Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 181014
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
614 AM EDT Mon Mar 18 2024

.KEY MESSAGES...

- Lake effect snow showers wane today with additional light snow
  arriving tonight into Tuesday.

- Breezy to brisk and cold Tuesday night into Wednesday night with
  lake effect snow. Blowing snow and significant reductions in
  visibility will be possible within any heavier snow showers.

- Additional light snow continues to be a possibility late this
  week.

&&

.UPDATE...
Issued at 614 AM EDT Mon Mar 18 2024

Given latest radar trends over the last several hours, will go
ahead and cancel the Winter Weather Advisory a few hours early.
Still some light snow showers out there this morning with
lingering snow-covered roads in spots from snow overnight, but
the bulk of accumulation is most certainly in the rear view
mirror.

&&

.NEAR TERM /THROUGH TONIGHT/...
Pattern Synopsis/Forecast: Deep trough axis is currently draped
across far eastern Canada down through the western Great Lakes and
mid-MS Valley. Heights are expected to rise briefly later this
afternoon/evening, but short-lived as additional energy races
toward the region from the northwest. As the surface, a weak
cold front tries to exit/wash out this morning with focus
turning to that inbound clipper later tonight as low pressure
dives out of northern Alberta and races toward far northern Lk
Superior by 12z Tuesday.

Lake effect today/additional light snow tonight:

Snow showers continue early this morning with the last vestiges of
synoptic support waning over the next couple of hours. In general,
expecting snow shower coverage/intensity to decrease with time today
given a temporary drying trend with low-level winds backing from
north-northwest to eventual west-northwest by early evening. This
should gradually push snow showers farther east with time, but the
loss of a Lake Superior connection across northern lower should
further aid to wane activity. Some localized additional accumulation
through late morning of up to 2 inches.

Winds continue to veer this evening becoming southwesterly for the
second half of the night in advance of aforementioned approaching
clipper system. Should be enough moisture and isentropic support for
additional mainly light to arrive late tonight, most widespread
across the northern half of the forecast area. Some lake enhancement
poking into the tip of the mitt/far northwest lower and perhaps
southern Mackinac County. Additional snow tonight thru 12z Tuesday
generally ranging from 1-3 inches in those lake enhanced areas
with lesser amounts elsewhere.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
Pattern Synopsis and Forecast:

Tuesday through Wednesday night will feature a parade of short waves
embedded within northwest flow aloft (think I count potential for ~3-
4ish? separate pieces) which will keep the threat of snow showers
through this period. Additionally, a few sfc fronts/boundaries move
through the area consequent of the energy aloft and subsequent sfc
cyclone to the northeast. As the more robust short wave moves
through on Wednesday, sfc cyclone will eject to the east across
Ontario/Quebec, thus advecting a chilly, below normal airmass on
Wednesday.

Primary Forecast Concerns:

Energy aloft within northwest flow will swing through Tuesday
resulting in snow shower activity across the area, especially across
eastern portions of northern lower and eastern upper as we head
through the daytime hours due in part to weak boundary/sfc troughing
shifting eastward. Next short wave will dive down late Tuesday into
Wednesday resulting in more snow shower generation, mainly within
northwest snow belts as a colder airmass advects over the Great
Lakes region. Progged soundings show inversion heights up to ~800mb
(occasionally near 750mb) with sufficiently cold low level
temperatures (850 temps ~-15C) and moisture. So we`ll keep an eye on
this going forward but expect snow showers with the potential for at
least a couple of inches (some guidance shows the potential for
several inches) of lake effect snow Tuesday night into Wednesday
night. This could be a pretty decent event for NW snow belts.
Another aspect will be the gusty conditions on Wednesday as the
pressure gradient tightens, thus low level winds increase, over the
region. We`ll be mixing into low to mid 30 knot winds aloft, thus
gusty conditions are expected. Consequently, blowing snow and
significant reductions in visibility will be possible within any
heavier snow showers.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Pattern Synopsis and Forecast:

Moisture will begin to wane briefly as we head through the day on
Thursday. 2D model parameters and progged soundings show as such,
thus lake effect potential will decrease throughout Thursday. That
being said, still could see a few lake effect snow showers during
the first half or so of the day (depending on how long low level
moisture hangs around) given the 850 temps/low level profiles. But,
by the afternoon and evening, upper trough moves well off to the
east, drier air advects in, and low level temperatures increase.
Thus, although another cool day is expected on Thursday, drier
conditions briefly fill in across the region. All this being said, a
weak piece of energy aloft along with a weak 850 mb wave will track
across the lower Great Lakes resulting in a quick hitting system and
the chance for some light snow Thursday night into Friday. Looks
like one of those "the farther south you go the best chance for
steadier precip" type of events. GFS continues to be bullish while
ensembles, CMC and ECM are more in line with a light snow event.
Ensembles 50th percentile snow accum for this event, a couple of
inches. Thus, will lean towards the potential for a light snow event
given the latest guidance.

Looking well into the future, deterministic GFS, CMC, ECM all hint
at the potential for a more significant system in the late weekend
early next week time frame. No outlook given this far in advance but
a storm will likely be in the vicinity of the Upper Midwest/Great
Lakes early next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Upper level trough axis and surface reflection will continue to
pivot thru Northern Michigan overnight...providing synoptic
support for ongoing NW flow lake enhanced snow shower activity
across our area into early Monday. Ridging and drier air will
begin to work its way into the Western Great Lakes region in the
wake of these features on Monday...resulting in diminishing
snow shower activity (both in areal coverage and intensity) as
we head into Monday afternoon and evening. Prevailing conditions
will remain low VFR/MVFR...periodically dropping to IFR within
some of the heavier snow showers. Surface winds will remain from
the NW at 15 to 25 kts.

&&

.MARINE...
Sporadic advisory level winds/waves continue on northern MI`s
nearshore waters today before firmly diminishing below criteria this
evening through tonight. Focus transitions to the Tuesday night -
Wednesday time frame as gusty conditions are expected to redevelop
behind another passing low pressure system. A period of gale force
winds looks possible during this midweek time frame.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 11 AM EDT this morning for LHZ345-
     346-349.
     Small Craft Advisory until 11 PM EDT this evening for LHZ347-
     348.
     Small Craft Advisory until 11 AM EDT this morning for LMZ323-
     341-342-344.
     Small Craft Advisory until 2 PM EDT this afternoon for LMZ345-
     346.
     Small Craft Advisory until 11 PM EDT this evening for LSZ321-
     322.

&&

$$

UPDATE...MJG
NEAR TERM...MJG
SHORT TERM...JLD
LONG TERM...JLD
AVIATION...MLR
MARINE...MJG


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