823  
FXUS63 KARX 191121  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
521 AM CST SUN JAN 19 2020  
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 320 AM CST SUN JAN 19 2020  
 
LATEST WATER VAPOR SATELLITE IMAGERY SHOWS UPPER LEVEL TROUGH OVER  
THE GREAT LAKES REGION WITH NORTHWEST FLOW ALOFT OVER THE NORTHERN  
PLAINS. SHORTWAVE TROUGH OVER WESTERN WISCONSIN AND EASTERN  
MINNESOTA IS PRODUCING FLURRIES MAINLY ALONG THE MISSISSIPPI  
RIVER VALLEY PER LATEST KARX RADAR.  
 
TODAY INTO TONIGHT...A COUPLE OF SHORTWAVE TROUGHS EMBEDDED IN THE  
NORTHWEST FLOW ALOFT WILL MOVE ACROSS THE UPPER GREAT LAKES/NORTHERN  
PLAINS. THE COMBINATION OF A COLD AIRMASS IN PLACE...WEAK  
LIFT/FORCING ASSOCIATED WITH EACH PASSING SHORTWAVE TROUGH...WILL  
PRODUCE LIGHT SNOW OR FLURRIES ACROSS MUCH OF THE FORECAST AREA. ANY  
MEASURABLE SNOWFALL MAY OCCUR WITH A STRONGER SHORTWAVE TROUGH  
THIS EVENING/TONIGHT. SNOWFALL AMOUNTS WILL MAINLY BE LESS THAN AN  
INCH.  
 
TEMPERATURES ARE EXPECTED TO BE SLIGHTLY BELOW NORMAL TODAY INTO  
MONDAY WITH HIGHS IN THE SINGLE DIGITS ABOVE ZERO TO AROUND 20  
DEGREES AND LOWS IN THE SINGLE DIGITS BELOW AND ABOVE ZERO.  
   
LONG TERM
 
(MONDAY THROUGH SATURDAY)  
ISSUED AT 320 AM CST SUN JAN 19 2020  
 
SHORTWAVE TROUGH TRACKS SOUTH OF FORECAST AREA DURING THE DAY MONDAY  
AND SHORTWAVE RIDGING BUILDS INTO THE UPPER GREAT LAKES MONDAY  
NIGHT INTO TUESDAY. SOUTHERLY WINDS ON THE BACKSIDE OF THE UPPER  
LEVEL RIDGE WILL ADVECT WARMER TEMPERATURES INTO THE FORECAST AREA  
TUESDAY AFTERNOON. 925MB TEMPERATURES WARM TO MINUS 9 TO MINUS 3  
DEGREES CELSIUS BY 00Z WEDNESDAY. HIGH TEMPERATURES ARE EXPECTED  
TO BE IN THE TEENS TO 20S.  
 
FIRST IMPULSE EJECTING OUT OF THE UPPER LEVEL TROUGH OVER THE ROCKY  
MOUNTAINS BREAKS DOWN UPPER LEVEL RIDGE WEDNESDAY. FORCING/VERTICAL  
MOTION INCREASES ACROSS FORECAST AREA WEDNESDAY AFTERNOON AND  
CHANCES OF PRECIPITATION INCREASE THROUGH THE DAY. PRECIPITATION  
TYPE WILL BE AN ISSUE...AS BUFKIT SOUNDINGS SUGGEST THE SOUTHERN  
HALF OF THE FORECAST AREA TO BE NEAR FREEZING OR SLIGHTLY ABOVE  
ALOFT/NEAR SURFACE. AT THIS TIME...NORTHERN PORTIONS WILL BE ALL  
SNOW WITH THE ATMOSPHERE COLUMN TO BE BELOW FREEZING.  
 
MAIN FORECAST CONCERNS WEDNESDAY NIGHT THROUGH SATURDAY ARE  
PRECIPITATION CHANCES AND PRECIPITATION TYPE THROUGH THE PERIOD. THE  
19.00Z GFS/ECMWF/GEM ARE IN DECENT AGREEMENT IN CUTTING OFF UPPER  
LEVEL LOW OVER THE CENTRAL UNITED STATES THURSDAY INTO  
FRIDAY...HOWEVER MODELS ARE IN DISAGREEMENT ON PLACEMENT AND  
MOVEMENT OF THE UPPER LEVEL LOW. PIECES OF ENERGY ROTATING AROUND  
THE UPPER LEVEL LOW WILL PROVIDE PRECIPITATION CHANCES THROUGH THE  
PERIOD. BIGGEST CONCERN WILL BE PRECIPITATION TYPE...AS THE  
DETERMINISTIC MODELS SUGGEST TEMPERATURES WARMING TO NEAR OR ABOVE  
FREEZING. THIS WILL PRODUCE CHANCES OF A WINTRY MIX OVER THE  
FORECAST AREA. AT THIS TIME...WILL CONTINUE WITH THE MENTION OF RAIN  
OR SNOW AND LATER FORECAST WILL DETERMINE EXACT AMOUNTS.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)  
ISSUED AT 521 AM CST SUN JAN 19 2020  
 
COLD CYCLONIC FLOW ALOFT WILL KEEP MVFR CLOUD COVER GOING THROUGH  
THE PERIOD ALONG WITH SCATTERED FLURRIES. PLAN ON PREVAILING  
NORTHWEST WINDS THROUGH THE PERIOD. GUSTINESS AT KRST IN THE  
20-25KT RANGE IS EXPECTED TO SUBSIDE BY LATER THIS AFTERNOON.  
 

 
   
ARX WATCHES/WARNINGS/ADVISORIES
 
 
WI...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR WIZ032-033-041-  
053>055-061.  
 
MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ079-086>088-  
094>096.  
 
IA...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR IAZ008>011-018-019-  
029-030.  
 

 
 

 
 
SHORT TERM...DTJ  
LONG TERM...DTJ  
AVIATION...DAS  
 
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