671  
FXUS63 KGRB 171837  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
137 PM CDT THU SEP 17 2026  
 
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE  
   
KEY MESSAGES  
 
- A PERIOD OF HEAVY RAINFALL IS EXPECTED FRIDAY AFTERNOON THROUGH  
SATURDAY, WITH THE HEAVIEST RAIN OCCURRING FRIDAY NIGHT. A 30 TO  
50 PERCENT CHANCE OF RAINFALL EXCEEDING 2 INCHES EXISTS ROUGHLY  
SOUTH OF HIGHWAY 29.  
 
- A QUIETER AND DRIER WEATHER PATTERN WILL SETTLE INTO THE REGION  
EARLY TO MID NEXT WEEK.  
 
 
   
DISCUSSION  
 
ISSUED AT 137 PM CDT THU SEP 17 2026  
 
HIGH PRESSURE WILL KEEP THE WEATHER DRY ACROSS THE REGION TONIGHT.  
LINGERING LOW LEVEL MOISTURE MAY CAUSE SOME FOG ACROSS FAR NORTH-  
CENTRAL WISCONSIN LATE TONIGHT INTO EARLY FRIDAY MORNING, MAINLY  
NORTH OF HIGHWAY 8. MEANWHILE, CLOUDS WILL INCREASE LATE TONIGHT  
INTO FRIDAY MORNING AHEAD OF THE NEXT LOW PRESSURE SYSTEM SLATED  
TO AFFECT THE REGION LATER ON FRIDAY THROUGH THE WEEKEND.  
 
THE TREND WITH THE HEAVIEST PRECIPITATION CONTINUES TO TREND SOUTH  
THIS RUN, WITH THE SWATH OF MODERATE TO HEAVY RAIN IN SOUTHERN  
WISCONSIN THIS RUN FRIDAY AND SATURDAY. THIS SCENARIO MAKES SENSE  
AS THE BEST INSTABILITY STAYS TO OUR SOUTH, LIMITING THE  
POTENTIAL FROM HEAVY RAIN DUE TO THUNDERSTORMS. THERE IS A  
CONTINUED INTERESTING TREND WITH THE GFS IN A BAND OF RAIN ACROSS  
NORTH-CENTRAL WISCONSIN FRIDAY AFTERNOON ASSOCIATED WITH MID  
LEVEL FRONTOGENESIS. MODEL SOUNDINGS INDICATE QUITE A BIT OF DRY  
AIR ALONG WITH A LACK OF INSTABILITY AS THIS AREA OF FRONTOGENESIS  
TRACKS THROUGH NORTHERN WISCONSIN. THEREFORE, EVEN IF THIS AREA  
DOES END UP DEVELOPING, THE IMPACT SHOULDN'T BE HIGH AS THE AREA  
IS HEAVILY FORESTED AND CURRENTLY IN A DROUGHT. MEANING ANY RAIN  
WOULD BE WELCOME AND SOAKED IN BY THE SOIL.  
 
CONFIDENCE IN HEAVY RAINFALL ACROSS OUR AREA HAS CONTINUED TO  
TREND SOUTH, WITH THE PROBABILITY OF 2 INCHES OR MORE FALLING  
TO 30 TO 50 PERCENT MAINLY SOUTH OF HIGHWAY 29. ALTHOUGH THE TREND  
CONTINUES TO DIVE SOUTH, THE ECMWF STILL BRINGS THE SWATH OF  
MODERATE TO HEAVY RAIN THROUGH CENTRAL AND EAST-CENTRAL WISCONSIN  
FRIDAY NIGHT. THEREFORE, THE HEAVY RAIN STAYING TO OUR SOUTH ISN'T  
A CERTAINTY AT THIS POINT. RAINFALL SHOULD FOR THE MOST PART END  
BY LATE SATURDAY, WITH LIGHT RAIN POSSIBLY CONTINUING SATURDAY  
NIGHT INTO SUNDAY.  
 
SHORTWAVE ENERGY FROM THE WESTERN NORTH AMERICAN TROUGH WILL  
SLOWLY MIGRATE EAST OVER THE CENTER OF THE COUNTRY THROUGH THE  
MIDDLE OF NEXT WEEK. THE ASSOCIATED LOW PRESSURE SYSTEM AND  
RAINFALL FOOTPRINT HAVE TRENDED FURTHER SOUTH OVER THE PAST 24  
HOURS. THEREFORE, IT APPEARS THAT THE BULK OF THE PRECIPITATION  
WILL REMAIN SOUTH OF THE REGION. ONLY SMALL CHANCES OF RAIN, UP TO  
30 PERCENT, ARE FORECAST FOR MONDAY. FOR THE REMAINDER OF THE  
WEEK, STRONG HIGH PRESSURE SETTLING OVER NORTHERN ONTARIO LOOKS TO  
FUNNEL AMPLE DRY AIR SOUTHWARD ACROSS NORTHERN WISCONSIN. RAIN  
CHANCES ARE EXPECTED TO REMAIN LOW FOR MUCH OF NEXT WEEK UNDER THE  
INFLUENCE OF THIS CANADIAN HIGH.  
 
 
   
AVIATION  
FOR 18Z TAF ISSUANCE  
ISSUED AT 1200 PM CDT THU SEP 17 2026  
 
DESPITE RAIN EXITING THE REGION THIS MORNING, MVFR/IFR CONDITIONS  
CONTINUE TO PLAGUE THE TAF SITES EARLY THIS AFTERNOON AS LOW LEVEL  
MOISTURE REMAINS ACROSS THE REGION. MODELS AND SATELLITE DATA  
INDICATE DRY AIR SHOULD EVENTUALLY SCATTER OUT THESE LOW CLOUDS,  
LEAVING VFR CONDITIONS IN ITS PLACE. FURTHER NORTH, THESE  
CONDITIONS MAY STICK AROUND A BIT LONGER AS THESE ARE DIURNALLY  
DRIVEN BUT SHOULD DISSIPATE ONCE THE SUN SETS.  
 
HIGH PRESSURE WILL BUILD IN ACROSS THE NORTH TONIGHT, BRINGING  
PRIMARILY VFR CONDITIONS TO THE REGION. SOME PATCHY FOG IS  
POSSIBLE ACROSS NORTH-CENTRAL WISCONSIN, MAINLY AFFECTING THE KRHI  
TAF SITE WITH MVFR/IFR CONDITIONS.  
 
MID AND HIGH CLOUDS WILL INCREASE LATE TONIGHT AHEAD OF AN  
APPROACHING LOW PRESSURE SYSTEM TAKING AIM FOR THE REGION ON  
FRIDAY. ALTHOUGH MANY OF THE LOWER CONDITIONS AND IMPACTS WILL BE  
FRIDAY AFTERNOON, CONDITIONS ARE EXPECTED TO FALL TO IFR WITH  
LIGHT TO MODERATE RAIN THROUGH FRIDAY NIGHT.  
 
 
   
MARINE  
 
ISSUED AT 137 PM CDT THU SEP 17 2026  
 
GUSTY EASTERLY WINDS AHEAD OF AND DURING THE PASSAGE OF THE  
AFOREMENTIONED LOW PRESSURE SYSTEM WILL BUILD WAVE HEIGHTS  
SIGNIFICANTLY ON LAKE MICHIGAN FROM FRIDAY NIGHT THROUGH THE  
WEEKEND. THIS WILL CREATE HAZARDOUS CONDITIONS FOR SMALL CRAFT AND  
INCREASE THE RISK FOR DANGEROUS RIP CURRENTS ALONG AREA BEACHES  
FROM LATE FRIDAY NIGHT THROUGH THE WEEKEND AND POSSIBLY INTO  
MONDAY.  
 
 
   
GRB WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
 
 
DISCUSSION.....KURIMSKI  
AVIATION.......KURIMSKI  
MARINE.........KURIMSKI  
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