269
FXUS63 KMQT 181001
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
501 AM EST SAT JAN 18 2025
KEY MESSAGES
- BLUSTERY SOUTHERLY WINDS CONTINUE THIS AFTERNOON, TURNING TO
THE NW TONIGHT BEHIND A PASSING COLD FRONT. WIND GUSTS UP TO
40-50 MPH WILL BE POSSIBLE ACROSS THE KEWEENAW TONIGHT.
- LAKE EFFECT SNOW DEVELOPS ACROSS THE NW WIND SNOW BELTS
TONIGHT, WITH 1-3 IN OF SNOW ACCUMULATIONS BY THE MORNING.
GUSTY WINDS MAY LEAD TO BLOWING SNOW AND REDUCED VISIBILITY.
- DANGEROUSLY COLD ARCTIC AIR SETTLES INTO THE AREA THIS WEEKEND
INTO EARLY NEXT WEEK, LEADING TO TEMPERATURES REMAINING
SUBZERO FROM SATURDAY NIGHT THROUGH AT LEAST TUESDAY MORNING
OVER INTERIOR WESTERN UPPER MICHIGAN. MUCH OF THE REST OF WEST
AND CENTRAL UPPER MICHIGAN MAY SEE TEMPERATURES FAIL TO RISE
ABOVE ZERO ON MONDAY AND MAYBE TUESDAY.
- HOMEOWNERS AND PROPERTY MANAGERS SHOULD TAKE ACTION NOW FOR
THIS COLD PERIOD, ESPECIALLY IF PAST VERY COLD PERIODS HAVE
YIELDED IMPACTS. ENSURE YOUR WINTER CAR SURVIVAL KIT IS UP-TO-
DATE. THIS WEEKEND THROUGH TUESDAY, LIMIT TIME OUTDOORS FOR
YOU AND YOUR PETS, AND CHECK ON VULNERABLE NEIGHBORS.
- FREQUENT WHITEOUTS ARE EXPECTED IN THE NORTHWEST WIND SNOW
BELTS SATURDAY THROUGH TUESDAY MORNING DUE TO THE FALLING SNOW
BEING A FINE, POWDERY TYPE SNOW THAT IS HIGHLY EFFECTIVE AT
REDUCING VISIBILITY. EXPECT VERY HAZARDOUS DRIVING CONDITIONS IN
THE LAKE EFFECT SNOW AREAS.
- NO WIDESPREAD, SIGNIFICANT SNOWFALLS FOR UPPER MI THROUGH NEXT WEEK.
NEARLY ALL OF THE SNOW THAT OCCURS WILL BE LAKE EFFECT DRIVEN.
SHORT TERM /THROUGH SATURDAY/
ISSUED AT 331 PM EST FRI JAN 17 2025
RAP ANALYSIS AND WATER VAPOR IMAGERY REVEAL A CLIPPER SHORTWAVE
SKIRTING ALONG THE MINNESOTA/ONTARIO BORDER INTO NORTHERN LAKE
SUPERIOR WITH A 986MB SFC LOW PRESSURE ANALYZED JUST NORTH OF LAKE
NIPIGON. DESPITE FAIRLY ACTIVE RADAR RETURNS THIS AFTERNOON ACROSS
PORTIONS OF THE SOUTH-CENTRAL AND EAST UP, VERY LITTLE PRECIP HAS
MADE IT TO THE GROUND THANKS TO A DRY LOW LEVEL AIR MASS. WILL NOTE
AN UPTICK IN RADAR RETURNS IN CENTRAL WISCONSIN, HOWEVER WITH DRY
AIR STILL HANGING AROUND CONFIDENCE IS LOW THAT ANY PRECIP SPREADING
INTO THE CENTRAL UP WILL AMOUNT TO ANYTHING AT ALL ASIDE FROM SOME
FLURRIES.
THE MAIN FORECAST CONCERN HEADING INTO TONIGHT AND SATURDAY IS THE
STRONG COLD FRONT CURRENTLY BARRELING THROUGH NORTH-CENTRAL
MINNESOTA. WITH ITS PASSAGE ACROSS THE UP THIS EVENING, WINDS WILL
BACK OUT OF THE NORTHWEST, USHERING IN COLD ARCTIC AIR AND STARTING A
PROLONGED PERIOD OF MUCH BELOW NORMAL TEMPERATURES AND LAKE EFFECT
SNOW. RAPID PRESSURE RISES ~6-9MB/3HR BEHIND THE COLD FRONT ACROSS
WESTERN LAKE SUPERIOR WILL ACCELERATE NORTHWEST WINDS UPWARDS OF 40
TO 50 MPH TONIGHT IN THE KEWEENAW, THUS, HAVE OPTED TO CONTINUE THE
UPCOMING WIND ADVISORY FOR NORTHERN HOUGHTON AND KEWEENAW COUNTIES.
COINCIDING THE WINDS, STRONG CAA ALOFT BRINGS IN 850MB TEMPS NEAR -
17C EAST AND -21C WEST BY SATURDAY MORNING, UPTICKING LAKE EFFECT
SNOW IN THE NORTHWEST SNOWBELTS.
SNOWFALL AMOUNTS WILL BE TRICKY TO NAIL CONSIDERING A FEW FACTORS
WORKING AGAINST EFFICIENT SNOW GROWTH. WITH DECREASING TEMPS THROUGH
THE EARLY MORNING HOURS, THERE WILL ONLY BE A ~6 HOUR PERIOD OF
SOLID LIFT THROUGH THE DGZ BEFORE IT ENDS UP BELOW THE SURFACE. ONCE
THE DGZ FALLS BELOW THE SURFACE, SNOW CRYSTAL HABIT WILL CHANGE TO A
FINE POWDERY TYPE OF SNOW THAT IS TOUGH TO ACCUMULATE, BUT CAN
DRASTICALLY REDUCE VISIBILITY AT TIMES. STRONG NORTHWEST WINDS
DURING THAT PERIOD WILL WORK TO FRACTURE DENDRITES AS THEY FALL,
LOWERING SLRS FURTHER LESSENING SNOW ACCUMULATION AT THE SURFACE.
INCOMING ARCTIC HIGH PRESSURE THROUGH SATURDAY WILL WORK TO LOWER
LAKE INDUCED INVERSION HEIGHTS. ALL OF THIS IS TO SAY THAT SNOW
AMOUNTS IN THE NW SNOW BELTS WILL BE 2" OR LESS PER 6 HOURS THROUGH
SATURDAY, WHERE TOTALS AMOUNTS OF 2-5" ARE POSSIBLE, MAINLY IN
TERRAIN ENHANCED PORTIONS OF THE KEWEENAW AND IN ALGER/LUCE COUNTIES
UNDER THE STRONGEST CONVERGENT BANDS. ELSEWHERE, 1-2" OR LESS IS
EXPECTED WHERE LES BANDS WOBBLE ABOUT.
OTHERWISE, LOOK FOR SURFACE TEMPERATURES TO BEGIN THEIR DECENT AS
ARCTIC AIR FILTERS IN THROUGH THE WEEKEND. LOWS WILL DROP TONIGHT TO
THE SINGLE DIGITS ACROSS THE INTERIOR / TEENS NEAR THE LAKESHORES
AND BARELY CLIMB ANY HIGHER FOR SATURDAY'S EXPECTED HIGHS.
LONG TERM /SUNDAY THROUGH FRIDAY/
ISSUED AT 500 AM EST SAT JAN 18 2025
BY 12Z SUNDAY, THE 500MB RIDGE OVER THE YUKON WILL BE AT ITS PEAK
INTENSITY, WITH RIDGING ALSO BUILDING OVER NEWFOUNDLAND AND
LABRADOR. THIS WILL SET UP AN EXTREMELY EFFICIENT SURGE OF FRIGID
ARCTIC AIR IN THE FORM OF AN ANOMALOUSLY DEEP TROUGH CENTERED OVER
THE UPPER GREAT LAKES, WITH THE GEFS SHOWING A NEARLY -35 DAM 500MB
HEIGHT ANOMALY OVER THE UP BY 06Z MONDAY, GOOD ENOUGH FOR BELOW THE
2.5TH PERCENTILE OF THE NAEFS CLIMATOLOGY. THE HREF MEAN 850MB
TEMPERATURE WILL BE AROUND THE -30C MARK SUNDAY (SLIGHTLY WARMER
VALUES OVER THE EASTERN UP, SLIGHTLY COOLER OVER WESTERN LAKE
SUPERIOR). THIS WILL TRANSLATE INTO SURFACE HIGH TEMPERATURES 50+%
LIKELY TO REMAIN BELOW 0F ON SUNDAY. SIMILAR HIGH TEMPERATURES ARE
EXPECTED MONDAY AND TUESDAY AS 850MB TEMPERATURES WILL NOT CHANGE
MUCH ACCORDING TO THE LREF MEAN. LOW TEMPERATURES WILL TAKE A
TUMBLE, ESPECIALLY OVER THE INTERIOR WEST, WITH THE NBM CALLING FOR
-22F FOR THE TUESDAY MORNING AND VARIOUS MOS GUIDANCE CALLING FOR AS
LOW AS -28F NEAR WATERSMEET. THE SURROUNDING MORNINGS WILL SEE LOWS
IN THE NEGATIVE DOUBLE DIGITS IN THE INTERIOR WEST AND NEGATIVE
SINGLE DIGITS ELSEWHERE, STILL COLD, BUT TUESDAY MORNING WILL BE THE
COLDEST. WITH DOMINANT SURFACE PRESSURE FEATURES FAR FROM THE UP
(1040S MB LOW OVER THE PLAINS, 960S MB LOW OVER NEWFOUNDLAND AND
LABRADOR), PERSISTENT WNW TO NW WINDS GUSTING TO AROUND 20 MPH ARE
EXPECTED. WHILE THOSE WINDS ARE NOT UNUSUAL FOR THIS TIME OF YEAR,
THE COMBINATION WITH THE FRIGID AIR TEMPERATURES WILL PROVIDE SOME
OF THE MOST HAZARDOUS WIND CHILLS SINCE AT LEAST FEB. 2021, IF NOT
JAN. 2019. AT THE LREF-MEAN WIND CHILL OF -44F IN THE IRONWOOD AREA
TUESDAY MORNING, FROSTBITE CAN TAKE PLACE IN 10 MINUTES, HALF AN
HOUR OR LESS FOR MUCH OF THE UP THAT IS EXPECTED TO SEE -20F OR
LOWER WIND CHILLS THROUGH WEDNESDAY MORNING. THESE HAVE ALREADY
PROMPTED COLD WEATHER ADVISORIES TO BE ISSUED AND IF THE WIND AND
TEMPERATURE FORECAST FOR TUESDAY MORNING IN PARTICULAR CONTINUES TO
GAIN CONFIDENCE IN SUCH FRIGID WIND CHILLS, EXTREME COLD WARNINGS
WILL BE NEEDED IN FUTURE PACKAGES. ADDITIONALLY, SUCH COLD AIR
MOVING OVER PARTICULARLY SHALLOW SNOWPACKS (OR IN THE CASE OF THE
SOUTHERN UP, NO SNOW PACK) COULD DRIVE A DEEP FROST DEPTH, WHICH
WOULD INCREASE THE THREAT OF DAMAGE TO PIPES/ETC THAT ARE NOT BURIED
PARTICULARLY DEEPLY, THOUGH FROST DEPTH FORECASTING IS CHALLENGING,
SO TO WHAT DEPTH WOULD BE CONSIDERED "SAFE" IS UNCERTAIN.
OF COURSE, WITH SUCH FRIGID TEMPERATURES ALOFT AND A WIDE-OPEN LAKE
SUPERIOR (ONLY 3-4% ICE COVER PER GLERL AND MOST OF IT IN BLACK BAY,
NIPIGON BAY, THE BAYS NORTH OF SAULT STE MARIE, AND THE APOSTLE
ISLANDS REGION), LAKE EFFECT SNOW WILL BE RAMPANT. SUCH FRIGID
AIRMASSES WILL SUPPORT TINY CRYSTALS AS THE PRECIPITATING LAYER WILL
BE WELL COLDER THAN THE DGZ. QPF VALUES ARE NOT EXPECTED TO BE
EXTREME WITH SUCH A COLD AIRMASS NOT BEING ABLE TO HOLD MUCH WATER
CONTENT, AS THE HREF ONLY SHOWS AROUND 30% CHANCES OF 6-HOURLY QPF
RATES ABOVE 0.2"/6HR IN BANDS MUNISING AND EAST AND DAILY QPF OF
0.15-0.4" ON SUNDAY EXPECTED ELSEWHERE IN NW FLOW LES BANDS. THIS
BROADLY SUPPORTS BORDERLINE WINTER WEATHER ADVISORY IMPACTS,
ESPECIALLY OVER THE EASTERN UP, PROMPTING AN ISSUANCE THIS PACKAGE.
EXTENSIONS IN TIME AND EXPANSIONS TO THE WEST MAY BECOME NECESSARY
IF A BLSN THREAT IS REALIZED WITH SUCH A DRY SNOW WITH TINY
PARTICLES THAT ARE EXTREMELY EFFICIENT AT REDUCING VISIBILITY. THE
EURO ENSEMBLE IS CALLING FOR 50% PROBABILITIES OF NEAR-WHITEOUT
CONDITIONS OVER THE KEWEENAW PENINSULA SUNDAY WITH 80+% CHANCE
OF SUB-QUARTER MILE VISIBILITY THROUGH MONDAY AND INTO TUESDAY.
HIGH PRESSURE SLIDING TO THE SOUTH AND EAST OF THE UP BY WEDNESDAY
WILL SHIFT THE BOUNDARY LAYER WIND PATTERN TO BE MORE SOUTHWESTERLY,
PROVIDING A 1-2 COMBINATION OF SHIFTING LAKE EFFECT BANDS OFFSHORE
AND ADVECTING WARMER SOUTHERN AIR OVER THE UP, GIVING SOME REPRIEVE
TO THE HAZARDOUS CONDITIONS AHEAD TO END THE WEEKEND AND BEGIN THE
WORK WEEK. GRANTED, CHANCES OF HIGH TEMPERATURES REACHING THE
"NORMAL" MARK (AROUND 20) FOR THIS TIME OF YEAR ARE BELOW 30% BEFORE
FRIDAY, BUT AFTER 48-72 HOURS OF SUBZERO TEMPERATURES, WEDNESDAY'S
HIGHS IN THE 11-16 DEGREE RANGE MIGHT JUST FEEL TROPICAL. THE GEFS
SHOWS A SMALL CLUSTER OF CLIPPER LOW POTENTIAL LATE WEDNESDAY INTO
THURSDAY BUT UNCERTAINTY IS HIGH AS ANY LOW FEATURE WOULD BE RUNNING
FACE-FIRST INTO HIGH PRESSURE RESIDING OVER THE EASTERN CONUS.
REGARDLESS OF EXACT SOLUTION, THE LREF SHOWS 925MB FLOW BECOMING 85%
LIKELY TO BE WITHIN 30 DEGREES OF NWERLY BY LATE THURSDAY INTO
FRIDAY WITH GREATER THAN 75% CHANCES OF 850MB TEMPERATURES
SUPPORTIVE OF AN LES PATTERN, A RETURN TO COOLER (BUT NOT FRIGID)
TEMPERATURES AND LES IS EXPECTED TO END THE WORK WEEK. MOVING INTO
NEXT WEEKEND, GENERAL TROUGHING OVER THE EASTERN CONUS WITH RIDGING
OVER THE WEST IS EXPECTED, BUT A PROGRESSIVE PATTERN IS EXPECTED, SO
DESPITE THE SIMILARITIES IN SETUP, A REPEAT OF A SEMI LONG-DURATION
COLD SNAP IS NOT EXPECTED.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1124 PM EST FRI JAN 17 2025
MVFR CONDITIONS WILL CONTINUE AT CMX AND IWD INTO SAT MORNING. AS
LAKE EFFECT SNOW SHOWERS PICK UP, BOTH PLACES WILL DROP INTO IFR.
CMX WILL HAVE EVEN WORSE CONDITIONS WITH BLOWING SNOW WITH THE GUSTY
WINDS AND WILL GET DOWN TO LIFR AND EVEN VLIFR SAT AFTERNOON AND
THEN STAY THERE INTO SAT NIGHT. AT SAW, VFR CONDITIONS WILL RETURN
BEFORE GOING MVFR ON SATURDAY. WITH THE NORTHWEST WINDS THERE, THE
LES WILL STAY MOSTLY TO THE WEST AND EAST OF THE AREA.
MARINE
ISSUED AT 500 AM EST SAT JAN 18 2025
NORTHWEST GALES TO 35 KNOTS ARE EXPECTED TO BECOME MORE ISOLATED
THROUGHOUT TODAY INTO TONIGHT WITH PROBABILITIES OF GALES
TONIGHT ONLY AROUND 30% OVER LAKE SUPERIOR. WITH LARGE-SCALE
SURFACE PRESSURE FEATURES FAR AWAY FROM LAKE SUPERIOR, NORTHWEST
WINDS GUSTING TO AROUND 25 KT WILL BE THE NORM THROUGH TUESDAY.
FRIGID ARCTIC AIR WILL CAUSE PERIODS OF HEAVY FREEZING SPRAY
THROUGHOUT THE WEEKEND AND EARLY PORTION OF NEXT WEEK. HIGH
PRESSURE SLIDING TO THE SOUTH AND EAST WILL CAUSE WINDS TO
BECOME MORE SOUTHWESTERLY WEDNESDAY, REMAINING AROUND 25 KT,
THOUGH WARMING TEMPERATURES AND A CHANGE IN WIND DIRECTION
REDUCING WAVE HEIGHTS SHOULD REDUCE THE FREEZING SPRAY TO LIGHT-
TO-MODERATE. BEYOND THEN, GALES WILL DEPEND ON WHETHER OR NOT A
CLIPPER LOW MATERIALIZES IN THE MID-TO-LATE WEEK PERIOD, IN
WHICH CASE GALES TO 35 KNOTS BECOME POSSIBLE IN THE LATE WEEK
PERIOD, BUT PROBABILITIES AT THIS TIME ARE ONLY AROUND 20-30%.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
COLD WEATHER ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING
TO 10 PM EST /9 PM CST/ MONDAY FOR MIZ001-003-009-010.
COLD WEATHER ADVISORY FROM 10 PM EST /9 PM CST/ SUNDAY TO 10
PM EST /9 PM CST/ MONDAY FOR MIZ002-004>006-011>014-084-
085.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ006-007-085.
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST
SUNDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
GALE WARNING UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR
LSZ162-240>248-263-264.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ SUNDAY
FOR LSZ162-240>242-263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST MONDAY FOR
LSZ243>251-264>267.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ249>251-
265>267.
LAKE MICHIGAN...
NONE.
SHORT TERM...BW
LONG TERM...GS
AVIATION...07
MARINE...GS
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