393  
FXUS63 KGRB 010630  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
130 AM CDT THU OCT 1 2026  
 
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE  
   
KEY MESSAGES
 
 
- PERIODS OF LIGHT TO MODERATE RAIN ARE FORECAST TO CONTINUE OVER  
CENTRAL AND EAST-CENTRAL WISCONSIN INTO THIS AFTERNOON.  
ADDITIONAL RAINFALL AMOUNTS UP TO AROUND 0.5" ARE EXPECTED.  
 
- PATCHY FROST WILL BE POSSIBLE AT TIMES ACROSS NORTHERN WISCONSIN  
INTO THE WEEKEND. GREATEST CHANCE FOR A WIDESPREAD FROST/FREEZE  
EVENT WILL BE SUNDAY NIGHT INTO MONDAY MORNING.  
 

 
   
DISCUSSION
 
 
ISSUED AT 100 AM CDT THU OCT 1 2026  
 
RAIN CHANCES TODAY... RADAR CURRENTLY SHOWS A BROAD AREA OF  
STRATIFORM RAIN SPREADING ACROSS SOUTHERN WISCONSIN EARLY THIS  
MORNING WHERE DECENT MOISTURE CONVERGENCE AND WEAK FGEN RESIDE.  
THIS RAIN SHOULD MAKE IT UP INTO PORTIONS OF CENTRAL AND EAST-  
CENTRAL WISCONSIN OVER THE NEXT SEVERAL HOURS AS MOIST CONVEYOR  
BELT LIFTS NORTH AND INTERACTS WITH COLD FRONTAL PASSAGE AND WEAK  
COUPLED SHORTWAVE. AXIS OF HEAVIEST RAIN SHOULD REMAIN OFF TO OUR  
SOUTH, WITH PROBABILISTIC GUIDANCE ONLY SHOWING A 40 TO 70% CHANCE  
FOR RECEIVING 0.5" OF QPF OVER EAST-CENTRAL WISCONSIN. AREAS  
NORTH OF HWY 29 HAVE A GOOD CHANCE OF MISSING OUT ON THE RAIN  
ENTIRELY. RAIN EVENTUALLY COMES TO AN END FROM NORTHWEST TO  
SOUTHEAST THIS AFTERNOON AS COOLER AND MORE STABLE AIR FILTERS IN  
BEHIND THE FRONT.  
 
PATCHY GROUND FOG, LOCALLY DENSE, WILL BE POSSIBLE THROUGH THIS  
MORNING DUE TO SATURATED BOUNDARY LAYER. WILL BE TOUGH TO PULL  
THE TRIGGER ON AN ADVISORY DUE TO LOW STRATUS REGIME AND GENERALLY  
MOIST AIRMASS, THOUGH WILL CONTINUE TO KEEP AN EYE ON OBS.  
 
EXTENDED... AFTER SHOWERS WRAP UP LATER TODAY, PATTERN THROUGH  
THE MIDDLE OF NEXT WEEK WILL BE CHARACTERIZED BY MOSTLY DRY  
WEATHER AND NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES AS UPPER  
FLOW FLATTENS OUT AND HIGH PRESSURE BUILDS. ONLY EXCEPTION WILL BE  
30 TO 50% CHANCE OF LIGHT RAIN NORTH OF HWY 29 SATURDAY EVENING AS  
TRANSIENT SHORTWAVE AND WEAK COLD FRONT MOVE THROUGH THE UPPER  
MIDWEST. OTHERWISE, FROST/FREEZE SETUP REMAINS ON TRACK FOR FRIDAY  
NIGHT INTO SATURDAY MORNING, AND AGAIN SUNDAY NIGHT INTO MONDAY  
MORNING AS SURFACE HIGH SITS OVERHEAD AND 850 MB TEMPERATURES FALL  
TO NEAR, OR EVEN SLIGHTLY BELOW, 0C. AS IT STANDS NOW, BETTER  
SETUP FOR A WIDESPREAD FROST/FREEZE EVENT LOOKS TO BE EARLY MONDAY  
MORNING. WITH MOSTLY CLEAR SKIES PROVIDING EFFECTIVE RADIATIONAL  
COOLING, SOME OF THE COLD SPOTS ACROSS THE NORTH MAY EVEN DIP  
BELOW FREEZING DURING THIS TIME. WILL CONTINUE TO MONITOR FOR  
HEADLINE POTENTIAL.  
 

 
   
AVIATION
 
FOR 06Z TAF ISSUANCE  
ISSUED AT 952 PM CDT WED SEP 30 2026  
 
A COLD FRONT OVER NORTHWEST WISCONSIN WILL GRADUALLY DROP  
SOUTHEAST AS A LOW PRESSURE SYSTEM TRACKS FROM THE CENTRAL PLAINS  
TONIGHT ACROSS NORTHERN ILLINOIS ON THURSDAY MORNING.  
 
AS THE LOW TRACKS CLOSER, LIGHT RAIN CHANCES WILL INCREASE IN THE  
08-18Z THU PERIOD, MAINLY OVER EAST-CENTRAL WI. KATW AND KMTW  
HAVE THE GREATEST POTENTIAL TO BE IMPACTED FROM THE SHOWERS. KGRB,  
KAUW, AND KCWA WILL BE ON THE NORTHERN PERIPHERY, BUT CONFIDENCE  
OF SHOWER ACTIVITY IS INCREASING IN THE 11-16Z TIMEFRAME.  
REGARDLESS, LOWERING CEILINGS SHOULD RESULT IN WIDESPREAD LIFR/IFR  
CONDITIONS ALONG WITH IFR/MVFR VISIBILITIES.  
 
AS RAIN POTENTIAL ENDS AFTER 16-18Z THU, WINDS WILL SHIFT TO THE  
NORTHWEST AND FINALLY USHER IN DRIER LOW LEVEL AIR. WILL THEREFORE  
SEE CEILINGS INCREASE WITH A RETURN TO VFR CONDITIONS POSSIBLE AT  
ALL TERMINALS BY 21-22Z THU.  
 

 
   
MARINE
 
 
ISSUED AT 100 AM CDT THU OCT 1 2026  
 
SOUTHERLY WINDS CONTINUE TO DECREASE OVERNIGHT, THOUGH WAVES  
REMAIN ELEVATED ALONG THE LAKE MICHIGAN NEARSHORE WATERS. WAVES  
SHOULD COME DOWN WITHIN THE NEXT COUPLE OF HOURS, AFTER WHICH  
MARINE AND BEACH HAZARDS WILL COME TO AN END.  
 

 
   
GRB WATCHES/WARNINGS/ADVISORIES
 
 
BEACH HAZARDS STATEMENT UNTIL 4 AM CDT EARLY THIS MORNING FOR  
WIZ022-040-050.  

 
 

 
 
DISCUSSION.....GOODIN  
AVIATION.......MPC  
MARINE.........GOODIN  
 
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