Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 170415
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
1115 PM EST Sun Jan 16 2022

.DISCUSSION...(Tonight through Sunday)
Issued at 403 PM EST SUN JAN 16 2022

Medium range models indicate that weak mean ridging over the eastern
Pacific and west coast of N America will become more amplified by
late next week. This more amplified ridge over the West Coast will
in turn induce a deeper and more amplified trof downstream into
central N America by late next week, including the Great Lakes
region. This trof will allow for more frequent intrusions of much
colder Arctic air into the region. Also, longer term
trends/predictions of a more negative AO index and the extended fcst
temperatures off the CFSv2 of 2-3.5 standard deviations blo normal
suggest this colder pattern could perhaps linger into the first half
of February.

Models resolve three clipper systems that will impact our area over
the next week. The first one moving thru today/tonight is fairly
weak and will bring a shot of light system snow today into this
evening and then some light nw flow LES behind it late tonight into
Mon night. The second clipper is stronger and will likely bring a
better chance for widespread late Tue into Wed morning with more
substantial nw flow LES behind it Wed into Thu. The final clipper of
the week moves trough late Saturday and should bring widespread
light snow to the area Saturday into Saturday evening with more
north flow LES behind it later Sat night into Sun.

Tonight, models show light system snow weakening over the east half
of the cwa toward evening due to weakening fgen ahead of sfc
trough/front. N-NW flow LES then develops behind the front tonight,
but instability is fairly weak as 850 mb temps don`t get
particularly cold behind the front. Also, the large scale flow
becomes increasingly anticyclonic through the night, so not
expecting much for LES accumulation, at most an inch or two. Min
temps tonight will be mostly in the 10 to 20 degree range, coldest
over the central and east interior.

Monday and Monday night, 850mb temps get slightly colder by late
Monday, dipping to -12 to -16C coldest east. As a result, the DGZ
will be positioned a bit more favorably in the CBL but with
increasingly drier air being advected in from nw of Lake Superior
and inversion hgts around 4 kft, LES amounts will still be light,
probably not much more than an inch or two every 12 hours. Highs
Monday will be in the lower to mid 20s with min temps Mon night
ranging from the low single digits abv zero over the central and
eastern interior to the high single digits to around 10F near the
Great Lakes shores.

A high pressure ridge shifting east across the area will keep
conditions mostly dry Tuesday morning but then a more substantial
clipper system moves in bringing a chance of widespread snow Tuesday
afternoon into early Wednesday. The exact track of this system is
still a bit uncertain as the ECMWF and NAM track the storm over Lake
Superior while the GFS tracks it more across the U.P. and the
Canadian is a compromise between the solutions. Model consensus qpf
ranging from .1 to .25 inch should yield system snow accumulation of
around an inch far south to 2-3 over northern sections. SE winds
ahead of the low will likely result in some lake enhancement, which
could boost snow totals into the advisory criteria across the
Keweenaw and into the southeast counties of the U.P.

As the clipper system exits e on Wednesday, cold arctic air will
move in behind it as an Arctic high pressure system builds across
the Northern/Central Plains. LES will remain possible in the NW wind
snow belts Wednesday through Thursday, but with 850mb temps dipping
near -25C snow accumulation may be limited by the DGZ descending
closer to the sfc. Best accums will be over the east half of the cwa
where longer fetch across eastern Lake Superior will lead to more
lake modification and could raise the DGZ higher leading to fluffier
accumulation. Overall, wouldn`t expect much more than maybe low-end
advisory snowfall into the east half.

Look for temps to fall through the day into the single digits on
Wednesday and remain there through Thursday. Brief shortwave ridging
may bring some relief from the bitter cold with a SW flow developing
Friday into Saturday with max temps rising into the teens, but
operational models and ensemble means suggest this will be warmup
will be short-lived as another shot of colder Arctic air and
northerly flow moves in for the second half of the weekend into next
week with more bitter cold temps and LES in store.
&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1102 PM EST SUN JAN 16 2022

Although the VFR category has emerged at KSAW as of this writing,
this is anticipated to be short-lived as clouds fill back in
under continued CAA. Light SHSN will continue to prevail within
the NW wind belts across Upper Michigan, impacting the terminals
(or at least their vicinities) as a result. There are some
indications that an incoming upper jet axis nosing in later on
Martin Luther King Jr. Day, coupled with vort max and very weak,
decaying surface "low" supported by enhanced atmospheric moisture
could allow for a brief period of SHSN to reduce visbys lower than
what`s currently in this TAF issuance. Essentially, aviation
interests should expect at least MVFR conditions to dominate the
TAF period, with IFR not entirely ruled out.

&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 403 PM EST SUN JAN 16 2022

There could be some sw gusts to 30 knots ahead of the trough early
evening, otherwise winds will shift north-northwest behind the
trough/front tonight into Monday with gusts to around 30 knots over
the eastern half of the lake. Conditions improve briefly Tuesday
morning as high pressure moves overhead but then se winds ramp up
ahead a strong clipper system moving in from the Northern Plains
with se gales to 35 kts possible over the east half late Tue into
Tue evening. An Arctic cold front moving through Tuesday night will
likely bring another round of NW gales Tue night into Wednesday with
more heavy freezing spray likely. This cold air will remain over the
lake into Thu with NW winds of 20 to 30 knots expected. Winds begin
to shift southwest on Friday on the backside of a passing sfc ridge
and could increase to 30 kts over the west and north central with
possible gale gusts.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&

$$

AVIATION...lg
MARINE...Voss


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