Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 161750

Area Forecast Discussion
National Weather Service Marquette MI
1250 PM EST Sat Dec 16 2017

.SHORT TERM...(Today and tonight)
Issued at 408 AM EST SAT DEC 16 2017

Moderate LES into Alger County will gradually weaken while shifting
W this morning, with 2-4" of additional snow in Alger County through
today. Once the snow shifts W, areas of Marquette County near Lake
Superior will be favored for light to briefly moderate LES through
the morning hours with 1-2" (maybe up to 3") of accumulation. Given
high snow to liquid ratios and weak winds, do not expect significant
impacts. Cancelled the Advisory for Marquette County since the
LES band that was expected over the eastern part of the county
stayed in Alger County and no other significant impacts are
expected. Also cancelled Baraga and southern Houghton Advisories
given no significant impacts expected. The Keweenaw will be
tricky today. The winds will become E to ESE, favoring the
Keweenaw for LES, but winds will be steadily shifting and will
also be variable with height, so not really expecting anything too
significant, maybe up to another 4" today. Will let the Advisory
continue for the Keweenaw given uncertainty in how that will

The E-SE winds may result in some light snow showers over the S-
central this afternoon and evening, possibly transitioning to very
light freezing drizzle tonight as moisture leaves the DGZ.

.LONG TERM...(Sunday through Friday)
Issued at 423 AM EST SAT DEC 16 2017

Sunday through Monday: Expect a relatively benign period of weather
during this time under mostly a zonal flow aloft. Weak WAA ahead
of a shortwave approaching from south central Canada may result in
very light snow or possibly freezing drizzle across mainly the
southeast half of the Upper MI Sunday into Sunday evening.
Otherwise, temps should be slightly above normal during this

Monday night through Wednesday afternoon: Stronger shortwave energy
from south central Canada will be diving through the Northern Plains
and reaching the Upper Great Lakes Mon night into Tue. Moderate snow
showers will accompany the initial shortwave and associated cold front
late Monday into early Tuesday morning, especially across the
north half. Strong NW winds behind the trough will be enhanced by
a modest isallobaric wind component. The combination of gusty W to
NW winds of 40-45mph and lake effect snow will likely cause
intermittent white out conditions across the Keweenaw Peninsula
through much of the day Tuesday, and along Lake Superior from
Munising eastward Tue afternoon and evening. Although nw winds
will diminish late Tue night into Wednesday and subsidence
inversions will lower blo 5 kft Wed afternoon, 850 mb temps near
-18 and favorable positioning of the DGZ within the lake
convective cloud layer should result in several more inches of
fluffy accumulation mainly into the eastern counties before snow
tapers off late Wed.

Wednesday night through Saturday: Models exhibiting plenty of
uncertainty with next system developing over the Plains for mid to
late next week. The 00z GFS and ECMWF have trended away from more
phased solution from previous night`s run with the ECMWF and Canadian
models showing a much weaker sfc low trending much farther south
through the Lower Great Lakes late Thu night into Fri. The operational
GFS remains the farthest north of the models still taking a low track
across central Lake Huron which is farther north than the GEFS mean.
Both the ECMWF and GFS indicate light to possibly moderate snow
spreading east across Upper Mi Wed night into Thu while the Canadian
model keeps the bulk of the synoptic snow se of the area. Lake enhanced
snow potential now appears fairly limited behind this system Thu night
into Friday given more southward trending track. Models then hint at
another clipper shortwave and associated shot of colder air moving
through the area Fri night into Sat which could enhance lake effect
snow showers over the west wind snow belts.

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1250 PM EST SAT DEC 16 2017

Some lingering light lake effect snow showers at KCMX will end early
this afternoon. Otherwise, VFR conditions will gradually give way to
MVFR cigs tonight as srly low level flow with increasing moisture
advection develops.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 408 AM EST SAT DEC 16 2017

Southwesterly winds will increase late Monday to 20 to 30 knots
before veering to northwesterly gales to 35-45 knots late Mon night
through Tue night. With increasing wave heights, freezing spray is
possible Tuesday night into Wednesday.

Upper Michigan...
  Winter Weather Advisory until 5 PM EST this afternoon for MIZ001-

Lake Superior...
Lake Michigan...


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