072
FXUS63 KGRB 121650
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1150 AM CDT WED AUG 12 2026
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
KEY MESSAGES
- SCATTERED STORMS EARLY THIS MORNING, WITH VERY SMALL CHANCES
(10-15%) FOR ADDITIONAL STORMS LATER TODAY. SEVERE POTENTIAL IS
LOW. CHANCES FOR SHOWERS AND STORMS HAVE INCREASED ON THURSDAY.
- PATCHY DENSE FOG EARLY THIS MORNING NEAR LAKE MICHIGAN AND THE
BAY.
- CHANCES FOR HEAVY RAIN HAVE INCREASED THIS WEEKEND, THOUGH
SEVERE RISK REMAINS LOW.
DISCUSSION
ISSUED AT 402 AM CDT WED AUG 12 2026
NEAR TERM THROUGH THURSDAY...CERTAINLY MORE THAN WE BARGAINED FOR
EARLY THIS MORNING WITH A SLEW OF WARNINGS ISSUED AS THERE WAS
JUST ENOUGH LIFT UPON ELEVATED INSTABILITY AND SHEAR OVER 40 KTS.
HAIL AS LARGE AS 1.5 INCHES WAS OBSERVED IN EASTERN MARATHON
COUNTY EARLY THIS MORNING. STORMS HAVE FINALLY FADED IN INTENSITY
AS THEY SHIFTED INTO FAR NORTHEAST WI (THOUGH SMALL HAIL AND HEAVY
RAIN MAY OCCUR), BUT SOME THUNDER TO WAKE PEOPLE UP EARLY THIS
MORNING IN THE GREEN BAY AREA AND OVER DOOR COUNTY. REST OF TODAY,
CANNOT RULE OUT ISOLATED SHOWERS AND STORMS LATER TODAY INTO THIS
EVENING, BUT CHANCES REMAIN PRETTY LOW. RISK FOR SEVERE WEATHER
LATER TODAY HAS DIMINISHED. ON THURSDAY, TREND MODELS STARTED TO
SHOWING YESTERDAY CONTINUES, WITH POPS RAMPING UP TO 30-45% AS
WAVE DRIFTS THROUGH INTERACTING WITH DAYTIME HEATING AND SOME
BUILDING INSTABILITY. RIGHT ENTRANCE REGION OF JET WILL HELP
ENHANCE ACTIVITY AS WELL.
DRY FOR FRIDAY WITH HIGH PRESSURE OVERHEAD, THEN MODERATE TO
HEAVY RAIN EXPECTED THIS WEEKEND. SHOWERS AND STORM CHANCES
(50-70%) WILL RETURN TO START THE WEEKEND AS A PROGRESSIVE
SHORTWAVE TROUGH MOVES ACROSS THE REGION. PRECIPITABLE WATER
VALUES INCREASE ABOVE THE 95TH PERCENTILE AHEAD OF THIS SYSTEM,
BUT SEASONABLY COOL TEMPERATURES AND RELATIVELY WEAK INSTABILITY
LOOK TO LIMIT THE SEVERE WEATHER RISK. HEAVY RAIN RISK IS THERE
THOUGH AND WPC HAS EXPANDED THE SLIGHT RISK FOR EXCESSIVE RAINFALL
(LEVEL 2 OF 4) OVER MUCH OF OUR AREA SOUTH OF HIGHWAY 29. PEAK OF
RAIN APPEARS TO BE SATURDAY AFTERNOON THROUGH SATURDAY EVENING.
LREF PROBABILITY OF 1" FROM THIS EVENT IS UP TO 25%, BUT LOOKING
AT HIGHER PERCENTILES INDICATE THAT THE "CEILING" WITH THE RAINFALL
COULD BE OVER 2 INCHES. ALSO DECENT AGREEMENT IT WOULD AFFECT THE
URBAN AREAS OF THE FOX VALLEY AND NORTHEAST WI. THIS WILL HAVE TO
BE WATCHED AS WE GET CLOSER. GENERALLY DRIER AND SEASONABLE WEATHER
IS FORECAST BEHIND THE WEEKEND SYSTEM.
TEMPERATURES/FOG...TEMPERATURES WILL BE SEASONABLY WARM INTO
THURSDAY WITH HIGHS IN THE LOWER 80S. SLIGHT COOLING INTO THE MID
TO UPPER 70S STILL PEGGED FOR FRIDAY INTO THE WEEKEND. NOT A BIG
COOL DOWN BY ANY STRETCH. IN TERMS OF FOG, THE OVERNIGHT STORMS
AND BLOWOFF CLOUDS FROM THEM DID HOLD DOWN THE FOG, EXCEPT NEAR
THE LAKESHORE AND CLOSER TO THE BAY/DOOR COUNTY. MORE PATCHY FOG
COULD OCCUR TONIGHT, BUT SIGNAL (ESPECIALLY FROM MOS GUIDANCE) IS
NOT AS STRONG AS IT HAS LOOKED IN THE LAST COUPLE NIGHTS.
AVIATION
FOR 18Z TAF ISSUANCE
ISSUED AT 1150 AM CDT WED AUG 12 2026
FOG FROM EARLY THIS MORNING HAS MOSTLY LIFTED, HOWEVER, A FEW AREAS
OF MVFR STATUS CONTINUES TO LINGER OVER THE FOX VALLEY EARLY THIS
AFTERNOON. EXPECT THE STATUS SO CLEAR OUT THIS AFTERNOON LEAVING VFR
CONDITIONS ACROSS THE REGION THROUGH THIS EVENING. ANOTHER ROUND OF
FOG IS POSSIBLE EARLY THURSDAY MORNING, MAINLY ACROSS EASTERN WI, AS
LIGHT EASTERLY WINDS PERSIST. HAVE INCLUDED TEMPO GROUPS WITH IFR
VSBYS AND CIGS AT GRB, ATW, AND MTW FROM 08-12Z. OTHER AVIATION
IMPACT WILL BE A ROUND OF SHOWERS PUSHING INTO THE REGION THURSDAY
MORNING, AFTER 15Z. CONFIDENCE IN ANY THUNDERSTORMS IS LOW AT THIS
POINT SO ONLY INCLUDED SHRA IN ALL THE TAFS.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION.....JLA
AVIATION.......GK
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