Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 272344
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
644 PM EST Mon Feb 27 2017

.SHORT TERM...(This evening through Tuesday)
Issued at 234 PM EST MON FEB 27 2017

Upper air pattern consists of a 500 mb trough in the western Rockies
this morning. This trough moves to the eastern Rockies by Tue
evening. Nam shows some 850-500 mb q-vector convergence and deeper
moisture late tonight into Tue. GFS and ECMWF show about the same
thing as well. Will use a blend of the forecast models for this
forecast.

Looked at some soundings off bufkit and only place I could find
freezing rain being possible for a short time was IMT off the Nam
sounding. Looked like it was going to be mostly a rain/snow and some
sleet at times for the pcpn types and do not expect icing to be much
of a problem. Pcpn starts late tonight, but before it does the
temperatures will be rising. Snow totals will not be that much
either as most of the qpf that falls will be rain, but could still
see up to an inch of snow in the Keweenaw. Overall, did not make too
many changes to the going forecast.

.LONG TERM...(Tuesday night through Monday)
Issued at 249 PM EST MON FEB 27 2017

The weather pattern continues to look active next week with multiple
chances for snow, especially LES in the northeast to northwest wind
snow belts later in the week. Temperatures will start off near
normal for this time of year, then dropping a few degrees each day
through the end of the week. The mild temperatures will return for
the weekend, with highs in the 30s/40s expected.

Tuesday night into Wednesday as colder air filters south across the
area, expect locations that see snow transition over to rain, to
transition back over to snow through the overnight hours. Across the
east, the rain will linger as a lead shortwave beings to exit the
area. With onshore northeast flow, expect locations across the
higher terrain in the northeast wind snow belts to see the best
chance for accumulating snow. As the main longwave trough ejects out
across the central plains, a broad surface low will lift northeast
out of the central plains up into lower Michigan on during the
overnight hours. The models have come into better agreement with the
timing and track of this system, with the GFS models trends
continuing to come back around to/close to the ECMWF solution, and
keeping the system well to the south. Therefore, expect the bulk of
the system precipitation is expected to stay south of the area, with
the except of far south central and eastern portions of Upper
Michigan. However, the majority of this precipitation looks like it
will fall as rain before transitioning over to light snow.

Wednesday into Thursday as the main system lifts across the
northeast portion of the CONUS, colder 850mb flow will begin to
filter south across the area. This will allow LES to transition from
the northeast to northwest wind snow belts. With lower inversion
heights and limited lift/cloud depth through the DGZ, only expect
the initial LES to be light. However, Thursday into Friday a
shortwave will dig south across the Upper Mississippi River Valley
bringing a reinforcing shot of colder air. This cold air advection
will allow inversion heights to raise and the lake induced
convective layer to grow across the northwest wind snow belts.
Therefore, expect at least moderate LES as BUFKIT soundings showing
good low-level lift with ample cloud depth through the DGZ. As a
surface cold front pushes through Thursday evening, could see a
transient band of snow move across the area as well as quasi-deep
lift, with elevated omega values from the surface through ~500mb,
develops along the eastward moving front. The LES will eventually
lift north and offshore as 850mb flow backs to the southwest and
warms as transient upper-level ridging moves overhead on Friday.

As the LES beings to weaken and push offshore, the warm air
advection arriving from the southwest will bring a chance for
widespread precipitation across the area Friday night into Saturday.
Temperature profiles look like they will remain cold enough that
precipitation should remain all snow. Through the weekend, a clipper
system is progged to dig just north of the area. With the better
warm air advection displaced northeast of the area, this should
allow widespread precipitation to lift northeast through the day on
Saturday. Sunday into Monday there is some uncertainty in how things
will unfold with the deterministic models suggesting another storm
system will eject out of the Rockies. The big question will be what
track the system will take. The GFS suggests the system will develop
across the northern Rockies and the Canadian is much further south
across the southern and central Rockies, with the ECMWF falling in
between the two solutions.
&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 640 PM EST MON FEB 27 2017

Llvl dry air under a good deal of mid/hi clds wl result in VFR
conditions at the TAF sites thru tngt. But as mixed pcpn in advance
of an aprchg upr disturbance arrives toward daybreak and overspreads
the area thru the mrng, predominant IFR conditions are likely to
prevail thru the day. Expect gusty n winds to arrive at CMX later
in the day following the cold fropa associated with the passing
disturbance.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 234 PM EST MON FEB 27 2017

Winds will remain 30 kts or less through mid Tue afternoon. There
will be a period of northeast gales late Tue afternoon through Wed
morning as the pressure gradient strengthens between high pressure
over nrn Ontario and a trough into the central Great Lakes. Winds
will then remain below 30 knots through the rest of the forecast
period.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning from 7 PM Tuesday to 10 AM EST Wednesday for
     LSZ265>267.

  Gale Warning from 4 PM Tuesday to 7 AM EST Wednesday for LSZ263-
     264.

Lake Michigan...
None.
&&

$$

SHORT TERM...07
LONG TERM...Ritzman
AVIATION...KC
MARINE...07



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