998  
FXUS63 KGRB 111719  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
1219 PM CDT SUN MAY 11 2025  
 
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE  
   
KEY MESSAGES  
 
- THERE IS AN INCREASED RISK OF FIRE ACTIVITY THROUGH TUESDAY DUE  
TO ABOVE NORMAL TEMPERATURES, LACK OF WIDESPREAD RAIN, AND LOW  
HUMIDITY VALUES (20-35%) EACH AFTERNOON. CRITICAL FIRE WEATHER  
CONDITIONS ARE EXPECTED TODAY WHERE A RED FLAG WARNING IS IN  
EFFECT FROM 1 PM TO 10 PM OVER PORTIONS OF NORTH-CENTRAL AND  
FAR NORTHEAST WI. NEAR CRITICAL FIRE CONDITIONS ARE AGAIN  
POSSIBLE ACROSS NORTHERN WISCONSIN ON MONDAY.  
 
- BELOW NORMAL PRECIPITATION IS EXPECTED OVER THE NEXT WEEK. THE  
NEXT CHANCE FOR A WIDESPREAD RAINFALL AND THUNDERSTORMS WILL BE  
IN THE THURSDAY-FRIDAY TIME FRAME. THERE IS SOME POTENTIAL FOR  
STRONGER STORMS DURING THIS PERIOD.  
 
 
   
DISCUSSION  
 
ISSUED AT 305 AM CDT SUN MAY 11 2025  
 
SHORT TERM...TODAY...TONIGHT...AND MONDAY  
 
HIGH PRESSURE WILL PUSH OFF TO THE EAST TODAY; HOWEVER, SURFACE  
RIDGING WILL REMAIN ACROSS THE WESTERN GREAT LAKES REGION. THE  
RIDGING WILL KEEP THE AREA DRY AS SOUTHERLY FLOW ALLOWS WARM AIR  
ADVECTION TO COMMENCE ACROSS THE AREA. THE MAIN CONCERNS WILL BE  
FIRE WEATHER AS DRY DEW POINTS WILL CONTINUE ACROSS THE REGION AS  
DAYTIME HIGHS SOAR TO ABOVE NORMAL LEVELS ALONG WITH GUSTY WINDS.  
HIGHS TODAY ARE EXPECTED TO SOAR INTO THE 70S AWAY FROM THE  
LAKESHORE, WITH 60S NEAR LAKE MICHIGAN. LOWS TONIGHT ARE ONLY  
EXPECTED TO FALL INTO THE 40S. BY MONDAY DAYTIME HIGHS ARE  
EXPECTED TO RISE TO AROUND 80 AWAY FROM THE LAKESHORE, WITH 70S  
NEAR THE LAKE.  
 
LONG TERM...MONDAY NIGHT THROUGH SATURDAY  
 
RIDGING ACROSS THE WESTERN GREAT LAKES WILL GIVE WAY TO FALLING  
500MB HEIGHTS BY THE MIDDLE OF NEXT WEEK AS THE CLOSED LOW ACROSS  
THE SOUTHEAST UNITED STATES OPENS UP. A PIECE OF ENERGY SWINGING  
WESTWARD AROUND THE UPPER LOW WILL MOVE INTO THE AREA ON TUESDAY.  
THE COMBINATION OF DAYTIME HEATING AND INCREASING LOW LEVEL  
MOISTURE WILL RESULT IN SOME DIURNALLY DRIVEN CONVECTION DURING  
THE AFTERNOON. ANY LINGERING SHOWERS OR STORMS SHOULD END BY MID  
EVENING WITH DRY CONDITIONS EXPECTED FOR THE REMAINDER OF THE  
NIGHT. ANY LOCATIONS THAT DO SEE RAIN TUESDAY AFTERNOON COULD SEE  
SOME PATCHY FOG LATE TUESDAY NIGHT. THE MODELS INDICATED BETTER  
COVERAGE OF DIURNALLY DRIVEN CONVECTION WEDNESDAY AFTERNOON. DID  
BUMP UP RAIN CHANCES WEDNESDAY AFTERNOON, AND DID LINGER RAIN  
CHANCES FOR A FEW HOURS PAST 00Z.  
 
ATTENTION THEN TURNS TO THE SYSTEM FOR THURSDAY. MODELS INDICATING  
0-6 KM SHEAR VALUES OF 30-40 KNOTS, MOST UNSTABLE CAPE VALUES OF  
1,000 TO 1,500 J/KG AND TOTAL TOTALS OF 50-55 TO SUPPORT THE  
POTENTIAL FOR STRONG/SEVERE STORMS. SEVERAL ISSUES TO CONTEND WITH  
WILL BE THE SOUTHEAST SURFACE FLOW OFF THE COOL WATERS OF LAKE  
MICHIGAN. THIS COULD HANG UP THE WARM FRONT ACROSS EASTERN  
WISCONSIN WHICH WOULD NOT ALLOW THE ATMOSPHERE TO BECOME UNSTABLE  
UNTIL RIGHT BEFORE THE IMMEDIATE COLD FRONT PASSAGE THURSDAY  
EVENING. THERE IS ALSO SOME POTENTIAL FOR CONVECTION LATE  
WEDNESDAY NIGHT INTO THURSDAY MORNING WHICH COULD PRODUCE MORE  
CLOUD COVER THAN EXPECTED DURING THE DAY THURSDAY. STILL SEVERAL  
DAYS OUT, THIS WILL CONTINUE TO WATCH HOW THIS EVENT WILL UNFOLD  
IN THE COMING DAYS.  
 
THE CHANCE OF RAIN WILL END THURSDAY NIGHT AFTER THE PASSAGE OF  
THE COLD FRONT. A CLOSED UPPER LOW IS EXPECTED TO MOVE INTO THE  
WESTERN GREAT LAKES FRIDAY, THEN ACROSS WISCONSIN FRIDAY NIGHT.  
THIS FEATURE WILL BRING ANOTHER CHANCE OF SHOWERS FRIDAY AFTERNOON  
INTO SATURDAY. ABOVE NORMAL TEMPERATURES WILL CONTINUE UNTIL AT  
LEAST THURSDAY, THEN FALLING TO OR SLIGHTLY BELOW NORMAL NEXT  
WEEKEND.  
 
 
   
AVIATION  
FOR 18Z TAF ISSUANCE  
ISSUED AT 1218 PM CDT SUN MAY 11 2025  
 
VFR FLYING CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD WITH  
MAINLY CLEAR SKIES. SOUTH WINDS WILL GUST TO 15 TO 20 KTS THIS  
AFTERNOON AND THEN SUBSIDE AROUND SUNSET. SIMILAR AFTERNOON GUSTS  
ARE FORECAST ON MONDAY.  
 
 
   
FIRE WEATHER  
 
ISSUED AT 305 AM CDT SUN MAY 11 2025  
 
A DRY AIRMASS WILL REMAIN IN PLACE TODAY INTO MONDAY AS CANADIAN  
HIGH PRESSURE PASSES EAST. WITH TEMPERATURES WARMING INTO THE 70S  
TODAY AND POTENTIALLY ABOVE 80 ON MONDAY ALONG WITH BREEZY  
SOUTHERLY WINDS, RH FALLING TO 15-30% FROM CENTRAL INTO NORTHERN  
WISCONSIN AND DRY FUELS, NEAR CRITICAL TO CRITICAL FIRE WEATHER  
CONDITIONS ARE POSSIBLE. COORDINATED WITH SURROUNDING OFFICES AND  
STATE PARTNERS TO ISSUE A RED FLAG WARNING FOR PARTS OF NORTHERN  
WISCONSIN THIS AFTERNOON INTO EARLY THIS EVENING WHERE CONFIDENCE  
IS HIGHEST FOR THE OVERLAP OF GUSTIER WINDS, LOW RH, AND  
FAVORABLE FUELS.  
 
WILL HAVE TO CLOSELY MONITOR TRENDS, AS MIXING CAN SOMETIMES BE  
DEEPER THAN EXPECTED IN THESE SITUATIONS WITH FULL SUNSHINE AND  
INCREASING SOUTHERLY FLOW, LEADING TO WARMER, DRIER, BREEZIER  
CONDITIONS. 75TH-90TH PERCENTILE NBM TEMPERATURES DO REACH THE UPPER  
70S TO LOW 80S EVEN ON SUNDAY, WHICH, IF ACHIEVED, LIKELY WOULD  
OCCUR WITH LOWER RH AND GUSTIER WINDS.  
 
MONDAY WILL BE EVEN WARMER THAN TODAY WITH SIMILAR RH VALUES;  
HOWEVER, WINDS ARE NOT EXPECTED TO BE AS GUSTY AS TODAY.  
THEREFORE, CONDITIONS MAY ONLY BE NEAR-CRITICAL INSTEAD OF  
CRITICAL. ANY INCREASE IN THE WINDS WOULD PUSH CRITERIA BACK INTO  
THIS CATEGORY THOUGH.  
 
 
   
GRB WATCHES/WARNINGS/ADVISORIES  
 
RED FLAG WARNING UNTIL 10 PM CDT THIS EVENING FOR WIZ005-010>013-  
018-019.  
 
 
 
 
DISCUSSION.....KURIMSKI/ECKBERG  
AVIATION.......KLJ  
FIRE WEATHER...KURIMSKI  
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab WI Page
Main Text Page