435
FXUS63 KMQT 180827
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
327 AM EST WED DEC 18 2024
KEY MESSAGES
- WINTER WEATHER ADVISORIES ARE IN EFFECT FOR PORTIONS OF THE
WESTERN AND EASTERN UP FOR LAKE EFFECT SNOW IN THE NORTHWEST
WIND SNOW BANDS INTO TONIGHT.
- EYES ARE ON A FAST-HITTING CLIPPER SYSTEM THAT COULD BRING
SOME FLUFFY LAKE ENHANCED SNOWFALL OVER THE U.P. LATE THURSDAY
INTO THURSDAY NIGHT.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 325 AM EST WED DEC 18 2024
WITH THE SURFACE COLD FRONT NOW PAST THE UP, SNOW WILL CONTINUE TO
BUILD IN THE NORTHWEST WIND LES BANDS. WITH EVEN THE 5TH PERCENTILE
OF THE NBM SHOWING OVER 20:1 SNOW RATIOS BY THIS EVENING, THE SNOW
FALLING TODAY AND TONIGHT WILL BE QUITE FLUFFY. MEAN HREF QPF
THROUGH 12Z THURSDAY IS AROUND A QUARTER TO A THIRD OF AN INCH,
LEADING TO 1-3 INCHES OF SNOWFALL EXPECTED WIDESPREAD ALONG LAKE
SUPERIOR WITH AREAS OF 3-5 INCHES IN ALGER, LUCE, AND N. SCHOOLCRAFT
COUNTIES AS WELL AS THE TERRAIN OF THE WEST HALF. SNOWFALL WILL END
IN THE WEST SOONER THAN THE EAST AS HIGH PRESSURE OF A GEFS-MEAN
1032 MB ENCROACHES ON THE REGION, WITH THE GEFS SHOWING THE CENTER
OVER NORTHWESTERN ONTARIO BY 06Z THURSDAY. THE SURFACE WIND PATTERN
DRIVING LAKE EFFECT SNOW BANDS WILL BE FURTHER COMPLICATED OVERNIGHT
TONIGHT BY A CLEAR LAND BREEZE SHOWN IN THE CAMS. ULTIMATELY, THIS
FORECAST PACKAGE WILL MAINTAIN THE CURRENT WINTER WEATHER ADVISORIES
THROUGH 00Z THURSDAY FOR GOGEBIC, ONTONAGON, AND N. HOUGHTON
COUNTIES WITH ADVISORIES CONTINUING THROUGH 06Z THURSDAY FOR ALGER,
LUCE, AND N. SCHOOLCRAFT COUNTIES. WITH SNOWFALL RATES DECREASING
THROUGH THE AFTERNOON IN THE WEST, A CANCELLATION MAY (30%
CHANCE) COME AS SOON AS 18Z, WHILE ~30% PROBABILITIES OF
6-HOURLY SNOWFALL RATES OF 2"/6- HR IN THE EAST HALF OF ALGER
COUNTY LINGER UNTIL AROUND 12Z, WHICH COULD JUSTIFY AN
EXTENSION. HOWEVER, UNCERTAINTY IN THE EVOLUTION OF SAID TIMING
CHANGES WILL LEAVE THE DECISION TO CHANGE HEADLINES TO BE MORE
REACTIVE THAN PROACTIVE. WIND GUSTS OF UP TO 30 MPH IN THE EAST
IN ADDITION TO FALLING FLUFFY SNOW WILL CREATE SOME PATCHY
BLOWING AND DRIFTING SNOW THREATS ALONG LAKE SUPERIOR IN THE
EAST TODAY. ATTENTION THEN TURNS UPSTREAM TO AN APPROACHING
CLIPPER LOW AND ASSOCIATED ISENTROPIC ASCENT AND WARM ADVECTION,
THOUGH EVEN THE 75TH TO 90TH PERCENTILE OF AVAILABLE GUIDANCE
ONLY BRINGS CHANCES OF PRECIPITATION PRIOR TO 12Z THURSDAY IN
THE IRONWOOD AREA OF ONLY AROUND 20%. IT WILL BE A PRETTY COOL
OVERNIGHT PERIOD, WITH WIDESPREAD 70-90% CHANCES OF SINGLE-DIGIT
LOWS IN THE WEST HALF PER THE NBM, WITH THE DETERMINISTIC NBM
SHOWING VALUES NEAR 0 FOR THE WESTERN MARQUETTE/SOUTHERN
BARAGA/NORTHERN IRON COUNTY REGION. THE APPROACHING HIGH
PRESSURE CALMING THE WINDS WILL AT LEAST HELP WIND CHILLS ONLY
BE SLIGHTLY BELOW 0 OVERNIGHT.
LONG TERM /WEDNESDAY THROUGH MONDAY/
ISSUED AT 256 PM EST TUE DEC 17 2024
THE LIGHT TO MODERATE AT TIMES LAKE EFFECT SNOWFALL CONTINUES OVER
THE NORTHWEST WIND SNOW BELTS WEDNESDAY AS COLD AIR ADVECTION
CONTINUES TO MOVE OVER THE AREA WITH MARGINAL CYCLONIC FLOW ACROSS
THE GREAT LAKES BASIN AS A SHORTWAVE LOW TRIES TO DEVELOP OVER IT.
WITH SOME ENHANCEMENT FROM THE DEVELOPING SHORTWAVE WEDNESDAY
MORNING, EXPECT THE STRONGEST SNOWFALL RATES TO BE DURING THE FIRST
HALF OF THE DAY, WITH THE TRANSITION TO PURE LAKE EFFECT BY THE
AFTERNOON HOURS AS THE DEVELOPING SHORTWAVE MOVES EAST AND HIGH
PRESSURE RIDGING BUILDS IN FROM OUR WEST. WITH DELTA-TS INCREASING
TO AROUND 20 C BY WEDNESDAY MORNING AND INCREASING THROUGHOUT THE
DAY, THE THERMODYNAMIC PROFILE WILL BE MORE THAN SUFFICIENT TO
SUPPORT LAKE EFFECT SNOWFALL, WITH PRECONDITIONING FROM LAKE NIPIGON
ALSO LENDING A HAND IN ADDING MOISTURE FLUX TO THE EASTERN LAKE
EFFECT BANDS TOO. OVERALL, EXPECT SLICK ROADS AND QUICKLY
ACCUMULATING SNOWFALL AT TIMES; SLOW DOWN AND BE SURE TO TAKE YOUR
TIME. BY THE TIME THE LAKE EFFECT DIES OUT LATE WEDNESDAY NIGHT,
EXPECT TO SEE AROUND 3 TO 7 INCHES OF FLUFFY SNOW OVER THE EASTERN
NORTHWEST WIND SNOW BELTS, WITH SOME PATCHY BLOWING SNOW
OCCASIONALLY DEVELOPING FROM TIME TO TIME ALONG THE LAKESHORES AS
WINDS PICK UP TO AROUND 35 MPH WEDNESDAY AFTERNOON. AS FOR THE
WESTERN NORTHWEST WIND SNOW BELTS, THE AREA CAN EXPECT TO SEE AROUND
3 TO 6 INCHES OF FLUFFY SNOW, WITH ISOLATED HIGHER AMOUNTS AROUND 8
INCHES NEAR THE PORKIES. THEREFORE, GIVEN THE SNOWFALL AMOUNTS AND
IMPACTS TO TRAVEL CONDITIONS LATE TONIGHT INTO WEDNESDAY NIGHT, A
WINTER WEATHER ADVISORY HAS BEEN ISSUED FROM 1 AM EST TONIGHT TO 7
PM EST WEDNESDAY FOR GOGEBIC, ONTONAGON, AND NORTHERN HOUGHTON
COUNTIES, AND FROM 1 AM EST TONIGHT TO 1 AM EST THURSDAY FOR ALGER,
NORTHERN SCHOOLCRAFT, AND LUCE COUNTIES.
OUR ATTENTION THEN GOES TO A WEAKENING CLIPPER SYSTEM THAT DROPS
TOWARDS THE CHICAGO AREA WEDNESDAY NIGHT THROUGH THURSDAY. WHILE WE
LOOK TO RECEIVE A QUICK REPRIEVE FROM SNOWFALL THURSDAY MORNING, THE
APPROACHING CLIPPER LOOKS TO HELP DEVELOP INVERTED SECONDARY
SHORTWAVE TROUGHS OVER BOTH NORTHERN LAKE MICHIGAN AND SOUTHERN LAKE
SUPERIOR. WHILE TRANSIENT HIGH PRESSURE MOVING FROM NORTHERN ONTARIO
INTO NORTHERN QUEBEC WILL LIKELY KEEP SYSTEM SNOWFALL OUT OF OUR
AREA TOO FAR TO THE SOUTH, WITH LAKE ENHANCEMENT DEVELOPING OFF OF
LAKE MICHIGAN AND LAKE SUPERIOR, WE COULD SEE SOME MODERATE TO
OCCASIONALLY HEAVY LAKE ENHANCED SNOWFALL OFF OF GREEN BAY IN
MENOMINEE AND SOUTHWESTERN DELTA COUNTIES LATE THURSDAY THROUGH
THURSDAY EVENING, AND LIGHT TO OCCASIONALLY MODERATE LAKE ENHANCED
SNOWFALL OVER THE EAST TO NORTH-NORTHEAST WIND SNOW BELTS OFF OF
LAKE SUPERIOR LATE THURSDAY TO FRIDAY MORNING. WHILE WINTER STORM
WARNINGS ARE NOT EXPECTED FOR THIS EVENT, WE MAY NEED TO ISSUE
WINTER WEATHER ADVISORIES FOR MENOMINEE AND POSSIBLY MARQUETTE
COUNTIES IN THE NEAR FUTURE FOR THIS EVENT AS SLICK ROADS AND
QUICKLY ACCUMULATING SNOWFALL AT TIMES COULD BE SEEN. AS HIGH
PRESSURE BUILDS IN FROM THE NORTHERN PLAINS FRIDAY, EXPECT THE
INCOMING SUBSIDENCE TO GREATLY DIMINISH THE SNOWFALL ACROSS THE
AREA. HOWEVER, REMNANT TROUGHING OVER THE GREAT LAKES BASIN MAY BE
JUST STRONG ENOUGH TO ALLOW WEAK LAKE EFFECT SNOWFALL TO CONTINUE
OVER THE NORTH WIND SNOW BELTS INTO EARLY THIS WEEKEND AS THE
THERMODYNAMIC PROFILE WILL BE VERY SUPPORTIVE OF LAKE EFFECT SNOW
DESPITE THE RIDGING PUSHING INTO THE AREA (DELTA-TS INCREASING TO
THE LOWER TO MID 20S C). THE LAKE EFFECT SNOW LOOKS TO EVENTUALLY
END THIS WEEKEND AS THE HIGH PRESSURE RIDGING FINALLY FIGHTS ITS WAY
INTO THE GREAT LAKES BASIN.
EXPECT A GENERAL WARMING TREND FOR CHRISTMAS WEEK AS WARM AIR FROM
MORE TROPICAL AREAS OF THE PACIFIC MOVES OVER THE ROCKIES AND
DOWNSLOPES INTO THE CANADIAN AND U.S. PLAINS. THAT BEING SAID, IT
DOES LOOK LIKE WE WILL HOLD ON TO COOLER TEMPERATURES A LITTLE
LONGER EARLY NEXT WEEK, AT LEAST ENOUGH TO POSSIBLY GIVE US ANOTHER
SNOWFALL EVENT AS ANOTHER CLIPPER DIPS INTO THE NORTHERN PLAINS
BEFORE BRINGING WARM FRONTOGENESIS OVER THE U.P. AROUND NEXT MONDAY.
WHILE THERE IS SURPRISINGLY A GOOD AMOUNT OF MEDIUM RANGE MODEL
CONVERGENCE ON THIS CLIPPER LOW'S TRACK EARLY NEXT WEEK, UNCERTAINTY
ON THE SNOW CHANCES EARLY NEXT WEEK STILL REMAINS FAIRLY HIGH AS THE
FORECAST COULD SIGNIFICANTLY CHANGE THAT FAR OUT (SYSTEM ENERGY HAS
NOT BEEN PICKED UP BY RADIOSONDES OVER THE CONUS YET). THAT BEING
SAID, IT DOES SEEM TO IMPROVE CONFIDENCE A LITTLE FOR A 'WHITE
CHRISTMAS' OVER THE U.P., BEFORE WE LIKELY SEE MORE SNOW MELT
CHRISTMAS DAY AND BEYOND AS SURFACE HIGH TEMPERATURES ARE CURRENTLY
PROJECTED TO RISE ABOVE FREEZING.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1132 PM EST TUE DEC 17 2024
MVFR CONDITIONS WILL DOMINATE FOR THIS FORECAST PERIOD AT ALL SITES.
SOME PERIODS OF IFR CONDITIONS ARE POSSIBLE IN SNOW SHOWERS.
MARINE
ISSUED AT 256 PM EST TUE DEC 17 2024
NORTHWEST WINDS OF 20 TO 30 KNOTS OVER THE EAST HALF OF THE LAKE
THIS AFTERNOON WEAKEN TO 20 KNOTS OR LESS THIS EVENING AS WEAK
RIDGING BUILDS INTO THE AREA. HOWEVER, AS A WEAK SHORTWAVE BUILDS
OVER THE GREAT LAKES BASIN WEDNESDAY BEFORE MOVING EAST, EXPECT
WINDS TO BUILD BACK TO 20 TO 25 KNOTS OVER THE WEST HALF OF LAKE
SUPERIOR WEDNESDAY MORNING, AND 20 TO 30 KNOTS OVER THE EAST HALF OF
LAKE SUPERIOR WEDNESDAY MORNING AND AFTERNOON; SOME FREEZING SPRAY
COULD BE SEEN ACROSS THE LAKE WEDNESDAY AS COLDER AIR DROPS DOWN
FROM CANADA. THE FREEZING SPRAY ENDS WEDNESDAY NIGHT AS WINDS WEAKEN
TO 20 KNOTS OR LESS AGAIN DUE TO A HIGH PRESSURE RIDGE MOVING
THROUGH THE UPPER GREAT LAKES. AS A CLIPPER DROPS DOWN TOWARDS THE
CHICAGO AREA WEDNESDAY NIGHT AND THURSDAY, SECONDARY INVERTED
SHORTWAVE TROUGHS OVER NORTHERN LAKE MICHIGAN AND SOUTHERN LAKE
SUPERIOR ASSOCIATED WITH THE CLIPPER MAY BE STRONG ENOUGH TO CREATE
NORTHEAST TO NORTHERLY WINDS OF 20 TO 25 KNOTS OVER WESTERN LAKE
SUPERIOR THURSDAY NIGHT BEFORE WEAKENING AGAIN BY FRIDAY. THE WEAK
WINDS LOOK TO CONTINUE THROUGH THE WEEKEND AS HIGH PRESSURE SLOWLY
FIGHTS ITS WAY INTO THE GREAT LAKES BASIN.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ002-003-009.
WINTER WEATHER ADVISORY UNTIL 1 AM EST THURSDAY FOR MIZ006-007-
085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
SHORT TERM...GS
LONG TERM...TAP
AVIATION...07
MARINE...TAP
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