438
FXUS63 KAPX 182345
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
645 PM EST WED DEC 18 2024
KEY MESSAGES
- LAKE EFFECT SNOW CONTINUES THROUGH TONIGHT. ADDITIONAL
SNOWFALL AROUND 1" FOR PARTS OF NORTHWEST LOWER AND EASTERN
UPPER. LOCALIZED AMOUNTS NEAR 2" POSSIBLE FOR ANTRIM,
KALKASKA, AND WESTERN CHIPPEWA COUNTIES.
- POTENTIAL LOCALLY HIGH AMOUNTS OF ACCUMULATING SNOW THURSDAY
NIGHT THROUGH FRIDAY. SNOW SHOWERS LINGER INTO THE WEEKEND.
- MILD TEMPERATURES SLOWLY BUILD NEXT WEEK. WATCHING FOR RAIN
TO MIX INTO SNOW SHOWERS THIS MONDAY/TUESDAY.
SHORT TERM /THROUGH THURSDAY/
ISSUED AT 231 PM EST WED DEC 18 2024
PATTERN SYNOPSIS:
LONGWAVE TROUGHING WILL CONTINUE TO SLIDE ACROSS THE EASTERN HALF OF
THE COUNTRY TODAY INTO TONIGHT AS AN EMBEDDED SHORTWAVE/SPEED MAX
PUNCHES ACROSS THE GREAT LAKES THIS EVENING. EXPANSIVE FORCING ALOFT
WILL SUPPORT SURFACE PRESSURE FALLS ACROSS THE EASTERN CONUS INTO
THIS EVENING AS HIGH PRESSURE TEMPORARILY BUILDS INTO MOST OF THE
MIDWEST/MISSISSIPPI VALLEY TONIGHT INTO THURSDAY. UPSTREAM, A SECOND
TROUGH WILL DIG ACROSS THE CENTRAL PLAINS THURSDAY MORNING,
PROVIDING AMPLE FORCING ALOFT TO SUPPORT A WEAK CYCLONE THAT LOOKS
TO TREK TOWARD THE WESTERN GREAT LAKES BY THURSDAY EVENING.
FORECAST DETAILS:
LAKE EFFECT SNOW THROUGH TONIGHT -- AS EXPECTED, LAKE-INDUCED
CONVECTION HAS INCREASED OVER THE LAST FEW HOURS ACROSS PARTS OF
NORTHWEST LOWER AND EASTERN UPPER. SATURATED AND RELATIVELY STEEP
LOW-LEVEL PROFILES WILL CONTINUE TO SUPPORT LIGHT LAKE EFFECT SNOW
ACROSS THESE AREAS THROUGH TONIGHT IN COMBINATION WITH NORTHWEST
WINDS. THESE WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT, HELPING
TO BRING LAKE EFFECT SNOW CHANCES TO AN END EARLY THURSDAY MORNING.
AN ADDITIONAL 1" OR SO IS ANTICIPATED ACROSS THE NORTHWEST SNOWBELTS
WITH LOCALIZED AMOUNTS NEAR 2" POSSIBLE FOR ANTRIM, KALKASKA, AND
WESTERN CHIPPEWA COUNTIES. MOST AREAS WILL STAY PRECIP-FREE THROUGH
THE MORNING ON THURSDAY BEFORE SNOW CHANCES RETURN TO NORTHERN
MICHIGAN DURING THE LATE AFTERNOON/EVENING HOURS AHEAD OF THE
AFOREMENTIONED SYSTEM WORKING INTO THE REGION DURING THAT TIME.
LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/
ISSUED AT 231 PM EST WED DEC 18 2024
CURRENT LONGWAVE TROUGHING SPANNED ACROSS THE NORTHERN HALF OF NORTH
AMERICA CONTINUES TO KEEP WINTER-LIKE TEMPERATURES SPANNED ACROSS
THE GREAT LAKES REGION. STRONG MIDLEVEL FLOW WILL KEEP THE REGION
ACTIVE AS A SHORTWAVE CURRENTLY OVER THE B.C COASTLINE WILL MAKE ITS
WAY TO THE MIDWEST BY THURSDAY, DELIVERING IMPACTFUL ACCUMULATING
SNOWFALL TO PARTS OF THE CWA THURSDAY NIGHT AND FRIDAY.
SNOWFALL WILL LIKELY LAST INTO THE WEEKEND AS LES KEEPS
PRECIPITATION ACROSS THE MORE TYPICAL SNOWBELTS. SUNDAY AND MONDAY
WILL REMAIN QUIET AS HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES
REGION AND TEMPERATURES SLOWLY BEGIN TO BUILD. ADDITIONAL CHANCES
OF PRECIPITATION CONTINUE AT THE END OF THE LONG TERM PERIOD AS
ANOTHER SHORTWAVE TRACKS ACROSS THE MIDWEST, POTENTIALLY RETURNING
RAIN AND SNOW SHOWERS TO THE NORTHWOODS.
PRIMARY FORECAST CONCERNS/KEY MESSAGES:
-POTENTIAL LOCALLY HIGH AMOUNTS OF ACCUMULATING SNOW THURSDAY NIGHT
THROUGH FRIDAY. SNOW SHOWERS LINGER INTO THE WEEKEND: PRIMARY FOCUS
OF THE LONG TERM FORECAST PERIOD REMAINS ON THE CLIPPER DELIVERING
ACCUMULATING SNOWFALL LATE THURSDAY THROUGH SATURDAY. THE MAJORITY
OF NORTHERN LOWER AND EASTERN UPPER CAN EXPECT A GENERAL 2-4" AS
SYNOPTIC MOISTURE WITH THIS SET-UP REMAINS LOW. HOWEVER; POTENTIAL
FOR HIGH AMOUNTS OF ACCUMULATING SNOWFALL VIA LAKE ENHANCEMENT ALONG
THE HURON SHORELINE REMAINS A REAL POTENTIAL. HI-REZ GUIDANCE IS
PICKING UP ON SOME LOCALIZED SNOWFALL TOTALS OF 7" OR MORE BY FRIDAY
AFTERNOON AS THE CORE OF LOW PRESSURE TRACKS ACROSS THE
IOWA/WISCONSIN/ILLINOIS REGION. CONFIDENCE OF THIS BAND SETTING UP
OVER A CERTAIN LOCATION REMAINS LOW, AS MODELS CONTINUE TO STRUGGLE
ON THE EXACT TRACK OF THIS CLIPPER. A MORE NORTHERN TRACK WOULD
LIKELY RESULT IN HIGHER TOTALS NEAR THUNDER BAY WHILE SOUTHERN
TRACKING WOULD RESULT IN A SOUTHERLY WIND COMPONENT PUSHING HIGHER
TOTALS TO EASTER UPPER OR OUTRIGHT MISS THE CWA.
-MILD TEMPERATURES SLOWLY BUILD NEXT WEEK. WATCHING FOR RAIN TO
MIX INTO SNOW SHOWERS THIS MONDAY/TUESDAY: SNOWFALL WILL
CONTINUE THIS SATURDAY AS CLASSIC NORTHWEST FLOW KEEPS
LINGERING LIGHT LES SHOWERS ACROSS THE TYPICAL SNOWBELTS. HIGH
PRESSURE BUILD THIS SUNDAY RETURNING MOSTLY SUNNY SKIES ALONG
WITH SEASONABLY CHILLY TEMPERATURES. OVERNIGHT LOWS IN THE
SINGLE DIGITS WITH HIGHS WELL BELOW FREEZING WILL CONTINUE
THROUGH SUNDAY BEFORE SHORTWAVE RIDGING ALLOWS WARMER/MILD AIR
TO BUILD INTO THE NORTHWOODS. SURFACE AND LOW LEVEL
TEMPERATURES REMAIN AROUND FREEZING AT THIS TIME RESULTING IN
LIGHT RAIN TO MIX INTO SNOW SHOWERS ALONG THE TYPICALLY WARMER
AREAS OF THE CWA BEFORE LAKE EFFECT SNOW SHOWERS LINGER THROUGH
THE END OF THE LONG TERM FORECAST PERIOD.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 641 PM EST WED DEC 18 2024
LIGHT SNOW SHOWERS THIS EVENING WILL TAPPER OFF EARLY TONIGHT. A
CLIPPER SYSTEM WILL SPREAD SNOW INTO THE REGION FROM SOUTHWEST
TO NORTHEAST LATE THURSDAY INTO THURSDAY NIGHT. WINDS WILL BE
GUSTY THIS EVENING THEN DIMINISH OVERNIGHT. CIGS WILL BE MAINLY
MVFR THEN SLOWLY LIFT TO LOW END VFR FOR THE MOST PART LATER
TONIGHT THEN FALL BACK TO MVFR LATE IN THE TAF PERIOD. VSBYS
WILL BE LARGELY VFR INTO THURSDAY AFTERNOON BUT MVFR OR EVEN
IFR IS EXPECTED AT MBL AND TVC LATE.
APX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ345>348.
SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR LMZ323-
342-344>346.
SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LSZ321.
SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR LSZ322.
SHORT TERM...DJC
LONG TERM...SJC
AVIATION...AJS
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