662  
FXUS63 KGRB 031130  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
630 AM CDT THU SEP 3 2026  
 
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE  
   
KEY MESSAGES
 
 
- FIRST ROUND OF THUNDERSTORMS WILL MOVE ACROSS THE AREA THIS  
MORNING INTO EARLY THIS AFTERNOON. SOME OF THE STORMS COULD  
BECOME SEVERE WITH DAMAGING WINDS AND LARGE HAIL ALONG AND  
SOUTH OF HIGHWAY 29.  
 
- THERE MAY BE A LULL OR A BREAK IN THE THUNDERSTORM ACTIVITY  
DURING THE AFTERNOON, ANOTHER ROUND OF STRONG OR SEVERE  
THUNDERSTORMS IS POSSIBLE AGAIN LATE THIS AFTERNOON AND  
TONIGHT.  
 
- ABOVE NORMAL TEMPERATURES AND PERIODIC RAIN/STORM CHANCES WILL  
CONTINUE INTO THE WEEKEND.  
 

 
   
DISCUSSION
 
 
ISSUED AT 215 AM CDT THU SEP 3 2026  
 
ANOTHER WARM EARLY SEPTEMBER MORNING WITH TEMPERATURES IN THE 60S  
TO LOWER 70S. PATCHY FOG DEVELOPED IN SOME SPOTS AND WILL MONITOR  
THE LAKESHORE WHERE SOME PATCHY DENSE FOG MAY BE POSSIBLE ON LAKE  
MICHIGAN WHERE RECENT UPWELLING HAS COOLED OFF WATER  
TEMPERATURES.  
 
COMPLEX FORECAST THIS MORNING DEALING WITH POTENTIAL FOR STRONG  
OR SEVERE THUNDERSTORMS AT TIMES THROUGH LATE TONIGHT. FIRST  
ROUND OF THUNDERSTORMS EXPECTED TO MOVE ACROSS THE AREA THIS  
MORNING INTO EARLY THIS AFTERNOON. LOOKING AT TWO SIGNALS FOR  
THIS TO HAPPEN. LATEST MODELS INDICATED SCATTERED THUNDERSTORMS  
WILL DEVELOP BETWEEN 08Z AND 11Z ACROSS CENTRAL INTO EAST-CENTRAL  
WI IN RESPONSE TO A 40 KNOT/850 WARM ADVECTION ON A LOW LEVEL JET.  
ALSO WATCHING CONVECTION DEVELOPING ACROSS SOUTHERN MINNESOTA AND  
NORTHERN IOWA THAT WILL MAKE ITS WAY EASTWARD INTO OUR AREA LATER  
THIS MORNING. BUFKIT SOUNDINGS AT GREEN BAY INDICATED 40-50 KNOTS  
OF 0-6 KM SHEAR, SURFACE BASE CAPE OF 1,000-1,500 J/KG WITH MOST  
UNSTABLE CAPE VALUES AROUND 2,000 J/KG. SOME OF THE STORMS COULD  
BECOME STRONG OR SEVERE WITH DAMAGING WINDS, LARGE HAIL AND  
TORRENTIAL RAINFALL THIS MORNING.  
 
THERE WILL LIKELY BE A LULL OR BREAK IN THE THUNDERSTORM ACTIVITY  
THIS AFTERNOON. WITH THE BEST INSTABILITY TO OUR SOUTH, SCATTERED  
THUNDERSTORMS MAY REDEVELOP DURING THE PEAK HEATING OF THE DAY  
ACROSS CENTRAL INTO EAST-CENTRAL WI CLOSER TO THE BEST INSTABILITY.  
SOME OF THESE STORMS COULD BECOME SEVERE AS WELL. THE PLOT  
THICKENS TONIGHT WITH A COMPLEX OF THUNDERSTORMS DEVELOPING  
ACROSS THE UPPER MIDWEST. THE LATEST CANADIAN/ECMWF/NAM/GFS MODEL  
WOULD SUGGEST A COMPLEX OF THUNDERSTORMS WOULD WORK INTO THE AREA  
DURING THE LATE EVENING AND OVERNIGHT HOURS. HOWEVER, THERE ARE A  
FEW MESO MODELS WOULD SUGGEST DEVELOPMENT WOULD OCCUR DURING THE  
EVENING CLOSER TO THE BETTER INSTABILITY AND THEN DROP SOUTH INTO  
SOUTHERN WI.  
 
THERE ARE PERIODIC CHANCES OF THUNDERSTORMS WHILE ABOVE NORMAL  
TEMPERATURES WILL CONTINUE FRIDAY INTO EARLY NEXT WEEK AS THE  
SUMMER TIME PATTERN CONTINUES.  
 

 
   
AVIATION
 
FOR 12Z TAF ISSUANCE  
ISSUED AT 625 AM CDT THU SEP 3 2026  
 
FIRST ROUND OF SHOWERS AND STORMS WILL MOVE ACROSS MUCH OF THE  
AREA THIS MORNING. THE GREATEST RISK FOR STRONG WINDS AND LARGE  
HAIL WILL BE ALONG AND SOUTH OF WAUSAU TO KEWAUNEE LINE.  
ADDITIONAL STORMS WILL DEVELOP SOUTH OF THIS LINE BY LATE  
AFTERNOON WHILE A COMPLEX OF STORMS WILL MOVE ITS WAY  
ACROSS THE AREA LATER THIS EVENING AND OVERNIGHT. BESIDES  
THUNDERSTORMS IMPACTING AVIATION, CIGS MAY DROP INTO THE IFR  
CATEGORY IN SOME SPOTS LATE TONIGHT INTO FRIDAY MORNING ALONG WITH  
PATCHY FOG. ANY LINGERING RAIN SHOULD COME TO AN END FRIDAY  
MORNING WITH IMPROVING CIGS AND VSBYS DURING THE DAY.  
 

 
   
GRB WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
 
DISCUSSION.....ECKBERG  
AVIATION.......ECKBERG  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab WI Page Main Text Page