414
FXUS63 KAPX 140445
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1145 PM EST MON JAN 13 2025
KEY MESSAGES
- ACCUMULATING LAKE SNOWS CONTINUE
- ORGANIZED LAKE EFFECT SNOWFALL WILL TRANSITION TO MUCH LESS INTENSE
LAKE EFFECT SNOW SHOWERS BY WEDNESDAY.
- ANOTHER CLIPPER SYSTEM PASSES THROUGH WEDNESDAY NIGHT INTO
THURSDAY BRINGING ANOTHER ROUND OF LIGHT SNOW. SOME LAKE
ENHANCEMENT POSSIBLE ALONG LAKE MICHIGAN.
- A BRIEF LULL IN THE WINTRY PATTERN LATER THIS WEEK BEFORE
MORE ACTIVE AND MUCH MORE (AND POSSIBLY DANGEROUSLY) COLD
WEATHER RETURNS TO CLOSE OUT THE HOLIDAY WEEKEND.
UPDATE
ISSUED AT 953 PM EST MON JAN 13 2025
WESTERLY FLOW LAKE EFFECT SNOW CONTINUES OVER MAINLY FAR
NORTHERN LOWER MI. MODERATE SNOW IS OCCURRING WITHIN SKINNY
STRONGER BANDS, THOUGH THESE HAVE BEEN SHIFTING AROUND THIS
TIME. SLOW VEERING HAS OCCURRED SINCE LATE AFTERNOON (WHEN WSW
FLOW WAS OCCURRING). A 275-280 FLOW CONTINUES ON NORTHERN LAKE
MI TONIGHT, UNTIL A TOUCH OF ADDITIONAL VEERING OCCURS TOWARD
12Z. GIVEN THIS FETCH, THE HRRR AND RAP CONTINUE TO ADVERTISE
TOO MUCH QPF/SNOW IN ANTRIM/OTSEGO COS, AND TOO LITTLE IN
EMMET/CHEBOYGAN COS. SOME TWEAKS WILL BE MADE TO THE FORECAST TO
REFLECT THIS.
BETTER BANDING ON SUPERIOR IS JUST SCRAPING BY WHITEFISH PT.
THAT AREA WILL CONTINUE TO BE GRAZED UNTIL 4-5AM, WHEN MORE
VEERING WILL PUSH THIS BAND ONSHORE INTO NW CHIP CO. 1-2"
POSSIBLE NEAR WHITEFISH PT.
SHORT TERM /THROUGH TUESDAY/
ISSUED AT 257 PM EST MON JAN 13 2025
PATTERN SYNOPSIS/PATTERN FORECAST:
DEEP TROUGHING CONTINUES TO BUILD SOUTHEAST ACROSS THE REGION, WITH
ATTENDANT SURFACE LOW WORKING ITSELF EAST INTO WESTERN QUEBEC. LAKE
AGGREGATE REINFORCED SURFACE TROUGH EXTENDS BACK WEST FROM THIS LOW
INTO CENTRAL LAKE SUPERIOR...PLACING NORTHERN MICHIGAN UNDER A WEST
TO SLIGHTLY SOUTHWEST BOUNDARY LAYER FLOW REGIME. COLD AIR ADVECTION
WRAPPING AROUND THIS LOW KICKING OFF LAKE SNOWS INTO THOSE FAVORED
WEST FLOW AREAS OF NORTHWEST LOWER MICHGIAN...WITH MOST ORGANIZED
LAKE SUPERIOR SNOWS TARGETING AREAS NORTH OF THE SOO.
COLD AIR ADVECTION ONLY INCREASES WITH TIME AS EMBEDDED SHORTWAVE
TROUGH WORKS ITS WAY ACROSS THE NORTHWOODS TONIGHT. LAKE AGGREGATE
TROUGHING WILL DROP SOUTH BEHIND THIS DEPARTING WAVE ON TUESDAY,
WITH THE COMBINATION OF BOTH KEEPING LAKE PROCESSES GOING THROUGH
THE ENTIRETY OF THE SHORT TERM PERIOD.
PRIMARY FORECAST CONCERNS:
ADDRESSING LAKE SNOWS AND ATTENDANT AMOUNTS/HEADLINE CONSIDERATIONS
RIGHT THROUGH TUESDAY.
DETAILS:
EXPECT LAKE SNOWS TO ORGANIZE AND INCREASE IN INTENSITY WITH TIME
TONIGHT AS BOTH SYNOPTIC SCALE MOISTURE CONTRIBUTION AND CONVECTIVE
CLOUD DEPTHS INCREASE. CONVECTIVE LAYER FLOW REGIME REMAINS A WEST
ONE OFF NORTHERN LAKE MICHGIAN...TARGETING THE M-68 TO M-32 CORRIDOR
FOR BEST SNOWS. EXPECT LAKE SNOWS OF LESSER INTENSITY ELSEWHERE
ACROSS NORTHWEST LOWER MICHIGAN. A BIT MORE COMPLICATED SCENARIO OFF
LAKE SUPERIOR, WITH THE INTIAL FLOW REGIME FAVORING ONTARIO FOR
BETTER SNOWS. PASSAGE OF LAKE AGGREGATE TROUGH WILL LIKELY BE
ACCOMPANIED BY A BURST OF SNOW, WITH QUICKLY VEERING POST-TROUGH
WINDS SHUNTING BEST SNOWS INTO CENTRAL UPPER MICHIGAN TOWARD TUESDAY
MORNING.
LAKE AGGREGATE TROUGHING WILL CONTINUE TO SLIDE SOUTH, VEERING WINDS
TO NORTH-NORTHWEST BY LATER TUESDAY AFTERNOON ACROSS THE AREA. LAKE
SNOWS WILL REALIGN ACCORDINGLY...FOCUSING BEST SNOWS TO AREAS WELL
WEST OF INTERSTATE 75 ACROSS NORTHWEST LOWER MICHIGAN. LAKE
PARAMETERS REMAIN HEALTHY WITH GOOD LIFT THROUGH THE FAVORED
DENDRITIC GROWTH LAYER, SUPPORTING POCKETS OF INCH PER HOUR SNOWFALL
RATES WITHIN BETTER BANDING. SHIFTING WINDS WILL KEEP DURATION OF
HEAVIER SNOWS LIMITED AT ANY ONE LOCATION.
UPSHOT TO THE ABOVE...STILL LOOKING AT SEVERAL ADDITIONAL INCHES OF
SNOW ACROSS NORTHWEST LOWER MICHIGAN...WITH AGAIN THE FOCUS FOR
BETTER SNOWS SHIFTING SOUTH WITH TIME ON TUESDAY. MUCH LESS
ACCUMULATION ACROSS EASTERN UPPER MICHIGAN...WITH HEAVIER SNOWS
REMAINING WELL TO THEIR WEST BY LATER TONIGHT AND THROUGH THE DAY
TUESDAY. INHERITED ADVISORIES WILL REMAIN, WITH SOME LIKELY SOUTH
EXTENSION TO THOSE ADVISORIES NEEDED FOR TUESDAY.
DEFINITELY SOME CHILLY WEATHER, BUT NOTHING EXTREME, WITH LOWS
TONIGHT IN THE SINGLE DIGITS AND LOWER TEENS...AND HIGHS TUESDAY IN
THE TEENS TO MIDDLE 20S. OF COURSE, GUSTY WINDS WILL MAKE IT FEEL
SEVERAL DEGREES COLDER (WIND CHILLS LIKELY A FEW DEGREES BELOW ZERO
TONIGHT).
LONG TERM /TUESDAY NIGHT THROUGH MONDAY/
ISSUED AT 257 PM EST MON JAN 13 2025
PATTERN SYNOPSIS / FORECAST:
CLOSED LOW WILL BE SLOWLY DEPARTING EASTWARD THROUGH ONTARIO AND
QUEBEC AT PERIOD ONSET, RESULTING IN 500MB HEIGHT RISES ACROSS THE
GREAT LAKES. A SECONDARY WAVE DIGGING THROUGH CENTRAL CANADA WILL
FURTHER REINFORCE SHORTWAVE RIDGING AHEAD OF IT THROUGH THE DAY
WEDNESDAY, LIKELY SUPPRESSING MUCH OF THE LAKE EFFECT ACTIVITY THAT
LINGERS INTO TUESDAY NIGHT. THE WAVE AND ASSOCIATED SURFACE LOW
PRESSURE PASS THROUGH THE REGION WEDNESDAY NIGHT INTO THURSDAY,
BRINGING THE NEXT ROUND OF WIDESPREAD SNOWFALL TO THE REGION. THIS
SYSTEM WILL NOT COME WITH A REINFORCING SHOT OF COLDER AIR... AS WE
LIKELY WARM / MOIST ADVECT IN THE LOW LEVELS ONCE THE SYSTEM PASSES,
WHICH LIKELY LEAVES US IN A DRIZZLY / STRATUS REGIME THROUGH THE
REST OF THURSDAY INTO THURSDAY NIGHT. WARMER TEMPERATURES, POSSIBLY
ABOVE FREEZING, BUILD BY FRIDAY AS ANOTHER SYSTEM APPROACHES FROM
THE WEST. THIS MORE SOUTHERLY FLOW WILL CARRY INTO LATER FRIDAY
BEFORE ANOTHER CLIPPER, THIS TIME A MORE NORTHERLY TRACK (HENCE THE
MILDER AIRMASS), PASSES THROUGH WITH ITS ASSOCIATED COLD FRONTAL
BOUNDARY THAT SETS THE STAGE FOR THE EVENTUAL INTRUSION OF A DEEP
ARCTIC AIRMASS... POTENTIALLY THE COLDEST AIR OF THE SEASON (TO
DATE) AS WE HEAD INTO NEXT WEEK... ACCOMPANIED BY MORE LAKE EFFECT
SNOWFALL.
PRIMARY FORECAST CONCERNS:
LAKE EFFECT SNOW TAPERING TUESDAY NIGHT INTO WEDNESDAY: ONGOING TRUE
NW FLOW LAKE EFFECT SNOWS WILL BE ON A DOWNWARD TREND LATER TUESDAY
NIGHT AS RIDGING OVERHEAD AND DRIER AIR ALOFT CREATES AN
INCREASINGLY HOSTILE ENVIRONMENT FOR LAKE EFFECT SNOW BAND
MAINTENANCE. REGARDLESS, STILL ANTICIPATING THE CORE OF THE NW FLOW
BELTS TO CONTINUE THEIR LAKE EFFECT SNOWS... NAMELY A DOMINANT BAND
ACROSS THAT ANTRIM / KALKASKA REGION, LEAKING SE INTO CRAWFORD AND
FAR NW ROSCOMMON. LESSER ORGANIZED LAKE EFFECT SNOWS WILL BE FOUND
ELSEWHERE. LATER TUESDAY NIGHT, THIS ACTIVITY SHOULD BEGIN TO BE
REALLY SUPPRESSED DUE TO THE RIDGING / DRYING ALOFT. OVERALL,
PERHAPS AN ADDITIONAL 2-4" OF SNOWFALL IN ANTRIM AND KALKASKA IN
THAT DOMINANT BAND, WITH 2" OR LESS ELSEWHERE IN THE SNOWBELTS. SOME
LIGHTER / LESS ORGANIZED LAKE EFFECT SNOW SHOWERS LIKELY CARRY INTO
THE DAY WEDNESDAY, PIVOTING AROUND TO FOCUS MORE ON THE EMMET /
CHEBOYGAN / STRAITS AREA WITH TIME AS WINDS SHIFT MORE SW BY
WEDNESDAY EVENING.
WEDNESDAY NIGHT CLIPPER AND LATE THURSDAY PRECIP: MOISTURE STARVED
CLIPPER SYSTEM WILL MAKE ITS WAY THROUGH THE REGION WEDNESDAY NIGHT
INTO THURSDAY. AFOREMENTIONED LOW INTENSITY LAKE SNOWS IN THE SW
FLOW BELT MAY GET A JOLT AND BECOME BRIEFLY BETTER ORGANIZED AS
SYNOPTIC MOISTURE INCREASES, AND LAKE ENHANCEMENT COMMENCES. THIS
WOULD BE A RELATIVELY SHORT WINDOW, BUT COULD PRODUCE SOME BETTER
INTENSITY SNOWS. OVERALL, THIS DOES NOT LOOK LIKE AN OVERLY
IMPRESSIVE SNOW PRODUCER, GENERALLY 1-3" OF SNOWFALL THROUGH MIDDAY
THURSDAY, WITH THE HIGHEST AMOUNTS FOCUSED ALONG / WEST OF I-75...
POTENTIALLY LOCALLY HIGHER IN THE STRAITS AREA IF ANY LAKE
ENHANCEMENT CAN OVERPERFORM. ACTIVITY WILL TRANSITION BACK TO SOME
LESSER ORGANIZED LAKE SNOWS THROUGH THE DAY THURSDAY... BUT WITH A
LACK OF COLD ADVECTION, FAVORABLE LAKE EFFECT PARAMETERS WILL BE ON
THE DOWNWARD TREND AS WARM ADVECTION COMMENCES (HIGHS 31-35
THURSDAY). THIS WILL KEEP THINGS RATHER CLOUDY FOR THURSDAY NIGHT...
AND WITH SATURATION IN THE DGZ POTENTIALLY COLLAPSING AND LEADING TO
FREEZING DRIZZLE AT TIMES AS TEMPERATURES FALL BACK BELOW 32
THURSDAY NIGHT.
HOLIDAY WEEKEND: NORTHERN STREAM CLIPPER WILL PASS ALONG AND NORTH OF
LAKE SUPERIOR FRIDAY INTO SATURDAY. SOME SNOW WILL BE POSSIBLE
ACROSS THE EASTERN YOOP, BUT WILL HAVE TO CONTEND WITH DRY SLOTTING
ACROSS NORTHERN LOWER AS HIGHS FRIDAY SPIKE INTO THE MID-TO-UPPER
30S. NO SIGNALS JUMP OUT ON GUIDANCE FOR HEAVY SNOWFALL, SO THIS
WILL PROBABLY BE ANOTHER LIGHTER SNOWFALL FOR OUR FRIENDS NORTH OF
THE BRIDGE. WHILE THIS SYSTEM WILL BE RATHER MUNDANE IN NATURE, IT
DOES BRING ABOUT SOME PRETTY IMPORTANT DEVELOPMENTS, NAMELY IN THE
FORM OF A REINFORCING, AND LIKELY QUITE IMPRESSIVE, INTRUSION OF
ARCTIC AIR TO THE REGION. STOUT COLD AIR ADVECTION WILL LIKELY DRUM
UP SOME MORE LAKE EFFECT SNOWS COME SATURDAY AS TEMPERATURES LIKELY
TUMBLE THROUGH THE DAY, AND BY SATURDAY NIGHT, MOST OF THE AREA IS
IN THE LOWER SINGLE DIGITS, AND PERHAPS EVEN BELOW ZERO IN THE
EASTERN YOOP. LAKE SNOWS WILL CONTINUE... BUT IF CURRENT GUIDANCE
TRENDS VERIFY... THIS WON'T BE YOUR IMPRESSIVE LAKE INDUCED MINIVAN
SIZED DENDRITES (SLIGHT EXAGGERATION) THAT YOU SEE IN THOSE HALLMARK
CHRISTMAS MOVIES... IF SURFACE TEMPERATURES HOLD IN THE LOWER SINGLE
DIGITS, THE SNOW COMPOSITION WILL REMAIN DRY, BUT TAKE ON MORE OF A
TALCUM POWDER COMPOSITION... WHICH WILL LIKELY BRING ABOUT
HEIGHTENED VISIBILITY ISSUES AND BLOWING / DRIFTING SNOW. THE COLD
AIR DOESN'T STOP THERE... LATEST INDICATIONS ARE THAT THERE MAY BE A
STRING OF DAYS EARLY NEXT WEEK WITH HIGHS IN THE LOW-TO-MID SINGLE
DIGITS AND OVERNIGHT LOWS WELL BELOW ZERO... WHICH MAY BRING ABOUT
OUR FIRST COLD AIR HEADLINES OF THE SEASON IF TRENDS HOLD.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1145 PM EST MON JAN 13 2025
LAKE EFFECT CLOUDS AND -SHSN CONTINUE. SNOW WILL BE MOST COMMON
NEAR PLN/TVC TONIGHT, BUT HEADING INTO TUE MORNING, VEERING
WINDS WILL SPREAD SNOW INTO TVC/MBL. IFR CONDITIONS WILL OCCUR
AT TIMES WITH MORE INTENSE SNOW SHOWERS. OTHERWISE, A MIX OF
MVFR TO VFR CONDITIONS.
BRISK W WINDS WILL BECOME NW TUESDAY.
APX WATCHES/WARNINGS/ADVISORIES
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ016-017-
021-022-099.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR LHZ345>349.
SMALL CRAFT ADVISORY UNTIL 7 PM EST TUESDAY FOR LMZ323-341-342-
344>346.
SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR LSZ321-322.
UPDATE...JZ
SHORT TERM...MSB
LONG TERM...HAD
AVIATION...JZ
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