733
FXUS63 KMQT 170510
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1210 AM EST MON FEB 17 2025
KEY MESSAGES
- NORTHWEST FLOW LAKE EFFECT SNOW CONTINUES FOR THE NEXT FEW
DAYS, HEAVIEST TONIGHT THROUGH MONDAY NIGHT. OVER WESTERN
UPPER MI, ONTONAGON COUNTY WILL BE FAVORED FOR MOST PERSISTENT
HEAVIER SNOW, UP TO AROUND 1 FOOT TONIGHT THROUGH MONDAY
NIGHT. OVER THE EAST, ALGER, NORTHERN SCHOOLCRAFT AND LUCE
COUNTIES WILL BE FAVORED FOR HEAVIER SNOW. SNOW ACCUMULATIONS
OF 10 TO 20 INCHES TONIGHT THROUGH MONDAY NIGHT, GREATEST
BETWEEN GRAND MARAIS AND SENEY.
- GUSTY NORTHWEST WINDS WILL CREATE AREAS OF BLOWING AND
DRIFTING SNOW. BRIEF WHITEOUTS EXPECTED IN ALGER COUNTY,
PARTICULARLY ALONG M-28 WHERE THE ROAD IS EXPOSED TO WINDS OFF
OF LAKE SUPERIOR.
- COLD CONDITIONS FOR THE NEXT FEW DAYS. LOW TEMPERATURES
MOSTLY ZERO TO AROUND 10 BELOW TONIGHT THROUGH TUESDAY NIGHT.
WIND CHILLS 15 BELOW TO 25 BELOW INTERIOR WESTERN UPPER
MICHIGAN MONDAY MORNING AND TUESDAY MORNING.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 243 PM EST SUN FEB 16 2025
UPPER AIR PATTERN CONSISTS OF A 500 MB CLOSED LOW NEAR LAKE WINNIPEG
AND A TROUGH OVER THE UPPER GREAT LAKES. THE CLOSED LOW HEADS SLOWLY
SOUTHEAST INTO WESTERN ONTARIO BY 12Z MON JUST NORTH OF
INTERNATIONAL FALLS. LAKE EFFECT SNOW WILL CONTINUE FOR THIS
FORECAST PERIOD WITH WINDS BECOMING NORTHWEST. NORTHWEST WIND
AFFECTED LAKE EFFECT SNOWBELTS WILL COME INTO PLAY THIS FORECAST
PERIOD WHERE THE HEAVIEST SNOW WILL BE. COUPLE OF THINGS TO BE
CONCERNED ABOUT FOR THIS FORECAST. FIRST IS THE LAKE EFFECT SNOW
WILL CONTINUE OVERNIGHT. WITH NORTHWEST WINDS OCCURRING, STRONG
DIRECTIONAL CONVERGENCE SETS UP WHICH WILL CAUSE SOME STRONG LAKE
EFFECT SNOW BANDS TO MOVE ACROSS ONTONAGON, ALGER AND NORTHERN
SCHOOLCRAFT COUNTIES AND THE WINTER STORM WARNING LOOKS GOOD STILL.
ADVISORY AREAS LOOK GOOD AS WELL WHERE THEY ARE. SECOND ISSUE IS
POSSIBLE APPARENT AIR TEMPERATURE VALUES. WITH NORTHWEST WINDS, THIS
WILL TEND TO CAUSE LAKE EFFECT CLOUDS TO CONTINUE TO MOVE INLAND.
THE WIND DOES NOT LOOK TO DECOUPLE TONIGHT, SO IDEAL RADIATIONAL
COOLING DOES NOT SET UP. THINK CLOUD COVER WILL BE PERSISTENT ENOUGH
OVER THE WEST COMBINED WITH THE WIND WHICH WILL KEEP APPARENT
TEMPERATURES ABOVE -25F, SO NO COLD ADVISORY WILL BE NEEDED. A FEW
PLACES WILL GET CLOSE THOUGH.
LONG TERM /MONDAY THROUGH SUNDAY/
ISSUED AT 423 PM EST SUN FEB 16 2025
SIGNIFICANT POSITIVE HEIGHT ANOMALIES HAVE RECENTLY DOMINATED THE
ARCTIC, DISLODGING ARCTIC AIR SOUTHWARD AS NEGATIVE HEIGHT ANOMALIES
TEND TO DOMINATE TO THE S TOWARD THE MID-LATITUDES IN THIS TYPE OF
SITUATION. THAT INCLUDES CANADA WHERE AN EXPANSIVE ARCTIC AIR MASS
STILL CURRENTLY RESIDES. WIDESPREAD -20S AND -30S F WERE OBSERVED
EARLY THIS MORNING ACROSS THE PRAIRIE PROVINCES INTO NORTHERN
ONTARIO. A -51F WAS EVEN NOTED IN NORTHERN SASKATCHEWAN. THIS ARCTIC
AIR IS SPILLING ACROSS THE INTERNATIONAL BORDER INTO THE NORTHERN
PLAINS AND UPPER MISSISSIPPI VALLEY. THE ARCTIC POSITIVE HEIGHT
ANOMALIES ARE CURRENTLY BREAKING DOWN AND ARE ON THE MOVE. ONE PIECE
WILL DROP S TO HUDSON BAY, FORCING NEGATIVE HEIGHT
ANOMALIES/TROFFING S INTO THE GREAT LAKES THRU TUE. THIS WILL
SUPPORT THE MODERATING CORE OF ARCTIC AIR PUSHING THRU THE UPPER
MISSISSIPPI VALLEY INTO THE GREAT LAKES REGION. SO, FOR UPPER MI,
BLO NORMAL TEMPS WILL PREVAIL THRU WED WITH THE COLDEST DAY LIKELY
ON MON. THEREAFTER, A TREND TOWARD POSITIVE HEIGHT ANOMALIES
EXPANDING ALL ALONG THE VCNTY OF THE INTERNATIONAL BORDER WILL LEAD
TO A WARMING TREND DURING THE LAST HALF OF THE WEEK, BRINGING TEMPS
BACK TO AROUND NORMAL OR A LITTLE ABOVE NORMAL BY THE WEEKEND. AS
FOR PCPN, THE EVOLVING PATTERN WILL NOT BE FAVORABLE FOR ANY SYSTEM
SNOWS THIS WEEK. THE LACK OF SYSTEM SNOWS FOR UPPER MI HAS BEEN A
THEME OF THIS WINTER, JUST LIKE IT WAS LAST WINTER. THE ARCTIC AIR,
HOWEVER, WILL SUPPORT LES THROUGH ABOUT THU MORNING.
BEGINNING MON, FCST SOUNDINGS SHOW INVERSION HEIGHTS AROUND 7-8KFT
AS MID-LEVEL LOW CURRENTLY OVER SOUTHERN MANITOBA SHIFTS OVER LAKE
SUPERIOR WHILE OPENING UP. COMBINED WITH 850MB TEMPS RANGING FROM
AROUND -23C OVER EASTERN LAKE SUPERIOR TO AROUND -28C OVER WESTERN
LAKE SUPERIOR, EXPECT VIGOROUS LES UNDER NORTHWESTERLY LOW-LEVEL
FLOW. MODELS OVER THE LAST 24HRS HAVE BEEN VERY CONSISTENT IN
SHOWING STRONG LOW-LEVEL CONVERGENCE OFF OF WESTERN LAKE SUPERIOR
INTO ONTONAGON COUNTY TONIGHT LINGERING THRU MON MORNING BEFORE
WEAKENING, BUT STILL REMAINING THRU THE AFTN. TO THE E, ANOTHER AREA
OF STRONG LOW-LEVEL CONVERGENCE PERSISTS THRU THE DAY AND HOLDS
NEARLY STEADY ACROSS EASTERN ALGER COUNTY, NE SCHOOLCRAFT COUNTY AND
WESTERN LUCE COUNTY. IN BOTH OF THESE AREAS, EXPECT HVY LES, BUT IT
WILL BE MOST PERSISTENT THRU THE ENTIRE DAY IN THE LATTER AREA. IN
ONTONAGON COUNTY, ANOTHER 2-5 TO LOCALLY 6 INCHES OF SNOW IS LIKELY
ON MON. IN EASTERN ALGER, NE SCHOOLCRAFT AND WESTERN LUCE, 8-12
INCHES OF NEW SNOW IS EASILY ACHIEVABLE DURING THE DAY MON. IF THE
CONVERGENCE BECOMES HIGHLY FOCUSED AND STATIONARY, ACCUMULATIONS ON
MON COULD REACH 12-16 INCHES IN A SMALL LOCALIZED AREA. ACROSS THE
REST OF THE EASTERN FCST AREA AFFECTED BY NW FLOW LES, EXPECT 2-5
INCHES OF SNOW IN GENERAL. OVER WESTERN UPPER MI, EXPECT 1-3 INCHES
OF SNOW OUTSIDE OF ONTONAGON COUNTY. WITH THE OPENING UP MID-LEVEL
LOW ARRIVING, EXPECT SOME DIURNAL COMPONENT -SHSN, RESULTING IN
-SHSN/FLURRIES EXTENDING WELL INLAND IN THE AFTN. WITH TEMPS OF -5
TO -10F IN THE MORNING ACROSS THE INTERIOR W AND WINDS 5-10MPH, WIND
CHILLS WILL BE -18 TO -25 RANGE, NOT QUITE TO COLD WEATHER ADVY
CRITERIA OF WIDESPREAD -25 OR LOWER. AFTERNOON HIGH TEMPS WILL RANGE
FROM THE LOWER SINGLE DIGITS ABOVE 0F INTERIOR W TO AROUND 10F ABOVE
S CENTRAL AND E.
INVERSIONS GRADUALLY BEGIN TO FALL DURING MON NIGHT AS TROFFING
WEAKENS/HEIGHTS RISE OVER THE AREA. SO, SNOWFALL RATES WILL ALSO
BEGIN TO EASE. THE LOW-LEVEL CONVERGENCE ZONE INTO ONTONAGON COUNTY
REMAINS NEARLY STATIONARY DURING MON NIGHT. TO THE E, THE LOW-LEVEL
CONVERGENCE ZONE INTO EASTERN ALGER/NORTHERN SCHOOLCRAFT/LUCE
COUNTIES ALSO REMAINS NEAR STATIONARY. AS A RESULT, THOSE AREAS WILL
CONTINUE TO SEE THE HEAVIER, MOST PERSISTENT SHSN, ABOUT 2-4 INCHES
OF NEW SNOW W AND 4-7 E. OUTSIDE OF THOSE FAVORED CONVERGENCE ZONES,
THE ONGOING NW FLOW LES WILL LEAVE ANOTHER 1-3 INCHES OF NEW SNOW
DURING MON NIGHT. TEMPS BY EARLY TUE MORNING WILL BE DOWN NEAR -10F
IN THE INTERIOR W WITH WIND CHILLS AGAIN DOWN IN THE -18 TO -25
RANGE.
INVERSIONS SETTLE IN THE 4-6KFT RANGE FOR TUE/WED, LOWEST W, LEADING
TO LIGHTER NW FLOW LES. EXPECT 1-3 TO LOCALLY 4 INCH ACCUMULATIONS
PER 12HRS WITH THE HIGHER ACCUMULATIONS OVER THE E. WINDS
TEMPORARILY VEER A LITTLE MORE NORTHERLY TUE NIGHT AND THEN AGAIN
WED NIGHT INTO THU MORNING, SO THE LES MAY SHIFT TO COVER MORE OF
NORTHERN UPPER MI DURING THOSE TIMES. WAA FROM THE N WILL THEN RAISE
850MB TEMPS TOWARD -10C ON THU, SO LES WILL WIND DOWN AND LIKELY
END. DRY WEATHER EXPECTED FOR AT LEAST FRI WITH BROAD SFC HIGH PRES
RIDGING MOVING ACROSS THE MISSISSIPPI RIVER VALLEY. WAA REGIME AND
UNCERTAIN TIMING OF SHORTWAVES IN WNW FLOW WILL PROBABLY LEAD TO A
LITTLE -SN AT SOME POINT OVER THE WEEKEND. TEMPS FRI THRU THE
WEEKEND WILL BE AROUND NORMAL TO A LITTLE ABOVE NORMAL FOR MID TO
LATE FEB.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 1209 AM EST MON FEB 17 2025
NORTHWESTERLY LAKE EFFECT SNOW WILL CONTINUE FOR THIS FORECAST
PERIOD. CONDITIONS WILL STAY MVFR UNDER SOME LIGHT LAKE EFFECT
SNOW FOR THE MOST PART AT IWD THROUGH THIS MORNING, ALTHOUGH
WITH WINDS SHIFTING VEERING EVER SO SLIGHTLY NORTHWEST LATE IN
THE DAY INTO TONIGHT, STEADY LAKE EFFECT BANDS COULD MOVE IN AND
LOWER VSBY TO IFR. PERSISTENT NORTHWEST WINDS AND GUSTS NEAR 25
KT AT CMX WILL RESULT IN PREVAILING IFR CONDITIONS WITH PERHAPS
SOME LOWER LIFR VSBY FROM BLOWING SNOW. VFR CONDITIONS AT SAW
INTO THE MORNING HOURS COULD TRANSITION TO MVFR DIURNAL CLOUDS
DURING THE DAY ON MONDAY WITH PERHAPS IMPROVEMENT AGAIN TO VFR
MON EVENING.
MARINE
ISSUED AT 423 PM EST SUN FEB 16 2025
NW WINDS OF 20-30KT WILL GENERALLY BE THE RULE ACROSS MUCH OF LAKE
SUPERIOR THRU TUE, STRONGEST ACROSS THE E HALF. SOME GALE FORCE
GUSTS WILL OCCUR INTO MON IN THE AREA GENERALLY BETWEEN GRAND
MARAIS, STANNARD ROCK AND MUNISING. THE GALE GUST POTENTIAL EXPANDS
OVER MORE THE EAST HALF OF THE LAKE DURING MON NIGHT AS PROBABILITY
OF PEAK GUSTS TO 35KT INCREASES TO 50-70PCT. WITH THE BRISK WINDS
AND THE COLD AIRMASS IN PLACE, EXPECT PERIODS OF HEAVY FREEZING
SPRAY THRU TUE. NW TO N WINDS DROP BACK TO MOSTLY BELOW 20KT FOR WED
AND THU.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ MONDAY FOR
MIZ001-003-009-084.
WINTER STORM WARNING UNTIL 7 PM EST MONDAY FOR MIZ002.
WINTER STORM WARNING UNTIL 1 AM EST TUESDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ TUESDAY
FOR LSZ240>251-263>267.
LAKE MICHIGAN...
NONE.
SHORT TERM...07
LONG TERM...ROLFSON
AVIATION...VOSS
MARINE...ROLFSON
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