671  
FXUS63 KGRB 101946  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
246 PM CDT SAT MAY 10 2025  
   
KEY MESSAGES
 
 
- ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS POSSIBLE SUNDAY/MONDAY  
DUE TO DRY FUELS, LOW RH, AND GUSTY WINDS.  
 
- PATCHY FROST IS POSSIBLE OVER FAR NORTHEAST WISCONSIN TONIGHT.  
 
- GENERALLY DRY, WARM WEATHER WILL CONTINUE INTO EARLY NEXT WEEK WITH  
LOWER END (20-30%) CHANCES FOR SHOWERS/STORMS TUESDAY AND  
WEDNESDAY AND THE NEXT POTENTIAL FOR MORE ORGANIZED STORMS  
NEXT THURSDAY.  
 

 
   
DISCUSSION
 
 
ISSUED AT 246 PM CDT SAT MAY 10 2025  
 
A WEAK SURFACE FRONT MOVED SOUTH ACROSS THE AREA OVERNIGHT, WITH  
MINIMAL SENSIBLE WEATHER IMPACTS LOCALLY. THE DOMINANT DRIVER IN OUR  
WEATHER PATTERN CONTINUES TO BE CANADIAN SURFACE HIGH PRESSURE THAT  
WILL SHIFT INTO THE EASTERN GREAT LAKES BY SUNDAY. DRY WEATHER WILL  
PERSIST THROUGH THIS TIME, WITH TEMPERATURES TRENDING UPWARD THROUGH  
EARLY NEXT WEEK AS RETURN SOUTHERLY FLOW DEVELOPS ON THE BACKSIDE OF  
THE HIGH. WITH THE DRY AIRMASS, SOME PATCHY FROST MAY DEVELOP  
OVERNIGHT. THE NBM SHOWS MEDIUM (40-60%) CHANCES FOR LOW TEMPS  
COOLER THAN 35F ACROSS FAR NORTHEAST WISCONSIN EARLY SUNDAY AND LOW  
(<20%) CHANCES FOR SUBFREEZING TEMPS. OTHERWISE, FIRE WEATHER WILL  
BE THE PRIMARY CONCERN OVER THE NEXT FEW DAYS WITH WARMING TEMPS AND  
ANTECEDENT DRY CONDITIONS. SEE BELOW FOR MORE FIRE WEATHER DETAILS.  
THE MOST ANOMALOUS WARMTH SHOULD BE CENTERED FARTHER WEST ACROSS THE  
DAKOTAS INTO MINNESOTA THROUGH MID-WEEK WHERE THE EFI (EXTREME  
FORECAST INDEX) SHOWS VALUES OVER 0.9.  
 
HEADING INTO THE WORK WEEK, A SPLIT FLOW PATTERN WILL CONTINUE WITH  
MID-LEVEL RIDGING BUILDING ACROSS THE GREAT LAKES AS WESTERN US  
TROUGHING DEVELOPS THROUGH MID-WEEK. MEANWHILE, A CLOSED LOW OVER  
THE LOWER MISSISSIPPI VALLEY WILL MEANDER NORTH THROUGH MID-WEEK.  
ALTHOUGH THIS LOW WILL DISRUPT THE NORTHWARD FLUX OF DEEP GULF  
MOISTURE, MOISTURE WILL BEGIN TO CREEP BACK NORTHWARD TUESDAY  
THROUGH THURSDAY WITH NAEFS PRECIPITABLE WATER VALUES CLIMBING NEAR  
THE 90TH PERCENTILE AT TIMES RELATIVE TO CLIMO.  
 
LOWER END SHOWER/STORM CHANCES (20-30%) RETURN TUESDAY AND WEDNESDAY  
AS THE INCREASING MOISTURE/MODEST INSTABILITY INTERACT WITH THE LOW  
LIFTING TOWARDS THE OHIO VALLEY AND ASSOCIATED WEAK SHORTWAVE  
PERTURBATIONS. WITH LIMITED SHEAR, ORGANIZATION OF ANY STORMS LOOKS  
LIMITED AND CONFIDENCE IS LOW OVERALL IN OCCURRENCE.  
 
A HIGHER RISK OF STORMS LOOKS TO OCCUR TOWARDS NEXT THURSDAY AS THE  
WESTERN TROUGH EJECTS INTO THE MIDWEST. INCREASING MID-LEVEL FLOW  
AND SOME INCREASE IN INSTABILITY COULD SUPPORT A RISK OF STRONGER  
STORMS, AS HIGHLIGHTED BY SPC AND SOME OF THE MACHINE LEARNING  
SEVERE WEATHER GUIDANCE. THERE ARE SOME DIFFERENCES IN HOW THE  
PARENT TROUGH EVOLVE AND TIMING OF THE FRONT THAT WILL NEED TO BE  
IRONED OUT OVER COMING DAYS. HOWEVER, THIS WILL BE THE NEXT PERIOD  
TO MONITOR FOR POTENTIAL IMPACTFUL STORMS. OTHERWISE, TRENDS  
STRONGLY SUPPORT ABOVE AVERAGE TEMPS THROUGH LATE IN THE WEEK, WITH  
SOME COOLING TOWARDS NEXT WEEKEND BEHIND THE TRAILING COLD  
FRONT.  
 

 
   
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
 
 
ISSUED AT 1125 AM CDT SAT MAY 10 2025  
 
HIGH CONFIDENCE IN VFR CONDITIONS PERSISTS THROUGH THE TAF  
PERIOD. NORTHERLY WINDS, WITH A FEW GUSTS UP TO 20 KTS THIS  
AFTERNOON, WILL BECOME LIGHT OVERNIGHT AND THEN SOUTHERLY FOR  
SUNDAY, INCREASING TO 10-15 KTS WITH GUSTS 15 TO 20 KTS.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 246 PM CDT SAT MAY 10 2025  
 
A DRY AIRMASS WILL REMAIN IN PLACE ON SUNDAY INTO MONDAY AS CANADIAN  
HIGH PRESSURE PASSES EAST. WITH TEMPERATURES WARMING INTO THE 70S ON  
SUNDAY AND POTENTIALLY ABOVE 80 ON MONDAY ALONG WITH BREEZY  
SOUTHERLY WINDS, RH FALLING TO 20-30% 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 FIRE WEATHER WATCH FOR PARTS OF NORTHERN  
WISCONSIN ON SUNDAY AFTERNOON 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.  
 

 
   
GRB WATCHES/WARNINGS/ADVISORIES
 
 
WI...MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LMZ521-  
522-541>543.  
 

 
 

 
 
DISCUSSION...JM  
AVIATION...JM  
FIRE WEATHER...JM  
 
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