694  
FXUS63 KARX 141025  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
525 AM CDT FRI MAY 14 2021  
   
SHORT TERM
 
(WEEKEND)  
ISSUED AT 240 AM CDT FRI MA4 13 2021  
 
MESSY UPPER LEVEL FLOW WITH BITS OF SHORTWAVE ENERGY TRAIPSING  
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. AMPLE VARIETY OF MODEL  
OUTCOMES OVER THE PAST SEVERAL DAYS MIGHT FINALLY BE SETTLING INTO A  
MORE UNIFIED (KIND OF) PREFERRED OUTCOME.  
 
CURRENTLY, SCATTERED SHOWERS MOVING INTO SOUTHWEST MN, ASSOCIATED  
WITH A BIT OF UPPER LEVEL ENERGY AND WEAK INSTABILITY/MOISTURE  
TRANSPORT. THIS FEATURE WILL CONTINUE TO SHIFT EASTWARD TODAY BUT  
WILL RUN INTO PLENTY OF DRY AIR AS IT NEARS THE MISSISSIPPI RIVER.  
CURRENT SFC DEWPOINTS IN THE 20S TO LOW 30S, WITH ONLY MINOR  
INCREASE TODAY. RAP/NAM12 BUFKIT SOUNDINGS SHOW AN INCREASE IN MID  
LEVEL SATURATION FROM WEST TO EAST AS THE DAY WEARS ON, BUT KEEPS  
THE DRYING IN THE SUB CLOUD LAYER. ANY PCPN WOULD HAVE A HARD TIME  
WORKING THROUGH THIS...ESPECIALLY IF WEAKLY FORCED. SECOND SHORTWAVE  
FOLLOWS ON THE HEELS OF THE FIRST, AND LOOKS A BIT STRONGER. PLUS,  
IT WILL THE ADVANTAGE OF HAVING THE INITIAL SHORTWAVE HELPING TO  
PRECONDITION THE ATMOSPHERE WITH A BIT MORE SATURATION. EXPECTATION  
IS TO HAVE A BETTER SHOT FOR RAIN WITH THIS FEATURE, FOCUSED ON  
LATER TONIGHT/SAT. SHOULD HAVE WEAK LOW LEVEL MOISTURE TRANSPORT TO  
AID THESE CHANCES, AND PERHAPS WEAK INSTABILITY THAT COULD RESULT IN  
A CRACK OR TWO OF THUNDER.  
 
MOST OF SUNDAY COULD BE DRY AS THE NEXT SHORTWAVE IN THE QUE LOOKS  
TO NEAR TOWARD THE EVENING, BUT CURRENTLY PROGGED TO TREK FROM THE  
NORTHERN PLAINS TO ACROSS IA. PERHAPS SOME RAIN CHANCES ACROSS THE  
FAR SOUTHERN PORTIONS OF THE FORECAST AREA THAT NIGHT, OR COULD  
COMPLETELY MISS US.  
 
SO, AS IT SITS RIGHT NOW, MODELS ARE FOCUSING IN ON SOME RAIN  
CHANCES IN THE WEST LATER TODAY INTO TONIGHT, WITH SCATTERED LIGHT  
PCPN CHANCES INTO SAT FOR A LARGER SWATH OF THE AREA. AMOUNTS STILL  
LOOKING MINOR...MAYBE 1/10 OF AN INCH OR SO. MANY COULD/WILL STAY  
DRY.  
   
LONG TERM
 
(MONDAY THROUGH THURSDAY)  
ISSUED AT 240 AM CDT FRI MAY 14 2021  
 
STRENGTHENING UPPER LEVEL RIDGING TRENDING IN THE GFS AND EC FOR THE  
START OF THE NEW WORK WEEK, WHICH SUGGESTS A DRY START AND A RETURN  
TO NORMAL (AND GREATER) TEMPS.  
 
BY MID WEEK, THE GFS AND EC START TO SHIFT THE RIDGE AXIS A BIT  
EAST, WITH SOUTHERN RETURN FLOW AND THE POTENTIAL FOR SOME  
SHORTWAVES TO SPIT NORTHEAST OUT OF A TROUGH OVER THE DESERT SW.  
WITH THAT COMES SOME RAIN CHANCES, WITH A FAIR AMOUNT OF AGREEMENT  
BETWEEN THE TWO (AND THERE ENSEMBLE MEMBERS) FOR WED NIGHT-THU.  
 
AFTER THAT, THE 13.12Z RUN OF THE EC WANTED TO RETROGRADE AN UPPER  
LEVEL TROUGH BACK ACROSS THE GREAT LAKES WHILE THE GFS HOLDS ONTO  
THE RIDGE THROUGH THE WEEKEND. HOWEVER, 14.00Z EC HAS SHIFTED BACK  
TO HOLDING ONTO THAT RIDGE...WHICH LOOKS MORE REASONABLE. THE  
UPSHOT? THE WARMTH WOULD CONTINUE THROUGH THE WEEK. OF NOTE, THE  
MODEL BLEND CONTINUES TO BE ON THE LOW END OF THE GUIDANCE, CLOSER  
TO THE 25TH PERCENTILE. THE 75% WOULD BRING LOW/MID 80S TO MUCH OF  
THE AREA. NOT GOING TO STRAY MUCH FROM THE MODEL BLEND FOR NOW, BUT  
THERE IS THE POTENTIAL FOR A (VERY) WARM WEEK (WELL ABOVE NORMAL).  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)  
ISSUED AT 525 AM CDT FRI MAY 14 2021  
 
VFR CONDITIONS WILL CONTINUE TODAY WITH INCREASING MID/HIGH CLOUDS  
AHEAD OF A SERIES OF MID-LEVEL SHORTWAVE TROUGHS. SCATTERED LIGHT  
SHOWERS MAY DEVELOP BY THIS AFTERNOON AT KRST, WITH SOMEWHAT  
HIGHER COVERAGE EXPECTED OVERNIGHT ACROSS THE REGION. WITH QUITE A  
BIT OF DRY AIR TO CONTEND WITH, CONFIDENCE IN ONSET OF SHOWERS IS  
LOW WITH PERHAPS ONLY SOME SPRINKLES THROUGH THE DAY AT BEST.  
CONTINUED TO MENTION MVFR CEILINGS AT KRST TONIGHT, ALBEIT LATER  
THAN THE PRIOR FORECAST, BUT GIVEN THE VERY DRY ENVIRONMENT,  
CONFIDENCE IS NOT PARTICULARLY HIGH IN THE DEGREE OF LOW-LEVEL  
MOISTENING/LOWER CEILINGS. THE 14.00Z HREF DOES NOT INDICATE  
GREATER THAN 50 PERCENT PROBABILITIES FOR MVFR CEILINGS UNTIL  
AROUND 15.09Z AT KRST. WINDS WILL REMAIN SOUTHERLY THROUGH THE  
PERIOD, WITH DIURNAL SPEEDS IN THE 10 TO 15 KT RANGE ALONG WITH  
OCCASIONAL GUSTS OVER 20 KTS.  
 

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

 
 

 
 
SHORT TERM...RIECK  
LONG TERM....RIECK  
AVIATION...JM  
 
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