520  
FXUS63 KARX 220245  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
945 PM CDT SAT JUN 21 2025  
   
KEY MESSAGES  
 
- DANGEROUS HEAT CONTINUES THROUGH SUNDAY WITH HEAT INDICES  
REACHING 100F TO 105F, POTENTIALLY CLIMBING ABOVE 105F.  
 
- NEW WEEK BRINGS PERSISTENT POTENTIAL FOR HEAVY RAIN BUT LOW  
FORECAST CONFIDENCE OVERALL IN AMOUNTS AND LOCATIONS MOST  
IMPACTED. MONDAY THROUGH FRIDAY WARRANT CLOSE MONITORING FOR  
POTENTIAL FLOODING IMPACTS.  
 
 
   
DISCUSSION  
 
ISSUED AT 208 PM CDT SAT JUN 21 2025  
 
DANGEROUS HEAT THROUGH SUNDAY  
 
WELL ADVERTISED HEAT EVENT IS UNFOLDING THIS AFTERNOON AS AN UPPER  
HIGH OVER THE LOW TO MID MISSISSIPPI VALLEY HAS BROUGHT VERY WARM  
TEMPERATURES ALOFT TO THE REGION WHILE ALSO BRINGING LOW LEVEL MOIST  
ADVECTION. ADDITIONALLY, 45/35 KNOT 850/925MB WINDS AND SUNNY SKIES  
IN MOST LOCATIONS ARE LEADING TO SURFACE WINDS MAINLY IN THE 15 TO  
25 MPH AND CONCOMITANT EFFICIENT MIXING. SURFACE HEATING HAS  
OCCURRED QUICKLY TODAY WITH TEMPERATURES AS OF 18Z ARE AROUND 90  
WITH DEWPOINTS IN THE LOW TO MID 70S, YIELDING HEAT INDICES IN THE  
UPPER 90S. EXPECT THESE TO REACH THE TRIPLE DIGITS AREAWIDE OVER THE  
NEXT FEW HOURS AS INSOLATION IS MAXIMIZED.  
 
TONIGHT, WITH LEE CYCLOGENESIS OCCURRING TO OUR WEST, RESULTING  
SURFACE GRADIENT SHOULD HELP A LIGHT BREEZE CONTINUE INTO THE  
NIGHTTIME HOURS. WHILE MOSTLY CLEAR SKIES ARE EXPECTED, HAVE LEANED  
TEMPERATURES UPWARD A BIT IN LINE WITH THE EXPECTED BREEZE. RECORD  
WARM LOWS APPEAR TO BE A GOOD BET AS TEMPERATURES ONLY FALL TO THE  
UPPER 70S.  
 
SUNDAY, DANGEROUS HEAT CONTINUES AS, WHILE THE RIDGE STARTS SHIFTING  
TO THE EAST, LOW LEVEL MOIST ADVECTION REFUSES TO YIELD AS FLOW  
THROUGH THE COLUMN BECOMES SOUTH-SOUTHWESTWERLY. THUS, WHILE AIR  
TEMPERATURES MAY BE A TOUCH LOWER THAN TODAY, 21.12Z HREF SUGGESTS A  
GOOD CHANCE (50-90%) FOR HEAT INDICES TO REACH OR EXCEED 100 ONCE  
AGAIN.  
 
MULTIPLE ROUNDS OF HEAVY RAIN POTENTIAL  
 
AFOREMENTIONED MOIST ADVECTION SHOULD LEAD TO ANOMALOUSLY MOIST  
CONDITIONS WITH 21.00Z NAEFS PWAT VALUES NEAR THE 99.5TH PERCENTILE  
MONDAY THROUGH WEDNESDAY. WITH THE RIDGE SHIFTING TO THE EAST,  
COOLER TEMPERATURES ALOFT SHOULD ALLOW FOR DEEP LIFT TO OCCUR AHEAD  
OF NUMEROUS DISTURBANCES PROGGED TO EJECT DOWNSTREAM. THAT SAID, AS  
TIME GOES ON, LAPSE RATES WILL MODERATE AND BEST FORCING FOR ASCENT  
LOOKS TO INCREASINGLY FOCUS ALONG AN E-W ORIENTED QUASI-STATIONARY  
FRONT, INTRODUCING THE POTENTIAL FOR HEAVY RAIN TO FOCUS ON THE SAME  
AREAS DEPENDING ON HOW MESOSCALE PROCESSES SHAKE OUT WITH RESPECT TO  
EXACT FRONTAL POSITION. GIVEN THE HIGH AMOUNT OF MOISTURE AVAILABLE  
THROUGH THE COLUMN, SHOULD HEAVY RAIN IN THE SAME LOCATION OCCUR  
DURING 1-2 CONSECUTIVE ROUNDS OF PRECIP, FLASH FLOODING WOULD BE A  
CONCERN. SHOULD HEAVY RAIN OCCUR WITHIN A BASIN ACROSS A FEW  
DIFFERENT ROUNDS, RIVER FLOODING WOULD EASILY BECOME A CONCERN. IN  
ANY CASE, 21.00Z LREF MEAN QPF VALUES ARE IN THE 2-3.5" RANGE ACROSS  
MOST OF THE CWA AND EVEN LREF MINIMUMS ARE AROUND AN INCH,  
SUGGESTING GETTING APPRECIABLE RAIN AT SOME POINT NEXT WEEK IS A  
NEAR CERTAINTY.  
 
AS FOR SEVERE CONVECTION, WITH THE MOVE TOWARD A MORE MOIST  
ADIABATIC PROFILE OCCURRING OVER TIME, FOCUS IS ON MONDAY WHEN  
STEEPER LAPSE RATES ARE STILL PRESENT, YIELDING MLCAPE VALUES OF  
AROUND 1500 J/KG IN THE PRESENCE OF SFC-6KM SHEAR OF 25-35 KNOTS.  
NEAR-SURFACE SHEAR PROFILES APPEAR UNSUPPORTIVE OF TORNADOES BUT MID-  
LEVEL LAPSE RATES AND AFOREMENTIONED SHEAR WOULD SUPPORT POTENTIAL  
FOR A BIT OF SEVERE HAIL AND, GIVEN MODELED DCAPE OF AROUND 1000  
J/KG, SEVERE WIND GUSTS.  
 
 
   
AVIATION /06Z TAFS THROUGH 06Z MONDAY/  
 
ISSUED AT 945 PM CDT SAT JUN 21 2025  
 
CIGS: SKC/FEW CONDITIONS THROUGH SUNDAY EVENING. TRENDS DON'T FAVOR  
AN INCREASE IN CLOUDS/CIGS UNTIL MONDAY AFTERNOON WHEN A SFC FRONT  
AND BITS OF SHORTWAVE ENERGY BRING THE PROMISE OF SHOWERS/STORMS.  
 
WX/VSBY: NO IMPACTS THROUGH SUNDAY NIGHT. NEXT SHOT FOR SHRA/TS WILL  
COME MONDAY AS A SFC FRONT EASES IN FROM THE WEST. THIS BOUNDARY IS  
LIKELY TO WOBBLE ACROSS THE REGION, IN A NORTHEAST-SOUTHWEST RUNNING  
ORIENTATION, PROVIDING A FOCUS FOR PERIODS OF SHRA AND A FEW TS  
THROUGH THE NEW WORK WEEK.  
 
WINDS: RELATIVELY STRONG/GUSTY FROM THE SOUTH WILL CONTINUE TONIGHT  
THROUGH SUNDAY NIGHT. IF THE WINDS WOULD DECOUPLE THIS EVENING  
(DON'T STAY GUSTY), SOME THREAT FOR LLWS AS RAP/HRRR HAVE WINDS  
BLOWING NEAR 50 KTS BY 2KFT THROUGH 06Z. CURRENT TRENDS FAVOR  
HOLDING ONTO THE GUSTS.  
 
 
   
CLIMATE  
 
ISSUED AT 238 AM CDT SAT JUN 21 2025  
 
DAILY RECORD HIGH AND WARM LOWS THIS WEEKEND (RECORD / FORECAST):  
 
MAXIMUM WARM LOW  
JUNE 21  
LA CROSSE: 102 (1988) / 9674 (1943) / 77  
ROCHESTER: 99 (1988) / 9572 (1943) / 76  
 
JUNE 22  
LA CROSSE: 97 (1995) / 9675 (1983) / 80  
ROCHESTER: 94 (1911) / 94 71 (1983) / 77  
 
WARMEST JUNE LOWS:  
 
LA CROSSE: 80F ON JUNE 29, 1931  
ROCHESTER: 77F ON JUNE 26, 1943 AND JUNE 19, 1953  
 
WARMEST ALL-TIME LOW TEMPERATURES:  
 
LA CROSSE: 81F ON JULY 21, 1901, JULY 13, 1995, AND JULY 4, 2012  
ROCHESTER: 85F ON JULY 3, 1911  
 
 
   
ARX WATCHES/WARNINGS/ADVISORIES  
 
WI...HEAT ADVISORY UNTIL 9 PM CDT SUNDAY FOR WIZ017-029-032>034-  
041>044-053>055-061.  
MN...HEAT ADVISORY UNTIL 9 PM CDT SUNDAY FOR MNZ079-086>088-094>096.  
IA...HEAT ADVISORY UNTIL 9 PM CDT SUNDAY FOR IAZ008>011-018-019-029-  
030.  
 
 
 
 
 
DISCUSSION...FERGUSON  
AVIATION.....RIECK  
CLIMATE...BOYNE  
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