757
FXUS63 KMQT 152018
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
318 PM EST WED JAN 15 2025
KEY MESSAGES
- A CLIPPER LOW WILL BRING A QUICK BATCH OF LIGHT SNOW (1-2
INCHES) FOR MOST OF THE UP THIS EVENING THROUGH THE FIRST HALF
OF THE NIGHT. LAKE EFFECT SNOW LINGERS IN THE WEST TO
NORTHWEST WIND BELTS THE SECOND HALF OF THE NIGHT. ANOTHER 1-3
IN OF SNOW IS EXPECTED IN THOSE WIND BELTS, WITH LIGHTER
TOTALS MAINLY OF AN INCH OR LESS ACROSS THE REST OF THE UP.
- SW GALES OF 35-40KTS CONTINUE THE WEST HALF OF LAKE SUPERIOR
THIS AFTERNOON, ENDING BY MIDNIGHT THURSDAY.
- GALES TO 40 KNOTS FROM THE SOUTHWEST, BECOMING NORTHWEST
FRIDAY AND FRIDAY NIGHT ARE POSSIBLE FOR PARTS OF LAKE
SUPERIOR.
- BITTER COLD ARCTIC AIR SETTLES INTO THE AREA THIS WEEKEND
INTO EARLY NEXT WEEK. SUBZERO TEMPERATURES SATURDAY NIGHT
THROUGH AT LEAST TUESDAY MORNING OVER INTERIOR WESTERN UPPER
MICHIGAN ARE POSSIBLE (75%). SINGLE DIGITS ABOVE ZERO HIGHS
AND SINGLE DIGITS BELOW ZERO LOWS ARE EXPECTED ELSEWHERE.
- SNOW SATURDAY INTO EARLY NEXT WEEK WILL CAUSE MINI WHITEOUTS
AND VERY HAZARDOUS DRIVING CONDITIONS IN THE NORTHWEST WIND
SNOW BELTS.
SHORT TERM /THROUGH THURSDAY/
ISSUED AT 317 PM EST WED JAN 15 2025
AFTERNOON RAP ANALYSIS AND WATER VAPOR IMAGERY DEPICT A CLIPPER
SYSTEM DIVING SOUTHEAST INTO THE UPPER GREAT LAKES WITH ASSOCIATED
ISENTROPIC LIFT KICKING OFF SNOW SHOWERS IN CENTRAL MINNESOTA. AS
THE SHORTWAVE NEARS CLOSER TO HOME, THESE SHOWERS WILL CONTINUE
THEIR EASTWARD MARCH INTO THE UP, EVENTUALLY REACHING THE FAR WEST
THIS EVENING BEFORE EXITING QUICKLY TO THE EAST BEFORE SUNRISE
TOMORROW MORNING. NOT EXPECTING ANY HEAVY SNOW ACCUMULATIONS WITH
THESE PASSING "SYSTEM" SNOW SHOWERS TONIGHT AS GUIDANCE ONLY
SUGGESTS LIGHT QPF GENERALLY <0.1" TIED WITH SLRS IN THE UPPER
TEENS:1, YIELDING LIGHT SNOW ACROSS THE UP 1-2" OR LESS THROUGH
TONIGHT.
BEHIND THE COLD FRONTAL PASSAGE EARLY THURSDAY MORNING,
WINDS VEER TO THE NORTHWEST AND 850MB TEMPERATURES ABOVE LAKE
SUPERIOR LOWER BETWEEN -10 TO -13C, SUPPORTING LIGHT LAKE EFFECT
SNOW FOR THE NW SNOWBELTS. LAKE EFFECT SNOW WILL BE SHORT LIVED,
HOWEVER, AS A BRIEF PERIOD OF RIDGING ALOFT AND DRIER AIR WORKS ITS
WAY IN ACROSS THE LAKE THURSDAY AFTERNOON, LOWERING INVERSION
HEIGHTS AND TAPERING OFF LES FROM WEST TO EAST. CONSIDERING LIGHT
QPF AND FLUFFIER SLRS CLOSER TO 20:1, AN ADDITIONAL 1-3" IS POSSIBLE
ACROSS THE KEWEENAW AND NW SNOWBELT BETWEEN MUNISING AND THE SOO.
OTHERWISE, SOUTHWEST WINDS OVERNIGHT WILL KEEP TEMPERATURES MOSTLY
ABOVE 10F TONIGHT, MUCH WARMER THAN THE PAST FEW NIGHTS. HIGH
TEMPERATURES TOMORROW ARE EXPECTED TO REMAIN IN THE MID TO UPPER
20S, POSSIBLE CLOSER TO OR ABOVE FREEZING NEAR LAKE MICHIGAN.
LONG TERM /THURSDAY THROUGH TUESDAY/
ISSUED AT 215 AM EST WED JAN 15 2025
THE EXTENDED PERIOD WILL INCLUDE RIDGING MOVING UP THE WEST COAST
WITH DOWNSTREAM TROUGHING ACROSS THE EASTERN HALF TO 2/3 OF
CANADA/CONUS. WITHIN THIS REGIME, UPPER MICHIGAN WILL BE EXPOSED TO
A SHORTWAVE/COLD FRONT DROPPING SOUTHEAST THROUGH ONTARIO LATE
FRIDAY INTO FRIDAY NIGHT. BEHIND THIS FRONT, A VERY COLD AIRMASS
WILL STRETCH SOUTH ACROSS THE GREAT LAKES FOR THE WEEKEND AND NEXT
WEEK. HOMEOWNERS AND PROPERTY MANAGERS WHO'VE HAD ISSUES WITH WATER
PIPES FREEZING DURING PERIODS OF VERY COLD CONDITIONS SHOULD
CONSIDER MAKING PREPARATIONS NOW. CURRENT THINKING IS FOR AN
EXTENDED PERIOD OF DAILY SUBZERO TEMPS IN THE INTERIOR WEST AND NEAR
ZERO HIGHS IN THE EAST. THESE TEMPERATURES AND THE LACK OF DAYTIME
HEATING COULD RESULT IN WATER SUPPLY PIPES FREEZING, ESPECIALLY IN
AREAS WITH VERY LITTLE SNOW COVER. ADDITIONALLY, THE ARCTIC AIR WILL
WORK AGAINST LARGE SNOW FLAKE GROWTH. INSTEAD OF BIG FAT DENDRITES,
FINER/POWDERY TYPE SNOW IS EXPECTED THIS WEEKEND. THIS KIND OF SNOW
IS VERY EFFECTIVE AT BLOWING AROUND AND REDUCING VISIBILITIES. MINI
WHITEOUTS AND VERY HAZARDOUS TRAVEL SHOULD BE EXPECTED SATURDAY
THROUGH AT LEAST TUESDAY IN THE NORTHWEST WIND SNOW BELTS,
PARTICULARLY AS VEHICLES PASS EACH OTHER.
LAKE EFFECT SNOW WILL CONTINUE THURSDAY DOWNWIND OF LAKE SUPERIOR;
BUT INCOMING SURFACE RIDGE AND DRY AIR WILL WORK AGAINST SIGNIFICANT
ACCUMULATIONS AND SUPPORTING A DIMINISHING TREND FROM WEST TO EAST
THROUGH THE DAY. I WOULD ALSO EXPECT A BLUSTERY DAY IN THE KEWEENAW,
WITH NORTHWEST WINDS POTENTIALLY ABOVE 30 MPH DURING THE MORNING
HOURS. AS THE RIDGE BUILDS INTO THE REGION THOUGH, WINDS SHOULD
GRADUALLY RELAX DURING THE AFTERNOON. MILD TEMPS ARE EXPECTED DURING
THE DAY, WITH MANY ACROSS THE REGION POTENTIALLY CLIMBING TO NEAR 30
OR BREAKING INTO THE LOW 30S.
ON FRIDAY, ANOTHER CLIPPER AND COLD FRONT WILL PRESS OUT OF CANADA
TOWARD THE REGION. GUIDANCE CONTINUES TO HANDLE THE CLIPPER'S
PASSAGE WELL, PRESENTING A CONSENSUS OF THE LOW PRESSING THROUGH
ONTARIO, WHICH SENDS A COLD FRONT THROUGH UPPER MICHIGAN FRIDAY
EVENING INTO FRIDAY NIGHT. THE FRONT ITSELF APPEARS TO STRUGGLE
OVERCOMING THE DRY AIR BUILDING IN THURSDAY, SO IMPACTFUL SNOW ISN'T
EXPECTED AT THIS TIME. WELL UPSTREAM, RIDGING IS EXPECTED TO FURTHER
BUILD UP THE WEST COAST INTO THE ARCTIC, WHICH WILL ENABLE ARCTIC
AIR TO SINK SOUTH THROUGH CANADA AND INTO UPPER MICHIGAN DURING THE
DAY SATURDAY. THE GRAND ENSEMBLE VERSION OF THE LREF SUGGESTS 30-80%
CHANCE OF 850MB TEMPS FALLING TO AT LEAST -30C ACROSS THE WEST HALF
AND NEAR 100% CHANCE OF 850MB TEMPS FALLING TO AT LEAST -25C ACROSS
THE ENTIRE FORECAST THROUGH AT LEAST TUESDAY MORNING. THIS HAS THE
POTENTIAL OF SUBZERO HIGHS AND LOWS FOR THE WESTERN INTERIOR
SATURDAY NIGHT THROUGH TUESDAY MORNING WHILE ELSEWHERE, SINGLE DIGIT
HIGHS ABOVE ZERO AND NEAR ZERO OR SINGLE DIGIT BELOW ZERO LOWS
SHOULD BE EXPECTED. COLDEST CONDITIONS LOOK TO BE SUNDAY AND MONDAY
NIGHTS WHICH COULD RESULT IN THE ENTIRE FORECAST AREA FALLING BELOW
ZERO AND MANY INTERIOR LOCATIONS BETWEEN -10 AND -20F. DURING THIS
COLD SNAP, EVEN MINOR WINDS COULD RESULT IN CONDITIONS FEELING LIKE -
15 TO -35F. IF WE END UP EXPERIENCING MULTIPLE SUBZERO OR NEAR ZERO
DAYS, INCREASING FROST DEPTH OR SUB-OPTIMAL INSULATION MAY RESULT IN
PIPES FREEZING, PARTICULARLY IN AREAS WITH LITTLE SNOW PACK.
THE COLD AIR WILL BE MORE THAN ENOUGH TO GENERATE LAKE EFFECT SNOW
SHOWERS INTO NEXT WEEK. THE ANTICIPATED TEMPERATURES WILL RESULT IN
A STRONG THERMAL GRADIENT BETWEEN THE LAKES AND LAND, WHICH WILL
HELP SOUTHWEST FLOW TO DEVELOP OFF NORTHWEST WISCONSIN AND MARQUETTE
COUNTIES AND NORTHEAST FLOW OFF ONTARIO. EXPECTING THESE TO ENHANCED
CONVERGENCE AND STRONG SNOW BANDING INTO ONTONAGON/HOUGHTON
COUNTIES, EASTERN MARQUETTE/ALGER COUNTIES, AND LUCE COUNTY. THE
COLD AIR WILL ALSO POSITION THE DGZ AT OR BELOW THE GROUND, WHICH
WOULD RESULT IN FINE, COLUMNAR AND PLATE-LIKE SNOW CRYSTALS THAT ARE
MORE SUSCEPTIBLE TO BLOWING IN THE WIND. THIS WILL SUPPORT HAZARDOUS
TO VERY HAZARDOUS DRIVING CONDITIONS WITHIN SNOW SHOWERS NEAR LAKE
SUPERIOR.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1217 PM EST WED JAN 15 2025
BRIEF WINDOW OF CLEARING IS QUICKLY GIVING WAY TO HIGH AND MID
CLOUDS ASSOCIATED WITH THE NEXT CLIPPER SYSTEM. BANDS OF SNOW
SHOWERS ARE ONGOING ACROSS NORTHERN MINNESOTA AND WILL APPROACH
THE WESTERN PORTIONS OF THE AIRSPACE IN THE NEXT 4 OR SO HOURS.
MVFR CEILINGS WILL QUICKLY WASH IN FROM THE WEST IN THE 22-00Z
TIMEFRAME - WITH THE ACCOMPANIED SNOW SHOWERS. THE GREATEST
CHANCE FOR SNOW WILL BE NEARER LAKE SUPERIOR WITH THE FIRST WAVE
OF FORCING - AND ADDITIONAL LAKE-ENHANCEMENT FOR CMX. THE SNOW
ASSOCIATED WITH THE SURFACE LOW OVERNIGHT WILL AFFECT ALL THREE
TERMINALS, WITH THE GREATEST INTENSITY STILL TIED TO THE LAKE-
ENHANCED RESPONSE (LESS THAN 1SM AT CMX). SOUTHWEST WINDS WILL
BE OCCASIONALLY BE GUSTY DURING THE DAYLIGHT HOURS THEN PICK UP
IN EARNEST AS THE SYSTEM APPROACHES AFTER SUNSET. FURTHERMORE,
EXPECTING GUSTS TO AROUND 30KTS IN THE LAKE MODIFIED AIRMASS
OVERNIGHT INTO EARLY THURSDAY- WITH SLIGHTLY REDUCED SPEEDS
FARTHER INLAND AT SAW.
MARINE
ISSUED AT 215 AM EST WED JAN 15 2025
MULTIPLE PASSING CLIPPERS WILL RESULT IN A STRONG PRESSURE GRADIENT
AT OVER THE LAKE AT TIMES IN THIS PERIOD, FOLLOWED BY CONTINUED AND
DEEPENING COLD AIR BUILDING OVER THE REGION THIS WEEKEND AND NEXT
WEEK.
TODAY, A CLIPPER WILL ROLL SOUTHEAST ALONG THE COAST OF HUDSON BAY,
WHICH WILL AMPLIFY THE PRESSURE GRADIENT OVER LAKE SUPERIOR AHEAD OF
ITS FRONT. ENSEMBLE SYSTEMS CONTINUE TO SUGGEST HIGH PROBABILITIES
(>75%) FOR SOUTHWEST GALES ACROSS THE WESTERN HALF OF LAKE SUPERIOR.
WHILE THE ENTIRE SPECTRUM OF DETERMINISTIC GUIDANCE IS WITHIN OR
NEAR THE GALE RANGE, EXACTLY HOW HIGH IS STILL UP FOR DEBATE. THERE
HAS BEEN A SLIGHT DECREASING TREND BETWEEN LAST NIGHT AND TONIGHT'S
GUIDANCE, BUT THE WARM NATURE OF THE LAKE AND ANTICIPATED PRESSURE
GRADIENT STILL SUGGESTS POTENTIAL FOR 40-45KTS. NO CHANGES WERE MADE
TO THE INHERITED GALE WARNING FOR TODAY. WINDS BECOME MORE WESTERLY
TONIGHT WEDNESDAY AND THEN NORTHWESTERLY THURSDAY.
WINDS SWING BACK AROUND TO THE SOUTH FRIDAY AHEAD OF THE NEXT
SHORTWAVE AND COLD FRONT. CURRENT THINKING IS FOR WINDS TO INCREASE
TO NEAR 30 KNOTS LAKE-WIDE. CONFIDENCE IS GROWING ON A SOUTHERLY
GALE EVENT LAKE-WIDE, PERHAPS A HIGH END GALE EVENT IN THE EAST HALF
PRIOR TO THE FRONT PRESSING WEST TO EAST THROUGH THE LAKE DURING THE
DAY FRIDAY. AT THIS POINT, PROBABILITY FOR THIS IS ABOUT 50%. AFTER
THE FRONT, CONTINUED PRESSURE GRADIENT FORCES AND COLD AIR WILL
SUPPORTED THE CONTINUED RISK FOR GALES UNDER NORTHWEST FLOW. VERY
COLD AIR WILL POUR OVER THE UPPER GREAT LAKES AFTERWARDS AND LINGER
INTO NEXT WEEK, LIKELY SUPPORTING WINDS 25-30KTS IN MANY LOCATIONS
ACROSS THE LAKE.
THESE STRONGER WINDS AND INCREASING COLDER AIR OVER THE REGION WILL
SUPPORT PERIODS WHERE ICE GROWTH FROM FREEZING SPRAY WILL BE
POSSIBLE. EXPECTING LOW TO MODERATE FREEZING SPRAY RATES PRIMARILY,
BUT THE INCREASINGLY COLDER AIR BUILDING INTO THE REGION THIS
WEEKEND MAY SUPPORT HEAVY FREEZING SPRAY RATES.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR
LSZ162.
GALE WARNING UNTIL 1 AM EST /MIDNIGHT CST/ THURSDAY FOR
LSZ241>244-263-264.
GALE WATCH FROM FRIDAY MORNING THROUGH SATURDAY AFTERNOON FOR
LSZ241>244-263-264.
GALE WATCH FROM FRIDAY MORNING THROUGH SATURDAY AFTERNOON FOR
LSZ249>251-266-267.
LAKE MICHIGAN...
NONE.
SHORT TERM...BW
LONG TERM...JTP
AVIATION...LC
MARINE...JTP
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