678  
FXUS63 KARX 291131  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
631 AM CDT MON MAY 29 2017  
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 331 AM CDT MON MAY 29 2017  
 
THE LATEST WATER VAPOR IMAGERY SHOWS A SHORT WAVE TROUGH MOVING  
EAST SOUTHEAST THROUGH SOUTHEAST SOUTH DAKOTA. THE 29.00Z MODELS  
ARE IN GOOD AGREEMENT THAT THIS SYSTEM WILL MOVE THROUGH THE AREA  
THIS AFTERNOON AND EVENING. IN ADDITION WITH COLD AIR ALOFT AND  
DIURNAL HEATING, THE 0-1 KM MIXED LAYER CAPES WILL CLIMB UP TO  
250 J/KG. THIS WILL RESULT IN THE DEVELOPMENT OF SCATTERED SHOWERS  
AND ISOLATED THUNDERSTORMS. THE COMBINATION OF STEEP 950 TO  
800 MB LAPSE RATES AND VERY DRY SUB CLOUD LAYER WILL RESULT IN  
OCCASIONAL WIND GUSTS UP TO 30 MPH AT TIMES.  
   
LONG TERM
 
(TUESDAY THROUGH SUNDAY)  
ISSUED AT 331 AM CDT MON MAY 29 2017  
 
ON TUESDAY AND TUESDAY EVENING, A SERIES OF SHORT WAVE TROUGHS  
WILL MOVE SOUTHEAST THROUGH THE REGION. WITH 0-1 KM MIXED LAYER  
CAPES UP TO 250 J/KG, EXPECT SCATTERED SHOWERS AND ISOLATED  
THUNDERSTORMS TO BE SEEN ACROSS THE UPPER MISSISSIPPI RIVER  
VALLEY. IN ADDITION, STEEP 950-800 MB LAPSE RATES WILL PRODUCE  
WIND GUSTS OF 20 TO 30 MPH.  
 
ON WEDNESDAY AND WEDNESDAY NIGHT, A 950 TO 850 MB RIDGE WILL BUILD  
ACROSS THE REGION. THIS WILL PROVIDE A BRIEF PERIOD OF DRY  
WEATHER.  
 
FROM THURSDAY INTO FRIDAY NIGHT, THE GFS, GEM, AND ECMWF ARE IN  
AGREEMENT THAT A WARM FRONT WILL BE LOCATED ACROSS THE REGION.  
MODERATE 850 MB MOISTURE TRANSPORT INTO THE REGION WILL RESULT IN  
THE DEVELOPMENT OF SHOWERS AND STORMS. WHILE THE INSTABILITY WILL  
BE INCREASING ACROSS THE REGION, THE DEEP SHEAR REMAINS DISPLACED  
FURTHER TO THE NORTHEAST, SO THE SEVERE WEATHER THREAT LOOKS  
MINIMAL. WITH WARM CLOUD LAYER DEPTHS INCREASING TO AROUND  
3500 J/KG FROM FRIDAY INTO FRIDAY NIGHT, WE WILL HAVE TO WATCH  
FOR THE POTENTIAL OF HEAVY RAIN.  
 
BEYOND THIS TIME PERIOD, MUCH UNCERTAINTY EXISTS ON THE LOCATION  
OF WARM FRONT. THE 29.00Z ECMWF AND GEM HAVE A CANADIAN HIGH  
PRESSURE AREA BUILDING ACROSS THE REGION. MEANWHILE THE GFS HAS A  
SHORT WAVE TROUGH MOVING THROUGH THE REGION; THUS, IT KEEPS A  
THREAT OF SHOWERS AND STORMS CONTINUING INTO THE WEEKEND.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)  
ISSUED AT 631 AM CDT MON MAY 29 2017  
 
VFR TO POSSIBLY MVFR CONDITIONS EXPECTED AT THE TAF SITES TODAY.  
PLAN INCREASING CLOUDS TODAY AS AN UPPER LEVEL TROUGH SETTLES OVER THE  
REGION. SCATTERED SHOWERS AND POSSIBLY ISOLATED THUNDERSTORMS ARE  
EXPECTED LATE THIS MORNING INTO THIS AFTERNOON. PLAN ON BKN TO  
OVC CLOUD COVER TODAY WITH CLOUD BASES IN THE 3 TO 4 KFT RANGE  
THIS MORNING INCREASING TO MAINLY VFR BY MID TO LATE AFTERNOON  
WITH BASES IN THE 4 TO 5 KFT RANGE. IT WILL BE BREEZY TODAY WITH  
WESTERLY WINDS OF 13 TO 16 KTS WITH GUSTS TO AROUND 25 KTS AT  
TIMES. CLOUDS WILL DECREASE TONIGHT WITH THE LOSS OF DAYTIME  
HEATING WITH VFR CONDITIONS EXPECTED.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 331 AM CDT MON MAY 29 2017  
 
A FLOOD WARNING CONTINUES ALONG THE MISSISSIPPI RIVER AT BOTH MCGREGOR  
AND GUTTENBERG DAM 10. MEANWHILE ELEVATED RIVER LEVELS CONTINUE  
ALONG THE MISSISSIPPI RIVER NORTH OF MCGREGOR. IF YOU ARE  
PLANNING ANY RECREATIONAL ACTIVITIES ON THE MISSISSIPPI RIVER BE  
ALERT FOR THESE HIGH WATER LEVELS AND WATCH OUT FOR DEBRIS IN THE  
WATER THAT MAY POSE A THREAT TO WATERCRAFT.  
 

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

 
 

 
 
SHORT TERM...BOYNE  
LONG TERM...BOYNE  
AVIATION...WETENKAMP  
HYDROLOGY...BOYNE  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab WI Page
The Nexlab IA Page
The Nexlab MN Page Main Text Page