Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 151953

Area Forecast Discussion
National Weather Service Marquette MI
253 PM EST Thu Feb 15 2018

.SHORT TERM...(This evening through Friday)
Issued at 252 PM EST THU FEB 15 2018

Patchy freezing drizzle should end later this afternoon and evening,
then some light to possible moderate lake effect snow is
expected over the eastern counties tonight.

Some lingering dry air above 850 mb has led to some patchy freezing
drizzle at a few western locations of the cwa this afternoon, but no
real ice accumulation nor impacts have been reported. Forecast
soundings suggest patchy freezing drizzle could mix with light snow
at a few locations west and north central into late afternoon/early
evening before gradually changing over to all -shsn from the north
and west.

Tonight: As the cold front continues south and east of the area,
north to northwest flow across Lake Superior will increase. This,
along with 850mb temperatures dropping to around -18C to -20C
overnight, will allow lake effect snow to increase for north to
northwest wind snowbelts. The best chances for lake effect snow will
be over the north central and especially the eastern U.P, downwind
of Lake Superior, due to a larger portion of the eastern lake
without ice coverage. The west half of Lake Superior is covered with
extensive ice cover, therefore, would not expect much more than
light, intermittent lake effect snow over the western U.P. The far
eastern portion of Alger County and the north half of Luce County,
northern Schoolcraft and Northern Luce county could see 2 to locally
4 inches of snow tonight into Fri morning, especially in the heavier
snowbands. The increase in snowfall intensity tonight could be aided
by a shortwave now over Saskatchewan moving across the Upper Lakes
later tonight which will help to steepen lapse rates and overwater
instability for those locations.

Friday, high pres building into the region will result in backing
anticyclonic westerly winds with dropping inversion heights. Any
lingering LES will diminish or shift offshore in the morning. Under
sunny skies expect high temps in the upper teens to lower 20s.

.LONG TERM...(Friday through Wednesday)
Issued at 503 AM EST THU FEB 15 2018

Models suggest that the broad mid/upper level trough from Hudson Bay
into the n cntrl CONUS will shift into the wrn CONUS as shortwave
energy drops se from the Gulf of Alaska resulting in sw flow into
the Great Lakes through the middle of next week. This will bring the
potential for periods of snow through the region as the main sfc-850
mb frontal boundary remains just to the south. A brief period of
below normal temps Friday will rebound to readings at or above
seasonal averages through Wednesday.

Friday, high pres building into the region will result in backing
anticyclonic westerly winds with dropping inversion heights. Any
lingering LES will diminish or shift offshore.

Saturday, a weak shortwave and sfc trough will bring potential for
some light snow, with the best chance for any accumulation downwind
of lake enhancing sw flow off of Lake Michigan east of Manistique.

Sunday into Sunday night, the models were in slightly better
agreement but the ECMWF remained farther north and lighter with the
initial area of snow late Sun into Sun night with broad
WAA/isentropic lift compared to the GFS/GEFS. Snow accumulations of
a few inches may be possible.

Monday-Tuesday, The models remain in reasonabler agreement Monday as
the pattern will be favorable for stronger fgen and isentropic
ascent that could bring moderate to heavy snow accumulations.
Differences remain in handling the timing/strength of shortwaves
lifting into the Great Lakes and the impact on sfc low development
especially into Tuesday that could bring additional snow

Wed-Fri, Models have trended toward pushing the frontal boundary and
area with highest snow potential gradually to the east by Tue night
into Wednesday. High pressure and drier air will build into the
region. There is more uncertainty with how quickly the high will
shift to the east with warm air moving back into the region.

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1223 PM EST THU FEB 15 2018

A cold front dropping se across the Upper Peninsula today,
has led to the development of IFR to low end MVFR cigs and
some -sn/-fzdz at times which will transition to
all -shsn/flurries, mainly at KIWD/KCMX. Arrival of drier air
will lead to cigs lifting to high MVFR at all terminals late
this afternoon into the evening hours. Ceilings should become
VFR late tonight into Friday morning.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 252 PM EST THU FEB 15 2018

A few southwest gale force gusts are possible on Saturday and north
to northeast gale force gusts Monday and Monday night, otherwise
winds will be below gales through the forecast period.

Upper Michigan...
Lake Superior...
Lake Michigan...


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