699  
FXUS63 KARX 230538  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
1139 PM CST TUE JAN 22 2019  
   
UPDATE
 
 
ISSUED AT 845 PM CST TUE JAN 22 2019  
 
BASED ON TRACK OF SOUTHERN SHORT WAVE AND ASSOCIATED LIFT, LOOKS  
LIKE PATCHY BAND OF SNOW WILL PERSIST TONIGHT ACROSS PARTS OF  
EASTERN IOWA INTO SOUTHWEST WISCONSIN WITH MODEST ACCUMULATIONS  
STILL POSSIBLE.  
 
ALLOWING FOR SOME BUFFER IF SNOW BAND WAVERS A BIT, WILL TRIM BACK  
NORTH AND WEST EDGE OF ADVISORY A TIER OF COUNTIES TONIGHT AS TROUGH  
AXIS PASSES. SHORT TERM GUIDANCE IN AGREEMENT THAT PRECIPITATION  
SHOULD REMAIN SOUTH AND EAST OF THESE AREAS, AND OUTSIDE OF SOME  
SNOW LEFT ON ROADS, NOT EXPECTING ANY ADDITIONAL IMPACT MOVING  
THROUGH THE OVERNIGHT.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH WEDNESDAY)  
ISSUED AT 239 PM CST TUE JAN 22 2019  
 
WATER VAPOR SATELLITE THIS AFTERNOON CONTINUES TO SHOW THAT THE  
NORTHERN AND SOUTHERN STREAM SHORT WAVE TROUGHS HAVE NOT PHASED.  
USING THE LAST SEVERAL RUNS OF THE RAP, APPEARS THERE IS LITTLE  
CHANCE OF THIS HAPPENING NOW. BECAUSE OF THIS LACK OF PHASING, THE  
SOUTHERN STREAM SYSTEM HAS BEEN PUSHED FARTHER TO THE SOUTHEAST THAN  
PREVIOUSLY EXPECTED. THIS SOUTHEAST PUSH IS NOW TAKING THE BEST PV  
ADVECTION IN THE 500-300 MB LAYER FROM KANSAS INTO SOUTHEAST  
WISCONSIN SO THAT IT JUST BRUSHES THE SOUTHERN SECTIONS OF THE  
FORECAST AREA. IN THE MID-LEVELS, A BAND OF FRONTOGENESIS IN  
ASSOCIATION WITH THE NORTHERN STREAM WAVE HAS FORMED A BAND OF  
MODERATE SNOW FROM SOUTHEAST MINNESOTA INTO WESTERN/CENTRAL  
WISCONSIN. THIS LOOKS TO CONTINUE MOVING EAST AND THEN WEAKEN DURING  
THE LATE AFTERNOON AS THE FRONTOGENESIS BECOMES FOCUSED FARTHER TO  
THE SOUTH WITH THE SOUTHERN STREAM SHORT WAVE TROUGH. THIS WILL  
FOCUS THE THREAT FOR THE HEAVIER SNOW FROM EASTERN IOWA INTO  
SOUTHERN WISCONSIN FOR THE OVERNIGHT HOURS. AFTER THE EARLIER  
ADJUSTMENTS TO THE SNOW AMOUNTS, WILL CONTINUE WITH THE IDEA THAT  
THE FRONTOGENESIS AND HEAVIER SNOW BAND COULD BE CLOSE ENOUGH TO  
GENERATE TOTAL ACCUMULATIONS OF 4 TO 6 INCHES FROM ALLAMAKEE AND  
CLAYTON COUNTIES NORTHEAST INTO CENTRAL WISCONSIN. HOWEVER, IF THE  
SHORT RANGE MODEL TRENDS CONTINUE TO SHOW A MORE SOUTHEAST PLACEMENT  
OF THE SNOW BAND, FURTHER ADJUSTMENTS TO THE HEADLINES WILL BE  
NEEDED.  
   
LONG TERM
 
(WEDNESDAY NIGHT THROUGH TUESDAY)  
ISSUED AT 239 PM CST TUE JAN 22 2019  
 
ON WEDNESDAY NIGHT, ANOTHER ARCTIC COLD FRONT WILL MOVE QUICKLY  
SOUTHEAST THROUGH THE REGION. WARM AIR ADVECTION AHEAD OF THIS  
FRONT WILL CAUSE TEMPERATURES TO WARM INTO THE TEENS AND LOWER  
20S. IN THE WAKE OF THIS FRONT, STRONG COLD AIR ADVECTION WILL  
CAUSE FALLING TEMPERATURES THROUGHOUT THURSDAY. BY MID-AFTERNOON  
TEMPERATURES WILL BE IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. A  
WIND CHILL ADVISORY WILL BE LIKELY NEEDED FOR THURSDAY AFTERNOON  
IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA.  
 
FROM THURSDAY NIGHT THROUGH SATURDAY, THE ARCTIC AIR WILL REMAIN  
ACROSS THE REGION. 850 MB STANDARDIZED TEMPERATURE ANOMALIES RANGE  
FROM -1.5 TO -2.5. THE LARGEST TEMPERATURE ANOMALIES WILL BE ON  
FRIDAY MORNING. LOW TEMPERATURES ON BOTH FRIDAY AND SATURDAY  
MORNINGS WILL LIKELY RANGE FROM -10 TO -25F. THERE MAY BE EVEN  
SOME COLDER TEMPERATURES IN CENTRAL WISCONSIN. WIND CHILLS WILL  
LIKELY RANGE FROM 25 TO 35 BELOW. A WIND CHILL ADVISORY WILL  
LIKELY BE NEEDED.  
 
ON FRIDAY, A NORTHERN STREAM SHORT WAVE TROUGH MAY BE CLOSE ENOUGH  
TO POTENTIALLY PRODUCE UP TO A HALF INCH OF SNOW ACROSS PARTS OF  
NORTHEAST IOWA AND SOUTHWEST WISCONSIN. HOWEVER, CONFIDENCE IS  
LOW. BOTH THE GFS AND NAM KEEPS THIS SNOW WELL TO OUR WEST AND  
SOUTH. MEANWHILE, THE ECMWF HAS LIGHT SNOW SOUTH OF INTERSTATE 90.  
FOR NOW JUST STAYED WITH 20 PERCENT SNOW CHANCES.  
 
ON SATURDAY NIGHT, ANOTHER ARCTIC COLD FRONT WILL MOVE SOUTHEAST  
THROUGH THE AREA. THIS SYSTEM MAY PRODUCE UP TO 1 INCH OF SNOW.  
 
FROM SUNDAY NIGHT INTO MONDAY, A MUCH STRONGER NORTHERN STREAM  
SHORTWAVE TROUGH WILL MOVE THROUGH THE REGION. UNLIKE THE PREVIOUS  
2 SYSTEMS, ACTUALLY THIS ONE HAS MORE MOISTURE TO WORK WITH. THE  
GEFS LSE PLUMES RANGING FROM 0.05 TO A HALF INCH. DEPENDING ON ITS  
TRACK, THERE COULD BE SOME TRAVEL IMPACTS.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)  
ISSUED AT 1139 PM CST TUE JAN 22 2019  
 
GENERAL IMPROVEMENT HAS BEEN NOTED THROUGH THE EVENING AS LOWER  
CEILINGS AND VISIBILITIES STARTING TO SHIFT SOUTHEAST WITH MAIN  
SHORT WAVE AND ASSOCIATED WINTER PRECIPITATION. WHILE SOME IFR STILL  
BEING OBSERVED SOUTH, CONDITIONS HAVE LIFTED TO MAINLY MVFR FOR THE  
TIME BEING.  
 
THIS TREND WILL CONTINUE OVERNIGHT IT APPEARS, BUT SATELLITE AND  
METARS SHOW BANDS OF LOWER CLOUDS MIXED WITH VFR THAT WILL MAKE TAF  
FORECASTING A BIT TRICKY.  
 
AS WAVE EXITS THE AREA, GENERALLY IMPROVING CONDITIONS EXPECTED WITH  
SHORT TERM RIDGE BUILDING IN LATER WEDNESDAY. VFR CONDITIONS SHOULD  
BE MORE WIDESPREAD AS WINDS BACK.  
 

 
   
ARX WATCHES/WARNINGS/ADVISORIES
 
 
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR WIZ041>044-  
053.  
 
WINTER STORM WARNING UNTIL 9 AM CST WEDNESDAY FOR WIZ054-055-061.  
 
MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR MNZ096.  
 
IA...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR IAZ010-011-  
019-029.  
 
WINTER STORM WARNING UNTIL 9 AM CST WEDNESDAY FOR IAZ030.  
 

 
 

 
 
UPDATE...SHEA  
SHORT TERM...04  
LONG TERM...BOYNE  
AVIATION...SHEA  
 
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