085
FXUS63 KGRB 040959
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
459 AM CDT THU SEP 4 2025
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
KEY MESSAGES
- TEMPERATURES WILL BE UNSEASONABLY COOL THROUGH THE WEEKEND.
FROST IS EXPECTED EARLY THIS MORNING ACROSS PARTS OF CENTRAL AND
NORTHERN WISCONSIN. ADDITIONAL PERIODS OF FROST ARE POSSIBLE
THIS WEEKEND.
- WIDESPREAD RAINFALL WILL IMPACT THE REGION TONIGHT INTO EARLY
FRIDAY WITH A SMALL (20%) CHANCE FOR A THUNDERSTORM. WINDS MAY
GUST NEAR 40 MPH FRIDAY MORNING, ESPECIALLY ACROSS EAST-CENTRAL
WISCONSIN AND ALONG THE LAKESHORE.
- GALE FORCE WINDS AND HIGH WAVES ARE EXPECTED LATE TONIGHT INTO
FRIDAY MORNING ON THE BAY AND ON THE NEARSHORE WATERS OF LAKE
MICHIGAN.
- TEMPERATURES WILL SLOWLY MODERATE INTO NEXT WEEK WITH LITTLE
SIGNAL FOR ADDITIONAL IMPACTFUL PRECIPITATION.
DISCUSSION
ISSUED AT 458 AM CDT THU SEP 4 2025
PRECIPITATION CHANCES...AN UPPER-LEVEL LOW, LOCATED OVER SOUTHERN
ONTARIO EARLY THIS MORNING, WILL BE THE MAIN FORECAST DRIVER FOR THE
FORECAST THROUGH THE WEEKEND AS THE FORECAST AREA WILL BE IN A
NORTHWEST FLOW. THE UPPER-LEVEL LOW WILL TAKE A SLIGHT JOG NORTHWARD
TODAY AND ALLOW FOR A FAST-MOVING EMBEDDED SHORTWAVE/LOW PRESSURE
SYSTEM TO DIVE SOUTHEAST/EAST ACROSS THE UPPER MISSISSIPPI VALLEY.
THIS SYSTEM WILL TRACK ACROSS THE FORECAST AREA THIS EVENING AND
EXIT TO THE NORTHEAST BY FRIDAY MORNING. MODELS HAVE COME INTO
AGREEMENT WITH A SLIGHTLY FURTHER NORTH LOW TRACK, PUTTING NORTHERN
WI IN THE AREA WITH THE BEST FORCING, AND THEREFORE HIGHER RAINFALL
TOTALS. WHILE WIDESPREAD RAINFALL IS EXPECTED, RAINFALL TOTALS OF
0.50 TO 1.00 INCH ARE ANTICIPATED MAINLY NORTH OF HIGHWAY 29, WITH
LESSER AMOUNTS SOUTH OF HIGHWAY 29. CANNOT RULE OUT SOME THUNDER
ACTIVITY GIVEN BRIEF STEEP MID-LEVEL LAPSE RATES, BUT SEVERE WEATHER
IS NOT EXPECTED. ADDITIONAL LIGHT SHOWER ACTIVITY WILL CONTINUE
MAINLY ACROSS NORTHERN WI FOR THE REMAINDER OF FRIDAY AND INTO
FRIDAY NIGHT WITHIN THE NORTHWEST FLOW.
ANOTHER EMBEDDED (WEAK) SHORTWAVE LOOKS TO MOVE OVER THE UPPER
MISSISSIPPI VALLEY REGION ON SATURDAY, WHICH MAY BRING AREA-WIDE
LIGHT SHOWER ACTIVITY THROUGHOUT THE DAY. SURFACE HIGH PRESSURE
LOOKS TO BUILD OVER THE AREA ON SUNDAY, PUTTING AN END TO THE SHOWER
ACTIVITY, EXCEPT PERHAPS ACROSS FAR NORTHEAST WI. AS THE HIGH
PRESSURE GRADUALLY DEPARTS SUNDAY NIGHT INTO MONDAY, SO WILL THE
UPPER-LEVEL LOW OVER ONTARIO, LEAVING DRY WEATHER IN PLACE THROUGH
AT LEAST MONDAY NIGHT. MODELS CONTINUE TO SHOW SIGNS OF THE NEXT
CHANCE FOR RAIN SOMETIME MIDWEEK.
WIND (TONIGHT THROUGH FRIDAY)...ACCOMPANYING THE QUICK-MOVING LOW
PRESSURE SYSTEM FOR TONIGHT INTO FRIDAY WILL BE A TIGHT PRESSURE
GRADIENT WITH A STRONG (50-60 KTS) SOUTHWESTERLY LOW-LEVEL JET AHEAD
OF THE LOW, FOLLOWED BY STRONG (35-45 KTS) WESTERLY LOW-LEVEL WINDS
AND STRONG CAA. THIS WILL ALLOW FOR SURFACE WINDS TO QUICKLY
INCREASE LATE TONIGHT WITH GUSTS OF 25 TO 40 MPH POSSIBLE--HIGHEST
GUSTS IN EAST-CENTRAL WI AND ALONG THE LAKESHORE. WINDS WILL COME
DOWN SOME BY FRIDAY AFTERNOON, BUT WILL CONTINUE TO GUST TO 25 TO 30
MPH THROUGH FRIDAY EVENING BEFORE FINALLY SUBSIDING OVERNIGHT.
FROST/FOG THIS MORNING AND TEMPERATURES...WHILE A FROST ADVISORY
REMAINS IN EFFECT FOR NORTH-CENTRAL AND PORTIONS OF CENTRAL WI
THROUGH 8 AM THIS MORNING, PATCHY FOG, LIGHT WINDS (5+ MPH), AND
ISOLATED CLOUDS HAVE HINDERED SOME SITES FROM FALLING TO OR BELOW
THE MID 30S, PREVENTING FROST DEVELOPMENT. DESPITE THESE HINDRANCES,
WILL NOT BE MAKING ANY CHANGES TO THE FROST ADVISORY AS SOME SITES
ARE STILL SEEING FAVORABLE CONDITIONS. THE ABNORMALLY COLD AIRMASS
CAUSING THE CHILLY TEMPERATURES FOR THIS MORNING WILL STICK AROUND
THROUGH SATURDAY. AS A RESULT, TEMPERATURES WILL BE WELL BELOW
NORMAL, ABOUT 15 TO 20 DEGREES BELOW NORMAL WITH THE POTENTIAL FOR
RECORD LOW MAXIMUMS TODAY THROUGH SATURDAY. SEE THE CLIMATE SECTION
FOR MORE DETAILS.
AVIATION
FOR 06Z TAF ISSUANCE
ISSUED AT 1028 PM CDT WED SEP 3 2025
BENEATH AN UPPER LOW, CEILINGS REMAIN PRIMARILY VFR LATE THIS
EVENING. SHOWER ACTIVITY HAS MOSTLY FIZZLED AND PARTIAL CLEARING
HAS OCCURRED. A SUBTLE BACKING OF WIND TRAJECTORIES SHOULD
SUPPORT RISING CEILINGS AND SLOW CLEARING OVERNIGHT.
SHALLOW FAIR WEATHER CLOUDS, AROUND 4-5 KFT, ARE LIKELY TO
REDEVELOP WITH THE HEAT OF THE DAY AROUND 15-16Z AND PERSIST
THROUGH THE AFTERNOON.
WINDS WILL SUBSIDE THIS EVENING, WITH SOME DIURNAL INCREASE ON
THURSDAY AS MIXING COMMENCES IN THE 15-16Z TIMEFRAME.
A STRONG LOW PRESSURE SYSTEM WILL BRING RAIN TO THE REGION AFTER
00Z FRI. LOOK FOR STEADY RAIN TO MOVE INTO NORTH-CENTRAL WI
BETWEEN 00-03Z AND INTO NORTHEAST WI BETWEEN 03-06Z FRI.
DETERIORATING FLIGHT CONDITIONS CAN BE EXPECTED WITH BOTH CEILINGS
AND VISIBILITIES FALLING TO MVFR.
MARINE
ISSUED AT 458 AM CDT THU SEP 4 2025
BREEZY SOUTHWEST/WEST WINDS, WITH GUSTS TO 15-20 KTS AND A FEW
HIGHER GUSTS, WILL PERSIST TODAY. MARINERS OF SMALL CRAFT ON THE
BAY OF GREEN BAY SHOULD EXERCISE CAUTION GIVEN THESE BREEZY
CONDITIONS.
WAVES AND SOUTHERLY WINDS WILL RAPIDLY INCREASE LATE THIS EVENING
AND TONIGHT DUE TO THE PASSAGE OF THE SURFACE LOW PRESSURE SYSTEM.
BY FRIDAY MORNING, WINDS WILL TURN WESTERLY, BUT WILL REMAIN GUSTY.
THERE IS A STRONG ENOUGH SIGNAL FOR A BRIEF PERIOD OF GALES (35-40
KTS) TO OCCUR ON THE BAY OF GREEN BAY AND THE NEARSHORE WATERS ALONG
LAKE MICHIGAN FROM LATE TONIGHT THROUGH MID-FRIDAY MORNING TO
WARRANT THE ISSUANCE OF A GALE WARNING (1 AM TO 10 AM FRIDAY).
DANGEROUS SWIMMING CONDITIONS ARE LIKELY TO OCCUR ALONG LAKE
MICHIGAN BEACHES LATE TONIGHT INTO FRIDAY MORNING AS WELL. A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOLLOWING THE GALE
WARNING AS GUSTY WESTERLY WINDS WILL CONTINUE THROUGH FRIDAY
EVENING. WHILE THERE IS A NON- ZERO CHANCE OF WATERSPOUTS FRIDAY
MORNING, THE GREATER POTENTIAL WILL BE NORTH AND EAST OF OUR
WATERS.
CLIMATE
ISSUED AT 458 AM CDT THU SEP 4 2025
THE UNSEASONABLY COLD AIRMASS WILL BRING THE CHANCE OF SETTING
RECORD LOW MAXIMUM TEMPERATURES TODAY (9/4), FRIDAY (9/5), AND
SATURDAY (9/6). HERE IS A LOOK THE CURRENT RECORDS AND FORECAST
VALUES FOR GREEN BAY, RHINELANDER, AND WAUSAU.
GREEN BAY
DATE RECORD LOW MAX FORECAST HIGH
---- -------------- -------------
9/4 61F(2008) 62F
9/5 60F(1981) 59F
9/6 58F(1965) 61F
RHINELANDER
DATE RECORD LOW MAX FORECAST HIGH
---- -------------- -------------
9/4 58F(2008) 57F
9/5 55F(2017) 53F
9/6 55F(1956) 55F
WAUSAU
DATE RECORD LOW MAX FORECAST HIGH
---- -------------- -------------
9/4 59F(1905) 59F
9/5 57F(1956) 57F
9/6 56F(1965) 58F.
GRB WATCHES/WARNINGS/ADVISORIES
FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ005-010-011-
018-019-030.
DISCUSSION.....KRUK
AVIATION.......MPC
MARINE.........KRUK
CLIMATE........BERSCH/KRUK
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