691  
FXUS63 KGRB 012337  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
637 PM CDT TUE SEP 1 2026  
 
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE  
   
KEY MESSAGES  
 
- WARM AND HUMID CONDITIONS CONTINUE FOR THE REMAINDER OF TODAY  
WITH HIGHS READING IN THE UPPER 80S TO LOW 90S.  
 
- SCATTERED STRONG/SEVERE STORMS POSSIBLE LATE TONIGHT INTO  
WEDNESDAY MORNING OVER PORTIONS OF CENTRAL TO EAST-CENTRAL  
WISCONSIN. MAIN THREATS WITH ANY STRONGER STORMS WILL BE  
DAMAGING WINDS AND UP TO 1" HAIL.  
 
- ABOVE NORMAL TEMPERATURES AND PERIODIC RAIN/STORM CHANCES WILL  
CONTINUE INTO THE WEEKEND.  
 
 
   
DISCUSSION  
 
ISSUED AT 1048 AM CDT TUE SEP 1 2026  
 
METEOROLOGICAL FALL IS OFF TO A WARM START AS EARLY AFTERNOON  
TEMPERATURES HAVE CLIMBED SOLIDLY INTO THE MID 80S, WITH DEWPOINT  
READINGS IN THE LOW 70S IN/AROUND THE FOX VALLEY. AS SUCH, HEAT  
INDICES HAVE RISEN INTO THE UPPER 80S TO LOW 90S ACROSS MUCH OF  
EAST-CENTRAL WISCONSIN.  
 
STORM CHANCES TONIGHT/WEDNESDAY MORNING... FOCUS FOR THE NEAR-TERM  
REVOLVES AROUND SEVERE STORM POTENTIAL LATE TONIGHT INTO EARLY  
WEDNESDAY MORNING AS SHORTWAVE ENERGY AND TANDEM FRONT TRAVERSE  
THE GREAT LAKES. STORMS SHOULD DEVELOP ON THE NOSE OF A 40 TO 45  
KNOT LLJ OVER CENTRAL WISCONSIN BETWEEN AROUND 06 AND 10Z  
WEDNESDAY, DIMINISHING IN COVERAGE AS THEY TRACK FURTHER EAST  
THROUGHOUT THE MORNING. CURRENT THINKING IS THAT STORMS WOULD  
REMAIN MOSTLY ELEVATED, THOUGH CANNOT RULE OUT DAMAGING WIND  
THREAT GIVEN 40+ KNOT WIND AT THE TOP OF THE DRY LAYER. HAIL WOULD  
BE A SECONDARY THREAT GIVEN MARGINAL LAPSE RATES AND SKINNY CAPE  
PROFILE. LOCALLY HEAVY RAIN WILL BE POSSIBLE WITH STORM ACTIVITY,  
THOUGH EXCESSIVE RAINFALL POTENTIAL SHOULD BE HELD DOWN DUE TO  
PROGRESSIVE STORM MOTION. GREATEST CHANCE (40 TO 50%) FOR  
RECEIVING 0.5" OF QPF WILL BE CONFINED TO CENTRAL WISCONSIN IN  
PROXIMITY TO AXIS OF HIGHER PWATS.  
 
EXTENDED... MAJORITY OF THE EXTENDED WILL BE CHARACTERIZED BY  
PERIODIC RAIN/STORM CHANCES AND ABOVE NORMAL TEMPERATURES AS  
WARMING RIDGE BUILDS OVER THE CONUS. HOWEVER, STORM  
TIMING/PREDICTABILITY REMAINS LOW THUS FAR GIVEN THE NATURE OF THE  
SYNOPTIC PATTERN AND MODEL UNCERTAINTY SURROUNDING RETROGRADING  
RIDGE. THIS WILL IN TURN AFFECT POTENTIAL COOLDOWN HEADING INTO  
NEXT WEEK, THOUGH SIGNS POINT TOWARD ENTERING INTO A MORE  
NORTH/NORTHWESTERLY FLOW REGIME.  
 
 
   
AVIATION  
FOR 00Z TAF ISSUANCE  
ISSUED AT 636 PM CDT TUE SEP 1 2026  
 
A MIX OF A FEW VFR CUMULUS CLOUDS AND OTHER MID AND HIGH CLOUDS  
WILL CONTINUE TO SPREAD ACROSS REGION THROUGH THE LATE AFTERNOON  
AND EVENING HOURS. ISOLATED TO SCATTERED SHOWERS AND STORMS WILL  
CONTINUE TO DEVELOP AND MOVE EAST ALONG/NEAR A WARM FRONT  
SITUATED ACROSS SOUTHERN MN/WI, SLOWLY WORKING INTO THE AREA  
OVERNIGHT, MAINLY AFTER 06Z. A LARGER COMPLEX OF SHOWERS AND  
STORMS MAY IMPACT THE AREA AFTER 08-09Z, BUT THERE IS STILL COME  
UNCERTAINTY ON JUST HOW LARGE/INTENSE THIS AREA WILL BE OR IF IT  
WILL TRACK FAR ENOUGH NORTH TO IMPACT THE TAF SITES. HAVE USED  
TEMPO GROUPS TO HIGHLIGHT THE GREATEST THREAT FOR STORMS AT  
AUW/CWA WHERE CHANCES FOR THUNDER ARE THE HIGHEST, AND PROB30  
GROUPS AT GRB/ATW/MTW WHERE CHANCES ARE LOWER. USED A TEMP GROUP  
FOR SHOWER CHANCES AT RHI OVERNIGHT. THE MAIN THREAT FROM THE  
STORMS WILL BE BRIEF REDUCTIONS IN CEILINGS/VISIBILITIES, GUSTY  
WINDS AND TORRENTIAL DOWNPOURS.  
 
PATCHY GROUND FOG WILL BE POSSIBLE OVERNIGHT ACROSS FAR  
NORTHEAST/EAST WI WHERE CLOUDS WILL BE SLOWEST TO ARRIVE AND  
DEWPOINTS ARE THE HIGHEST. OUTSIDE OF GUSTY WINDS IN/NEAR ANY  
STORM, WINDS WILL REMAIN UNDER 10 KTS.  
 
 
   
FIRE WEATHER  
 
ISSUED AT 1048 AM CDT TUE SEP 1 2026  
 
COMBINATION OF DRY AIR, SUBSIDENCE/MIXING FROM HIGH PRESSURE, AND  
WARM TEMPERATURES MAY RESULT IN ELEVATED FIRE WEATHER CONDITIONS  
DEVELOPING OVER NORTH-CENTRAL WISCONSIN LATER THIS AFTERNOON. RHS  
HAVE ALREADY DIPPED DOWN INTO THE MID 30S ACROSS THE SANDY SOIL  
REGIONS IN THE FAR NORTH, AND SHOULD CONTINUE TO DECREASE INTO  
THE LOW 30S AND EVEN UPPER 20S OVER THE NEXT SEVERAL HOURS. GUSTS  
TO 25 MPH WILL BE POSSIBLE DURING THIS TIME. HOWEVER, MOISTURE  
FROM PRIOR RAINFALL SHOULD KEEP FUELS FROM REACHING CRITICAL  
THRESHOLDS. LOOKING FORWARD, EXTREME DROUGHT CONTINUES TO EXPAND  
OVER PORTIONS OF NORTHWEST WISCONSIN, WITH LITTLE TO NO CHANCES  
FOR SOAKING RAINFALL CURRENTLY IN THE FORECAST. WILL CONTINUE TO  
MONITOR FIRE WEATHER CONDITIONS THROUGHOUT THE MONTH, ESPECIALLY  
AFTER WE GET OUR FIRST FROST/FREEZE.  
 
 
   
GRB WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
 
 
DISCUSSION.....GOODIN  
AVIATION.......BERSCH  
FIRE WEATHER...GOODIN  
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