097  
FXUS63 KARX 132249  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
549 PM CDT SAT SEP 13 2025  
   
KEY MESSAGES
 
 
- A SUMMERY AIRMASS SETTLES IN THROUGH AT LEAST NEXT TUE WITH HIGHS  
TOPPING OUT IN THE 80S. COOLER, MORE SEASONABLE CONDITIONS SET TO  
RETURN BY THE END OF NEXT WEEK.  
 
- SPOTTY RAIN CHANCES FOR THE START OF THE NEW WEEK (20%) WITH  
INCREASED SHOWER/STORM CHANCES BY MID WEEK (40-50%).  
 

 
   
DISCUSSION
 
 
ISSUED AT 130 PM CDT SAT SEP 13 2025  
 
* WEEKEND INTO START OF NEXT WEEK: SUMMER HEAT!  
 
THE UPPER LEVEL RIDGE AXIS SHIFTS EASTWARD FROM THE PLAINS TO ACROSS  
THE UPPER MISSISSIPPI RIVER VALLEY TODAY, GRADUALLY EASING EAST  
ACROSS THE GREAT LAKES AS AN UPPER LEVEL TROUGH SWINGS OVER THE  
NORTHERN PLAINS. A FEW LOBES OF SHORTWAVE ENERGY MOVE THROUGH THE  
TROUGH (FROM THE SOUTH AND NORTH), BUT GEFS AND EPS HOLD THE BULK OF  
THAT UPPER LEVEL FORCING WEST/NORTH OF THE LOCAL AREA. WARM/MOIST  
AIR POOLS UNDER THE RIDGE - MAKING IT FEEL A LOT MORE LIKE MID  
SUMMER RATHER THAN THE START OF FALL.  
 
> TEMPERATURES: THE CALENDAR SAYS SEPTEMBER BUT WALK OUTSIDE AND IT  
FEELS LIKE JULY. 925 MB TEMPS IN THE NAM/GFS/EC ALL HOVER IN THE  
LOW/MID 20S C THROUGH TUE. 850 MB TEMP ANOMALIES IN THE NAEFS AND EC  
HOLD 1.5+ WHILE EFIS FOR HIGH TEMPS RUN FROM 0.5 TO 0.7 (HIGHEST TO  
THE SOUTH). THE UPPER 75% OF THE GEFS AND EPS ENSEMBLE SUITES WARM  
HIGHS INTO THE LOW TO MID 80S THROUGH TUE. THE GEFS REMAINS THE  
WARMER OF THE GUIDANCE ALTHOUGH NOT QUITE AS WARM AS IT WAS A FEW  
DAYS PRIOR. SOME UPPER 80S IN THE RIVER VALLEYS POSSIBLE AND CAN'T  
COMPLETELY RULE OUT A LOCATION OR TWO FLIRTING WITH 90. NOT LOOKING  
LIKE RECORD HEAT AT THIS TIME. ADD IN MID 60 DEWPOINTS AND THE HEAT-  
HUMIDITY COMBO WILL HAVE MANY/MOST STARTING THEIR AC BACK UP.  
 
> RAIN CHANCES: WHILE THE RIDGE LOOKS TO KEEP THE BULK OF THE  
SHORTWAVE ACTIVITY TO THE WEST, THE LONG RANGE GUIDANCE REMAINS  
ADAMANT THAT SOME RIPPLES IN THE FLOW WILL WORK ACROSS THE RIDGE,  
SPINNING OVER THE REGION. WITH A SUMMERY AIRMASS IN PLACE, AMPLE  
INSTABILITY (ESP FOR SEP) WILL BE ON HAND TO AID CONVECTIVE  
POTENTIAL. SFC WARM FRONT MAY ALSO BE WAVERING ACROSS THE REGION.  
HOWEVER, DIFFERENCES IN OPINION ON WHERE THESE SMALLER SCALE  
"FORCERS" WILL BE, ALONG WITH TIMING, BETWEEN THE ENSEMBLE SUITES.  
CONFIDENCE LOW IN THE DETAILS AS A RESULT. BECAUSE OF THE  
DIFFERENCES, THE MODEL BLEND HOLDS POPS FROM 20-30% -  
WHICH LOOK REASONABLE GIVEN THE CURRENT SETUP.  
 
* MID NEXT WEEK INTO WEEKEND: COOLING DOWN, HIGHER RAIN CHANCES  
 
THE UPPER LEVEL TROUGH GETS A PUSH EASTWARD BY MID WEEK, MARCHING A  
COLD FRONT ACROSS THE MISSISSIPPI RIVER VALLEY. MUCH COOLER, LESS  
HUMID (SEASONABLE) AIRMASS RETURNS. 75% OF THE GEFS AND EPS MEMBERS  
FAVOR HIGHS IN THE UPPER 60S TO LOWER 70S BY THE FOLLOWING WEEKEND.  
 
THE TROUGH WILL OFFER UP SOME SHOWER/STORM CHANCES WITH COLD  
FRONT/SHORTWAVES ALL HAVING ROLES. HOW ORGANIZED ANY OF THESE RAIN  
CHANCES WILL BE ISN'T CLEAR AT THIS TIME.  
 

 
   
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
 
 
ISSUED AT 548 PM CDT SAT SEP 13 2025  
 
THERE CONTINUES TO BE MIXED SIGNALS FOR VALLEY FOG TONIGHT.  
WHILE THE NOCTURAL INVERSION AND LONGER NIGHTS ARE FAVORABLE.  
THE WINDS ALOFT ARE NOT LIGHT ALL NIGHT ARE NOT. AS A RESULT,  
THINKING THAT THERE WILL BE SOME VALLEY FOG IN THE TRIBUTARIES  
AND WISCONSIN RIVER VALLEY.  
 

 
   
ARX WATCHES/WARNINGS/ADVISORIES
 
 
WI...NONE.  
MN...NONE.  
IA...NONE.  
 

 
 

 
 
DISCUSSION...RIECK  
AVIATION...BOYNE  
 
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