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
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