001  
FXUS63 KARX 160900  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
400 AM CDT SAT AUG 16 2025  
   
KEY MESSAGES
 
 
- PERIODIC STORMS CAPABLE OF HEAVY RAIN THROUGH MONDAY. HIGHER  
CONFIDENCE FOR STORMS THIS MORNING, OVERNIGHT THROUGH SUNDAY  
MORNING, AND SUNDAY NIGHT THROUGH MONDAY MORNING.  
 
- LOCALIZED FLASH FLOODING AND RIVER RISES REMAIN A CONCERN  
THROUGH THE WEEKEND WITH 2"+ RAINFALL POSSIBLE PRIMARILY NORTH  
OF INTERSTATE 90.  
 
- HOT TODAY WITH HEAT INDICES FROM 90 TO 105 DEGREES. HEAT  
ADVISORY ISSUED FOR COUNTIES IN NORTHEAST IOWA WITH HEAT  
INDICES ABOVE 100.  
 
 

 
   
DISCUSSION
 
 
ISSUED AT 339 AM CDT SAT AUG 16 2025  
 
HOT TODAY, HEAT ADVISORY ISSUED IN NORTHEAST IOWA:  
 
LITTLE CHANGE IN THE MOIST AIRMASS FROM YESTERDAY MEANS ANOTHER  
HOT DAY IS EXPECTED. WARMEST TEMPERATURES WILL BUILD THROUGH  
IOWA TODAY, BRINGING UPPER 80 DEGREE SURFACE TEMPERATURES  
LOCALLY. THEREFORE, HIGHEST CONFIDENCE FOR 100 DEGREE HEAT  
INDICES IN NORTHEAST IOWA RESULTED IN HEAT ADVISORY ISSUED FROM  
NOON TO 8PM TONIGHT.  
 
LINE OF STORMS THIS MORNING:  
 
A LOW LEVEL JET THROUGH THE CENTRAL PLAINS, CONFINED TO TIGHTENING  
ISOHEIGHT GRADIENT BETWEEN A ROCKY MOUNTAIN LOW OVER EASTERN COLORADO  
AND ANTICYCLONIC SYNOPTIC FLOW OVER THE SOUTHEAST CONUS, INITIATED  
STORMS OVER SOUTHWEST MINNESOTA EARLY THIS MORNING. INTERACTION  
BETWEEN THIS MOST RECENT STORM INITIALIZATION AND AN UPSTREAM ONGOING  
MCS QUICKLY PROGRESSING EAST THROUGH SOUTH DAKOTA ON EARLY MORNING  
RADAR IMAGERY IS CAUSING FORECAST CHALLENGES LOCALLY. PREVIOUS FORECASTS  
CALLED FOR THIS MCS TO CONTINUE THROUGH MINNESOTA INTO WEST-CENTRAL  
WISCONSIN THIS MORNING HOWEVER THE NEWEST STORM INITIALIZATION STANDS  
BETWEEN THE LOCAL FORECAST AREA AND THE MCS.  
 
EXPECT STORMS TO CONTINUE ALONG AN EASTERLY TRAJECTORY WITH MEAN MID  
LEVEL FLOW, PLACING THE NEWEST STORMS POTENTIALLY IN THE CROSSHAIRS  
OF THE MCS THROUGH THE EARLY MORNING. THE MORE NORTHEASTERLY TRAJECTORY  
INITIALLY TO THE RECENT STORMS WILL EVENTUALLY LOCALLY INFLUENCE SOUTHERN  
EXTENT OF STORMS.  
 
STORM STRENGTH IS EXPECTED TO PEAK UPSTREAM OF THE LOCAL FORECAST  
AREA, LOCALLY DEPENDENT ON LOCATION OF EVENTUALLY OUTGOING COLD  
POOL. A SLOWER STORM MOTION OR STUTTER STEP IN PROGRESSION FROM THE  
EARLY MORNING COULD ALSO ALLOW ADDITIONAL DIURNALLY-FED INSTABILITY  
TO BRING STRONGER STORMS. DAMAGING WINDS WILL BE THE MAIN  
THREAT IN PART DUE TO A STORM MOTION OF 50+ KTS. LARGE HAIL OR  
AN ISOLATED TORNADO CANNOT BE RULED OUT HOWEVER AS STORMS BOW.  
 
A MORE UNSTABLE AIRMASS ALONG AND SOUTH OF THESE STORMS WILL BE  
CAUSE FOR CONCERN THROUGH THE MORNING HOURS AS WEST-NORTHWEST MID  
LEVEL FLOW CAN ADVECT STRONGER STORMS SOUTHEAST. CURRENT CONFIDENCE  
PLACES LOCAL CONCERNS IN CENTRAL WISCONSIN COUNTIES WITH DAMAGING  
WIND AND LARGE HAIL AS THE POTENTIAL THREATS SHOULD STORMS MANAGE TO  
BECOME SEVERE.  
 
HEAVY RAIN TONIGHT THROUGH SUNDAY MORNING:  
 
REINVIGORATION OF THE NOCTURNAL LOW LEVEL JET OVERNIGHT INCREASES  
LOW LEVEL MOISTURE TRANSPORT TOWARDS THE UPPER MISSISSIPPI RIVER  
VALLEY, INCREASING HEAVY RAIN CHANCES TONIGHT. A CORRIDOR OF 2" PWATS  
EXTENDS ACROSS THE FORECAST AREA, STRUNG BETWEEN A STRENGTHENING  
SURFACE LOW OVER THE NORTHERN PLAINS AND THIS MORNING'S LOW, DOWNSTREAM  
OF THE FORECAST AREA. A STRENGTHENING ANTICYCLONE SAGGING SOUTHEAST  
THROUGH CENTRAL CANADA TIGHTENS THE ACCOMPANYING WEST-NORTHWEST TO  
EAST-SOUTHEAST ORIENTED FRONTAL BOUNDARY ACROSS THE FORECAST AREA,  
TIGHTENING AN ACCOMPANYING AXIS OF DILATATION ALONG THE ANOMALOUS  
(SPC CLIMATOLOGY) MOISTURE AXIS. A NARROW BAND OF HEAVY PRECIPITATION  
IS EXPECTED ALONG THIS WEST-NORTHEAST TO EAST-SOUTHEAST GRADIENT,  
LINGERING OVERNIGHT THROUGH SUNDAY MORNING. EXACT LOCATION OF  
THE AXIS OF DILATATION AND MOISTURE AXIS WILL DETERMINE LOCATION  
OF HIGHEST IMPACTS WITH HIGH RESOLUTION MODEL GUIDANCE FOR QPF  
VARYING FROM 2" IN CENTRAL IOWA IN THE ARW (16.00Z) TO 7" IN  
CENTRAL WISCONSIN IN THE FV3 (16.00Z). OTHER THAN SPATIALLY,  
INTER-MODEL TRENDS EXHIBIT MINIMAL CONTINUITY POINTING TO THE  
LACK OF OVERALL CONFIDENCE IN EXACT LOCATION OF HIGHEST RAINFALL.  
INCREASED RAINFALL RATES OF 1"+ PER HOUR COMBINED WITH MINIMAL  
MEAN FLOW MEANS HEAVY RAIN WILL HAVE LONGER RESIDENCE TIMES,  
QUICKLY EXACERBATING POTENTIALLY DANGEROUS IMPACTS.  
 
HEAVY RAIN SUNDAY NIGHT THROUGH MONDAY MORNING:  
 
HEAVY RAIN AND STORM CHANCES INCREASE AGAIN ON SUNDAY NIGHT AS AN  
UPPER LEVEL WAVE, CURRENTLY PLACED ALONG THE BASE OF THE  
LONGWAVE TROUGH OFF THE CALIFORNIA BAJA COAST, FLATTENS THE  
RIDGE PERIPHERY AND REINVIGORATES LOW LEVEL MOISTURE TRANSPORT  
THROUGH THE CENTRAL PLAINS. THE TERMINUS IS EXPECTED TO BE  
ALONG THE LINGERING NORTHWEST TO SOUTHEAST ORIENTED FRONTAL  
BOUNDARY OVER THE UPPER MISSISSIPPI RIVER VALLEY. MINIMAL  
CHANGE IN THE SYNOPTIC AIRMASS KEEPS PWATS NEAR 1.5" AND HEAVY  
RAIN WITH LOCALIZED FLOODING THE MAIN CONCERNS. CURRENT LREF  
CONFIDENCE KEEPS HEAVIEST RAIN CONFINED CLOSER TO THE SURFACE  
LOW LIFTING NORTHWEST OF THE LOCAL FORECAST AREA, PROVIDING AN  
ADDITIONAL 0.5"+ OF RAINFALL.  
 
LINGERING HEAVY RAIN THOUGH MONDAY, COOLER THROUGH MIDWEEK:  
 
REGRESSIVE UPPER LEVEL HEIGHTS TRAVERSE INTO THE DESERT SOUTHWEST  
THROUGH MONDAY, USHERING IN NORTHWEST FLOW AS THE ANOMALOUSLY MOIST  
AIRMASS EXITS EAST. PRECIPITATION CHANCES ARE SLOW TO EXIT,  
LINGERING ALONG EASTERN PERIPHERAL COUNTIES IN CENTRAL WISCONSIN  
THROUGH MONDAY MORNING.  
 
STRONGEST RETURN FLOW EXPECTED TO REMAIN THROUGH THE CENTRAL PLAINS  
THROUGH MIDWEEK, KEEPING THE LOCAL FORECAST AREA IN THE HIGH 70S TO  
LOW 80S HOWEVER MUCH TO BE IRONED OUT.  
 

 
   
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
 
 
ISSUED AT 1245 AM CDT SAT AUG 16 2025  
 
STORMS HAVE EXITED THE REGION LEAVING BEHIND VFR CONDITIONS  
THROUGH THE REST OF THE OVERNIGHT, HOWEVER EXPECTING STORMS TO  
MOVE THROUGH THE REGION BY THE MORNING HOURS ON SATURDAY.  
CURRENTLY, MUCH OF THE RECENT CAMS HAVE BOTH KLSE AND KRST ON  
THE EXTREME SOUTHERN END OF THE CONVECTIVE LINE SO STILL QUITE A  
LARGE AMOUNT OF UNCERTAINTY ON IF IFR CONDITIONS AND TSRA WILL  
REACH EITHER TERMINAL. AS A RESULT, HAVE CONTINUED WITH A PROB30  
DURING THE MORNING HOURS AND WILL CONTINUE TO MONITOR HOW  
STORMS CURRENT OVER THE DAKOTAS TREND. OTHERWISE, NBH GUIDANCE  
SUPPORTS A BRIEF PERIOD OF MVFR CIGS TO BE POSSIBLE ACROSS  
PORTIONS OF SOUTHEAST MN DURING THE LATE MORNING BEFORE TRENDING  
VFR BY THE AFTERNOON. VFR CONDITIONS EXPECTED THROUGH THE  
EVENING UNTIL STORMS BEGIN TO DEVELOP RIGHT AROUND 06Z. WINDS  
WILL GENERALLY REMAIN UNDER 10 KTS OUTSIDE OF ANY THUNDERSTORMS  
THROUGH MUCH OF THE TAF PERIOD, BUT WILL OBSERVE A SHIFT DURING  
THE EVENING FROM SOUTHERLY TO EASTERLY AS A BOUNDARY NUDGES  
SOUTHWARD.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 555 AM CDT FRI AUG 15 2025  
 
SEVERAL ROUNDS OF STORMS ARE ANTICIPATED TO MOVE THROUGH THE REGION  
BEGINNING THIS EVENING AND CONTINUING THROUGH EARLY NEXT WEEK.  
A VERY MOIST AIRMASS IN PLACE WILL BE CONDUCIVE FOR HEAVY  
RAINFALL WITH PRECIPITABLE WATERS OF 1.75" TO 2", NEARING THE  
SPC CLIMATOLOGICAL MAXIMUM AT KDVN. AS A RESULT, WIDESPREAD  
RAINFALL AMOUNTS OF 1-3", WITH LOCALLY HIGHER AMOUNTS WHERE  
STORMS FREQUENT ARE ANTICIPATED THROUGH SUNDAY. ADDITIONALLY,  
GIVEN THE MOISTURE-RICH AIRMASS, RAINFALL RATES WITHIN HEAVIER  
STORMS OF 1-2"/HR OR GREATER WILL BE POSSIBLE WHICH MAY  
CONTRIBUTE TO LOCALIZED FLASH FLOODING. RECENT HEFS GUIDANCE HAS  
SOME LOW-END PROBABILITIES (5-25% CHANCE) TO REACH FLOOD STAGE  
ON MANY AREA RIVERS, HOWEVER THIS IS LIKELY A RESULT OF LOWER  
CONFIDENCE ON WHERE STORMS WILL DEVELOP AND WHICH BASINS WILL BE  
IMPACTED.  
 

 
   
ARX WATCHES/WARNINGS/ADVISORIES
 
 
WI...NONE.  
MN...NONE.  
IA...HEAT ADVISORY FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR  
IAZ008-018-019-029-030.  
 

 
 

 
 
DISCUSSION...JAR  
AVIATION...NAYLOR  
HYDROLOGY...NAYLOR  
 
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