411
FXUS63 KMQT 201730
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1230 PM EST SAT DEC 20 2025
KEY MESSAGES
- WIDESPREAD LIGHT TO OCCASIONALLY MODERATE SNOW WILL MOVE
THROUGH THE U.P EARLY THIS MORNING THROUGH MID-MORNING. 1 TO 4
INCHES OF TOTAL SNOWFALL IS EXPECTED WITH THE HIGHEST AMOUNTS
ACROSS THE NORTHERN COUNTIES.
- LAKE EFFECT SNOW FOR THE WEST TO NORTHWEST WIND SNOWBELTS
INCREASES THIS AFTERNOON THROUGH SUNDAY MORNING. 3 TO 7 INCHES
OF SNOWFALL IS EXPECTED ALONG LAKE SUPERIOR FROM MUNISING AND
EAST WHERE A WINTER WEATHER ADVISORY HAS BEEN ISSUED. 2 TO 4
INCHES IS EXPECTED IN THE WESTERN U.P, HIGHEST OVER THE HIGHER
TERRAIN.
- A WIND ADVISORY IS IN EFFECT FOR KEWEENAW AND NORTHERN
HOUGHTON COUNTIES THIS AFTERNOON THROUGH SUNDAY MORNING FOR
WESTERLY WIND GUSTS UPWARDS OF 45 MPH.
DISCUSSION
ISSUED AT 952 AM EST SAT DEC 20 2025
EARLY THIS MORNING MODEL ANALYSIS AND WATER VAPOR IMAGERY SHOWED A
BROAD TROUGH EXTENDING SOUTH FROM CANADA SETTING UP A FAIRLY ZONAL
FLOW ACROSS THE WESTERN AND CENTRAL U.S. OVER THE NORTHEAST A SHARP
TROUGH WAS LIFTING TO THE NORTHEAST AWAY FROM AREA. A CLIPPER LOW
WAS OVER CENTRAL MANITOBA AND MOISTURE FROM AN ATMOSPHERIC RIVER
COMING INTO NORTHERN CALIFORNIA WAS STREAMING ACROSS THE CENTRAL
ROCKIES AND INTO THE MIDWEST. RADAR HAS BEEN SHOWING MAINLY ELEVATED
ECHOES ACROSS THE U.P OVERNIGHT BUT DRY AIR WAS STARTING TO SATURATE
IN THE LOW WITH SURFACE OBSERVATIONS AND WEBCAMS IN THE CENTRAL AND
WEST STARTING TO SHOW SNOW REACHING THE GROUND. TEMPERATURES WERE
MAINLY IN THE TEENS AND SOUTH WINDS WERE BEGINNING TO PICK UP,
GUSTING 20 TO 30 MPH.
SNOW WILL CONTINUE TO SPREAD ACROSS THE AREA EARLY THIS MORNING,
WITH ISENTROPIC LIFT RESULTING IN A BROAD AREA OF LIGHT SNOW. A BAND
OF MODERATE SNOWFALL SHOULD DEVELOP DURING THE MORNING HOURS ALONG
AN AREA OF 700MB FRONTOGENESIS WHICH COINCIDES WITH MOISTURE FROM
THE WESTERN ATMOSPHERIC RIVER MAKES ITS WAY INTO THE U.P. MODELS
DIVERGE ON THE PLACEMENT OF THIS RELATIVELY NARROW BAND OF SNOWFALL
BUT GIVEN THE CURRENT RAP MESOANALYSIS AND RADAR TRENDS SEEM TO BE
IN-LINE WITH SOLUTIONS THAT BRING THE BAND THROUGH THE NORTHER
COUNTIES. WHILE THE FORECAST GRIDS ARE GENERALLY 1-3" OF SNOWFALL
THROUGH MID-MORNING ISOLATED AMOUNTS ALONG A NARROW AXIS OF 4 TO 5
INCHES ARE POSSIBLE, HOWEVER IT IS DIFFICULT TO PIN DOWN THE EXACT
PLACEMENT. REFS PROBABILITIES FOR 0.5"/HR SNOWFALL RATES (MODERATE
SNOW) ARE 50-65% THROUGH MID-MORNING IN OVER THE NORTHERN AND
CENTRAL U.P. THOSE TRAVELING THIS MORNING SHOULD BE PREPARED FOR
SLIPPERY ROADS AND REDUCED VISIBILITY.
SNOW SHOULD DIMINISH QUICKLY LATE THIS MORNING AS DRIER AIR WORKS
INTO THE AREA AND THE MAIN FORCING PUSHES EAST. A COLD FRONT WILL
THEN DROP THROUGH THE AREA THIS AFTERNOON BRINGING STRONG
NORTHWESTERLY WINDS, WITH GUSTS TO 45 MPH, OVER THE KEWEENAW WHERE A
WIND ADVISORY IS IN EFFECT. LAKE EFFECT SNOW WILL ALSO DEVELOP AS
THERMODYNAMIC PROFILES BECOME CONDUCIVE FOR CONVECTION. INVERSION
HEIGHTS INCREASE TONIGHT WITH MODERATE TO OCCASIONALLY HEAVY LAKE
EFFECT SNOW SHOWERS EXPECTED IN THE EASTERN U.P WITH LIGHT TO
POSSIBLY MODERATE SNOW SHOWERS IN THE WEST. A WINTER WEATHER
ADVISORY HAS BEEN ISSUED FOR THE EASTERN U.P WHERE UP TO 7 INCHES OF
SNOWFALL IS EXPECTED IN THE WEST TO NORTHWEST WIND SNOWBELTS FROM
MUNISING AND EAST. IT WILL BE COLD TONIGHT WITH LOW TEMPERATURES IN
THE SINGLE DIGITS (A FEW SINGLE DIGITS BELOW ZERO NEAR THE MI/WI
BORDER IN THE WEST). WITH BREEZY CONDITIONS EXPECT WIND CHILLS IN
THE NEGATIVE SINGLE DIGITS OVER THE NORTH AND EAST WITH NEGATIVE
TEENS OVER THE WEST, COLDEST NEAR THE MI/WI BORDER.
LAKE EFFECT SNOW WINDS DOWN ON SUNDAY WITH WINDS BECOMING SOUTHERLY
AGAIN BY LATE IN THE DAY. HIGHS WILL BE IN THE TEENS, 5 TO 10
DEGREES BELOW AVERAGE FOR THIS TIME OF YEAR. A WARM FRONT WILL LIFT
THROUGH THE AREA ON SUNDAY NIGHT INTO MONDAY, INTRODUCING ANOTHER
CHANCE FOR WIDESPREAD LIGHT SNOW. A WARMING TREND IS EXPECTED
THEREAFTER WITH HIGHS IN 30S BY MIDWEEK AND HIGHS IN THE LOW 40S FOR
CHRISTMAS DAY, ABOUT 15 DEGREES ABOVE AVERAGE.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1230 PM EST SAT DEC 20 2025
AS A CLIPPER LOW DEPARTS EAST, SYNOPTIC SNOW HAS MOVED AWAY FROM ALL
SITES THIS AFTERNOON. LAKE EFFECT SNOW IS BEGINNING TO RAMP UP
ACROSS THE WEST. STRONG WESTERLY WINDS ARE EXPECTED INTO TONIGHT,
GUSTING UP TO 30-40 KTS (STRONGEST AT CMX). BLOWING SNOW PRIMARILY
WILL BE SEEN AT CMX AS A RESULT OF THE STRONG WINDS, BUT COULD BE
OBSERVED AT TIMES AT IWD/SAW THIS AFTERNOON. CMX LIKELY WON'T
IMPROVE BEYOND IFR THROUGH THIS PERIOD. VFR/MVFR WILL BE THE PRIMARY
CATEGORY AT IWD/SAW WITH PERIODS OF IFR UNDER SNOW SHOWERS.
MARINE
ISSUED AT 952 AM EST SAT DEC 20 2025
IMPACTFUL MARINE WEATHER REMAINS IN THE FORECAST AS A SURFACE LOW
PRESSURE MOVES JUST NORTH OF LAKE SUPERIOR THROUGH THIS AFTERNOON.
SOUTHERLY GALES OF 35 KTS ACROSS THE EAST AND NORTH-CENTRAL LAKE ARE
EXPECTED THIS MORNING. AS THE SYSTEM KICKS TO THE NORTHEAST OF THE
LAKE A COLD FRONT WILL PUSH THOUGH THE AREA WITH SOUTHERLY WINDS
VEERING TO THE WEST AND NORTHWEST THIS AFTERNOON. THERE, STRONG
PRESSURE RISES COUPLED WITH MIXING INTO THE 40-50 KT LOW LEVEL JET
WILL RAMP UP WIND GUSTS UPWARDS OF 45 KTS ACROSS THE WESTERN LAKE,
SPREADING TO THE CENTRAL AND EAST BY THE AFTERNOON. SIGNIFICANT WAVE
HEIGHTS OF 15-20 FT ARE POSSIBLE WEST OF THE KEWEENAW BY TOMORROW
EARLY AFTERNOON, THEN EAST OF THE KEWEENAW FOR MUCH OF THE OPEN
WATERS OVERNIGHT INTO SUNDAY MORNING. AT THIS TIME, THERE IS A 25%
CHANCE FOR STORM FORCE GUSTS TO 50 KTS. GALE WARNINGS FOR NEARLY ALL
OF LAKE SUPERIOR ARE IN EFFECT. IN ADDITION, HEAVY FREEZING SPRAY IS
LIKELY TOMORROW AFTERNOON INTO SUNDAY MORNING AS TEMPERATURES FALL
INTO THE TEENS AND 20S LAKEWIDE. WINDS BEGIN TO DECREASE BELOW GALE
FROM WEST TO EAST SUNDAY MORNING.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
WIND ADVISORY UNTIL 1 AM EST SUNDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
SUNDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
GALE WARNING UNTIL 1 AM EST /MIDNIGHT CST/ SUNDAY FOR LSZ162-
240>243-263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ SUNDAY
FOR LSZ162-240>244-263-264.
GALE WARNING UNTIL 7 AM EST SUNDAY FOR LSZ244>248-264>267.
HEAVY FREEZING SPRAY WARNING FROM 4 PM THIS AFTERNOON TO 8 AM
EST SUNDAY FOR LSZ245>251-265>267.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 7 AM EST SUNDAY FOR
LSZ249>251.
LAKE MICHIGAN...
GALE WARNING FROM 4 PM THIS AFTERNOON TO 1 AM EST SUNDAY FOR
LMZ221-248-250.
DISCUSSION...NL
AVIATION...BW
MARINE...BW/NL
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