436  
FXUS63 KMQT 222359  
AFDMQT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MARQUETTE MI  
659 PM EST SUN DEC 22 2024  
   
KEY MESSAGES  
 
- SOUTHERLY WIND LAKE EFFECT SNOW INTO EASTERN UPPER MICHIGAN  
WILL BE FOLLOWED BY A CLIPPER SYSTEM MOVING IN FROM THE  
WEST. TOGETHER THESE WILL BRING WET SNOW TO SOUTH-CENTRAL AND  
EASTERN UPPER MICHIGAN THROUGH MONDAY.  
 
- LAKE EFFECT MAY PRODUCE ANOTHER INCH OR TWO IN LUCE AND SCHOOLCRAFT  
COUNTIES BEFORE THE CLIPPER BRINGS ANOTHER 1 TO 3 INCHES.  
ISOLATED HIGHER AMOUNTS WILL BE POSSIBLE IN THE LUCE AND  
SCHOOLCRAFT COUNTIES. TOGETHER THIS SNOW MAY RESULT IN MINOR  
TRAVEL IMPACTS THROUGH MONDAY.  
 
- DRIER AND WARMER CONDITIONS EXPECTED BEHIND THE EARLY WEEK  
SYSTEM FOR CHRISTMAS EVE AND CHRISTMAS DAY.  
 
 
   
SHORT TERM /THROUGH MONDAY/  
 
ISSUED AT 212 PM EST SUN DEC 22 2024  
 
UPPER MICHIGAN CONTINUES TO BE CAUGHT BETWEEN MID-UPPER LEVEL  
TROUGHING ACROSS THE EAST COAST WITH A RIDGE EXTENDING THROUGH THE  
NORTHERN PLAINS. WITHIN THIS NORTHWEST FLOW, A WEAK SHORTWAVE  
SUPPORTED FLURRIES HERE AND THERE THIS MORNING THANKS TO SOME SEEDER  
FEEDER ACTION. FURTHER UPSTREAM, A CLOSED LOW WITH A SHORTWAVE  
EXTENDING SOUTH JUST WEST OF THE RIDGE HAS SUPPORTED THE DEVELOPMENT  
OF A SURFACE LOW OVER SOUTH DAKOTA, PER RAP ANALYSIS. WITH UPPER  
MICHIGAN BEING CAUGHT BETWEEN THE UPSTREAM SURFACE LOW AND A SURFACE  
HIGH STRETCHING FROM QUEBEC INTO THE OHIO RIVER VALLEY, IN ADDITION  
TO CONTINUED COLD AIR ALOFT AND THE WEAK PROGRESSING SHORTWAVE, A  
LONG AXIS LAKE EFFECT SNOW BAND STREAMING NORTHWARD INTO EASTERN  
UPPER MICHIGAN HAS BEEN OBSERVED ON GOES SATELLITE PRODUCTS AND KAPX  
RADAR. WEBCAMS ALSO SHOW SOME OCCASIONAL LIGHT SNOW IN PARTS OF  
SCHOOLCRAFT, LUCE, AND MACKINAC COUNTIES. FROM THESE NOTED  
OBSERVATIONS, IMPACTS SO FAR APPEAR TO BE MINIMAL.  
 
SOME CAMS, NAMELY THE RAP AND HRRR HAVE REALLY DIALED BACK THE  
INTENSITY OF THESE SNOW SHOWERS INTO EASTERN UPPER MICHIGAN IN THE  
PAST 24 HOURS. THIS IS ALSO REFLECTED IN THE RECENT HREF RUN, WHICH  
HAS DIALED PROBABILITIES OF SNOWFALL RATES EXCEEDING AN INCH PER HOUR  
TO <10%. A GOOD BIT OF THE 06Z AND 12Z DETERMINISTIC GUIDANCE  
THOUGH, CONTINUES TO SUGGEST THE POTENTIAL FOR AN INCH OR TWO OF  
SNOW IN SCHOOLCRAFT AND LUCE COUNTIES THROUGH MIDNIGHT. HOWEVER, IT  
SHOULD BE NOTED THAT MOST OF THESE PACKAGES HAVE LOWERED  
ACCUMULATIONS AND HAVE A POOR HANDLE ON THE PLACEMENT OF THE CURRENT  
BAND. WITH ALL THIS BEING SAID THOUGH, GENERALLY BELIEVE SNOW  
ACCUMULATIONS SHOULD AMOUNT TO AN INCH OR TWO, WITH HIGHER AMOUNTS  
BEING POSSIBLE IN A VERY NARROW BAND. CURRENT RADAR TRENDS SUGGESTS  
THIS WOULD LIKELY BE FROM NEAR OR EAST OF MANISTIQUE NORTHEASTWARD  
INTO LUCE COUNTY NEAR MCMILLAN. ANY SNOW THROUGH THE REMAINDER OF  
TODAY AND THROUGH MIDNIGHT WILL ALSO BECOME INCREASINGLY WETTER,  
WITH MORNING SNOW RATIOS ESTIMATED NEAR 15:1 TRENDING TOWARD 10:1  
THIS EVENING.  
 
THE UPSTREAM CLIPPER LOW WILL CONTINUE ORGANIZING BEFORE SHIFTING  
EAST INTO IOWA/SOUTHERN MINNESOTA THIS EVENING. THROUGH MONDAY, THE  
LOW WILL TRACK EAST-NORTHEAST THROUGH WISCONSIN, ACROSS LAKE  
MICHIGAN, AND THEN INTO LOWER MICHIGAN. THIS WILL POSITION UPPER  
MICHIGAN ALONG THE LOW'S NORTHERN FLANK AND UNDER THE INFLUENCE OF  
CONTINUED WARM AIR ADVECTION AND A WEAK 850-500MB TROWAL BEFORE THE  
LOW'S INVERTED TROUGH AND A WEAK SHORTWAVE SHIFTS THROUGH. THE  
EFFECT WILL BE A SWATH OF WET SNOW MOVING THROUGH THE UPPER GREAT  
LAKES AFTER MIDNIGHT TONIGHT THROUGH EARLY AFTERNOON MONDAY, WITH  
LAKE ENHANCEMENT OF THIS SWATH BEING POSSIBLE INTO EASTERN UPPER  
MICHIGAN. A MAJORITY OF GUIDANCE PACKAGES STRETCH THIS SWATH FROM  
NEAR IRON MOUNTAIN THROUGH MENOMINEE AND DELTA COUNTIES, INTO  
SCHOOLCRAFT COUNTY WHERE LAKE ENHANCEMENT POTENTIAL BEGINS. THIS  
SAID THOUGH, THE NORTHERN EXTEND OF THE BAND IS UP FOR SOME DEBATE  
THANKS TO THE 12Z NAMNEST AND HRRR KEEPING A MAJORITY OF THIS SOUTH  
OF WATSON. DESPITE THESE DIFFERENCES THOUGH, WET SNOW ACCUMULATIONS  
SHOULD STILL AMOUNT TO TWO INCHES OR LESS THROUGH THE EVENT UNDER  
THIS SWATH. IN SCHOOLCRAFT AND LUCE COUNTIES, LAKE ENHANCEMENT IN THE  
MORNING SHOULD END BY AFTERNOON THANKS TO MID-LEVEL WINDS SHIFTING  
WITH THE TRANSITING LOW. ADDITIONALLY, SURFACE TEMPS POTENTIALLY  
CLIMBING ABOVE FREEZING MONDAY MAKE ANYTHING MORE THAN 3 INCHES  
DIFFICULT TO ACHIEVE. CURRENT THINKING IS THAT 2 INCHES COULD BE  
WIDESPREAD WITH AMOUNTS POTENTIALLY APPROACHING 4 INCHES BEING  
LOCALIZED THROUGH MONDAY EVENING. GIVEN ALL THIS UNCERTAINTY AND  
THAT HOLIDAY TRAVEL IS IN FULL SWING, OPTED TO ISSUE AN SPS FOR  
LUCE/SCHOOLCRAFT FOR THE TIME BEING. ALL SOLUTIONS KEEP THE WEST  
DRY, SAVE FOR SCATTERED SNOW SHOWER POTENTIAL DEVELOPING BY MONDAY  
AFTERNOON.  
 
 
   
LONG TERM /MONDAY NIGHT THROUGH SUNDAY/  
 
ISSUED AT 343 PM EST SUN DEC 22 2024  
 
HIGH PRESSURE OVER NORTHERN ONTARIO AND MN AT 1026 MB DESCENDS  
SOUTHEAST INTO THE GREAT LAKES MONDAY NIGHT AS A MID LEVEL SHORTWAVE  
DROPS SOUTH OVER THE UP EARLY ON. THIS DECREASING CYCLONIC FLOW AND  
INCREASING DRY AIR WORKS AGAINST LINGERING LES. AT THE SAME TIME,  
WAA INCREASING 850 MB TEMPS CLOSER TO NEGATIVE 1-2C DIMINISHES THE  
SUPERIOR SFC-850 MB DELTA-TS GIVEN THAT AVERAGE WATER SFC TEMPS ARE  
AROUND 4.5C. ANY SNOWFALL WILL YIELD NEGLIGIBLE ACCUMULATIONS AND NO  
IMPACTS. SOME CLOUD COVER LIKELY WILL CONTINUE, BUT DRY WEATHER  
SHOULD RETURN TO THE UP BY TUESDAY MORNING. OTHERWISE, UNDER PARTLY  
TO MOSTLY CLOUDY SKIES, LOWS SETTLE INTO THE TEENS TO MID 20S. BRIEF  
MID LEVEL RIDGING RETURNS FOR THE DAY TUESDAY AS THE SFC HIGH  
BECOMES CENTERED OVER SOUTHERN QUEBEC, BUT EXTENDS SOUTHWEST OVER  
THE GREAT LAKES BASIN. DRY WEATHER CONTINUES WITH SOME MORE DAYTIME  
CLEARING LIKELY, ALLOWING FOR HIGHS TO PEAK BETWEEN 28 TO 33, WARMER  
BY THE LAKESHORES.  
 
THE MID LEVEL RIDGE GIVES WAY TO A SHORTWAVE FOR TUESDAY NIGHT INTO  
WEDNESDAY AND THE NAM/NHCANDIAN/ECMWF TRY TO SQUEEZE OUT SOME LIGHT  
SNOW OUT OF THAT AND SOME ADDITIONAL POSSIBLE LAKE ENHANCEMENT OFF  
LAKE MI. THAT SAID, THE SFC HIGH PRESSURE MENTIONED EARLIER REMAINS  
PRETTY STAGNANT DURING THIS PERIOD, AND LIFT IS NOT STRONG WITH  
SIGNIFICANT DRY LAYERS NOTED ABOVE 900 MB. THUS THE FORECAST  
REFLECTS DRY WEATHER PERSISTING UNDER CLOUDY SKIES. OTHERWISE,  
EXPECT ANOTHER MILD DAY WITH HIGHS NEAR FREEZING ON TUESDAY WITH  
TEMPS THEN FALLING MAINLY INTO THE 20S OVERNIGHT INTO CHRISTMAS DAY.  
 
AFTER CHRISTMAS DAY, ANOTHER RIDGE MOVES OVER THE GREAT LAKES,  
CONTINUING THE DRY WEATHER THROUGH THURSDAY. WITH TROUGHING OVER  
ROCKIES/PLAINS, SOUTHERLY FLOW BRINGS WELL THAN NORMAL TEMPS (10-20F  
ABOVE NORMAL) BY NEXT WEEKEND. ENSEMBLES PROBABILITIES SUPPORT  
OVERNIGHT LOWS REMAINING ABOVE FREEZING, ESPECIALLY THE GFS WITH 0%  
ACROSS THE UP THURSDAY NIGHT THROUGH THE DAY SUNDAY. THE ECWMF AND  
CANADIAN ENSEMBLES SHOW SOMEWHERE BETWEEN 20-40% CHANCES FOR BELOW  
FREEZING IN THE INTERIOR FRIDAY NIGHT AND SATURDAY NIGHT. GUIDANCE  
SPREADS ON ARRIVAL TIME OF TROUGHS PIVOTING OVER THE GREAT LAKES  
LATE NEXT WEEK, BUT THERE IS SUPPORT FOR ANOMALOUS WARMTH AND  
MOISTURE SURGING UP FROM THE GULF OF MEXICO OVER THE WEEKEND  
ACCOMPANIED BY A SFC LOW. PRIMARY P-TYPE LIKELY WILL BE RAIN GIVEN  
THE AIRMASS EXPECTED, BUT THERE ARE LOW CHANCES (15-30%) OF SNOW  
MIXING IN RETURN SUNDAY ONWARD. ALSO, DEW POINT TEMPS REACH INTO THE  
30S STARTING ON THURSDAY WITH ABOVE FREEZING DEW POINT TEMPS OVER  
MUCH OF THE UP FRIDAY NIGHT THROUGH SATURDAY NIGHT. THIS ALONGSIDE  
HIGHS IN THE UPPER 30S TO MID 40S WILL HELP MELT SNOWPACK AND ALSO  
POSSIBLY RESULT IN SOME PATCHY FOG. WHILE IT'S A WAYS OUT YET, WILL  
CONTINUE TO WATCH THE FOG POTENTIAL IN UPCOMING FORECAST PACKAGES AS  
THIS COULD HAVE SOME IMPACTS ON HOLIDAY TRAVEL.  
 
 
   
AVIATION /00Z TAFS THROUGH 00Z TUESDAY/  
 
ISSUED AT 658 PM EST SUN DEC 22 2024  
 
LOW-LEVEL DRY AIR THAT IS CURRENTLY ALLOWING FOR VFR AT IWD/CMX/SAW  
WILL GIVE WAY TO INCREASING LOW-LEVEL MOISTURE TONIGHT AS A  
DISTURBANCE APPROACHES. AS A RESULT, MVFR CIGS WILL DEVELOP  
OVERNIGHT AT ALL TERMINALS WITH FURTHER REDUCTION TO IFR AT IWD/SAW  
EARLY MON MORNING. A LITTLE -SN OR -FZDZ COULD DEVELOP LATE  
TONIGHT/MON MORNING, BUT POTENTIAL FOR OCCURRENCE IS TOO LOW TO  
INCLUDE MENTION IN FCST. PASSING SFC TROF LATE MORNING OR EARLY AFTN  
MAY SUPPORT OCNL -SHSN/FLURRIES. AS FOR WINDS, LOW-LEVEL JET OVER  
THE AREA THIS EVENING IS NOT QUITE STRONG ENOUGH TO WARRANT  
INCLUSION OF LLWS. SOUTHERLY WINDS TONIGHT WILL BECOME LIGHT/VRBL  
FOR A TIME MON MORNING, THEN BECOME NORTHERLY MON AFTN.  
 
 
   
MARINE  
 
ISSUED AT 343 PM EST SUN DEC 22 2024  
 
SOUTH WINDS OF 20-30 KTS OVER THE EAST AND 15-25 KTS OVER THE WEST  
CONTINUE INTO TONIGHT. WINDS FALL BELOW 20 KTS BY AROUND MIDNIGHT IN  
THE WEST AND BY MONDAY MORNING IN THE EAST AS A CLIPPER SYSTEM  
BEGINS TO MOVE OVER WISCONSIN. THERE IS A LOW CHANCE (15-30%) OF  
GALE FORCE GUSTS TO 35 KTS THIS EVENING/EARLY TONIGHT OVER EAST,  
MAINLY IN A CORRIDOR BETWEEN MARQUETTE AND GRAND MARAIS NORTHWARD.  
AS THE CLIPPER CONTINUES EAST OVER THE GREAT LAKES, WINDS VEER  
NORTHERLY MONDAY MORNING, CONTINUING AROUND 20 KTS THROUGH MONDAY  
EVENING BEFORE FALLING BACK BELOW 20 KTS FOR MONDAY NIGHT. SOUTHERLY  
WINDS, MAINLY 20 KTS OR LESS, ARE EXPECTED TUESDAY THROUGH THE WEEK  
AND LIKELY INTO NEXT WEEKEND FOR MOST OF THE LAKE.  
 
 
   
MQT WATCHES/WARNINGS/ADVISORIES  
 
UPPER MICHIGAN...  
NONE.  
LAKE SUPERIOR...  
NONE.  
LAKE MICHIGAN...  
NONE.  
 
 
 
 
 
SHORT TERM...JTP  
LONG TERM...JABLONSKI  
AVIATION...ROLFSON  
MARINE...JABLONSKI  
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