ITS WAY INTO THE REGION. WITH GENERALLY DRIER
AIR EAST OF THE RIVER, MOST ACTIVITY WILL REMAIN ACROSS SE
MINNESOTA AND NE IOWA THROUGH THE MORNING HOURS BEFORE
DISSIPATING AS SYNOPTIC LIFT FROM THE EXITING UPPER TROUGH
WEAKENS. GENERALLY DRY CONDITIONS WILL PREVAIL FOR LATE SUNDAY
THROUGH MONDAY WITH TEMPERATURES RANGING FROM RANGING FROM THE
MID 60S TO THE MID 70S.
FOR THE EARLY PORTIONS OF THE WORK WEEK, OUR AREA WILL BE IN
BETWEEN TWO PRIMARY WEATHER SYSTEMS: A LOW PRESSURE SYSTEM
ACROSS THE NORTHEASTERN US AND STRONG TROUGH ACROSS THE
SOUTHWESTERN CONUS. THIS WILL LEAVE OUR AREA IN A REALM OF
INCREASING SOUTHWESTERLY FLOW ALOFT. DEEP MOISTURE IS ALSO
EXPECTED TO BE ON AN UPTICK MOVING INTO TUESDAY AS IT SURGES
NORTHWARD AHEAD OF THE TROUGH. THIS DEEP MOISTURE COMBINED WITH
EMBEDDED SHORTWAVE IMPULSES WILL ALLOW FOR THE DEVELOPMENT OF
SHOWERS AND POTENTIALLY THUNDERSTORMS ACROSS THE REGION TUESDAY
THROUGH TUESDAY NIGHT. PRECIPITABLE WATER VALUES COULD CERTAINLY
EXCEED 1.75 INCHES, MAYBE EVEN NEARING THE 2 INCH THRESHOLD,
THROUGH THE COURSE OF THE EVENT. CURRENT WPC FORECASTS SHOW QPF
AMOUNTS GENERALLY BETWEEN 0.5-0.75 INCHES FOR MUCH OF THE AREA
WITH SOME LOCATIONS APPROACHING OR EVEN JUST BARELY EXCEEDING
THE 1 INCH THRESHOLD FROM 12Z TUESDAY TO 12Z WEDNESDAY. WHILE
THE 90TH PERCENTILE RAINFALL AMOUNTS FROM THE LREF DO HIGHLIGHT
THE POTENTIAL FOR SOME LOCATIONS TO SEE AN INCH OR MORE,
CONFIDENCE IN THIS OCCURRING IS STILL FAIRLY LOW AS APPRECIABLE
LOW LEVEL FORCING MIGHT BE HARD TO COME BY (CERTAINLY HARD TO
MAKE OUT AT THIS TIME) AND MOISTURE QUALITY WILL BE A FACTOR.
REST OF NEXT WEEK: DAILY RAIN CHANCES MAY CONTINUE
THE REMAINDER OF THIS FORECAST PERIOD IS HIGHLY UNCERTAIN AS IT
WILL DEPEND UPON THE EVOLUTION OF THE LOW PRESSURE CENTER
ASSOCIATED WITH THE SYNOPTIC SCALE TROUGH AS WELL AS HOW THIS
FEATURE COMBINES WITH THE REMNANTS OF NOW HURRICANE POLO.
ENSEMBLE GUIDANCE ALONG WITH DETERMINISTIC FORECAST MODELS
INDICATE PLENTY OF DIFFERENCES IN TIMING AND LOCATION IN THE
AXIS OF BETTER RAIN CHANCES FOR WEDNESDAY AND BEYOND. THIS IS
SHOWN REALLY WELL IN THE NBM POP VALUES, WHICH KEEP AT LEAST LOW
TO MEDIUM (20-50%) CHANCES FOR RAIN THROUGH FRIDAY. THE CURRENT
EXPECTATION IS THAT THE HEAVIEST RAINFALL WILL STAY SOUTH OF
THE UPPER MIDWEST, BUT THERE ARE OUTLIER SOLUTIONS THAT PRODUCE
2+ INCHES OF RAINFALL DURING THE LATER HALF OF THIS UPCOMING
WEEK. TEMPERATURES ARE FORECAST TO REMAIN NEAR AVERAGE TO END
THE MONTH OF SEPTEMBER.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1243 AM CDT SUN SEP 27 2026
SCATTERED SHOWERS AND PERHAPS A RUMBLE OF THUNDER WILL CONTINUE
OVERNIGHT, MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER,
ALTHOUGH SOME LIGHT RAIN IS POSSIBLE ACROSS WISCONSIN AS WELL.
ALONG WITH THESE SHOWERS, MVFR CONDITIONS ARE EXPECTED WITH
CEILINGS POSSIBLY FALLING BELOW 1KFT ACROSS SOUTHEAST MINNESOTA
AND NORTHEAST IOWA LATER THIS MORNING, A 20-40% CHANCE PER THE
27.00Z REFS/HREF. LIGHT SOUTHERLY WINDS CONTINUE THIS MORNING,
BECOMING VARIABLE THIS AFTERNOON.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...BARENDSE/MUSCHA
AVIATION...FALKINHAM
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