Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 160912

Area Forecast Discussion
National Weather Service Marquette MI
412 AM 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...(Saturday night through Friday)
Issued at 259 PM EST FRI DEC 15 2017

Saturday night through Monday: A relatively benign period of weather
is expected during this time. Weak WAA may bring result in very
light snow or possibly freezing drizzle across mainly the southeast
half of the Upper MI Sunday afternoon and evening. Otherwise,
temperatures should be slightly above normal during this period.

Monday night through Wednesday afternoon: The somewhat disjointed
phasing of two mid-level troughs will be ongoing across the Upper MS
Valley Monday evening. Moderate snow showers will accompany this
trough across the CWA late Monday evening into early Tuesday
morning, especially across the north half. Strong NW winds behind
the trough will be enhanced by a modest isallobaric wind. The
combination of gusty W to NW winds to 40mph 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 east of Marquette Tuesday afternoon and evening. While even
stronger winds are not out of the question, the complicated phasing
of the troughs and that fact that this event is still four days out
supports a more modest forecast at this time. Either way, a period
of moderate lake effect snow for the W to NW wind snow belts is
expected Tuesday afternoon through Wednesday afternoon.

Wednesday night through Saturday: A potent mid-level trough moving
over the NW CONUS Tuesday night will become stretched across the
central CONUS by Thursday afternoon. There is considerable model
disagreement on the evolution of the northern portion of this trough
as it crosses the region late Wednesday night into Friday. The
deterministic GFS and a handful of GEFS members are indicating a
swath of moderate WAA snow across the CWA late Wednesday night
through Thursday afternoon. All other solutions favor a stronger
southern flank of the trough across the Lower MS Valley, with some
northern energy bringing a couple rounds of light snow Thursday
through Friday. However, it is far too early to take much stock in
any of these solutions given the expected complex evolution of the
western trough.

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1240 AM EST SAT DEC 16 2017

At KIWD: There is a slight chance that some lake effect could
briefly impact the terminal over the next few hours, but thinking it
will stay dry.

At KCMX: Lake effect snow showers with IFR-MVFR conditions will
continue overnight and through most of Sat at CMX. Could see
occasional LIFR visibility on Sat at CMX if a stronger easterly wind
band of lake effect snow ends up impacting the terminal.

At SAW: As winds turn northerly late tonight into Sat morning, could
see IFR to MVFR conditions briefly develop before improving by
midday Sat.

.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 Storm Warning until 1 PM EST this afternoon for MIZ006.

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

Lake Superior...
Lake Michigan...


LONG TERM...Kluber
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