918
FXUS63 KMQT 191132
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
632 AM 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DISSIPATING IN THE WEST HAVE QUICKLY BEEN REPLACED BY A STREAM OF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 435 AM EST THU DEC 19 2024
HIGH PRESSURE GRADUALLY BUILDS IN FROM THE NORTHERN PLAINS AND
NORTHERN ONTARIO FRIDAY INTO SATURDAY BEHIND TODAY'S CLIPPER LOW
WHICH WILL BE DEPARTING SOUTHEAST THROUGH THE OHIO VALLEY ON FRIDAY.
SFC-850 MB WINDS WILL BE BACKING NORTHEAST-NORTH EARLY IN THE
MORNING AND THEN NORTH-NORTHWEST IN THE AFTERNOON BEHIND THE CLIPPER
SYSTEM AS FLOW BECOMES SHARPLY ANTICYCLONIC BY AFTERNOON. WITH
INCREASED RIDGING AND STRONG SUBSIDENCE/DRYING AS NOTED ON FCST
SOUNDINGS WOULD EXPECT LES TO SHARPLY DIMINISH TO FLURRIES FROM WEST
TO EAST IN THE AFTERNOON WITH AN INCH OR LESS OF SNOW ACCUMULATION
OCCURRING MAINLY IN THE MORNING. DEVELOPING LAND BREEZES FRIDAY
NIGHT OFF ONTARIO AND CENTRAL UP WILL ENHANCE LOW-LEVEL CONVERGENCE
WHICH PERHAPS COULD FOCUS A MORE DOMINANT LES BAND INTO ALGER AND
SCHOOLCRAFT COUNTIES IN THE EVENING/EARLY OVERNIGHT WHICH A FEW CAMS
SUGGEST COULD PUSH WEST INTO DELTA AND MARQUETTE COUNTIES OVERNIGHT.
DESPITE THE LIMITING FACTORS OF A LOW INVERSION 4-5 KFT AND VERY DRY
AIR UPSTREAM, FAVORABLE SNOW GROWTH WITH THE ENTIRE CONVECTIVE
LAYER WITHIN THE DGZ COMBINED WITH THE ENHANCED LOW-LEVEL
CONVERGENCE COULD MAYBE SQUEEZE OUT AN INCH OR TWO OF FLUFFY LES
ACCUMULATION WHEREVER THE DOMINANT LES BAND SETS UP. BY
SATURDAY, LES SHOULD BE TAPERING OFF QUICKLY TO FLURRIES AS THE
SFC HIGH FROM ONTARIO BUILDS MORE FIRMLY OVER THE AREA. EXPECT
LESS THAN A HALF INCH OF ADDITIONAL LES ACCUMULATION ON
SATURDAY.
AS THE SURFACE HIGH PRESSURE RIDGE PUSHES EAST ON SUNDAY, A
DEVELOPING S-SW FLOW ON THE BACKSIDE OF THE RIDGE AND 850 MB TEMPS
NEAR -12C AT LEAST EARLY IN THE DAY WILL PROBABLY LEAD TO LIGHT LES
ACCUMULATION OFF OF LAKE MI AND THE BAY OF GREEN BAY INTO EASTERN
COUNTIES OF THE U.P.
EXPECT A GENERAL WARMING TREND FOR CHRISTMAS WEEK AS WARM AIR FROM
MORE TROPICAL AREAS OF THE PACIFIC MOVES OVER THE ROCKIES AND
DOWNSLOPES INTO THE CANADIAN AND U.S. PLAINS AND EVENTUALLY INTO THE
UPPER GREAT LAKES. AHEAD OF THE MORE SIGNIFICANT WARMING SET TO TAKE
PLACE MIDWEEK (AROUND CHRISTMAS), IT DOES LOOK LIKE WE WILL HOLD ON
TO SOMEWHAT COOLER TEMPERATURES INTO EARLY NEXT WEEK, ENOUGH TO
ALLOW ANOTHER WARM ADVECTION SNOWFALL EVENT TO OCCUR ON MONDAY AS A
WAVE MOVING OVER THE NORTHERN ROCKIES IS FORECAST TO TRACK THROUGH
THE NORTHERN PLAINS INTO THE WESTERN GREAT LAKES. WHILE MODELS ARE
STILL IN FAIRLY GOOD AGREEMENT WITH THIS WAVE MOVING INTO THE UPPER
GREAT LAKES ON MONDAY THERE ARE SOME DIFFERENCES IN TRACK, TIMING
AND STRENGTH OF THIS SYSTEM WHICH LEAD TO DECREASED FORECAST
CONFIDENCE ON THE EXACT AMOUNTS OF SNOWFALL. AT THIS TIME, IT LOOKS
LIKE MOSTLY A SUB-ADVISORY SNOWFALL EVENT WITH PROBABLY NO MORE THAN
AN INCH OR TWO OF ACCUMULATION ACROSS MUCH OF THE AREA ON MONDAY.
MAYBE A FEW LOCATIONS IN THE EASTERN COUNTIES OF THE CWA COULD PUSH
NEAR 3 INCHES WITH PERHAPS POSSIBLE WEAK LAKE ENHANCEMENT OFF LAKE
MICHIGAN, ALTHOUGH 850 MB TEMPS ARE PRETTY MARGINAL (AROUND -5C)
AFTER MONDAY'S SYSTEM WEAKENS AND MOVES EAST, MODELS INDICATE
GENERALLY DRIER AND WARMER CONDITIONS THROUGH THE REST OF CHRISTMAS
WEEK AS MEAN RIDGING MOVES OVER THE REGION AND HIGH TEMPERATURES
TREND ABOVE FREEZING. THE CPC 8-14 DAY OUTLOOK PAINTS A BLEAK
PICTURE FOR WINTER RECREATIONISTS IN THE GREAT LAKES REGION AS
THERE LOOKS TO BE A HIGH PROBABILITY THAT THE ABOVE NORMAL AND
PROBABLY ABOVE FREEZING TEMPS COULD LAST INTO AT LEAST EARLY
JANUARY.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 631 AM EST THU DEC 19 2024
A CLIPPER LOW PASSING SOUTH OF THE AREA WILL BRING WIDESPREAD -SHSN
TO ALL TERMINALS THIS TAF PERIOD. -SHSN WILL FIRST IMPACT KIWD AT
AROUND 17Z, BRINGING THE CURRENT VFR CONDITIONS DOWN TO MVFR FOR
CEILINGS AND VIS. IFR VIS THEN BECOMES LIKELY (60+%) THROUGH THE
EVENING INTO THE OVERNIGHT HOURS INCLUDING A BRIEF PERIOD OF
POSSIBLE LIFR VIS (~25% FROM 19Z-22Z), ONLY IMPROVING BACK TO MVFR
IN THE FEW HOURS PRECEDING 12Z FRIDAY. -SHSN ARRIVES AT KSAW AND
KCMX AROUND 21Z, WITH BOTH TERMINALS SEEING A MORNING PERIOD OF VFR
IMPROVEMENT THIS MORNING BEFORE FALLING BACK TO MVFR CEILINGS AND
EVENTUAL IFR VIS.
MARINE
ISSUED AT 435 AM EST THU DEC 19 2024
WINDS GENERALLY BELOW 20 KNOTS WILL LAST THROUGH TODAY BUT THEN
NORTHEAST-NORTH WINDS WILL INCREASE TO 30 KNOTS TONIGHT OVER THE
WEST HALF ON THE BACKSIDE OF A CLIPPER LOW MOVING THROUGH THE LOWER
GREAT LAKES/OHIO VALLEY. AS OF RIGHT NOW, 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.
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.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM EST
FRIDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY FROM 1 PM EST /NOON CST/ THIS
AFTERNOON TO 10 AM EST /9 AM CST/ FRIDAY FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 3 AM CST FRIDAY FOR
MIZ010-011.
WINTER STORM WARNING FROM NOON TODAY TO 6 AM CST FRIDAY FOR
MIZ012.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST
FRIDAY FOR MIZ013-014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
SHORT TERM...GS
LONG TERM...VOSS
AVIATION...GS
MARINE...VOSS
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