049
FXUS63 KAPX 171750
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1250 PM EST TUE DEC 17 2024
KEY MESSAGES
- BREEZY THROUGH EARLY AFTERNOON.
- PERIODS OF LAKE EFFECT SNOW TODAY THROUGH TONIGHT, WITH SOME
ENHANCEMENT ARRIVING TONIGHT INTO WEDNESDAY.
- WIDESPREAD SNOW CHANCES ON FRIDAY WITH COLDER TEMPERATURES
THIS WEEKEND.
UPDATE
ISSUED AT 916 AM EST TUE DEC 17 2024
CURRENT FORECAST LARGELY REMAINS ON TRACK WITH NO MAJOR CHANGES.
LIGHT RAIN/SNOW SHOWERS WILL CONTINUE ACROSS PARTS OF THE AREA THIS
THROUGH THIS AFTERNOON, WITH THE BEST SNOW CHANCES PRIMARILY
CONFINED TO THOSE NEAR WHITEFISH BAY. AROUND 1" OR LESS OF
ACCUMULATION IS ANTICIPATED THROUGH THE DAY TODAY CLOSE TO THE
WESTERN SHORES OF THE BAY NEAR PARADISE/TAHQUAMENON FALLS. GUSTY
WINDS WILL ALSO GRADUALLY DIMINISH THROUGH TODAY INTO TONIGHT.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 203 AM EST TUE DEC 17 2024
PATTERN SYNOPSIS/FORECAST: AT THIS EARLY HOUR, MID-LEVEL TROUGH AXIS
IS STRETCHED FROM NORTHERN ONTARIO SOUTHEASTWARD INTO THE EASTERN
GREAT LAKES. ATTENDANT SURFACE LOW POSITIONED NEAR JAMES BAY WITH
THE OCCLUDED FRONT THAT CROSSED NORTHERN MI YESTERDAY NOW WELL TO
OUR EAST. THE PRESSURE GRADIENT IS IN THE PROCESS OF CONTINUING TO
STRENGTHEN WITH GUSTINESS ACROSS MUCH OF THE FORECAST AREA IN THE
MIDST OF INCREASINGLY STRONG LOW-MID LEVEL COLD AIR ADVECTION. THIS
HAS BEGUN TO GARNER A LAKE RESPONSE OFF BOTH LAKE SUPERIOR AND LAKE
MICHIGAN WITH PRIMARILY WESTERLY FLOW TARGETING AREAS NEAR AND NORTH
OF WHITEFISH BAY AND ACROSS THE TYPICAL LAKE BELTS OF NORTHWEST
LOWER MI. NOT A TON OF CHANGE FOR THE DAYTIME HOURS AHEAD, ALTHOUGH
WE DO AT LEAST TEMPORARILY THIS AFTERNOON LOSE DEEPER MOISTURE
BEFORE ATTENTION TRANSITIONS TO AN UPSTREAM WAVE YIELDING ADDITIONAL
SUPPORT FOR AN UPTICK IN SNOW COVERAGE AND INTENSITY LATER TONIGHT
INTO EARLY WEDNESDAY.
FORECAST DETAILS: BREEZY CONDITIONS CONTINUE THIS MORNING THROUGH AT
LEAST EARLY AFTERNOON WITH STRONGEST GUSTS UPWARDS OF 30 MPH. WINDS
BEGIN TO RELAX MID-LATE AFTERNOON AND MORE CONSIDERABLY TONIGHT WITH
SUSTAINED WINDS BEYOND SUNSET AOB 10 MPH AREA-WIDE.
LAKE PROCESSES ARE SLOWLY IN THE PROCESS OF RAMPING UP LOCALLY WITH
AT LEAST A MARGINAL RESPONSE NOTED ON KAPX RADAR OVER THE PAST HOUR
OR TWO. AN INCREASINGLY FAVORABLE OVER-WATER THERMAL GRADIENT
CONTINUES TO FILTER INTO THE REGION ON THE HEELS OF AFOREMENTIONED
STRENGTHENING COLD ADVECTION. INITIAL LAKE EFFECT RAIN SHOWERS
LIKELY TO MIX WITH AND EVENTUALLY TRANSITION TO SNOW OVER THE NEXT
FEW HOURS -- OCCURRING FIRST IN AREAS NEAR WHITEFISH PT AND THE
HIGHER TERRAIN OF NORTHERN LOWER. MAINLY LIGHT TO BRIEFLY MODERATE
SNOW SHOWERS EXPECTED TO CONTINUE AT TIMES TODAY IN THE TYPICALLY
FAVORED WEST FLOW SNOW BELTS WITH LOCALIZED ACCUMULATIONS OVER
INTERIOR NORTHERN LOWER UP TO AN INCH BY 00Z THIS EVENING. SOME
LOCALIZED 1-2" AMOUNTS NEAR WHITEFISH PT/PARADISE POSSIBLE DURING
THIS SAME TIME FRAME -- ALTHOUGH WORTH MONITORING THESE FAR NORTHERN
AREAS FROM WHITEFISH PT TO THE SOO LATE THIS AFTERNOON AS LATEST HI-
RES GUIDANCE SUGGESTS A FAIRLY IMPRESSIVE CONVERGENCE CORRIDOR WITH
A BAND OF HEAVIER SNOWFALL AT LEAST BRIEFLY SAGGING INTO THOSE AREAS
WITH SOME BETTER ACCUMS AND SIGNIFICANTLY REDUCED VISIBILITIES NOT
OUT OF THE QUESTION.
LITTLE CHANGE THROUGH THE EVENING HOURS WITH OCCASIONAL SNOW SHOWERS
CONTINUING TO DOT THE MAP WITH MINOR ADDITIONAL ACCUMS. FOR THE
SECOND HALF OF THE NIGHT AHEAD, AT LEAST LIGHT SNOW COVERAGE IS
EXPECTED TO INCREASE IN RESPONSE TO AN INCOMING MID-LEVEL WAVE AND
ASSOCIATED UPTICK IN DEEPER MOISTURE AND FORCING. WHILE POPS
INCREASE AREA-WIDE DURING THIS TIME FRAME, THE MOST FAVORED AREAS
FOR ADDITIONAL LOCALIZED INCH OR TWO BY 12Z WEDNESDAY ARE FOCUSED IN
AN AREA FROM PETOSKEY TO GAYLORD TO KALKASKA.
LONG TERM /WEDNESDAY THROUGH MONDAY/
ISSUED AT 203 AM EST TUE DEC 17 2024
FORECAST PATTERN:
PROGRESSIVE UPPER LEVEL TROUGHING WILL CONTINUE MOVING OVER MI
WEDNESDAY, WITH SURFACE WINDS GRADUALLY TURNING NORTHWESTERLY DURING
THE MORNING HOURS. CONTINENTAL MOISTURE WILL MOVE IN WITH THE UPPER
TROUGH, AND YIELD CHANCES FOR SNOW OVER MOST OF NORTHERN MI DURING
THE DAY WEDNESDAY. THERE WILL BE LES ENHANCEMENT FOR TYPICAL SNOWBELT
AREAS, RESULTING IN CHANCES FOR TIMES OF MORE MODERATE TO HEAVY
SNOWFALL. WITH BULK SHEAR OF AROUND 20 TO 30 KTS (ESPECIALLY WED
MORNING), A FEW DEFINED BANDS OF LES WILL BE POSSIBLE TO START THE
DAY WITH. INSTABILITY WILL INCREASE AND SHEAR DECREASE THROUGHOUT
THE AFTERNOON, RESULTING IN A MORE CELLULAR MODE OF SNOW SHOWERS
WHICH SHOULD SPREAD OUT THE SNOW ACROSS NORTHERN MI VS FOCUSING A
HEAVIER BAND OF SNOW OVER ONE AREA. DUE TO THIS, SNOW AMOUNTS REMAIN
RELATIVELY LOWER FOR WEDNESDAY (3 TO 5 INCHES MAX DURING A 24 HOUR
PERIOD STARTING WED MORNING). AT THIS TIME, THE HIGHEST AMOUNTS
RESIDE IN KALKASKA COUNTY HOWEVER THERE IS PLENTY OF TIME FOR THAT
TO CHANGE. IF THE TIMING AND SPEED OF THE UPPER WAVE IS SLIGHTLY
SLOWER OR FASTER AS IT APPROACHES MI AND MOVES OVER MI, SNOW AMOUNTS
AND LOCATIONS OF AMOUNTS WILL CHANGE.
SURFACE PRESSURE WILL GRADUALLY RISE WEDNESDAY NIGHT AS A 1030MB
HIGH MOVES OVERHEAD. TEMPERATURES WILL COOL BACK TO NEAR SEASONAL OR
SLIGHTLY BELOW FOR THURSDAY. A BRIEF BREAK FROM PRECIPITATION
THURSDAY MORNING, BUT BY THE LATE AFTERNOON MORE SNOW CHANCES MOVE
IN FROM THE WEST. A WEAKENING SURFACE CYCLONE AND PARENT SHORT WAVE
WILL MOVE EASTWARD OVER THE OHIO RIVER VALLEY LATER THURSDAY AND
INTO FRIDAY MORNING. THERE IS STILL DECENT SPREAD ON HOW MUCH
CONTINENTAL MOISTURE WILL REMAIN IN THIS SYSTEM ONCE THE NORTHERN
TIER REACHES MI. HOWEVER MORE WIDESPREAD SYNOPTICALLY FORCED SNOW
CHANCES EXIST FOR THIS SYSTEM. SOME GUIDANCE HINTS AT SOME LAKE
ENHANCEMENT FROM LK HURON FOR NE LOWER ON FRIDAY AS THE WAVE
GRADUALLY EXISTS. COLD AIR BECOMES REINFORCED FOR THE WEEKEND, WITH
POSSIBLE TEENS FOR HIGH TEMPS AND SINGLE DIGITS TO BELOW 0F FOR LOW
TEMPS.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1249 PM EST TUE DEC 17 2024
MAINLY MVFR CIGS ARE EXPECTED TO PERSIST ACROSS MOST AREAS OF
NORTHERN MICHIGAN THROUGH THE ISSUANCE PERIOD. GUSTY WEST WINDS WILL
GRADUALLY DIMINISH WITH TIME LATER THIS AFTERNOON INTO TONIGHT AS
THE PRESSURE GRADIENT RELAXES. LAKE EFFECT SNOW WILL INCREASE IN
COVERAGE ACROSS PARTS OF NORTHWEST LOWER AND EASTERN UPPER MICHIGAN
LATER TONIGHT AND WEDNESDAY, RESULTING IN LOCALIZED DROPS IN VSBY
DOWN TO IFR/MVFR SHOULD SNOW SHOWERS WORK OVER TAF SITES.
APX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
LHZ345>347.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LHZ348-
349.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LMZ323-
341-342-344>346.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LSZ322.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR LSZ321.
UPDATE...DJC
SHORT TERM...MJG
LONG TERM...ELD
AVIATION...DJC
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