146  
FXUS63 KARX 190805  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
305 AM CDT TUE MAR 19 2024  
   
KEY MESSAGES
 
 
- ELEVATED FIRE WEATHER CONDITIONS THROUGH WEDNESDAY; STILL  
QUITE DRY EAST OF THE MISSISSIPPI RIVER THURSDAY.  
 
- ACCUMULATING SNOW CONTINUES TO LOOK LIKELY FROM THURSDAY NIGHT  
INTO FRIDAY (70-100%). THIS COULD RESULT IN TRAVEL IMPACTS FOR  
FRIDAY MORNING.  
 
- FROM THIS WEEKEND INTO EARLY NEXT WEEK, STILL A LOT OF  
UNCERTAINTY RELATED TO STORM TRACK, TEMPERATURES,  
PRECIPITATION TYPES, AND AMOUNTS, BUT COULD BE AN IMPACTFUL  
STORM.  
 

 
   
DISCUSSION
 
 
ISSUED AT 305 AM CDT TUE MAR 19 2024  
 
TODAY - THURSDAY:  
 
CLOUDS WILL FILL INTO THE AREA THROUGH THE MORNING AND THE COVERAGE  
WILL DECREASE BY THE AFTERNOON RESULTING IN MOSTLY CLEAR SKIES  
THROUGH WEDNESDAY AFTERNOON. SOUTHWEST FLOW ALOFT WILL ALLOW FOR  
BROAD WAA TO BE IN THE AREA FOR TUESDAY ALLOWING TEMPERATURES TO BE  
THE WARMEST OF THE FORECAST PERIOD WITH VALUES RANGING FROM THE MID  
40S UP TOWARDS NORTH CENTRAL WISCONSIN, TO THE LOW TO MID 50S ACROSS  
MUCH OF THE FORECAST AREA. WINDS ON TUESDAY WILL BE QUITE GUSTY WITH  
GUSTS BEING BETWEEN 25MPH AND 35MPH. A COLD FRONT WILL THEN MOVE  
THROUGH THE AREA ON TUESDAY ALLOWING FOR NORTHWEST FLOW ALOFT  
TO BE IN PLACE. THIS WILL BRING CAA AND CONTINUED DRY CONDITIONS  
TO THE AREA.  
 
THURSDAY NIGHT INTO FRIDAY:  
 
GUIDANCE CONTINUES TO SUPPORT A CLIPPER SYSTEM COMING DOWN FROM  
CANADA AND BRINGING WITH IT THE CHANCE OF SEEING ACCUMULATING SNOW.  
THIS SYSTEM STILL HAS A LOT OF UNCERTAINTY WITH IT IN REGARDS  
TO HOW FAST THE CLIPPER MOVES THROUGH AND WHERE THE MAIN BAND OF  
SNOW SETS UP. THERE ARE OTHER DETAILS TO MONITOR SUCH AS THE  
SNOW RATIO AND PWAT VALUES WHICH COULD IN TURN LOWER OR RAISE  
THE FORECASTED SNOW AMOUNTS. NOW THERE IS GOOD AGREEMENT WITH  
WHAT THE NAM IS BEGINNING TO SHOW WITH A HEAVIER BAND OF SNOW  
MOVING THROUGH SOME PORTION OF THE FORECAST AREA WITH OTHER  
MODELS, HOWEVER, WHEN COMPARING THIS TO THE EC AND GFS, THE  
HEAVIEST SNOWFALL AREA IS FURTHER NORTH COMPARED TO THESE TWO.  
CURRENT GUIDANCE DOES HAVE PWAT VALUES BETWEEN 0.4" AND 0.6"  
WHICH INDICATES THAT THERE WILL BE A DECENT BIT OF MOISTURE AS  
THIS CLIPPER MOVES THROUGH, WHICH COULD HELP INCREASES THE SNOW  
AMOUNTS. QPF VALUES COULD DECREASE IF THE CLIPPER MOVES THROUGH  
THE AREA QUICKER. WITH ALL THE AFOREMENTIONED SCENARIOS, CURRENT  
FORECASTED SNOW AMOUNTS IN THE 25TH AND 75TH PERCENTILES RANGE  
FROM 3" TO 7" ACROSS MUCH OF THE FORECAST AREA. OVERALL THERE IS  
GOOD AGREEMENT ON A CLIPPER IMPACTING THE REGION THURSDAY NIGHT  
INTO FRIDAY AND PRODUCING ACCUMULATING SNOW. WHERE THE HEAVIEST  
SNOW BAND SETS UP AND HOW MUCH SNOW WE GET IS STILL UNCERTAIN.  
 
SATURDAY THROUGH EARLY NEXT WEEK:  
 
AFTER THIS CLIPPER MOVES OUT, SHORTWAVE RIDGING RETURNS FOR SATURDAY  
INTO SUNDAY BEFORE THE NEXT POTENTIAL STORM ARRIVES. GUIDANCE  
CONTINUES TO SHOW A LOW MOVING OFF THE ROCKIES AND INTO THE REGION  
ON SUNDAY AND BRINGING BACK ANOTHER CHANCE OF ACCUMULATING SNOW.  
JUST LIKE THE THURSDAY NIGHT STORM, THERE IS STILL QUITE A BIT OF  
UNCERTAINTY WITH THIS STORM. SIMILAR TO THE THURSDAY STORM, THERE IS  
SOME BROAD WAA AHEAD OF THE ARRIVAL OF THE STORM. THIS COULD  
INDICATE THAT PRECIPITATION COULD START OUT AS RAIN BEFORE CHANGING  
TO SNOW, AS NORTHWEST FLOW WOULD EVENTUALLY BE IN PLACE. WHEN  
LOOKING AT THE ENSEMBLES, THERE IS ABOUT A 50/50 SPLIT IN A  
DRIER/WETTER SOLUTION THAN THE ENSEMBLE MEAN. WE WILL CONTINUE TO  
MONITOR TO BOTH STORMS AS THEY GET CLOSER. STAY TUNED FOR FURTHER  
UPDATES AS NEW GUIDANCE COMES INTO THE FRAME IN THE COMING DAYS.  
 

 
   
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
 
 
ISSUED AT 950 PM CDT MON MAR 18 2024  
 
VFR CONDITIONS ARE FORECAST FOR THE TAF PERIOD, THOUGH LOW VFR  
CEILINGS CREEP INTO SOUTHEAST MINNESOTA AND CENTRAL WISCONSIN  
EARLY IN THE MORNING BEFORE LIFTING. SOUTHWESTERLY WINDS  
INCREASE OVERNIGHT, THOUGH LLWS IS NOW EXPECTED AT BOTH VALLEY  
AND HIGHER ELEVATION SITES THROUGH 10-12Z. A FRONT SWEEPS  
THROUGH EARLY IN THE MORNING AND CAUSES WINDS TO SHIFT TO THE  
NORTHWEST FOR THE DAYTIME HOURS AND INCREASE TO 15-20G20-30KTS  
BY THE AFTERNOON.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 305 AM CDT TUE MAR 19 2024  
 
ELEVATED FIRE WEATHER CONDITIONS THROUGH WEDNESDAY AND THROUGH  
THURSDAY EAST OF THE MISSISSIPPI RIVER  
 
GUSTY NORTHWEST WINDS 25MPH TO 35MPH TUESDAY WITH HIGH TEMPERATURES  
5F TO 8F ABOVE NORMAL AND 30-40% RELATIVE HUMIDITIES. DRIER FOR  
WEDNESDAY AND STILL BREEZY WITH WINDS 15MPH TO 25MPH AND COOLER  
TEMPERATURES, BUT LOWER RELATIVE HUMIDITY VALUES BETWEEN 15% AND  
25%. THE DRY CONDITIONS CONTINUE THROUGH THURSDAY EAST OF THE  
MISSISSIPPI VALLEY WITH RELATIVE HUMIDITIES AS LOW AS 15 TO 25%.  
 
DROUGHT AREAS WITH DRY GRASSES WILL BE SUSCEPTIBLE TO THE SPREAD OF  
FIRES DUE TO THE WINDS EACH DAY.  
 

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

 
 

 
 
DISCUSSION...CECAVA  
AVIATION...SKOW  
FIRE WEATHER...CECAVA  
 
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