677  
FXUS63 KGRB 120820  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
320 AM CDT MON MAY 12 2025  
 
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE  
   
KEY MESSAGES  
 
- ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS REMAIN TODAY DUE TO  
DRY FUELS, LOW HUMIDITY, AND WINDS GUSTING TO AROUND 15 MPH. A  
RED FLAG WARNING HAS BEEN ISSUED FROM 12 PM TO 9 PM OVER  
PORTIONS OF NORTH-CENTRAL AND FAR NORTHEAST WISCONSIN.  
 
- THERE IS A MEDIUM CHANCE (20-40%) OF SCATTERED SHOWERS AND  
THUNDERSTORMS TUESDAY AND WEDNESDAY, ESPECIALLY DURING THE  
AFTERNOON.  
 
- HIGHER CHANCES (50-80%) FOR RAIN AND THUNDERSTORMS ON THURSDAY  
AND THURSDAY NIGHT. STRONG OR SEVERE STORMS WILL BE POSSIBLE  
WITH THE PASSAGE OF A COLD FRONT.  
 
 
   
DISCUSSION  
 
ISSUED AT 319 AM CDT MON MAY 12 2025  
 
SHORT TERM...TODAY...TONIGHT...AND TUESDAY  
 
ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS WILL CONTINUE TODAY  
AS TEMPERATURES WARM INTO THE 80S AWAY FROM THE LAKE WITH  
CONTINUED DRY DEW POINTS ACROSS THE REGION. MOSTLY SUNNY SKIES ARE  
EXPECTED ACROSS THE REGION TODAY WITH CONTINUED DRY CONDITIONS.  
 
WARM CONDITIONS WILL CONTINUE ON TUESDAY AS HIGHS ONCE AGAIN REACH  
THE UPPER 70S TO LOWER 80S. HOWEVER SOME MODEST INSTABILITY WILL  
COMBINE WITH A WEAK SHORTWAVE TRACKING ACROSS THE REGION, WHICH  
COULD BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TUESDAY  
AFTERNOON. SOUTHEASTERLY SURFACE WINDS WILL KEEP THE LAKESHORE AND  
FOX VALLEY COOLER THAN FURTHER INLAND, WITH HIGHS IN THE MIDDLE  
70S ACROSS THE FOX VALLEY AND 60S NEAR THE LAKESHORE. ANY  
THUNDERSTORMS THAT DEVELOP SHOULD NOT BE STRONG OR SEVERE AS CAPE  
PROFILES WILL BE VERY NARROW.  
 
LONG TERM...TUESDAY NIGHT THROUGH SUNDAY  
 
ANY LINGERING SHOWERS/STORMS WILL END AROUND SUNSET TUESDAY  
EVENING, OTHERWISE DRY CONDITIONS SHOULD PREVAIL TUESDAY NIGHT.  
THE 500MB RIDGING ACROSS THE WESTERN GREAT LAKES EARLY THIS WEEK  
WILL WEAKEN AS 500MB HEIGHTS FALL, AS THE CLOSED UPPER LOW OVER  
THE TENNESSEE VALLEY OPENS UP AND BECOMES ELONGATED FROM  
NORTHWEST TO SOUTHEAST FROM WISCONSIN INTO THE TENNESSEE VALLEY  
WEDNESDAY. THE COMBINATION OF DAYTIME HEATING AND SOME INSTABILITY  
WILL RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING ON  
WEDNESDAY, ESPECIALLY DURING THE AFTERNOON. SURFACE DEWPOINTS WILL  
BE SEVERAL DEGREES HIGHER COMPARED TO TUESDAY AS SOUTHERLY WINDS  
BRING SOME LOW LEVEL MOISTURE INTO THE AREA. ANY SHOWERS OR  
STORMS SHOULD END AROUND SUNSET WEDNESDAY EVENING.  
 
THE MAIN CONCERN DURING THIS PERIOD WILL BE THE POTENTIAL FOR  
STRONG OR SEVERE THUNDERSTORMS ON THURSDAY. THE PREVIOUS DAY 5  
OUTLOOK FROM THE STORM PREDICTION CENTER HAD PORTIONS OF CENTRAL  
AND EAST-CENTRAL OUTLINED FOR THE POTENTIAL FOR SEVERE WEATHER.  
THE NEW DAY 4 OUTLOOK FROM SPC WILL BE ISSUED A LITTLE LATER  
THIS MORNING. OTHERWISE, THE LATEST CANADIAN/ECMWF AND THE NAM (UP  
TO 84 HOURS) INDICATED A SLOWER TREND IN THE ARRIVAL OF THE FRONT  
AND STORMS. THE LATEST ECMWF HAD STORMS ARRIVING ACROSS CENTRAL  
WISCONSIN DURING THE MID TO LATE AFTERNOON AND WOULD NOT REACH  
NORTHEAST WISCONSIN UNTIL THE EVENING HOURS. 0-6 KM SHEAR VALUES  
A LITTLE STRONGER TONIGHT (40-50 KTS) OFF THE ECMWF/CANADIAN  
MODEL, AND WERE EVEN STRONGER ON THE GFS MODEL. SOUTHEAST FLOW  
OFF LAKE MICHIGAN WILL BRING A MORE STABLE MARINE LAYER INTO  
EAST-CENTRAL AND NORTHEAST WISCONSIN. MODELS ARE INDICATING  
A RIBBON OF CAPE BETWEEN 1,000 AND 2,000 J/KG AHEAD OF THE FRONT.  
WITH THE MORE STABLE SOUTHEAST FLOW OFF LAKE MICHIGAN, THE AREA  
OF CAPE NEAR 2,000 J/KG WILL GET PINCHED OFF ACROSS NORTHEAST  
WISCONSIN. DAMAGING WINDS WILL BE THE MAIN SEVERE WEATHER RISK  
ALTHOUGH LARGE HAIL CAN'T BE RULED OUT.  
 
AFTER THE PASSAGE OF THE COLD FRONT, A DRY SLOT WILL MOVE ACROSS  
THE AREA LATER THURSDAY NIGHT, BRINGING DRY CONDITIONS TO MUCH OF  
THE ARE. IT WILL BE WINDY/BLUSTERY. A CHANCE OF SHOWERS WILL  
CONTINUE ACROSS THE FAR NORTH LATER THURSDAY NIGHT CLOSER TO THE  
UPPER LOW. THE CHANCE OF SHOWERS CONTINUES ACROSS THE ENTIRE  
AREA ON FRIDAY AS THE UPPER LOW MOVES ACROSS THE WESTERN GREAT  
LAKES. ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THURSDAY,  
RETURNING CLOSER TO NORMAL ON FRIDAY AND THEN BECOME BELOW NORMAL  
NEXT WEEKEND. LOOKING AT SOME OF THE TEMPERATURES SPREADS ACROSS  
THE NORTH, IT WILL BE COOL WITH HIGHS IN THE 50S, WITH THE LOWEST  
GUIDANCE VALUES ONLY IN THE LOWER 50S AT LAND O"LAKES. BREEZY  
OR WINDY CONDITIONS ARE EXPECTED FRIDAY INTO SATURDAY. GUSTY  
SOUTHWEST WINDS ARE EXPECTED ON FRIDAY AND THEN FROM THE  
WEST/NORTHWEST ON SATURDAY.  
 
 
   
AVIATION  
FOR 06Z TAF ISSUANCE  
ISSUED AT 1008 PM CDT SUN MAY 11 2025  
 
VFR FLYING CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD WITH  
MAINLY CLEAR SKIES. SOUTH WINDS WILL SUBSIDE AROUND SUNSET.  
SIMILAR AFTERNOON GUSTS ARE FORECAST ON MONDAY.  
 
 
   
FIRE WEATHER  
 
ISSUED AT 319 AM CDT MON MAY 12 2025  
 
TEMPERATURES WILL BE WARMER TODAY, AS HIGHS ARE EXPECTED TO SOAR  
INTO THE 80S. CONTINUED DRY DEW POINTS WILL MEAN RELATIVE HUMIDITY  
VALUES WILL ONCE AGAIN PLUMMET TO 15 TO 25 PERCENT ACROSS NORTHERN  
WISCONSIN AND 20 TO 30 PERCENT ACROSS THE REST OF THE AREA WEST  
OF THE FOX VALLEY. FUELS WILL CONTINUE TO BE DRY, WITH SOUTHERLY  
WINDS OF 10 TO 20 MPH. THEREFORE, WILL UPGRADE THE CURRENT FIRE  
WEATHER WATCH TO A RED FLAG WARNING GIVEN THE WARM TEMPERATURES,  
LOW RH VALUES, AND DRY FUELS. THE REST OF THE AREA WEST OF THE FOX  
VALLEY WILL GET AN SPS LIKE YESTERDAY.  
 
WARM TEMPERATURES WILL CONTINUE ACROSS THE REGION ON TUESDAY;  
HOWEVER, DEW POINTS WILL RISE EVEN FURTHER AS MOISTURE ADVECTS  
INTO THE REGION. RELATIVE HUMIDITY VALUES ARE EXPECTED TO RECOVER  
INTO THE 30S TUESDAY AFTERNOON ACROSS NORTH-CENTRAL WISCONSIN AS  
WINDS REMAIN LIGHT.  
 
 
   
GRB WATCHES/WARNINGS/ADVISORIES  
 
RED FLAG WARNING FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR  
WIZ005-010>013-018-019.  
 
 
 
 
DISCUSSION.....KURIMSKI/ECKBERG  
AVIATION.......KOTENBERG  
FIRE WEATHER...KURIMSKI  
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