758
FXUS63 KGRB 170344
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1044 PM CDT TUE SEP 16 2025
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
KEY MESSAGES
- PATCHY DENSE FOG POSSIBLE OVERNIGHT INTO EARLY WEDNESDAY MORNING
MAY IMPACT TRAVEL OVER NORTH-CENTRAL TO FAR NORTHEAST WI, AND
OVER EAST-CENTRAL WI.
- ISOLATED STRONG STORMS COULD PRODUCE SMALL HAIL AND GUSTY WINDS
OVER FAR NORTHERN WISCONSIN ON WEDNESDAY AFTERNOON AND EVENING.
ADDITIONAL SCATTERED SHOWERS AND STORMS ARE POSSIBLE AT TIMES
THURSDAY THROUGH MONDAY. NO SEVERE STORMS ARE EXPECTED.
- TEMPERATURES ABOUT 10 TO 15 DEGREES ABOVE NORMAL THROUGH
WEDNESDAY, BEFORE RETURNING TO NEAR NORMAL FROM FRIDAY INTO THE
WEEKEND.
DISCUSSION
ISSUED AT 238 PM CDT TUE SEP 16 2025
FOG TONIGHT...
LOW LEVEL MOISTURE INCREASES THROUGH THE OVERNIGHT PERIOD WILL
BRING BACK GROUND FOG TO THE REGION TONIGHT AND MAY ALLOW FOR SOME
FOG ACROSS LAKE MICHIGAN AND ALONG THE SHORELINE AS WELL. BEST
FOG POTENTIAL WILL LIKELY BE AROUND PORTIONS OF NORTH- CENTRAL
WISCONSIN, WHICH WILL BE ALONG THE NORTHERN EDGE OF THE MOISTURE
PUSH WHILE ALSO HAVING THE COOLER AIR TEMPERATURES. PROBABILITY OF
LESS THAN A MILE VISIBILITY REMAINS LOW (<20%) SO WIDESPREAD DENSE
FOG SEEMS UNLIKELY.
PRECIPITATION...
A SLOW MOVING COLD FRONT MOVE TOWARDS THE REGION OVERNIGHT,
GETTING INTO CENTRAL WISCONSIN BY WEDNESDAY MORNING. SOME ELEVATED
INSTABILITY IS EVIDENT ON SOUNDINGS, BUT OVERALL PRECIPITATION
CHANCES SEEM LOW FOR THIS PERIOD (~20%). WEDNESDAY AFTERNOON WILL
BE A BETTER WINDOW FOR ANY CONVECTION, AS THE FRONT SLOWLY CROSSES
INTO THE AREA AROUND PEAK HEATING. SURFACE BASED INSTABILITY
BRINGS CAPE VALUES TO AROUND 1500-2000 J/KG, WHICH WOULD READILY
SUPPORT SOME SHOWERS AND THUNDER. THE LIMITING FACTORS FOR STORM
ACTIVITY WILL BE A LACK OF UPPER SUPPORT AND VIRTUALLY NO SHEAR IN
THE ENVIRONMENT. AS A RESULT, THE AFTERNOON WOULD LIKELY SEE SOME
ISOLATED TO SCATTERED PULSE STORMS. THE PULSY NATURE OF THE STORMS
WILL MAKE FOR AN ISOLATED WIND CONCERN, AS ANY STRONGER STORMS
COULD PRODUCE A BRIEF, LOCALIZED DOWNBURSTS. IF STRONGER STORMS
WERE TO FORM, THE BEST POTENTIAL WILL BE AROUND AND JUST AFTER
PEAK HEATING WEDNESDAY EVENING. THE SLOW MOVING AND PULSY NATURE
OF THE STORMS WILL ALSO LEAD TO VERY LOCALIZED RAINFALL, SO KEPT
POPS TO AROUND 40% AS NOT ALL OF THE AREA WILL SEE RAIN TOMORROW
AFTERNOON.
THE AFOREMENTIONED FRONT WILL STALL OUT ACROSS NORTHERN WISCONSIN
BY WEDNESDAY NIGHT AS UPPER RIDGING TO OUR EAST LEADS TO A MORE
STAGNANT PATTERN. SCATTERED SHOWERS AND STORMS WILL BE POSSIBLE AT
TIMES ALONG THIS FRONT, AFFECTING PRIMARILY PORTIONS OF WESTERN,
NORTHWESTERN, AND NORTH-CENTRAL WISCONSIN WHILE LITTLE IN THE WAY
OF RAIN GETS INTO EAST-CENTRAL WISCONSIN. THE FRONT WILL THEN
FINALLY PROGRESS THROUGH THE REGION OVER THE WEEKEND. ASIDE FROM
WEDNESDAY, STRONG OR SEVERE POTENTIAL WITH ANY OF THESE ADDITIONAL
STORMS WILL BE LITTLE TO NONE.
FINALLY, ANOTHER PUSH OF PRECIPITATION ARRIVES EARLY NEXT WEEK,
WITH SOME STORM POTENTIAL AGAIN. SEVERE POTENTIAL IS STILL TOO
EARLY TO DETERMINE.
TEMPERATURES...
THE WARMEST DAYS IN THE FORECAST WILL BE TODAY AND WEDNESDAY,
WITH HIGHS INTO THE 80S. A SLOW COOL DOWN IS THEN EXPECTED INTO
THE WEEKEND, WITH HIGHS GETTING BACK INTO THE 70S OVER THE
WEEKEND.
AVIATION
FOR 06Z TAF ISSUANCE
ISSUED AT 1039 PM CDT TUE SEP 16 2025
PRIMARY CONCERN OVERNIGHT WILL BE FOG POTENTIAL. GROUND FOG IS
LIKELY FROM CENTRAL TO NORTH-CENTRAL WI, AND ALSO NEAR THE
LAKESHORE. GREATEST RISK OF IFR OR LOWER CONDITIONS WILL BE AT MTW
WHERE IT IS NEARLY SATURATED ALREADY AND ADDITIONAL COOLING IS
EXPECTED WITH LIGHT WINDS. ALSO HAVE A MENTION FOR LOWER
CONDITIONS AT RHI, THOUGH THICKER MID AND HIGH CLOUDS OVERNIGHT
MAY DAMPEN THE POTENTIAL. ALSO, KEPT MENTION OF MVFR GROUND FOG
AT AUW/CWA, BUT THIS IS LOOKING LESS LIKELY, AGAIN DUE TO THE
CLOUDS. FINALLY, AT GRB/ATW, GIVEN THE MIXING THAT OCCURRED
TUESDAY AFTERNOON, EXPECT MINIMAL FOG TO OCCUR.
ONCE ANY FOG BURNS OFF AFTER 12Z-13Z WEDNESDAY, THE MAIN FOCUS
WILL TURN TO SCATTERED SHOWERS AND STORMS EXPECTED TO DEVELOP
AFTER 19Z-21Z AS A COLD FRONT SETTLES OVER NORTHWEST WI AND
INSTABILITY BUILDS AHEAD OF IT. GREATEST POTENTIAL FOR STORMS WILL
BE OVER NORTH-CENTRAL WI, BUT COVERAGE DOES NOT LOOK EXTENSIVE
ENOUGH TO CARRY ANYTHING MORE THAN PROB30 MENTIONS FOR RHI, AUW
AND CWA. STRONGEST STORMS WILL PRODUCE SMALL HAIL, GUSTY WINDS AND
HEAVY RAIN, ALONG WITH BRIEF MVFR VSBY.
ONCE THE SHOWERS AND STORMS DIMINISH ON WEDNESDAY EVENING, EXPECT
THE COLD FRONT TO DROP ACROSS THE AREA. THERE MAY BE LOW CLOUDS
LATE WEDNESDAY NIGHT OVER THE NORTH BEHIND THE FRONT, INCLUDING
AT RHI.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION.....UHLMANN
AVIATION.......JLA
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