159  
FXUS63 KARX 262328  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
628 PM CDT FRI MAY 26 2017  
   
SHORT TERM
 
(TONIGHT THROUGH SATURDAY NIGHT)  
ISSUED AT 215 PM CDT FRI MAY 26 2017  
 
CURRENT WATER VAPOR/MID-LEVEL ANALYSIS HAS A SHORTWAVE TROUGH  
PROGRESSING EASTWARD ACROSS EASTERN IA WHILE ANOTHER TROUGH WAS  
PUSHING ACROSS MN. RADAR HAD SHOWERS BRUSHING NORTHEAST IA INTO FAR  
SOUTHWEST WI ASSOCIATED WITH THE SOUTHERN WAVE WHILE NORTHERN WAVE  
WAS GENERATING FAIRLY WIDESPREAD MID/HIGH CLOUD COVER ACROSS THE  
REST OF THE AREA. OTHERWISE, TEMPERATURES ACROSS THE AREA RANGED  
FROM THE MIDDLE/UPPER 60S IN THE THICKER CLOUD COVER ACROSS THE  
SOUTH, TO THE LOWER/MIDDLE 70S ALONG THE I-90/94 CORRIDORS.  
 
GOING INTO THIS EVENING, WE WILL BE WATCHING THAT MID-LEVEL TROUGH  
OVER MN PUSH A WEAK COLD FRONT INTO THE AREA. ALL THE CAMS SHOW A  
NARROW LINE OF SHOWERS/THUNDERSTORMS DEVELOPING ALONG THE FRONT,  
THEN RAPIDLY DIMINISHING IN INTENSITY AS THEY MOVE INTO NORTHERN WI  
BY EARLY THIS EVENING WITH LOSS OF SURFACE HEATING. LOOK FOR THIS  
WAVE/FRONT TO PUSH THROUGH THE AREA BY MIDNIGHT WITH SKIES BECOMING  
PARTLY CLOUDY OVERNIGHT. DIMINISHED CLOUD COVER AND FAIRLY LIGHT  
WINDS WILL LIKELY LEAD TO SOME FOG FORMATION. WILL HAVE TO KEEP AN  
EYE ON HOW DENSE THIS FOG GETS TOWARD MORNING.  
 
FOR SATURDAY...ANOTHER MID-LEVEL WAVE EJECTS NORTHEAST FROM THE  
PLAINS, COMBINING WITH INCREASING MID-LEVEL FRONTOGENESIS AND  
LINGERING SURFACE BOUNDARY/CONVERGENCE. THIS WILL PRODUCE A CHANCE  
OF SHOWERS AND THUNDERSTORMS IN THE AFTERNON DURING PEAK SURFACE  
HEATING. WILL HAVE TO WATCH FOR THE POTENTIAL OF A FEW  
STRONGER/POSSIBLY SEVERE STORMS ACROSS SOUTHERN WI INTO NORTHEAST IA  
LATE IN THE AFTERNOON AS THE NAM DEVELOPS A NARROW CORRIDOR OF 1500-  
2500J/KG OF 0-6KM MUCAPE ALONG WITH INCREASING 0-6KM BULK SHEAR IN  
THE 35-50KT RANGE AFTER 21Z. THIS IS PROBABLY THE EXTREME OF ALL THE  
MODELS, BUT CERTAINLY BEARS WATCHING FOR THE POSSIBILITY OF STRONG  
TO SEVERE STORMS IF THIS HIGHER-END CAPE AND SHEAR IS REALIZED.  
 
SCATTERED SHOWERS EXPECTED TO CONTINUE INTO SATURDAY NIGHT AS A  
STRONG MID-LEVEL TROUGH/ASSOCIATED CYCLONIC FLOW ROTATES IN  
FROM THE NORTHERN PLAINS.  
   
LONG TERM
 
(SUNDAY THROUGH FRIDAY)  
ISSUED AT 215 PM CDT FRI MAY 26 2017  
 
LONG WAVE TROUGH SETS UP ACROSS THE AREA SUNDAY THROUGH WEDNESDAY AS  
A CLOSED LOW MOVES THROUGH SOUTHERN CANADA. THIS WILL SET UP ON/OFF  
SHOWER CHANCES THROUGH THE PERIOD ALONG WITH THE POSSIBILITY OF A  
FEW AFTERNOON STORMS IN PEAK HEATING/STEEPENING LAPSE RATES. LOOK  
FOR HIGHS SUNDAY IN THE UPPER 60S TO MIDDLE 70S, COOLING INTO THE  
60S MEMORIAL DAY THROUGH WEDNESDAY.  
 
COULD STILL SEE A SLIGHT CHANCE OF SHOWERS THURSDAY AND FRIDAY AS  
AREA REMAINS IN NORTHWEST FLOW ON THE BACKSIDE OF THE DEPARTING  
CLOSED LOW.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)  
ISSUED AT 628 PM CDT FRI MAY 26 2017  
 
A WEAK COLD FRONT CONTINUES TO WORK EAST EARLY THIS EVENING, AND  
IS EXPECTED TO MAKE IT TO ABOUT LSE LATER TONIGHT BEFORE STALLING  
AND DISSIPATING. A COUPLE OF ISOLATED SHOWERS HAVE DEVELOPED ALONG  
THAT FRONT, BUT SHOULD STEER CLEAR OR LSE OR RST TO THE NORTH  
THROUGH 02Z, WITH VFR CONDITIONS EXPECTED FOR MUCH OF THE NIGHT.  
HOWEVER, WHERE THAT FRONT ENDS UP STALLING MAY PROVE DIFFICULT, AS  
THERE IS AN INCREASING RISK FOR SOME FOG AND/OR STRATUS  
DEVELOPMENT TO THE EAST OF THE FRONT, WHERE HIGHER MOISTURE LEVELS  
WILL REMAIN PRESENT. AT THIS TIME, IT APPEARS THE GREATEST RISK  
FOR IFR STRATUS AND/OR FOG WILL EXIST JUST TO THE EAST AND SOUTH  
OF LSE, BUT TRENDS WILL NEED TO BE MONITORED CLOSELY, AS THE RISK  
FOR A SEVERAL HOUR WINDOW OF LOWERED CEILINGS DOES EXIST.  
OTHERWISE, A GRADUAL INCREASE AND LOWERING OF CEILINGS IS EXPECTED  
FROM WEST TO EAST THROUGH THE DAY ON SATURDAY AS OUR NEXT SYSTEM  
APPROACHES, WITH ONLY A VERY LIMITED RISK FOR AN ISOLATED SHOWER  
PRIOR TO 00Z. THE GREATER RISK FOR RAIN AND POTENTIAL REDUCED  
CEILINGS WILL HOLD OFF UNTIL SATURDAY EVENING AND NIGHT.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 215 PM CDT FRI MAY 26 2017  
 
ELEVATED RIVER LEVELS/MINOR FLOODING WILL CONTINUE ALONG THE  
MISSISSIPPI RIVER THROUGH THE WEEKEND INTO EARLY NEXT WEEK. THOSE  
WITH INTERESTS ALONG OR ON THE MISSISSIPPI RIVER SHOULD MONITOR THE  
LATEST RIVER FORECASTS AND STATEMENTS CLOSELY. IF YOU ARE PLANNING  
ANY RECREATIONAL ACTIVITIES/BOATING BE AWARE OF THESE ELEVATED RIVER  
LEVELS AND WATCH OUT FOR OBJECTS IN THE WATER THAT MAY POSE A THREAT  
TO WATERCRAFT.  
 

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

 
 

 
 
SHORT TERM...DAS  
LONG TERM....DAS  
AVIATION...LAWRENCE  
HYDROLOGY....DAS  
 
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