430  
FXUS63 KARX 291702  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
1202 PM CDT THU JUL 29 2021  
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 310 AM THU JUL 29 2021  
 
PASSING OF CONVECTIVE COMPLEX THIS MORNING WILL BRING A RETURN TO  
QUIET WEATHER AND START TO A PERIOD OF LOWER HEAT AND HUMIDITY  
VALUES. AS WAVE CONTINUES TO PUSH SOUTHEAST OF THE AREA, SURFACE  
BOUNDARY WILL CONTINUE TO SHIFT WITH IT USHERING IN DRIER AIR  
GRADUALLY TODAY.  
 
BEFORE THAT FOG HAS BEEN EXPANDING ACROSS PARTS OF NORTH CENTRAL  
WISCONSIN ALONG AND NORTH OF BOUNDARY IN AREAS WHERE HEAVIER RAIN  
FELL ON WEDNESDAY EVENING. THIS SHOULD DISSIPATE LATER THIS MORNING  
WITH GOOD PERIOD OF SUNSHINE.  
 
COMBINATION OF CANADIAN FIRES AND SOME SMOKE CROSSING WESTERN RIDGE  
COULD IMPACT PARTS OF THE AREA TODAY WITH THE HRRR VERTICALLY  
INTEGRATED SMOKE SUGGESTING AN INCREASE IN CONCENTRATION LEVELS  
THROUGH THE DAY. IN FACT NEAR SURFACE SMOKE COULD ALSO INCREASE,  
ESPECIALLY ACROSS MINNESOTA AS SUBSIDENCE TAKES PLACE WITH SURFACE  
RIDGE BUILDING IN. MINNESOTA POLLUTION CONTROL AGENCY ALREADY HAS  
HOISTED AIR QUALITY ALERTS IN MINNESOTA.  
   
LONG TERM
 
(FRIDAY THROUGH WEDNESDAY)  
ISSUED AT 310 AM CDT THU JUL 29 2021  
 
LONG TERM WILL BE SUMMARIZED BY SLIGHT PATTERN SHIFT AS UPPER RIDGE  
BUILDS OR AMPLIFIES ACROSS ROCKY MOUNTAINS AND NORTHWEST FLOW ACROSS  
UPPER MISSISSIPPI RIVER VALLEY BECOMES EVEN MORE NORTHERLY. THIS  
WILL MAKE FOR SOME RAIN OR STORM ACTIVITY TO START WEEKEND BUT THEN  
A TRANSITION INTO A PLEASANT, COOLER PATTERN FOR NEXT WEEK.  
 
SPEAKING OF WHICH, WILL NEED TO WATCH SHORT WAVES IN NORTHWEST FLOW  
ON FRIDAY THAT COULD ACT ON BOUNDARY TO OUR SOUTHWEST. BULK OF  
ACTIVITY, AND CERTAINLY ANY SEVERE RISK, WILL REMAIN SOUTHWEST OF  
AREA BUT SOME SUGGESTION IN MODEL GUIDANCE OF AT LEAST SOME PASSING  
SHOWERS. WILL WARRANT RISK AND WILL ALSO HAVE TO WATCH IMPULSE  
DROPPING SOUTH THROUGH THE GREAT LAKES WITH A RISK ALONG AND NORTH  
OF I-94 IN WISCONSIN.  
 
PERHAPS THE MORE INTERESTING DAY IS SATURDAY WHEN A STRONGER SHORT  
WAVE AND ASSOCIATED COLD FRONT WILL DROP INTO AMPLIFYING FLOW AND  
PASS THROUGH WESTERN GREAT LAKES AT PEAK HEATING. WIND SHEAR DOES  
NOT LOOK OVERLY IMPRESSIVE AND UNSURE HOW MUCH INSTABILITY WILL FORM  
ALONG FRONT, BUT SOME HINTS THERE COULD BE ENOUGH FOR A FEW STRONG  
STORMS CLOSER TO GREAT LAKES AS BOUNDARY DROPS SOUTH, PERHAPS WITH  
ADEQUATE LAPSE RATES TO WORK WITH. SEE SPC DAY 3 OUTLOOK FOR FURTHER  
DETAILS.  
 
AFTER THAT SOME GOOD LOOKING WEATHER TO START OUT AUGUST WITH A STEP  
BACK IN TEMPERATURES AND CERTAINLY DRIER AIR AROUND. LOWS BACK IN  
THE 50S OR EVEN 40S IN COOLER SPOTS WILL BRING A NICE BREAK TO NEED  
FOR AIR CONDITIONS AND UNPLEASANT OUTDOOR CONDITIONS.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)  
ISSUED AT 1202 PM CDT THU JUL 29 2021  
 
VFR CONDITIONS THROUGH THE PERIOD AS HIGH PRESSURE BUILDS  
OVERHEAD. PLAN ON NORTHERLY WINDS GENERALLY LESS THAN 10KT.  
BY THE WAY, THIS IS MY LAST FORECAST DUTY SHIFT...RETIRING! IT'S  
BEEN A PLEASURE AND HONOR FOR ME TO SERVE THE AVIATION COMMUNITY  
AS WELL AS ALL THE OTHER CUSTOMERS OUT THERE THAT DEPEND ON OUR  
FORECAST/WARNING PRODUCTS.  
 

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

 
 

 
 
SHORT TERM...SHEA  
LONG TERM...SHEA  
AVIATION...DAS  
 
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