014  
FXUS63 KARX 221118  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
618 AM CDT MON JUL 22 2024  
   
KEY MESSAGES
 
 
- LIKE LAST NIGHT, WE ARE MONITORING THE AREA FOR THE POTENTIAL  
OF DENSE FOG EARLY THIS MORNING.  
 
- THE HIGHEST RAIN CHANCES (55-90%) FOR THIS WEEK CONTINUES TO  
LOOK THEY WILL OCCUR FROM LATE TONIGHT INTO TUESDAY.  
 
- NEXT CHANCE OF SHOWERS AND STORMS LOOK TO BE ON SUNDAY.  
 

 
   
UPDATE
 
 
ISSUED AT 430 AM CDT MON JUL 22 2024  
 
WITH THE DENSE FOG BECOMING WIDESPREAD NORTH OF INTERSTATE 90,  
DECIDED TO ISSUE A DENSE FOG ADVISORY UNTIL 8 AM.  
 

 
   
DISCUSSION
 
 
ISSUED AT 306 AM CDT MON JUL 22 2024  
 
TODAY -  
 
WE ARE MONITORING THE AREA FOR THE POTENTIAL OF DENSE FOG EARLY  
THIS MORNING. CURRENTLY ONLY BLACK RIVER FALLS AND BOSCOBEL ARE  
AT A HALF MILE OR LESS. BOSCOBEL IS CURRENTLY DOWN DUE TO VALLEY  
FOG WHICH IS VERY COMMON AND TYPICALLY LOCALIZED FOR THIS TIME  
OF YEAR. IF THE DENSE FOG DOES BECOME A BIT MORE WIDESPREAD, IT  
IS MORE LIKELY NORTH OF INTERSTATE 90 WHERE THERE IS LESS  
CLOUDS CURRENTLY AND THEY HAD RAIN ON SUNDAY. HOWEVER, WITH  
TEMPERATURE AND DEW POINT SPREADS STILL UP TO 2F, THIS MIGHT  
KEEP THE DENSE FOG MORE SCATTERED.  
 
WITH MORE SHORTWAVE RIDGING ALOFT AND LITTLE CONVERGENT  
BOUNDARIES NOTED OVER THE AREA TODAY, THINKING THAT ANY SHOWERS  
AND STORMS TODAY WILL BE MORE ISOLATED THAN THE PAST COUPLE OF  
DAYS.  
 
TONIGHT INTO WEDNESDAY -  
 
A SHORTWAVE TROUGH WILL MOVE SOUTHEAST THROUGH THE AREA. IT  
CONTINUES TO LOOK LIKE MUCH OF THE AREA WILL SEE SHOWERS AND  
STORMS. THE HIGHEST RAIN CHANCE (55-90%) LOOK TO BE FROM LATE  
TONIGHT INTO TUESDAY. WHILE THERE ARE HIGH RAIN CHANCES, THE  
CAMS CONTINUE TO SUGGEST THAT THERE WILL PLENTY OF DRY HOURS  
TOO. RAIN CHANCES ON TUESDAY NIGHT AND WEDNESDAY CONTINUE TO  
LOOK MAINLY ACROSS OUR EAST AND SOUTH AND CONTINUE TO REMAIN ON  
THE LOW SIDE (20-30%). WITH LIMITED SHEAR ACROSS THE AREA, NOT  
ANTICIPATING ANY SEVERE WEATHER.  
 
WEEKEND -  
 
THE MODELS CONTINUE TO STRUGGLE ON WHEN THE UPPER LEVEL RIDGE  
WILL BREAK DOWN. AS THIS OCCURS, UPPER LEVEL SHORTWAVE MOVE  
ALONG THE NORTHERN PERIPHERY OF THIS RIDGE, IT SHOULD GRADUALLY  
FLATTEN. THIS WILL ALLOW RAIN CHANCES TO RETURN TO THE FORECAST.  
WITH INCREASING WINDS ALOFT, SHEAR WILL GRADUALLY INCREASE. IN  
ADDITION, THERE WILL AMPLE INSTABILITY EITHER OVER THE AREA OR  
JUST TO THE SOUTH. THIS WILL PROVIDE A CHANCE OF SEVERE WEATHER.  
COLORADO STATE INDICATES SOME SMALL CHANCES OF SEVERE WEATHER  
FROM THE NORTHERN PLAINS INTO THE GREAT LAKES, BUT WITH SUCH A  
SPREAD IN THE ENSEMBLE ON WHEN THIS RIDGE MIGHT BREAK DOWN,  
CONFIDENCE REMAINS VERY LOW AT THIS TIME, SO KEPT THIS OUT OF  
THE HAZARDOUS WEATHER OUTLOOK AT THIS TIME.  
 

 
   
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
 
 
ISSUED AT 630 AM CDT MON JUL 22 2024  
 
LIFR FOG EXTENDS FROM SOUTHERN MINNESOTA INTO CENTRAL  
WISCONSIN NEAR 22.12Z TAF ISSUANCE. EXPECT THE FOG TO LIFT  
QUICKLY THIS MORNING GIVEN THE JULY SUN ANGLE. THEREFORE, HAVE  
LIFTED IMPACTS 1 HOUR INTO TAF AT 22.13Z. IMPORTANT TO MONITOR  
OBSERVATIONS OVER THE NEXT COUPLE OF HOURS AS LIFR FOG WILL  
WAIVER IMPACTS.  
 
SUBSEQUENT IMPACTS WILL BE SCATTERED SHOWERS AND STORMS THROUGH  
MUCH OF THE DAY. WIDESPREAD SHOWERS AND STORMS ARE EXPECTED  
TOWARDS THE END OF THE TAF PERIOD AS A LINE OF STORMS FORMS FROM  
NORTHERN WISCONSIN, SINKING SOUTH-SOUTHEAST THROUGH THE  
OVERNIGHT HOURS. HAVE HINTED AT THIS AT KLSE. HOWEVER, SOUTHWESTERN  
EXTENT REMAINS A CHALLENGE SO HAVEN'T INCLUDED AT KRST AT 22.12Z TAF  
ISSUANCE. WILL EVENTUALLY SPREAD FARTHER SOUTHWEST NEAR 22.12Z  
TAF TERMINUS. ONSET HAS BEEN DELAYED COMPARED TO PREVIOUS  
FORECAST GIVEN LINGERING DRIER AIR IN PLACE.  
 

 
   
ARX WATCHES/WARNINGS/ADVISORIES
 
 
WI...DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ017-029-  
032>034.  
MN...DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR MNZ079-  
086>088-094.  
IA...NONE.  
 

 
 

 
 
UPDATE...  
DISCUSSION...BOYNE  
AVIATION...JAR  
 
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