465  
FXUS63 KGRB 291726  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
1226 PM CDT THU JUL 29 2021  
 
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE  
   
SHORT TERM...TODAY...TONIGHT
 
AND FRIDAY  
ISSUED AT 327 AM CDT THU JUL 29 2021  
 
SHOWERS AND THUNDERSTORMS HAVE ENDED ACROSS THE REGION, BUT  
AREAS OF LOW STRATUS AND FOG WERE FORMING IN NORTHERN WI, IN THE  
WAKE OF A COLD FRONTAL PASSAGE. THERE SHOULD BE ENOUGH WIND TO  
PREVENT WIDESPREAD DENSE FOG FROM OCCURRING, AND WOULD EXPECT  
A QUICK IMPROVEMENT IN VSBYS EARLY IN THE MORNING. STRATUS WILL  
LIKELY LINGER UNTIL MID TO LATE MORNING, FOLLOWED BY SCATTERED  
DIURNAL CUMULUS FOR THE REST OF THE DAY. RAP/HRRR SMOKE MODELS  
DEPICT A BAND OF SMOKE DRIFTING SOUTH THROUGH THE FORECAST TODAY  
INTO EARLY TONIGHT, BUT SUGGEST THAT MOST OF THE NEAR-SURFACE  
IMPACTS WILL OCCUR WELL TO OUR WEST IN MN. NORTH TO NORTHEAST  
WINDS WILL GUST TO AROUND 20 MPH, AND BRING A LESS HUMID CANADIAN  
AIR MASS TO THE REGION. HIGH TEMPERATURES SHOULD RANGE FROM THE  
MIDDLE TO UPPER 70S NORTH TO THE LOWER TO MIDDLE 80S SOUTH.  
 
CANADIAN HIGH PRESSURE WILL BRING PARTLY CLOUDY SKIES AND COOLER  
WEATHER TONIGHT INTO FRIDAY. LOWS TONIGHT SHOULD RANGE FROM THE  
MIDDLE TO UPPER 40S NORTH TO THE 50S SOUTH. HIGHS ON FRIDAY WILL  
BE IN THE 70S, WITH VERY COMFORTABLE DEW POINTS IN THE UPPER 40S  
TO MIDDLE 50S.  
   
LONG TERM
 
FRIDAY NIGHT THROUGH WEDNESDAY  
ISSUED AT 327 AM CDT THU JUL 29 2021  
 
THE LATEST ENSEMBLE MEANS POINT TOWARDS AMPLIFICATION OF THE UPPER  
AIR PATTERN THIS WEEKEND, FOLLOWED BY DEAMPLIFICATION NEXT WEEK. AS  
THE UPPER RIDGE BUILDS OVER NORTHWEST NORTH AMERICA IN THE FRIDAY-  
SATURDAY TIME PERIOD, DIGGING SHORTWAVE ENERGY WILL PASS ACROSS THE  
REGION ON SATURDAY AND PROVIDE THE NEXT CHANCE OF THUNDERSTORMS.  
POTENTIAL FOR SEVERE WEATHER ON SATURDAY IS THE MAIN FORECAST  
CONCERN IN THIS PART OF THE FORECAST.  
 
FRIDAY NIGHT THROUGH SATURDAY NIGHT...HIGH PRESSURE WILL BE CENTERED  
OVER THE SOUTHERN GREAT LAKES AT THE START OF FRIDAY NIGHT. IT WILL  
SHIFT SOUTH THROUGH THE NIGHT AS CLOUDS INCREASE AHEAD OF A COLD  
FRONT, WHICH IS FORECAST TO ARRIVE INTO FAR NORTHERN WI BY LATE  
FRIDAY NIGHT OR EARLY SATURDAY MORNING. MINOR ELEVATED INSTABILITY  
WILL ACCOMPANY THE FRONT, SO WILL KEEP A LOW CHANCE OF STORMS OVER  
THE FAR NORTH. WHILE THERE IS SOME DIFFERENCES OF TIMING OF THE  
FRONT ON SATURDAY, INDICATIONS ARE THAT THE FRONT WILL CROSS THE  
FORECAST AREA DURING THE AFTERNOON. MID-LEVEL HEIGHT FALLS WILL  
PROVIDE LARGE SCALE ASCENT IN A REGION OF 1000-1500 J/KG OF  
INSTABILITY AND DEEP LAYER SHEAR AROUND 30 KTS. THESE PARAMETERS  
WILL FAVOR SOME STRONG STORMS IF TIMING REMAINS AROUND THE TIME  
OF PEAK HEATING. THEN CLEARING SHOULD OCCUR ON SATURDAY NIGHT.  
 
REST OF THE FORECAST...ANOTHER SHORTWAVE IS FORECAST TO MOVE ACROSS  
THE AREA ON MONDAY. THE ATMOSPHERE WILL BE CONSIDERABLY LESS  
UNSTABLE THAN ON SATURDAY, SO PERHAPS ONLY A SPOTTY SHOWER OR STORM  
WILL BE POSSIBLE (MOST GUIDANCE IS DRY FOR MONDAY). WITH HIGH  
PRESSURE AT THE SURFACE, DRY AND SEASONABLE WEATHER LOOKS TO BE IN  
THE CARDS THROUGH THE MIDDLE OF NEXT WEEK.  

 
   
AVIATION
 
FOR 18Z TAF ISSUANCE  
ISSUED AT 1226 PM CDT THU JUL 29 2021  
 
EXPECT A MIX OF VFR/MVFR CONDITIONS THIS AFTERNOON WITH SCATTERED  
TO BROKEN CLOUDS WITH BASES AROUND 2500 FEET. SITES WILL LIKELY  
OSCILLATE BETWEEN SCT AND BKN AS THE CLOUDS MOVE THROUGH.  
MEANWHILE, SATELLITE IMAGERY DEPICTING AND LARGE AREA OF SMOKE  
ACROSS MN WITH A PIECE STRETCHING INTO CENTRAL WI. THIS SMOKE MAY  
PRODUCE A HAZE AT TIMES, BUT NOT EXPECT MUCH FOR SURFACE IMPACTS  
ACROSS NE WI. A COUPLE SITES HAVE HAD VISIBILITY DROP TO 6SM OR  
7SM FROM THE SMOKE, BUT DO NOT EXPECT ANY VISIBILITY DROP TO LAST  
VERY LONG AT ANY SITE; THEREFORE, DID NOT INCLUDE IN 18Z TAF  
UPDATE. OTHERWISE, NORTH WINDS WILL GUST TO 15 TO 20 KNOTS THROUGH  
EARLY THIS EVENING THEN BECOME LIGHT OVERNIGHT. LOW CLOUDS WILL  
ALSO DISSIPATE THIS EVENING WITH ONLY SOME PASSING HIGH CLOUDS OR  
HIGH SMOKE OVERNIGHT AND INTO FRIDAY MORNING.  

 
   
GRB WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM.....KIECKBUSCH  
LONG TERM......MPC  
AVIATION.......KLJ  
 
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