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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