Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 181443
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1043 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 1042 AM EDT Mon Mar 18 2024

Blocky pattern over the Western US. Niblets of energy overtopping
the longwave ridge...including one such niblet over northern
Saskatchewan this morning...with positively tilted shortwave ridge
axis just to our northwest attm and attendant warm advection in the
upper levels. Surface high pressure encompasses the bulk of the
central US, with surface reflection of aforementioned niblet still
poised well to our west toward the Rockies. Closer to home...we
remain under a troughy regime, with weak surface trough drifting
down through the UP this morning. Slight low-level cold advection
ahead of a PV strand stretching from northern Ontario into the Upper
Midwest, which has been steadily drifting SE this morning...and have
seen a brief uptick in radar returns over MQT...along with some
slightly deeper clouds over the EUP.

Expect this latter feature to continue to drift through the region
this morning from NW-SE...with a brief uptick in lingering snowfall
for an hour or two as it passes. Breezy winds should slowly diminish
and back around toward the west and eventually southwest by late
afternoon...as the ridge axis drifts in...and warm advection
commences. Lingering LES should begin to shift around
accordingly...though not expecting it to totally stop this afternoon
(should diminish to nuisance flurries/light snow showers though), as
925mb temps remain cold enough. May even look for an uptick in LES
going into this evening in those typical SW flow areas as top-down
saturation commences.

&&

.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 /UNTIL 6 AM TUESDAY MORNING/...
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 /6 AM TUESDAY MORNING 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 MONDAY/...
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/...
MVFR to low VFR CIGs continue today with lingering light lake
effect snow showers most frequently at TVC/MBL with a gradual
diminishing trend. Breezy northwest winds veer more west-
northwesterly and diminish by this evening. Southwest winds for
the second half of tonight, becoming breezy once again by early
Tuesday morning. Additional snow becomes likely at CIU/PLN by
late tonight.

&&

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


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