855
FXUS63 KMKX 161002
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
402 AM CST TUE DEC 16 2025
KEY MESSAGES
- MILDER TEMPERATURES EXPECTED THIS AFTERNOON THROUGH EARLY
THURSDAY, WITH HIGHS IN THE MIDDLE TO UPPER 30S.
- 60-80% RAIN CHANCES ARE FORECAST FROM LATE WEDNESDAY NIGHT
THROUGH THURSDAY MORNING. THERE ARE 20-40% CHANCES FOR LIGHT
PRECIPITATION TO CONTINUE THURSDAY AFTERNOON AND EVENING, WITH
A GRADUAL TRANSITION TO LIGHT SNOW.
- SIGNIFICANTLY COLDER TEMPERATURES (SINGLE DIGIT LOW TEMPS)
EXPECTED THURSDAY NIGHT, FREEZING ANY SURFACES THAT REMAIN WET
FROM THURSDAY'S RAIN AND SNOW.
SHORT TERM
ISSUED 400 AM CST TUE DEC 16 2025
TODAY THROUGH THURSDAY NIGHT:
DRY WEATHER AND ABOVE AVERAGE TEMPERATURES EXPECTED THIS
AFTERNOON THROUGH WEDNESDAY, WITH HIGH TEMPS IN THE MID TO UPPER
30S. BREEZY SOUTHWEST WINDS (WITH SOME 20 TO 30 MPH GUSTS)
ARRIVE LATER THIS MORNING, PROVIDING THE LOW-LEVEL WAA NEEDED TO
BOOST TEMPERATURES FROM THE CURRENT (AS OF 3 AM) SINGLE DIGITS
TO MID TEENS TO JUST ABOVE THE FREEZING MARK. BREEZY WINDS
SLOWLY DIMINISH THROUGH TONIGHT, VEERING WEST-NORTHWEST LATE AS
A WEAK FRONTAL BOUNDARY CROSSES THE REGION. A COMBINATION OF
HIGH ALTITUDE CLOUDS AND DRY ADVECTION (STEADILY FALLING
DEWPOINTS AFTER MIDNIGHT) ARE EXPECTED TO PREVENT FOG FORMATION
ONCE AGAIN TONIGHT.
STRONG LOW PRESSURE TRACKS EASTWARD ALONG THE USA/CANADA
BORDERLINE WEDNESDAY, CROSSING THE UPPER PENINSULA OF MICHIGAN
MID THURSDAY BEFORE LIFTING NORTHEAST. STRONG WAA AHEAD OF THE
ASSOCIATED COLD FRONT (AS WELL AS ASCENT ALONG THE FRONT ITSELF)
WILL DRIVE A WIDESPREAD RAINFALL EVENT (60-80% CHANCES) LATE
WEDNESDAY NIGHT THROUGH THURSDAY MORNING, WITH BREEZY SOUTH
WINDS AT THE SURFACE. OUR BEST GUESS IS A TENTH TO A QUARTER
INCH OF RAINFALL, WITH UP TO A HALF INCH POSSIBLE (USING OUR
90TH PERCENTILE QPF).
WINDS VEER WEST (AND EVENTUALLY NW) BEHIND THE COLD FRONT MID
DAY THURSDAY. WE HAVE 20-40% CHANCES FOR PRECIP TO CONTINUE INTO
THE AFTERNOON AND EVENING THURSDAY, AND IF APPLICABLE, THIS
WOULD BE A RAIN TO SNOW TRANSITION, WITH MINIMAL SNOW
ACCUMULATIONS (IF APPLICABLE). THAT BEING SAID, TEMPERATURES
WILL PLUMMET RAPIDLY BEHIND THE FRONT, OUR CURRENT FORECAST HAS
2-METER AIR TEMPS HITTING FREEZING AROUND SUNSET INLAND, 2 HOURS
LATER FOR THE LAKE MI SHORELINE. OVERNIGHT LOWS ARE IN THE
SINGLE DIGITS (INLAND) TO AROUND 10 (SHORELINE) THURSDAY NIGHT,
AND ANY WET SURFACES FROM THURSDAY'S RAIN AND SNOWFALL WILL
FREEZE SOLID. THE COLD TEMPERATURES WILL BE SHORT LIVED,
REBOUNDING INTO THE WEEKEND AS DISCUSSED IN THE LONG TERM
SECTION OF THIS AFD.
SHEPPARD
LONG TERM
ISSUED 400 AM CST TUE DEC 16 2025
FRIDAY THROUGH MONDAY:
GEFS AND ECMWF ENS SHOW FAIRLY GOOD AGREEMENT DURING THIS PERIOD
BUT WITH THE EC A LITTLE SLOWER AND MORE AMPLIFIED THAN THE GEFS.
NWLY SFC WINDS AND COLD ADVECTION WILL CEASE FRI AM AS LOW
PRESSURE MOVES AWAY ACROSS SRN ONTARIO AND QUEBEC. A SURFACE RIDGE
PASSAGE WILL THEN FOLLOW FOR THE AFTERNOON WITH TEMPERATURES
REMAINING COLD.
SLY WINDS AND WARM ADVECTION WILL THEN BEGIN FRI NT AS LOW
PRESSURE IN THE 990S MILLIBARS TRACKS ALONG THE US/CANADIAN BORDER
IN THE NRN GREAT PLAINS. THE LOW TO MID LEVEL WARM ADVECTION WILL
BRING 20-30 PERCENT CHANCES FOR LIGHT SNOW MAINLY NORTH OF MADISON
AND MILWAUKEE. THE ASSOCIATED UPPER WAVE AND SFC LOW WILL THEN
MOVE ACROSS ONTARIO AND THE LAKE SUPERIOR REGION ON SAT. SLY WINDS
WILL SHIFT WLY WITH AN INITIAL COLD FRONT, BUT THE STRONGER POLAR
COLD FRONT WILL ARRIVE SAT NT. TEMPERATURES WILL WARM INTO THE 30S
ON SAT THEN DROPPING INTO THE SINGLE DIGITS NORTH OF MADISON BY
12Z SUN WITH TEENS ELSEWHERE. POLAR HIGH PRESSURE WILL THEN PASS
SUN AFTERNOON AND EVENING WITH COLD TEMPERATURES CONTINUING.
ANOTHER PERIOD OF SLY WINDS AND WARM ADVECTION WILL THEN ENSUE
LATE SUN NT AND MON AS LOW PRESSURE DEVELOPS IN THE NRN HIGH
PLAINS. LATER FORECASTS MAY HAVE TO INCLUDE CHANCES FOR LIGHT
SNOW GIVEN THE AFOREMENTIONED WARM ADVECTION.
GEHRING
AVIATION
ISSUED 400 AM CST TUE DEC 16 2025
A COMBINATION OF SCATTERED HIGH ALTITUDE CLOUD COVER REDUCING
RADIATIONAL COOLING AND THE LACK OF SURFACE MOIST AIR ADVECTION
OVERNIGHT HAVE MANAGED TO PREVENT FOG FORMATION, WITH ALL
AIRPORTS CURRENTLY REPORTING P6SM VISIBILITY IN SOUTHERN WI (AS
OF 3 AM CST).
DRY WEATHER AND VFR CONTINUE TODAY AND TONIGHT, WITH SOME SCT TO
BKN HIGH ALTITUDE CLOUDS. FORECAST SOUNDINGS HINT AT SOME SLIGHT
POTENTIAL FOR MVFR ALTITUDE CLOUDS OR EVEN SOME RADIATION FOG
LATE TONIGHT, BUT IN A SIMILAR MANNER TO THE ONGOING CONDITIONS,
WE EXPECT THIS TO FAIL TO PRODUCE ANY FOG / LOW CEILINGS. DRY
ADVECTION IS EXPECTED LATE TONIGHT, WITH DEWPOINTS STEADILY
FALLING AFTER MIDNIGHT.
BREEZY SOUTH TO SOUTHWEST WINDS FOR THE DAYTIME HOURS TODAY,
SOME 20 TO 25 KT GUSTS IN THE FORECAST. BREEZY CONDITIONS
CONTINUE TONIGHT, WITH SURFACE WINDS VEERING WEST / NORTHWEST
LATE. THROUGH THIS AFTERNOON INTO TONIGHT, 2,000 FT AGL WINDS
WILL BE VEERED ROUGHLY 30 DEGREES OFF FROM THE SURFACE WIND
VECTOR (SEE THE TAFS FOR LLWS GROUPS IF / WHERE APPLICABLE). ONE
OR TWO WINDOWS OF LOW-LEVEL WIND SHEAR MAY OCCUR IN THIS
TIMEFRAME.
SHEPPARD
MARINE
ISSUED 400 AM CST TUE DEC 16 2025
LIGHT SOUTH TO SOUTHWEST WINDS ARE EXPECTED EARLY THIS MORNING
BEFORE INCREASING AHEAD OF AN APPROACHING STRONG LOW PRESSURE
AROUND 29.0 INCHES. THIS LOW WILL MOVE EAST FROM CENTRAL MANITOBA
INTO NORTHERN ONTARIO THIS MORNING, LIFTING NORTHEAST INTO QUEBEC
THROUGH TONIGHT. SOUTHWESTERLY GALES TO 40 KT ARE EXPECTED ACROSS
THE NORTHERN THIRD OF THE LAKE LATE THIS MORNING INTO TONIGHT.
WEAKER GALES (35 KT) MAY OCCUR AS FAR SOUTH AS A WIND POINT WI TO
HOLLAND MI LINE, PARTICULARLY OVER EASTERN PORTIONS OF THE LAKE.
HENCE, THE GALE WARNING NOW INCLUDES ALL OPEN WATERS NORTH OF THIS
LINE (NORTHERN THREE QUARTERS OF THE LAKE), FROM 10 AM CST THIS
MORNING THROUGH 3 AM CST WEDNESDAY MORNING. WINDS VEER NORTHWEST
LATE TONIGHT AS A COLD FRONT EXTENDING SOUTH OF THE LOW CROSSES
THE LAKE, DIMINISHING BEHIND THE FRONT.
ANOTHER STRONG LOW PRESSURE SYSTEM IS EXPECTED TO TRACK EASTWARD
ALONG THE CANADIAN BORDER WEDNESDAY INTO THURSDAY. WINDS WILL TURN
SOUTH AND REMAIN LIGHT IN THE MIDDLE OF THE DAY WEDNESDAY, RAPIDLY
ACCELERATING WEDNESDAY EVENING.
STRONG SOUTH WINDS WILL DEVELOP AHEAD OF THE LOW WEDNESDAY NIGHT
(GALES LIKELY FOR MOST OF THE LAKE, STRONGEST FURTHER NORTH). A
COLD FRONT CROSSES THE LAKE MID DAY THURSDAY, WITH WINDS VEERING
NORTHWEST BEHIND IT. GALES ARE LIKELY BEHIND THIS FRONT AS WELL,
AND MAY LAST INTO FRIDAY MORNING BEFORE DISSIPATING.
A LULL IN THE WINDS OCCURS FRIDAY AFTERNOON, BEFORE A WEAKER
LOW PRESSURE SYSTEM FOLLOWS IN THE PRIOR SYSTEM'S TRACKS.
SOUTHERLY GALES ARE POSSIBLE FRIDAY NIGHT.
SHEPPARD
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-LMZ870-LMZ872-
LMZ874...10 AM TUESDAY TO 3 AM WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ643-LMZ644-LMZ645-LMZ646...9 AM
TUESDAY TO 6 AM WEDNESDAY.
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