877
FXUS63 KMQT 192052
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
352 PM EST SUN JAN 19 2025
KEY MESSAGES
- DANGEROUSLY COLD ARCTIC AIR SETTLES INTO THE AREA THIS WEEKEND
INTO EARLY NEXT WEEK, LEADING TO TEMPERATURES REMAINING
SUBZERO FROM TONIGHT THROUGH AT LEAST TUESDAY MORNING OVER THE
INTERIOR WEST HALF OF UPPER MICHIGAN. MUCH 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 TODAY 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 TONIGHT/
ISSUED AT 344 PM EST SUN JAN 19 2025
BITTER COLD TEMPERATURES AND LAKE EFFECT SNOW ACROSS THE NORTHWEST
WIND SNOW BELTS CONTINUE TO BE THE MAIN STORY THROUGH TONIGHT. BROAD
MID-LEVEL TROUGHING PATTERN OVER MUCH OF THE CONUS WILL CONTINUE
ADVECTING ARCTIC AIR INTO UPPER MICHIGAN. CURRENT GROUND-BASED OBS
ARE REPORTING -8 DEGREES AND -4 DEGREES IN IRONWOOD AND WAKEFIELD,
RESPECTIVELY, WITH MUCH OF THE WESTERN TWO-THIRDS OF THE FORECAST
AREA IN THE SINGLE DIGITS BELOW ZERO. ELSEWHERE, THE EASTERN THIRD
OF THE U.P. IS GENERALLY IN THE SINGLE DIGITS ABOVE ZERO AT THIS
TIME. WITH 850 MB TEMPERATURES PLUMMETING TO THE -30C MARK TONIGHT,
SURFACE TEMPERATURES WILL BECOME ESPECIALLY DANGEROUS. ALL OF UPPER
MICHIGAN WILL BE BELOW ZERO TONIGHT WITH THE INTERIOR WEST NEAR
-20F. SO, COLD ADVISORIES REMAIN IN PLACE ACROSS ALL OF UPPER
MICHIGAN. IF YOU MUST GO OUTSIDE TODAY, DRESS WARMLY IN LAYERS
AND MAKE SURE TO HAVE A WINTER SURVIVAL KIT IN YOUR VEHICLE IN
CASE OF EMERGENCY. LIMIT EXPOSURE OUTSIDE FOR YOU, YOUR FAMILY,
AND YOUR PETS!
IN ADDITION TO THE FRIGID TEMPERATURES, LAKE EFFECT SNOW WILL
CONTINUE TO IMPACT ALGER AND LUCE COUNTIES WITH STRONG LOW-LEVEL
CONVERGENCE SUPPORTING 3 TO 6 INCHES (LOCALIZED AMOUNTS UP TO
10 INCHES) OF ACCUMULATION THROUGH TONIGHT. DUE TO THE
FINE/POWDERY COMPOSITION OF THE SNOW, WHITEOUT CONDITIONS HAVE
BEEN OCCURRING OVER PORTIONS OF M-28 AND WILL CONTINUE TO DO SO
THROUGH THE NIGHT. AND, DUE TO AN UPTICK IN SNOW ACCUMULATIONS
WITH LATEST GUIDANCE ACROSS THE WESTERN COUNTIES OF ONTONAGON
AND NORTHERN HOUGHTON, A WINTER WEATHER ADVISORY HAS BEEN ISSUED
FOR THOSE COUNTIES AS WELL THROUGH MONDAY NIGHT. 2 TO 4 INCHES
OF SNOW ACCUMULATION IS POSSIBLE THROUGH TONIGHT ACROSS THAT
WESTERN SECTOR.
LONG TERM /MONDAY THROUGH SATURDAY/
ISSUED AT 458 AM EST SUN JAN 19 2025
BY 12Z MONDAY, 500MB RIDGING WILL HAVE SHIFTED OVER BRITISH
COLUMBIA AND NORTHWEST TERRITORIES, CONTINUING 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 -30 DAM 500MB HEIGHT ANOMALY OVER THE UP
BY 12Z MONDAY, GOOD ENOUGH FOR BELOW THE 2.5TH PERCENTILE OF
THE NAEFS CLIMATOLOGY. THE HREF MEAN 850MB TEMPERATURE WILL BE
AROUND THE -30C MARK MONDAY (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 MONDAY. SIMILAR IF NOT SLIGHTLY COOLER HIGH
TEMPERATURES ARE EXPECTED 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 INTERIOR WEST TUESDAY MORNING AND
VARIOUS MOS GUIDANCE CALLING FOR AS LOW AS -27F 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 (A TRAIN
OF 1040-1050MB SHORTWAVE HIGHS 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. 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. ONE IMPORTANT NOTE WITH THIS HAZARDOUS WIND CHILL IS
THAT FOR MULTIPLE DAYS, THE DAYTIME WIND CHILL VALUES WILL STILL
BE IN THE NEGATIVE TEENS TO NEGATIVE 20S, SO NO REPRIEVE IS
EXPECTED WHEN THE SUN COMES UP, PUTTING SOME VULNERABLE
POPULATIONS EVEN FURTHER AT RISK AS IT BECOMES MUCH MORE
DIFFICULT TO JUST "RIDE IT OUT". IMPACTS TO PEOPLE, PETS, PIPES,
AND PLANTS ARE EXPECTED, SO TAKE PRECAUTIONS IF ANY OF THE
ABOVE APPLY. DUE TO CONTINUED HIGH CONFIDENCE IN WIND CHILLS AS
LOW AS -45 IN THE INTERIOR WEST BY TUESDAY MORNING, EXTREME COLD
WARNINGS WILL BE ISSUED WITH THIS FORECAST PACKAGE IN ADDITION
TO THE ONGOING COLD WEATHER ADVISORIES.
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 PRESENT. SUCH FRIGID
AIRMASSES WILL SUPPORT TINY CRYSTALS AS EVEN THE BOUNDARY LAYER WILL
BE COLDER THAN THE DGZ, BRINGING EXPECTED QPF TO NEAR 10:1. QPF
VALUES ARE NOT EXPECTED TO BE EXTREME WITH SUCH A COLD AIRMASS NOT
BEING ABLE TO HOLD MUCH WATER CONTENT, AS THE HREF MEAN ONLY SHOWS
ABOUT 0.07"-0.12"/24-HR QPF RATES. SLIGHTLY BETTER QPF RATES MIGHT
LOCALLY BE REALIZED OVER THE EAST WHERE CAMS SHOW A REMNANT "SURFACE
INVERTED TROUGH"-LIKE FEATURE THAT IS EXPECTED TO BRING BETTER
CONVERGENCE FOR THE BANDS. THIS RESULTS IN SNOWFALL RATES OF AROUND
1"/6 HR BROADLY ALONG THE SPINE OF THE KEWEENAW AND 2-3"/6HR RATES
OVER THE EASTERN LAKE SUPERIOR SHORES. AS SUCH, A WINTER WEATHER
ADVISORY CONTINUES FOR A PORTION OF THE EASTERN UP THROUGH MONDAY.
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 70+% CHANCE OF SUB-QUARTER MILE
VISIBILITY THROUGH MONDAY AND INTO TUESDAY FOR THE KEWEENAW WITH
LESSER VIS RESTRICTIONS EXPECTED ELSEWHERE.
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. ENSEMBLES
ARE INCREASING IN CONFIDENCE IN A SHORTWAVE PIVOTING FROM THE JUNEAU
VICINITY MONDAY AFTERNOON TO THE DAKOTAS BY WEDNESDAY MORNING, WITH
THE GEFS SHOWING A CLUSTER OF WEAKENING CLIPPER SURFACE LOWS LATE
WEDNESDAY INTO THURSDAY OVER THE UP. WHILE SYNOPTIC PRECIPITATION IS
POSSIBLE WITH THAT POTENTIAL SYSTEM, BLOCKING FROM VARIOUS SYNOPTIC
SYSTEMS FAR TO THE SOUTH AND EAST WILL BLOCK MOISTURE TRANSPORT FROM
EFFECTIVELY REACHING THE UP, LIMITING QPF POTENTIAL. 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, SOME EARLY
INDICATIONS IN THE ENSEMBLES SHOW ANOTHER POTENTIAL CLIPPER LOW
AROUND SATURDAY MORNING, BUT UNCERTAINTY IS UNDERSTANDABLY HIGH. THE
GENERAL PATTERN REMAINS LARGELY UNCHANGED FROM PRIOR EXPECTATIONS
WITH CONTINUED COOL AIR ALOFT SUPPORTING FAVORABLE CONDITIONS FOR
POST-CLIPPER LES.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1254 PM EST SUN JAN 19 2025
FLIGHT RESTRICTIONS CONTINUE AT ALL TAF SITES DUE TO LAKE EFFECT
SNOW AND BLOWING SNOW, BUT WORST CONDITIONS REMAIN AT IWD AND CMX.
IWD WILL MAINLY TREND TOWARD MVFR WITH PERIODS OF IFR, WHILE CMX
WILL PREVAIL AT IFR AND FURTHER DETERIORATE TO LIFR AT TIMES.
MEANWHILE, MVFR CONDITIONS AT SAW SHOULD IMPROVE TO VFR LATER
TODAY WHERE THE LAKE EFFECT IS NOT AS PREDOMINANT. STRONG
NORTHWEST WINDS GUSTING TO 20-25 KTS WILL CONTINUE THE BLOWING
SNOW/REDUCED VISIBILITY THREAT AT IWD AND CMX.
MARINE
ISSUED AT 458 AM EST SUN JAN 19 2025
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 AND AGAIN OVER THE
WEEKEND, IN WHICH CASE GALES TO 35 KNOTS BECOME POSSIBLE, BUT
PROBABILITIES AT THIS TIME ARE ONLY AROUND 20-30%.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
COLD WEATHER ADVISORY UNTIL 1 PM EST TUESDAY FOR MIZ001.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
TUESDAY FOR MIZ002-003.
COLD WEATHER ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING
TO 10 PM EST /9 PM CST/ MONDAY FOR MIZ002-004-005-007-
011>013-084.
EXTREME COLD WARNING FROM 10 PM EST /9 PM CST/ MONDAY TO 1 PM
EST /NOON CST/ TUESDAY FOR MIZ002-004-005-011>013-084.
COLD WEATHER ADVISORY UNTIL 4 AM EST TUESDAY FOR MIZ003.
EXTREME COLD WARNING FROM 4 AM TO 1 PM EST TUESDAY FOR MIZ003.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ006-007-
085.
COLD WEATHER ADVISORY FROM 10 PM THIS EVENING TO 1 AM EST
TUESDAY FOR MIZ006-014-085.
EXTREME COLD WARNING FROM 1 AM TO 1 PM EST TUESDAY FOR MIZ006-
014-085.
COLD WEATHER ADVISORY UNTIL 4 AM CST MONDAY FOR MIZ009-010.
EXTREME COLD WARNING FROM 4 AM MONDAY TO NOON CST TUESDAY FOR
MIZ009-010.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ TUESDAY
FOR LSZ162-240>251-263>267.
LAKE MICHIGAN...
NONE.
SHORT TERM...TDUD
LONG TERM...GS
AVIATION...TDUD
MARINE...GS
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