066  
FXUS63 KARX 012329  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
629 PM CDT TUE JUL 1 2025  
   
KEY MESSAGES  
 
- SMATTERING OF STORM CHANCES WED-THU. A FEW STRONGER STORMS BUT THE  
THREAT FOR ORGANIZED SEVERE WEATHER CURRENTLY LOOKS LOW.  
 
- STEAMY START TO THE HOLIDAY WEEKEND WITH HEAT INDICES TOPPING OUT  
IN THE MID TO UPPER 90S FOR THE 4TH. COOLER END WITH SUNDAY HIGHS IN  
THE UPPER 70S/LOWER 80S.  
 
- HIGHEST RAIN THREAT OVERNIGHT FRI INTO SAT. SMALLER CHANCES FOR  
STORMS FRI AFTERNOON, BUT MORE UNCERTAIN.  
 
 
   
DISCUSSION  
 
ISSUED AT 100 PM CDT TUE JUL 1 2025  
 
> WED-THU: SCATTERED STORM CHANCES. A FEW STRONG STORMS POSSIBLE.  
 
CONVECTION EXPECTED TO SPARK OVER THE NORTHERN PLAINS LATER TONIGHT,  
IN RESPONSE TO RIPPLES IN THE 500 MB FLOW ALONG WITH NOSE OF THE 850  
MB JET/MOISTURE TRANSPORT. THESE SHOWER/STORM CLUSTERS SHOULD  
EXPERIENCE A DECREASE IN COVERAGE/INTENSITY AS THEY MOVE SOUTHEAST  
WED MORNING. HOWEVER, THESE NOW CONVECTIVELY ENHANCED BITS OF UPPER  
LEVEL ENERGY WILL STAY INTACT, SPINNING ACROSS THE LOCAL AREA FOR  
THE AFTERNOON/EARLY EVENING. THE SUMMERY AIRMASS PAINTS 1500-2500  
J/KG OF SBCAPE FOR THE AFTERNOON WITH MUCH/IF NOT ALL LOW LEVEL  
CAPPING ERODING BY MID AFTERNOON. ROUGHLY 35-40 KTS OF 0-6KM SHEAR  
VIA THE NAM/GFS COULD/WOULD ADD SUPPORT TO CONVECTIVE UPDRAFTS AND  
SUSTAINABILITY-DEVELOPMENT. ENOUGH THERE FOR A STRONGER STORM  
POTENTIAL. MORE UNCERTAINTY ON IF THERE WOULD BE A SEVERE RISK.  
 
IT'S NOT CLEAR WHERE THE UPPER LEVEL FEATURES WILL BE BY THE  
AFTERNOON, AND POTENTIALLY ANY RELATED SFC/OUTFLOW BOUNDARIES.  
EXPECTATION IS FOR STORMS TO POP IN RELATION TO THE UPPER LEVEL  
FORCING AND INCREASING INSTABILITY, TRACKING SOUTHEAST ACROSS PARTS  
OF THE AREA. CAMS DON'T INDICATE MUCH AREAL COVERAGE AT THIS TIME.  
 
THE LOW LEVEL JET LOOKS TO REASSERT ITSELF INTO NORTHWEST IA WED  
NIGHT, WITH ANOTHER CLUSTER OF CONVECTION FIRING THERE - MOVING  
SOUTHEAST DURING THE NIGHT.  
 
FOR THURSDAY, A WARM FRONT IS LIKELY TO BE WAVERING ACROSS CENTRAL  
MN INTO CENTRAL WI WITH MORE BITS OF CONVECTIVELY ENHANCED SHORTWAVE  
ENERGY DROPPING OVER THE PLAINS RIDGE. MORE SCATTERED CONVECTION  
SHOULD SPARK. DETERMINISTIC RUNS OF THE GFS/NAM/EC KEEP MOST OF THIS  
ALONG/NORTH OF THE WARM FRONT - ROUGHLY NORTH OF I-90. AGAIN, FAIR  
AMOUNT OF UNCERTAINTY AS VARIOUS SMALL SCALE INTERACTIONS WILL  
IMPACT WHERE STORMS DEVELOP/MOVE. ALSO, NOT A LOT OF AREAL COVERAGE  
IN THE QPF FOOTPRINT. LACK OF DEEP LAYER SHEAR COULD/WOULD BE A  
LIMITING FACTOR TO STORM DEVELOPMENT/SUSTAINABILITY.  
 
> 4TH OF JULY WEEKEND: STEAMY FOR THE 4TH. SHOWERS, STORMS LIKELY  
FRI NIGHT AND SAT.  
 
WITH THE UPPER LEVEL RIDGE SHIFTING FROM THE NORTHERN PLAINS TO  
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY FRI, A STRONGER SOUTHERLY  
FETCH SETS UP. SFC DEWPOINTS ON THE CLIMB, LIKELY REACHING/PUSHING  
PAST 70 DEGREES. INCREASING MOISTURE TRANSPORT WITH PWS UPWARDS OF 1  
3/4". +1 TO +2 IN NAEFS AND EC PW ANOMALIES.  
 
GOING TO BE HUMID FOR THE 4TH AS A RESULT, BUT WITH HIGHS CURRENTLY  
EXPECTED TO TOP OUT AROUND 90, HEAT INDICES WILL PEAK IN THE MID TO  
UPPER 90S. VERY UNCOMFORTABLE, BUT NOT QUITE HEAT ADVISORY. STILL,  
WITH IT BEING A HOLIDAY AND LOTS OF OUTDOOR ACTIVITIES, A LOT OF  
CARE SHOULD BE TAKEN TO PROTECT YOURSELF, FAMILY AND FRIENDS FROM  
THE HEAT.  
 
THE HEAT/HUMIDLY PORTENDS TO AN INCREASINGLY UNSTABLE AIRMASS - THE  
GRAND ENSEMBLE LAYS OUT 2500-3000 J/KG OF MUCAPE FOR FRI AFTERNOON.  
HOWEVER, NOT MUCH WIND SHEAR TO COMPLIMENT THE INSTABILITY. THERE  
WILL BE A LOW LEVEL CAP TO CONTEND WITH TOO, WHICH MIGHT NOT ERODE  
UNTIL LATE IN THE DAY. WHETHER GENERAL AIRMASS STORMS COULD KICK OFF  
IS UNCERTAIN.  
 
GEFS AND EPS STILL ON TRACK TO LIFT A SHORTWAVE TROUGH OUT OF THE  
SOUTHERN ROCKIES FRIDAY, ACROSS THE PLAINS AND THEN OVER PARTS OF  
THE UPPER MISSISSIPPI RIVER VALLEY OVERNIGHT FRI/SAT. GEFS IS  
STRONGER OVERALL WITH THE FEATURE. ALL HAVE A RELATED SFC COLD  
FRONT, BUT SOME SMALL DIFFERENCES IN TIMING/LOCATION. THE UPSHOT IS  
A MORE EXPANSIVE AREA OF PCPN RELATING THE SHORTWAVE AND DEEPER  
FORCING WITH THE SHORTWAVE AND NORTH OF IT'S ASSOCIATED SFC LOW.  
CONVECTION WOULD STILL FIRE ALONG THE FRONT, BUT COVERAGE IS MORE  
QUESTIONABLE. CURRENT TIMING PLACES THE HIGHER RAIN THREAT OVERNIGHT  
FRI THROUGH SAT. THAT SAID, DOESN'T LOOK LIKE A "WASHOUT" FOR SAT.  
 
FOR SUNDAY, MOST OF THE ENSEMBLE MEMBERS LAYOUT A WESTWARD HANGING  
SFC TROUGH THAT COULD BE THE FOCUS FOR CONTINUE RAIN GENERATION.  
WHERE THIS WOULD TRACK IS UNCERTAIN WITH NOT MUCH AGREEMENT BETWEEN  
THE GEFS AND EC. COULD BE MOSTLY DRY, COULD HAVE PERSISTENT  
SHOWER/STORM CHANCES.  
 
OVERALL, STEAMY START TO THE HOLIDAY WEEKEND AND A COOLER END.  
HIGHEST RAIN CHANCES LATE FRIDAY NIGHT INTO SAT.  
 
 
   
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/  
 
ISSUED AT 609 PM CDT TUE JUL 1 2025  
 
LIGHT WINDS OVERNIGHT MOSTLY REMAIN OUT OF THE WEST POTENTIALLY  
VARYING SOUTHWEST. SCATTERED CUMULUS BUILDS AGAIN WEDNESDAY.  
VFR EXPECTED AREA WIDE THROUGH THE 02.00Z TAF PERIOD. POTENTIAL  
FOR MVFR NEAR 03.06Z PRIMARILY IN CENTRAL WISCONSIN. FOG  
POTENTIAL ALONG THE WISCONSIN RIVER VALLEY (KOVS) EARLY THURSDAY  
MORNING.  
 
 
   
ARX WATCHES/WARNINGS/ADVISORIES  
 
WI...NONE.  
MN...NONE.  
IA...NONE.  
 
 
 
 
 
DISCUSSION...FERGUSON  
AVIATION...JAR  
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab WI Page
The Nexlab IA Page
The Nexlab MN Page
Main Text Page