Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 142134

Area Forecast Discussion
National Weather Service Marquette MI
434 PM EST Tue Nov 14 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 335 PM EST TUE NOV 14 2017

Tonight into Wednesday: The main focus for this time period will be
precipitation associated with a low pressure system sliding from
southern Manitoba eastward into Lake Superior and Ontario.  An
associated cold front is progged to shift from the Northern Plains,
tonight, into the far eastern U.P. by Wednesday afternoon.
Initially, late this afternoon into the early evening hours, the
moisture will be fairly shallow, leading to mainly drizzle/very
light rain and some fog across the area. Widespread forcing and
deeper moisture along and ahead of the front, by mid to late
evening, will lead to widespread precipitation across much of the
U.P. Soundings show that the lower levels of the atmosphere are warm
enough that the precipitation should mainly fall in the form of rain
tonight through early Wednesday afternoon. After the low shifts to
the east and frontal passage occurs by early afternoon, winds will
shift to the west, then northewest by mid to late afternoon. As
colder air advects into the area on the back side of the low, expect
breezy conditions to develop through the day with gusts as high as
25 to 35 mph along the Lake Superior shoreline during the mid to
late afternoon. Wrap-around moisture along with uplope westerly flow
over the western U.P. will allow rain showers to continue through
much of the day before transitioning to snow by late in the
afternoon. As temperatures continue to cool aloft, expect lake
effect snow showers to begin developing by late Wednesday afternoon,
probably closer to 00Z/16 before the lake effect really gets going,
mainly over the western U.P. 850mb temperatures by 21Z-00Z are
progged to drop to around -4C to -6C over the western U.P. while the
central and eastern U.P. sees 850mb temps around 0C to -3C. Lows
tonight are expected to be mainly in the mid 30s with daytime . This
would only be marginally favored for lake enhancement over the far
west by late Wednesday afternoon.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 432 PM EST TUE NOV 14 2017

Models suggest that a progressive pattern will prevail through this
weekend with a couple of mid level troughs and sfc lows moving
through the region bringing rain followed by colder air and LES.

Wednesday night, a shortwave trough will slide to the southeast
with the strongest 700-300 qvector conv through northern and
eastern Lake Superior. The combination of deep moisture and 850 mb
temps to around -10C (over water temps around 6C) with cyclconic
low level winds veering from nw to n will bring LES through the
nrn cwa. With the steadily shifting winds and marginal
instability, snow totals should remain in the 1 to 3 inch range.
In addition the colder air will arrive overnight, after the
stronger low level conv moves through during the evening.

Thursday, dropping inversion heights to 3k ft as high pres builds
into the area will bring diminishing LES with some clearing in the
afternoon along with diminishing winds.

Friday-Sunday, The GFS/GEFS/GEM have trended weaker and faster
toward the previous ECMWF runs as the nrn and srn streams phase
slightly later as the low moves away from the central Great Lakes.
Expect widespread pcpn mainly as rain to spread across Upper
Michigan Friday into Friday night with strong WAA and moisture
advection (PWAT above 0.75 inch) as the sfc trough moves through the
Upper MS valley into the wrn Great Lakes. There may be some isold
fzra cntrl early Friday before sfc temps climb by midday. Fzra or
ice potential will be limited by initial dry 900-700 mb layer.
Although strong CAA and nw flow LES will develop Saturday behind the
deepening low, confidence in wind strength is still low given models
variability. Moderate LES with with some heavier bands will be
possible with considerable blsn. Lingering LES will diminish Sunday
as sfc and mid level ridging build into the area.

Monday-Tuesday, confidence in details regarding a clipper shortwave
depicted by the GFS/ECMWF/GEM is low but this feature could bring
additioinal light sn/LES ino the area.

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1236 PM EST TUE NOV 14 2017

MVFR conditions will be IFR/LIFR at KSAW in fog/low stratus/rain
through early Wednsday morning before slowly improving by Wednesday
afternoon. Ocassional MVFR conditions at KCMX/KIWD will also lower
down to LIFR tonight in heavier rain and fog. Slow improvemnt will
occur at the western TAF sites during the afternoon, before lake
effect/enhanced snow showers develop.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 335 PM EST TUE NOV 14 2017

South winds will gust to 20-30 kts through tonight as the pressure
gradient tightens between departing high pressure and low pressure
tracking over south central Canada. The low will cross Lake Superior
and northern Ontario Wednesday morning with northwest gales to 35
kts over all but far western Lake Superior Wednesday afternoon into
Wednesday night. Gale warnings are in effect from late Wednesday
afternoon into Thursday morning. Winds will diminish Thursday but
strong winds are expected again Fri-Sun as a strong low pressure
system tracks from Upper Great Lakes to eastern Canada. At the least
there will be gales with this system and there could even be storm
force winds behind the storm system Sat Night into Sun morning.

Upper Michigan...
Lake Superior...
  Gale Warning from 6 PM Wednesday to 10 AM EST Thursday for

  Gale Warning from 4 PM Wednesday to 7 AM EST Thursday for

  Gale Warning from 4 PM Wednesday to 4 AM EST Thursday for LSZ263.

Lake Michigan...
  Gale Warning from 9 PM this evening to 8 AM EST Wednesday for



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