523
FXUS63 KMKX 212330
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
630 PM CDT MON SEP 21 2026
KEY MESSAGES
- A PROLONGED PERIOD OF HIGH SWIM RISK CONDITIONS CONTINUES INTO
EARLY WEDNESDAY EVENING FOR ALL BEACHES ALONG LAKE MICHIGAN.
- SCATTERED LIGHT RAIN SHOWERS ARE EXPECTED ROUGHLY ALONG AND
WEST OF A LINE FROM FOND DU LAC TO JANESVILLE THIS EVENING
INTO EARLY TUESDAY.
- BELOW NORMAL TEMPS ARE EXPECTED FOR THE FIRST
HALF OF THE WEEK, WITH GRADUALLY WARMING TEMPS INTO THE
WEEKEND.
UPDATE
ISSUED 630 PM CDT MON SEP 21 2026
PERSISTING EAST-NORTHEASTERLY FLOW SEEMS TO BE ADDING EXTRA
MOISTURE (PWATS +1 INCH) TO THE ENVIRONMENT SUPPORTING THE MORE
ROBUST SHOWER ACTIVITY ACROSS OUR WESTERN CWA WITH THE MID-
LEVEL SHORTWAVE TROUGH. HAVE INCREASED POPS THROUGH THE EVENING
AS OBS HAVE OBSERVED ANYWHERE FROM A FEW HUNDREDTHS TO JUST
UNDER A TWO TENTHS OF AN INCH. DO THINK THIS WILL WEAKEN AS IT
PUSHES EAST, BUT MAY BE ENOUGH TO SUPPORT LIGHT SHOWERS/DRIZZLES
TO THE LAKESHORE. OTHERWISE ADDITIONAL LIGHT SHOWER CHANCES
WILL BE POSSIBLE AGAIN OVERNIGHT INTO EARLY TUESDAY MORNING FOR
SOUTHWESTERN WI AND ALONG THE WI/IL BORDER AS THE UPPER WAVE
CONTINUES TO SLIDE EAST.
WAGNER
SHORT TERM
ISSUED 1254 PM CDT MON SEP 21 2026
TONIGHT THROUGH TUESDAY NIGHT:
LATEST GUIDANCE CONTINUES TO SHOW SHOWER CHANCES THIS EVENING
INTO EARLY TUESDAY AS A WEAKENING SHORTWAVE MOVES THROUGH.
SOUNDINGS SHOW PLENTY MID AND UPPER LEVEL MOISTURE, SO HOW MUCH
RAIN MAKES IT TO THE GROUND WILL DEPEND ON HOW MUCH THE LOW
LEVELS SATURATE. OVERALL, THE LOWER LEVELS ARE LOOKING MORE
SATURATED PER LATEST MODELS COMPARED TO 24 HOURS AGO. BASED ON
THIS AND UPSTREAM RADAR, HAVE BUMPED UP THE PRECIP CHANCES
ROUGHLY FROM MADISON TO JANESVILLE AND WESTWARD. FARTHER EAST,
THE LOWER LEVELS WILL LIKELY REMAIN DRIER DUE TO THE INFLUENCE
OF STRONG SURFACE HIGH PRESSURE CENTERED NEAR THE ONTARIO/QUEBEC
BORDER. THUS KEPT THE FORECAST DRY IN THE EAST/NORTHEAST,
THOUGH A FEW SPRINKLES ARE POSSIBLE. TEMPS TOMORROW WILL BE
SEVERAL DEGREES BELOW NORMAL AGAIN GIVEN THE COOLER AIRMASS IN
PLACE AND EXPECTED MOSTLY CLOUDY SKIES MUCH OF THE DAY AS THE
WAVE SLOWLY EXITS.
THE BEACH HAZARDS STATEMENT REMAINS IN EFFECT UNTIL 7 PM CDT
WEDNESDAY EVENING FOR ALL LAKE MICHIGAN BEACHES, WITH PERSISTENT
GUSTY EAST NORTHEAST WINDS AND HIGH WAVES OF 4 TO 8 FEET. STAY
OUT OF THE WATER, AND AWAY FROM DANGEROUS AREAS LIKE PIERS AND
BREAKWALLS.
DDV
LONG TERM
ISSUED 1254 PM CDT MON SEP 21 2026
WEDNESDAY THROUGH MONDAY:
STRONG HIGH PRESSURE CENTERED JUST NORTH OF THE EASTERN GREAT
LAKES EARLY WEDNESDAY WILL LARGELY REMAIN IN PLACE THE SECOND
HALF OF THE WEEK WHILE GRADUALLY WEAKENING. MEANWHILE, UPPER
LEVEL RIDGING WILL ATTEMPT TO BUILD IN FROM THE WEST THROUGH
LATE WEEK. MODELS STILL DIFFER AS TO WHETHER SOUTHERN WISCONSIN
WILL BE MORE UNDER THE INFLUENCE OF THE DEPARTING TROUGHING
PATTERN OR THE APPROACHING RIDGE BY THE END OF THE WEEK INTO THE
WEEKEND. THUS THERE REMAINS SOME UNCERTAINTY WITH TEMPS DURING
THIS PERIOD, THOUGH AN OVERALL SLIGHT WARMING TREND LOOKS
LIKELY. ADDITIONALLY, MODELS SUGGEST A SHORTWAVE MAY COME OVER
THE TOP OF THE RIDGE LATE WEEK OR DURING THE WEEKEND, BRINGING
SHOWER CHANCES BACK TO THE AREA. AS WITH TEMPS, THERE IS STILL
UNCERTAINTY WITH THE TIMING OF ANY PRECIP GIVEN THE DIFFERENCES
WITH THE TROUGH/RIDGE AMONG MODELS.
DDV
AVIATION
ISSUED 630 PM CDT MON SEP 21 2026
SEEING MORE ROBUST SHOWER ACTIVITY AROUND MSN AND JVL, AND THERE
MAY BE A FEW POCKETS OF LOWER CEILINGS AND VISIBILITY WITH ANY
MODERATE RAINFALL. HOWEVER, VFR CEILINGS AND VISIBILITY PREVAIL
ACROSS MUCH OF THE AREA. SOME DECAYING SHOWERS AND DRIZZLE MAY
MAKE IT INTO THE EASTERN TERMINALS, BUT GENERALLY EXPECTING THIS
ACTIVITY TO GRADUALLY DIMINISH AFTER SUNSET. OTHERWISE, COULD
SEE SOME ADDITIONAL LIGHT SHOWER CHANCES TOWARD THE WI/IL BORDER
OVERNIGHT INTO EARLY TUESDAY MORNING, BUT THEN DRIER AND VFR
CONDITIONS ARE EXPECTED FOR THE DAY TUESDAY. WITH HIGH PRESSURE
SITTING TO OUR NORTHEAST, EXPECT BREEZY EAST TO NORTHEASTERLY
WINDS TO CONTINUE AND BECOMING GUSTY THROUGH TUESDAY AFTERNOON
BEFORE WEAKENING BY TUESDAY EVENING.
WAGNER
MARINE
ISSUED 1254 PM CDT MON SEP 21 2026
HIGH PRESSURE AROUND 30.4 INCHES NORTH OF LAKE SUPERIOR TODAY
WILL SHIFT EASTWARD INTO QUEBEC TONIGHT. THE HIGH WILL THEN
LARGELY REMAIN IN PLACE THROUGH THE MIDDLE OF THE WEEK, WHILE
STRENGTHENING TO AROUND 30.7 INCHES BY WEDNESDAY MORNING. GUSTY
EAST TO NORTHEAST WINDS ARE EXPECTED TODAY THROUGH WEDNESDAY.
WINDS THEN LOOK TO DIMINISH TOWARD THE END OF THE WEEK, AS THE
HIGH PRESSURE SYSTEM SLOWLY WEAKENS AND MOVES FARTHER EAST.
DDV
MKX WATCHES/WARNINGS/ADVISORIES
WI...BEACH HAZARDS STATEMENT...WIZ052-WIZ060-WIZ066-WIZ071-WIZ072
UNTIL 7 PM WEDNESDAY.
LM...SMALL CRAFT ADVISORY...LMZ643-LMZ644-LMZ645-LMZ646 UNTIL 7 PM
WEDNESDAY.
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