633  
FXUS63 KGRB 231108  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
608 AM CDT SAT OCT 23 2021  
 
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE  
   
SHORT TERM...TODAY...TONIGHT
 
AND SUNDAY  
ISSUED AT 251 AM CDT SAT OCT 23 2021  
 
ABUNDANT CLOUD COVER IS CURRENTLY PLAGUING THE WESTERN GREAT LAKES  
REGION, AS A MID LEVEL SHORTWAVE TRACKS THROUGH THE AREA. A RIDGE  
OF HIGH PRESSURE WILL BUILD IN ACROSS THE REGION AS THIS SHORTWAVE  
EXITS TO THE EAST. THE RIDGE WILL ALLOW FOR SOME BREAKS IN THE  
CLOUDS ALONG WITH AN EVENTUAL END TO THE LAKE EFFECT SHOWERS  
ACROSS NORTH-CENTRAL WISCONSIN AND AROUND DOOR COUNTY AS WINDS  
BACK TO THE WEST-NORTHWEST. THE CLEARING MAY BE SHORT LIVED, AS  
CONTINUED STEEP LAPSE RATES LEAD TO COME CUMULUS DEVELOPMENT.  
TEMPERATURES WILL REMAIN COOL TODAY, WITH HIGHS RANGING FROM THE  
MIDDLE TO UPPER 40S ACROSS THE NORTH, AND HIGHS AROUND 50 ACROSS  
CENTRAL AND EAST-CENTRAL WISCONSIN.  
 
MOSTLY CLEAR SKIES AND LIGHT WINDS TONIGHT WILL LEAD TO IDEAL  
RADIATIONAL COOLING CONDITIONS TONIGHT. LOWS ARE EXPECTED TO RANGE  
FROM THE MIDDLE TO UPPER 20S ACROSS NORTH-CENTRAL WISCONSIN, WITH  
LOWS IN THE LOWER TO MIDDLE 30S ACROSS EAST-CENTRAL WISCONSIN AND  
AROUND 40 ACROSS THE DOOR PENINSULA.  
 
INCREASING CLOUDS ARE EXPECTED ON SUNDAY AS A LOW PRESSURE SYSTEM  
TRACKS THROUGH ILLINOIS. WHILE PREVIOUS MODEL RUNS BROUGHT  
PRECIPITATION ACROSS THE FAR SOUTH AND SOME MODELS DO GRAZE THESE  
AREAS; INSPECTION OF MODEL SOUNDINGS INDICATED QUITE A BIT OF DRY  
AIR IN THE 750 TO 850 MB LEVEL THROUGH SUNDAY AFTERNOON.  
THEREFORE, WILL REMOVE POPS ACROSS THE FAR SOUTH AND KEEP THE AREA  
DRY WITH THIS FORECAST ISSUANCE AS THE TREND HAS BEEN A BIT  
FARTHER SOUTH WITH EACH RUN. HIGHS ON SUNDAY ARE EXPECTED TO RANGE  
FROM THE UPPER 40S ACROSS THE NORTH, WITH UPPER 40S TO LOWER 50S  
ACROSS CENTRAL AND EAST-CENTRAL WISCONSIN.  
   
LONG TERM
 
SUNDAY NIGHT THROUGH FRIDAY  
ISSUED AT 251 AM CDT SAT OCT 23 2021  
 
THE FIRST SYSTEM TO IMPACT THE AREA WILL BE SUNDAY NIGHT INTO  
MONDAY AS LOW PRESSURE PASSES TO THE SOUTH OF THE AREA. KEPT  
SMALL CHANCES OF SHOWERS ACROSS CENTRAL AND EAST-CENTRAL WISCONSIN  
TO ACCOUNT FOR THE NORTHERN EDGE OF THE SYSTEM PASSING TO THE  
SOUTH OF THE AREA, AND SOME POTENTIAL FOR SOME LAKE EFFECT RAIN  
SHOWERS DUE TO PERSISTENT EAST-NORTHEAST FLOW OFF THE RELATIVELY  
WARMER WATERS OF LAKE MICHIGAN. THE GUSTY NORTHEAST WINDS MAY  
CREATE DIFFICULT TRAVEL FOR HIGH PROFILE VEHICLES ACROSS THE FOX  
VALLEY EAST TO THE LAKESHORE WHERE WINDS MAY GUST TO AROUND 35  
MPH.  
 
AFTER THAT SYSTEM DEPARTS, THE MAIN QUESTION IS WHEN THE RAIN WILL  
ARRIVE LATER IN THE WEEK. A SLOWER ARRIVAL OF THE RAIN IS EXPECTED  
AS THE ECMWF IS INDICATING A CLOSED 500MB LOW DEVELOPING ACROSS  
CENTRAL AND EASTERN GREAT LAKES. MEANWHILE, A 500MB TROUGH ACROSS  
THE WESTERN UNITED STATES IS EXPECTED TO DEVELOP INTO A CLOSED LOW  
ACROSS THE SOUTHERN PLAINS. IN RESPONSE TO THESE TWO FEATURES, A  
SHARP RIDGE IS EXPECTED TO DEVELOP ACROSS THE WESTERN GREAT LAKES  
BY THE MIDDLE OF NEXT WEEK. THIS SCENARIO WILL REALLY SLOW THE  
ARRIVAL OF THE PRECIPITATION. PER COORDINATION WITH SURROUNDING  
OFFICES, REMOVED MOST IF NOT ALL THE PRECIPITATION TUESDAY NIGHT  
AND WEDNESDAY MORNING. BASED ON THE LATEST MODEL RUNS TONIGHT,  
WOULD HAVE REMOVED MOST OF THE PRECIPITATION CHANCES WEDNESDAY  
AFTERNOON AND WEDNESDAY NIGHT AS WELL. HOWEVER, DID LOWER RAIN  
CHANCES FOR NOW PER COORDINATION WITH SURROUNDING OFFICES. LATER  
SHIFTS WILL LIKELY TO NEED TO LOWER THEM SOME MORE OR REMOVE RAIN  
CHANCES ENTIRELY OVER THE NEXT DAY OR TWO. THE ECMWF FINALLY  
BRINGS RAIN INTO THE AREA THURSDAY AFTERNOON AND THURSDAY NIGHT.  
 
TEMPERATURES SHOULD BE AROUND NORMAL, IF NOT A LITTLE BIT ABOVE  
OVER THE NEXT WEEK.  

 
   
AVIATION
 
FOR 12Z TAF ISSUANCE  
ISSUED AT 607 AM CDT SAT OCT 23 2021  
 
VFR CONDITIONS ARE EXPECTED ACROSS MUCH OF THE REGION THROUGH THE  
TAF PERIOD. SOME MVFR CONDITIONS WILL BE POSSIBLE ACROSS FAR  
NORTH-CENTRAL WISCONSIN WITH LAKE EFFECT CLOUDS AND SHOWERS, WHICH  
SHOULD DISSIPATE BY THE AFTERNOON. A BAND OF MID LEVEL CLOUDS WILL  
TRACK THROUGH CENTRAL AND EAST-CENTRAL WISCONSIN THIS MORNING,  
GIVING WAY TO MOSTLY CLEAR CONDITIONS LATER THIS MORNING AS THE  
CLOUDS ERODE FROM NORTH TO SOUTH. WINDS WILL BE LIGHT THROUGH THE  
TAF PERIOD.  

 
   
GRB WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM.....KURIMSKI  
LONG TERM......ECKBERG  
AVIATION.......KURIMSKI  
 
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