694  
FXUS63 KARX 042312  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
512 PM CST MON MAR 4 2024  
   
KEY MESSAGES
 
 
- RAIN/SNOW SHOWERS MOVE OUT THIS EVENING WITH QUIET WEATHER ON  
TAP THROUGH MIDWEEK. A STRONG THUNDERSTORM MAY CLIP AREAS NEAR  
DUBUQUE LATE THIS AFTERNOON.  
 
- TEMPERATURES REMAIN 10 TO 15 DEGREES ABOVE NORMAL THROUGH  
MIDWEEK. THERE WILL BE A COOLING TREND TO END THE  
WEEK/WEEKEND, BUT WE WARM RIGHT BACK UP FOR NEXT WEEK.  
 
- NEXT SHOT OF PRECIPITATION COMES THURSDAY INTO FRIDAY, MAINLY  
IN THE FORM OF RAIN BUT CANNOT RULE OUT A MIX OF SNOW ON  
FRIDAY.  
 

 
   
DISCUSSION
 
 
ISSUED AT 150 PM CST MON MAR 4 2024  
 
THIS EVENING: RAIN AND SNOW SHOWERS DEPART  
 
THE EARLY AFTERNOON WEATHER SETUP FEATURES A LITTLE BIT OF  
EVERYTHING--SNOW IN SOUTHEAST MN AND WEST-CENTRAL WI AND SHOWERS  
AND THUNDERSTORMS WITH SMALL HAIL IN NORTHEAST IA AND SOUTHWEST  
WI. THIS IS ALL COURTESY OF A FRONTAL BOUNDARY THAT HAS BEEN  
LIFTING THROUGH THE FORECAST AREA AHEAD OF A SURFACE LOW  
TRACKING OVER THE SOUTHERN MISSOURI RIVER VALLEY. THE SURFACE  
WARM FRONT AT OF 1 PM STRETCHED FROM SOUTH-CENTRAL IOWA  
NORTHEASTWARD TOWARDS JANESVILLE, WI WITH THE LOWER TROPOSPHERIC  
FRONTAL SURFACE SLOPED TO THE NORTHWEST.  
 
THE COMBINATION OF STRONG ISENTROPIC AND FRONTOGENETICAL ASCENT  
ALONG THE 285-295K BOUNDARY UNDERNEATH A COMPRESSED BUT  
PROMINENT AREA OF UPRIGHT INSTABILITY IS LEADING TO WIDESPREAD  
SHOWERS AND THUNDERSTORMS. WITH LOWER TROPOSPHERIC PROFILES ONLY  
SLIGHTLY ABOVE FREEZING AND NEAR-SURFACE WARM LAYERS QUITE  
SHALLOW, A MIXTURE OF RAIN, SNOW, AND HAIL/GRAUPEL HAS BEEN  
OBSERVED WITH THESE CELLS. THE BEST REGIONS OF FRONTOGENESIS ARE  
FOCUSED IN SOUTHEAST MINNESOTA AND WEST-CENTRAL WI WITHIN THE  
850-700-MB LAYER. MULTIPLE, VERY NARROW, BANDS OF SNOW HAVE  
FORMED ALONG A CORRIDOR FROM ALBERT LEA TO WEST OF EAU CLAIRE  
AND HAVE PRODUCED A QUICK 1" OF SNOW WHERE NEAR SURFACE WET  
BULBS HAVE BEEN COOL ENOUGH TO SUPPORT ACCUMULATIONS. THESE  
BANDS SHIFT EAST THROUGH THE AFTERNOON AND WEAKEN THIS EVENING  
AS THEY REACH THE LA CROSSE AREA.  
 
FURTHER TO THE SOUTHEAST, THERE STILL EXISTS A VERY NARROW  
WINDOW OF OPPORTUNITY FOR DEEPER CONVECTION TO IMPACT AREAS  
AROUND DUBUQUE BETWEEN THE 2 TO 5 PM TIMEFRAME. THE SURFACE  
FRONT IS NOT EXPECTED TO REACH INTO THE FORECAST AREA, BUT ABOUT  
500-900 J/KG OF MUCAPE WILL EXIST ABOVE THE 900-MB WARM NOSE  
THAT COULD RESULT IN A STRONGER CELL IMPACTING THESE AREAS  
BEFORE THE FRONT SAGS TO THE SOUTH. HAIL UP AN INCH IN DIAMETER  
WOULD BE THE MAIN THREAT.  
 
THE COMPLEX AS A WHOLE SHIFTS TO THE SOUTHEAST THIS EVENING  
WITH TRENDS IN THE LATEST HIGH RESOLUTION GUIDANCE SHOVING THE  
PRECIPITATION EAST OF THE AREA BEFORE MIDNIGHT.  
 
TUESDAY AND WEDNESDAY: QUIET AND WARM  
 
WITH THE REGION RESIDING WITH THE SOUTHERN PERIPHERY OF A  
1030-MB HIGH PRESSURE CELL OVER SOUTH-CENTRAL CANADA, LITTLE IN  
THE WAY OF SENSIBLE WEATHER IMPACTS ARE FORECAST FOR TUESDAY AND  
WEDNESDAY. DESPITE A "COOLER" NORTHERLY TO EASTERLY FETCH,  
THERE EXISTS LITTLE COLD AIR UPSTREAM TO TAP INTO AND  
TEMPERATURES WILL STILL RUN 10-15 DEGREES ABOVE NORMAL.  
 
THURSDAY AND FRIDAY: NEXT WEATHER SYSTEM ARRIVES  
 
LONGWAVE TROUGHING CARVES OUT ACROSS THE WESTERN CONUS  
WEDNESDAY INTO THURSDAY, WITH THE SURFACE LOW REFLECTION  
EJECTING OFF THE SOUTHERN HIGH PLAINS AND INTO THE CENTRAL  
CONUS. THERE HAVE BEEN SOME HINTS IN THE LATEST ENSEMBLE AND  
DETERMINISTIC GUIDANCE THAT THE LOW MAY EJECT FARTHER TO THE  
SOUTH AND SHUNT MORE PRECIPITATION SOUTH OF THE FORECAST AREA.  
THE LATEST DETERMINISTIC EC ACTUALLY TAKES NEARLY ALL OF THE  
PRECIPITATION SOUTH OF THE FORECAST AREA. WHILE THE VAST  
MAJORITY OF THE ENSEMBLE MEMBERS BRING PRECIPITATION OVER MUCH  
OF THE REGION, THIS SOUTHWARD SHIFT WILL BE WORTH WATCHING. RAIN  
LOOKS TO BE THE PREDOMINANT PRECIPITATION TYPE, BUT SOME SNOW  
COULD MIX IN LATE FRIDAY AS MODEST COLD AIR ADVECTION TAKES  
PLACE ON THE BACKSIDE OF THE COLD FRONT.  
 
LOOKING AHEAD: ANOTHER WARM UP  
 
COLD AIR ADVECTION ON THE BACKSIDE OF THIS LATE WEEK SYSTEM  
WILL LAST A DAY OR TWO AT MOST BEFORE WARMER AIR SURGES BACK  
NORTHWARD. ABOUT 25 TO 40% OF THE EPS/GEFS MEMBERS ALREADY HAVE  
HIGHS IN THE LOW 60S FOR NEXT WEEK.  
 

 
   
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
 
 
ISSUED AT 512 PM CST MON MAR 4 2024  
 
CIGS: MESO MODELS ADAMANT THAT LOW IFR/MVFR CIGS WILL DEVELOP ACROSS  
NORTHWEST WI AND SPREAD SOUTH/SOUTHWEST - IMPACTING BOTH KRST AND  
KLSE FOR A FEW HOURS. LATEST SFC OBS SHOWS THIS IS OCCURRING AT KRST,  
INCREASING CONFIDENCE THAT THE MESO MODELS HAVE THE RIGHT TREND.  
CIGS SHOULD IMPROVE/SCATTER THIS EVENING...MORE 02Z FOR KRST AND  
TOWARD 06Z AT KLSE. LOOKING AT SKC/SCT CONDITIONS THEN FOR THE REST  
OF THE NIGHT THROUGH TUE NIGHT.  
 
WX/VSBY: -SHRA CONTINUES TO SHIFT EAST EARLY THIS EVENING, MIXED  
WITH SOME SLEET AT TIMES. COULD STILL BE BRIEF MVFR VSBY IMPACTS  
WITH ANY VIGOROUS SHOWER. PCPN LIKELY EAST OF KRST BY 00Z BUT  
LINGERING FOR KLSE TIL 02Z ISH.  
 
WINDS: NORTH/NORTHEAST AT 10 KTS OR LESS THROUGH THE PERIOD.  
 

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

 
 

 
 
DISCUSSION...SKOW  
AVIATION...RIECK  
 
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