931
FXUS63 KGRB 161140
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
640 AM CDT SUN AUG 16 2026
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
KEY MESSAGES
- SCATTERED SHOWERS (30-60%) EARLY THIS MORNING OVER NORTHERN WI.
15-30% CHANCE OF A BRIEF SHOWER EARLY THIS AFTERNOON MAINLY IN
DOOR COUNTY.
- NEXT CHANCE OF A FEW SHOWERS (20-40%) OVER CENTRAL WI LATE
MONDAY NIGHT. SHOWER AND STORM CHANCES TUESDAY INTO WEDNESDAY
HAVE DECREASED.
- SCATTERED RAIN CHANCES RETURN ON FRIDAY, BUT THE RAIN THIS WEEK
WILL DO LITTLE TO PUT DENT INTO GROWING DROUGHT CONDITIONS OVER
THE AREA.
DISCUSSION
ISSUED AT 137 AM CDT SUN AUG 16 2026
NEAR TERM THROUGH MONDAY: FINALLY ARE SEEING A FEW SHOWERS OVER
NORTHERN WI THIS MORNING. LIGHT RAIN FOR SURE, WITH TOP WINNER
THUS FAR NOT EVEN UP TO 0.10 INCH IN VILAS COUNTY. NO LIGHTNING
AS INSTABILITY IS MINIMAL. MOST AREAS SOUTH OF HIGHWAY 8 WILL
STAY DRY THIS MORNING WITH STRONGER SHORTWAVE FORCING CROSSING
UPPER MICHIGAN/LAKE SUPERIOR. MIX OF LOW CLOUDS AND SOME FOG COULD
OCCUR THIS MORNING AS WEAK WARM FRONT LIFTS THROUGH, JUST BEFORE
FRONT ENTERING NW WI SHIFTS THROUGH. STILL LOOKS LIKE A BRIEF
SHOWER (15-30% CHANCE) MAY OCCUR EARLY THIS AFTERNOON OVER MAINLY
DOOR COUNTY. CAMS POINT TO NORTHERN DOOR, INCLUDING WASHINGTON
ISLAND, AS MOST FAVORED AREA FOR ANY RAIN. DESPITE THE PASSAGE OF
THE FRONT, WHICH IS ESSENTIALLY A GLORIFIED WIND SHIFT FROM S TO
NW, HIGHS WILL REACH THE LOWER TO MIDDLE 80S THIS AFTERNOON. NW
WINDS MAY GUST TO 20 MPH WITH THE MIXING BEHIND THE FRONT.
STEADY NW FLOW AND DRY WEATHER PERSISTS INTO MONDAY AS WE WILL BE
WITHIN INFLUENCE OF HIGH PRESSURE OVER THE PLAINS. PRIMARY
TAKEAWAY FOR MONDAY IS IT LOOKS LIKE A LESS HUMID DAY ACROSS THE
BOARD. TEMPS WILL BE SIMILAR TO TODAY.
MINIMAL RAIN CHANCES REST OF THE WEEK: AS EARLY AS MONDAY NIGHT
SHORTWAVES IN NW FLOW AND APPROACHING FRONT WILL BRING NEXT CHANCE
FOR SCATTERED SHOWERS AND MAYBE A STORM LATE EVENING AND OVERNIGHT
ESPECIALLY CENTRAL WI. THIS FRONT SWEEPS THROUGH FAIRLY QUICKLY ON
TUESDAY AND A RESULT, CHANCES FOR SHOWERS AND STORMS THAT LOOKED
DECENT A COUPLE DAYS AGO HAVE FADED FAST, DOWN TO A 20-30% CHANCE
DURING THE AFTERNOON INTO THE EVENING CENTRAL TO EAST-CENTRAL WI.
EVEN SO, GIVEN DAYTIME INSTABILITY (CAPES OVER 1000J/KG) AND SHEAR
OVER 40 KTS, CANNOT COMPLETELY RULE OUT A STRONGER STORM. BETTER
CHANCES FOR SEVERE AND HEAVY RAIN, BY FAR, NOW LOOK TO STAY SOUTHWEST
AND SOUTH OF THE AREA. RECENTLY, IT APPEARED THAT SOME RAIN MAY
LINGER INTO WEDNESDAY, BUT WITH QUICKER FROPA, IT NOW LOOKS DRY
FOR WEDNESDAY. ANOTHER CHANCE FOR SHOWERS AND SOME STORMS SHOWS UP
ON FRIDAY WITH SHARPENING NW FLOW BRINGING SHORTWAVE/FRONT THROUGH.
BETTER INSTABILITY THOUGH LOOKS TO REMAIN SOUTHWEST OF THE STATE.
AS OF RIGHT NOW, NO WIDESPREAD RAIN CHANCES ARE IN THE OFFING
GIVEN THIS KIND OF SPLITTING PATTERN WE ARE STUCK IN, WITH
STRONGER NORTHERN STREAM FORCING STAYING NORTH AND GREATEST
INSTABILITY GRADIENT PERSISTING SOUTH. THAT IS TOO BAD AS WE COULD
CERTAINLY USE SOME RAIN. RAINFALL DEFICITS SINCE MID JULY ARE NOW
RUNNING OVER 3 INCHES FOR MUCH OF NORTH-CENTRAL WI, AND 1 TO 2
INCHES ELSEWHERE THAT HAVE NOT BEEN FORTUNATE TO SEE ISOLATED
SUMMER DRENCHING STORMS. THUS, DROUGHT CONDITIONS HAVE EXPANDED
STEADILY. AS OF EARLY JULY NOT EVEN 50% OF OUR FORECAST AREA WAS
IN A D0 (ABNORMALLY DRY) CLASSIFICATION. NOW, AS OF THE LATEST
DROUGHT MONITOR (8/11), OVER 90% OF OUR AREA IS WITHIN D1 (MODERATE
DROUGHT), WITH PARTS OF ONEIDA AND VILAS COUNTIES INTO D2 (SEVERE
DROUGHT).
AVIATION
FOR 12Z TAF ISSUANCE
ISSUED AT 634 AM CDT SUN AUG 16 2026
WARM FRONT LIFTING ACROSS LAKE MICHIGAN HAS RESULTED IN LIFR-IFR
STRATUS AND POCKETS OF LIFR-IFR VSBY OVER EASTERN WI (GRB/ATW/MTW)
TO START THE TAF PERIOD. QUICK IMPROVEMENT TO MVFR STRATUS IS
EXPECTED NEXT FEW HOURS (BY 14Z-15Z) AS COLD FRONT SETTLING ACROSS
CENTRAL AND NORTH-CENTRAL WI SWEEPS ACROSS. STRATUS WILL MIX OUT
TO VFR STRATOCU THIS AFTERNOON IN WAKE OF THE FRONT. MVFR STRATUS
OVER CENTRAL AND NORTH-CENTRAL WI THIS MORNING WILL ALSO IMPROVE
TO SCATTERED VFR STRATOCU THIS AFTERNOON.
LIGHT SW-W WINDS WILL SHIFT TO NW THIS MORNING, INCREASING TO
10 KTS THIS AFTERNOON, WITH GUSTS OF 15-20 KTS. WINDS WILL BECOME
LIGHT TONIGHT. MAY SEE SOME PATCHY FOG CENTRAL TO NORTH-CENTRAL WI
LATE, BUT JUST KEPT IT MVFR VSBY NOW WITH SCATTERED LIFR CLOUD
MENTION.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION.....JLA
AVIATION.......JLA
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