227
FXUS63 KMQT 191955
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
255 PM EST THU DEC 19 2024
KEY MESSAGES
- A CLIPPER SYSTEM WILL BRING WIDESPREAD LIGHT TO MODERATE SNOW
ACROSS THE UP TODAY THROUGH FRIDAY MORNING. HIGHEST SNOWFALL
TOTALS WILL BE IN MENOMINEE COUNTY WHERE LAKE ENHANCEMENT
COULD PRODUCE UPWARDS OF 6 TO 8 INCHES.
- ANOTHER SYSTEM COULD POTENTIALLY BRING A FEW INCHES OF SNOW ON
MONDAY WITH LIKELY DRIER AND WARMER CONDITIONS AFTER THIS
SYSTEM THROUGH CHRISTMAS WEEK.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 356 AM EST THU DEC 19 2024
NWERLY WIND LES IS ONGOING ACROSS THE EASTERN UP AS EVIDENT ON KMQT
AND CASMR RADAR REFLECTIVITY. REFLECTIVITY VALUES ARE INDICATING
OCCASIONAL SPIKES UP TO 1"/HR SNOWFALL RATES BUT ONLY FOR A FEW
MINUTES AT A TIME. HREF PROBABILITIES OF 0.1" ACCUMULATED QPF BY
NOON EST ARE AROUND 40-60% RIGHT ALONG LAKE SUPERIOR DEERTON AND
EAST. WITH FLUFFY SLRS OF AT LEAST 17:1 OBSERVED WITH THESE BANDS,
ANOTHER HALF INCH TO INCH OF SNOW IS EXPECTED THE REST OF THE
MORNING FOR THE EASTERN THIRD NEAR LAKE SUPERIOR. INLAND PENETRATION
AND INTENSITY OF LES BANDS WILL DECREASE THROUGHOUT THE MORNING AS
WIND SPEEDS DECREASE AND SUBSIDENCE OCCURS IN RESPONSE TO
APPROACHING SURFACE HIGH PRESSURE OF AT LEAST 1030MB OVER THE
NORTHERN SHORES OF LAKE SUPERIOR THROUGH THIS MORNING. MORNING LOWS
HAVE BEEN A TRICKY FORECAST AS THE LOWER LEVEL LAKE-EFFECT CLOUDS
DISSIPATING IN THE WEST HAVE QUICKLY BEEN REPLACED BY A STREAM OF
HIGHER CLOUDS, PREVENTING A COMPLETE CLEARING FOR EFFICIENT
RADIATIONAL COOLING, BUT EVEN STILL, LOWS IN THE SINGLE DIGITS
FOR MUCH OF THE INTERIOR WEST HALF ARE STILL EXPECTED, THOUGH
WIND CHILLS ARE ONLY A COUPLE OF DEGREES LOWER AS WINDS ARE
CALMING DOWN, EVEN TO 00000KT AT THE 08Z OB AT KIWD.
ATTENTION THEN TURNS TO A CLIPPER LOW CURRENTLY OVER WESTERN ND AT
1006MB PER RAP ANALYSIS. ENSEMBLES HAVE FINALLY COALESCED AROUND THE
CHICAGO TRACK, WITH A TIGHT GROUPING OF LOW CENTERS IN THE GEFS AT
AROUND 1015MB BY 06Z FRIDAY. MODEL TRENDS OVER THE LAST 24 HOURS
HAVE SERVED TO SLOW DOWN THE ARRIVAL OF PRECIPITATION, WITH THE
GENERAL ONSET OF SNOWFALL OVER IRONWOOD NOW EXPECTED AROUND 15Z
TODAY, MENOMINEE AROUND 18Z TODAY, AND MUCH OF THE REST OF THE UP BY
21Z. EASTERLY FLOW AHEAD OF THE PASSAGE OF THE LOW WILL CAUSE LAKE-
ENHANCED UPSLOPE FLOW FOR MENOMINEE COUNTY IN PARTICULAR WITH THE
HREF 25TH PERCENTILE PROVIDING A QPF FLOOR OF AROUND A QUARTER OF AN
INCH WITH 75TH PERCENTILE QPF OF AROUND A HALF INCH PROVIDING A
REASONABLE HIGHER-END SOLUTION. WITH SLRS EXPECTED BETWEEN 15 AND 20
TO 1, 8+ INCHES OF SNOW FOR INLAND MENOMINEE COUNTY IS WELL WITHIN
THE REALM OF POSSIBILITY (20-40%). ELSEWHERE, MORE WIDESPREAD
PROBABILITIES OF 4+ INCHES OF SNOW ARE IN THE 20-60% RANGE FOR THE
WESTERN 2/3 OF THE UP. CURRENT WINTER WEATHER HEADLINES REMAIN ON-
TRACK, SO NO CHANGES EXPECTED TO THE TIMING OR LEVEL OF THE HEADLINE
FOR THIS FORECAST PACKAGE.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
ISSUED AT 252 PM EST THU DEC 19 2024
BY 12Z FRIDAY, A WEAKENING SURFACE LOW PRESSURE WILL HAVE TRACKED
INTO THE OHIO RIVER VALLEY WHILE 1040MB HIGH PRESSURE DESCENDS
SOUTHEAST INTO THE NORTHERN PLAINS. THIS WILL WORK TO BACK THE FLOW
ACROSS LAKE SUPERIOR FROM NE TO NNW AND SHIFT A DOMINANT LES BAND
FROM THE KEWEENAW INTO THE CENTRAL UP. RECENT HREF GUIDANCE HINTS AT
A 20-40% CHANCE FOR 0.5"/HOUR RATES DURING THE MORNING COMMUTE HOURS
IN MARQUETTE COUNTY AS IT TRANSLATES EASTWARD. A QUICK 1-2" OF SNOW
IS POSSIBLE WHEREVER THE HEAVIEST RATES MANIFEST. LES WILL BE
WEAKENING THROUGH THE AFTERNOON HOURS AS DRY AIR AND SUBSIDENCE WORK
ITS WAY ACROSS LAKE SUPERIOR. LAND BREEZES SETUP OVERNIGHT INTO
SATURDAY AND FOCUS A MORE DOMINANT BAND INTO THE EAST-CENTRAL.
THERMODYNAMICS ARE FAVORABLE FOR HEAVY LES WITH DELTA-TS PUSHING 20-
2 5C, HOWEVER, THE LIMITING FACTOR WILL BE VERY DRY AIR LOWERING
INVERSION HEIGHTS DOWN TO 4-6 KFT. AT THE SAME TIME, THE SURFACE
HIGH WILL BE SOLIDLY OVERTOP THE UPPER GREAT LAKES AND BOUNDARY
LAYER WIND WILL BE DECREASING INTO THE AFTERNOON, LIKELY BREAKING UP
ALREADY WEAK LES BANDS TO MORE SHOWERY SEGMENTS. ALL OF THIS IS TO
SAY THAT THE EAST AND CENTRAL COULD SQUEEZE OUT ANOTHER INCH OR SO
THROUGH SATURDAY MORNING.
LINGERING LES SHOWERS OFF OF LAKE MICHIGAN IN THE FAR EAST UP ARE
LIKELY ON SUNDAY AS HIGH PRESSURE SLIDES EAST, CREATING A S-SW FETCH
ACROSS THE LONG AXIS OF THE LAKE. THERE ARE STILL SOME UNCERTAINTIES
ON SNOW ACCUMULATIONS GIVEN A NARROW WINDOW FOR LIFT WITHIN THE DGZ
AND WAA RAMPING UP SUNDAY AFTERNOON. FOR NOW, AT LEAST AN INCH OR
TWO OF SNOW IN SCHOOLCRAFT AND LUCE COUNTIES IS ON THE TABLE SUNDAY.
OTHERWISE, LOW TEMPERATURES THIS WEEKEND WILL BE ON THE COLD SIDE,
DIPPING AROUND 10-15F NEAR THE LAKESHORES AND 0-10F INLAND, WITH A
FEW SPOTS IN THE INTERIOR WEST POTENTIALLY REACHING JUST BELOW ZERO.
THE TREND FOR A WHITE CHRISTMAS STILL HOLDS ON AS A WEAK SHORTWAVE
IS PROGGED TO DEVELOP IN THE NORTHERN PLAINS AND MEANDER INTO THE
UPPER GREAT LAKES MONDAY INTO TUESDAY. THE CURRENT DETERMINISTIC
MODEL SUITE IS STILL WORKING OUT THE KINKS ON THE TIMING AND
PLACEMENT OF SURFACE FEATURES, HOWEVER, LREF GUIDANCE SUGGESTS A
WET 1-2" OF SNOW ACROSS THE UP, POSSIBLY UPWARDS OF 3" IN THE
EAST COINCIDING ENHANCEMENT VIA LAKE MICHIGAN. BEHIND MONDAY'S
WEAK SYSTEM, ENSEMBLES ARE IN GOOD AGREEMENT ON A PERIOD OF
WARMTH CHARACTERIZED BY 850MB TEMP ANOMALIES UPWARDS OF +5-10
THROUGH THE REST OF 2024 AND INTO EARLY JANUARY. YOOPER WINTER
WEATHER RECREATIONISTS SHOULD PREPARE FOR A DWINDLING SNOWPACK
AS WE ROUND OUT THE YEAR.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1242 PM EST THU DEC 19 2024
VFR CONDITIONS WILL SLOWLY DETERIORATE TO MVFR THIS AFTERNOON AND
EVENTUALLY IFR BY THIS EVENING/TONIGHT AS SNOW SHOWERS
OVERSPREAD THE AREA WITH A CLIPPER SYSTEM. ONSET OF MVFR WILL
COMMENCE AT IWD AROUND THU 20Z, FOLLOWED BY SAW AROUND THU
21/22Z AND CMX CLOSER TO FRI 00Z. PERIODS OF LIFR ALSO CANNOT BE
RULED OUT IN HEAVIEST SNOW BANDS/REDUCED VISIBILITIES. WINDS
WILL GENERALLY REMAIN UNDER 10 KTS, THOUGH, HELPING TO REDUCE
THE BLOWING SNOW THREAT.
MARINE
ISSUED AT 252 PM EST THU DEC 19 2024
NORTHEAST WINDS INCREASE TO 30 KNOTS TONIGHT OVER THE WEST HALF ON
THE BACKSIDE OF A CLIPPER LOW MOVING THROUGH THE LOWER GREAT
LAKES/OHIO VALLEY. CURRENTLY, NOT EXPECTING ANY GALE FORCE GUSTS,
HOWEVER AN ISOLATED GUST TO 35 KNOTS CAN'T BE COMPLETELY RULED OUT
TONIGHT(<20% CHANCE). WAVE HEIGHTS WILL BUILD TO 4-7 FEET TONIGHT IN
THE WEST HALF, WITH THE HIGHEST WAVES EAST OF THE APOSTLE ISLANDS.
AS THE SURFACE LOW PRESSURE CONTINUES PULLING FURTHER SOUTHEAST AND
HIGH PRESSURE BEGINS TO BUILD IN FROM THE HIGH PLAINS, WINDS WILL
TURN OUT OF THE NORTH-NORTHWEST THROUGH FRIDAY EVENING, GUSTING
UPWARDS OF 20-30 KNOTS ACROSS THE EAST AND CENTRAL LAKE, WITH AN
ISOLATED GALE TO 35 KNOTS POSSIBLE (<20% CHANCE). WAVE HEIGHTS BUILD
TO 4-7 FEET LATE FRIDAY INTO EARLY SATURDAY MORNING.
WINDS AND WAVES THEN SUBSIDE QUICKLY ON SATURDAY AND REMAIN CALM
THROUGH SUNDAY MORNING. LOW PRESSURE MOVING THROUGH THE UPPER
MIDWEST COULD INCREASE SOUTHERLY WINDS TO 20-30 KNOTS SUNDAY
AFTERNOON INTO MONDAY, HIGHEST EAST HALF. ENSEMBLE GUIDANCE PRESENTS
A 30-40% CHANCE FOR GALE FORCE GUSTS ACROSS THE EAST-CENTRAL LAKE
EARLY MONDAY THROUGH THE EVENING.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 AM EST FRIDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 10 AM EST /9 AM CST/ FRIDAY FOR
MIZ002-009.
WINTER WEATHER ADVISORY UNTIL 3 AM CST FRIDAY FOR MIZ010-011.
WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ FRIDAY FOR
MIZ012>014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
SHORT TERM...GS
LONG TERM...BW
AVIATION...GS/TDUD
MARINE...BW
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page