Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 020449

Area Forecast Discussion
National Weather Service Marquette MI
1149 PM EST Thu Dec 1 2016

.SHORT TERM...(This evening through Friday)
Issued at 343 PM EST THU DEC 1 2016

Sfc low has moved east of Lk Superior but sfc troughing remains
across Upper Michigan and northern WI. Cool moist northwest flow
north of the trough is resulting in lake effect precip in the form
of mostly snow across the west half and mainly in the form of rain
across the east half of the cwa. Lake effect was heavier and more
widespread late last night into late this morning as a shortwave
wrapping around the western portion of the larger scale trough moved
across. Some higher terrain areas saw 2-4 inches of snow during that
time but based on web cams and sfc obs seems that the snow into this
aftn has become lighter. Expect marginal setup for lake effect to
continue through tonight and Friday with h85 temps -7c or so and
inversion heights around h85/5kft. Another couple of shortwaves
north of Lk Superior look poised to drop across Lk Superior and
parts of Upper Michigan later tonight into Friday morning. Stronger
forcing and deeper moisture look to mainly affect eastern cwa but
should see increase in lake effect for all areas as these waves
drop across similar to what occurred last night and this morning.

Additional snow amounts tonight into Fri morning will mainly be an
inch or two, but isolated higher terrain spots over the west and
maybe just inland from Lk Superior in the east could see higher
amounts of 3 to 4 inches. Only real bigger adjustment into Fri was
to ramp up pops over east cwa late tonight and Friday morning even
south to the Lk Michigan shore as that area will be most directly
impacted by the shortwave dropping down across eastern Lk Superior
and will have the advantage of being at the end of the longer fetch
with nw winds off Lk Superior. Consensus of probability of ice
present grids indicate that if enough deeper moisture does not
materialize, especially west, there could be some chance of drizzle
or freezing drizzle. Only have a slight chance of drizzle mainly
late tonight and into Fri.

Temperatures will fall back into the upper 20s tonight over the
interior west and central and that could lead to slippery spots as
moisture from the light snow today refreezes. Will mention that in
the hazardous weather outlook (HWOMQT). Farther east, temps will
fall into the lower 30s inland and stay in the mid 30s near the
shore. Should eventually see the rain near the shore mix with and
change to snow. Feasible it could stay warm enough right near the
shore to keep ptype mainly rain. Temps will stay cool on Fri with
low 30s over interior west and as warm as upper 30s near Lk Michigan
and over the far east.

.LONG TERM...(Friday night through Thursday)
Issued at 442 PM EST THU DEC 1 2016

Models suggest that a progressive pattern will transition to an
amplified pattern next week with a prominent trough developing over
the west that will slide into the cntrl/ern CONUS toward the end of
the week. This may result in more active weather with much colder air
also moving in by the end of the week.

Friday night into Saturday night, weak to moderate instability will
prevail with 850 mb temps around -7C and inversion heights to around
5k ft. Expect light LES to continue into areas favored by wnw to nw
flow. As a ridge of high pressure builds into the region and winds
gradually back to the west and southwest late Saturday into Saturday
night, any lingering LES will diminish or end. Snow amounts up to an
inch are possible over the west Fri night with another half inch
possible Sat morning. Warmer air over the east may limit
accumulations with the snow mixing with rain at times, especially
along the lakeshore.

Sunday into Monday, A shortwave trough moving from the nrn plains
through the nrn Great Lakes will bring the potential for light snow
across the area by late Sunday into Sunday night as 285K-290K
isentropic lift increases. With a brief duration of the stronger
lift and limited moisture inflow, any amounts will be light (QPF of a
few hundredths). Temperatures into the mid 30s near the lakes and
east will also bring a mix with rain. A dry period is expected Monday
into Mon night with a period of mid level ridging and the return of
waa and srly low level flow. Temperatures will remain above normal
with highs into the mid to upper 30s Monday.

Tuesday through Thursday, uncertainty remains high given large model
and ensemble spread in handling the evolution of the mid level
trough and any strong shortwaves that emerge with their impact on
sfc low development. The ECMWF has been more consistent in bringing
a strong low through the wrn Great Lakes while the GFS/GEFS show
more unphased nrn/srn streams with colder air sliding in much
earlier. The potential remains for a significant low or storm into
the region but confidence is low with any details.

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1148 PM EST THU DEC 1 2016

Abundant low-level moisture will result in prevailing MVFR
conditions at KIWD/KCMX/KSAW thru this fcst period. With
northwesterly winds the rule, winds will have a downslope component
at KSAW, so some periods of VFR are possible. Conversely, the nw
upslope flow at KCMX/KIWD will result in generally lower cigs with
KIWD possibly seeing some periods of IFR. -SHSN are also expected
off Lake Superior, especially at KIWD/KCMX, but coverage will
diminish today. Not out of the question that there could be a little
-FZDZ at KCMX/KIWD overnight thru this morning.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 343 PM EST THU DEC 1 2016

Surface low continues to drift east away from Lk Superior but
tighter pressure gradient across Lk Superior will keep nw winds 20
to 30 kts into Fri, strongest on the east half. High pressure moving
across will diminish the winds to 20 kts or less Fri night into the
weekend. Approaching low pressure trough for the middle of next week
will result in southeast winds increasing to 25 kts, strongest over
eastern sections.

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


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