Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 131728

Area Forecast Discussion
National Weather Service Marquette MI
1228 PM EST Tue Feb 13 2018

.SHORT TERM...(Today and tonight)
Issued at 452 AM EST TUE FEB 13 2018

WV imagery and RAP analysis indicated an upstream shortwave trough
from nw Ontario into cntrl North Dakota. The shrtwva and associated
280k-290k isentropic lift supported some patchy light snow over
portions of nrn and cntrl MN while just mid clouds prevailed over nw
WI where radars showed weak returns.

Today, expect clouds will continue to increase over the cwa this
morning with some area of light snow possible west and n cntrl this
morning. However, with the limited moisture and weak forcing/ascent
mainly must flurries are expected with little or no accumulation.
Increasing low level WAA will also help push temps above normal with
highs in the upper 20s to around 30.

Tonight, even through skies will become mostly clear, breezy sw
winds will keep enough mixing going so that min temps will only drop
into the upper teens.

.LONG TERM...(Wednesday through Monday)
Issued at 429 AM EST TUE FEB 13 2018

No major weather impacts expected through the extended with
occasional light snow chances and generally near to below normal
temperatures expected. There will be a couple a brief periods of
near to above normal as well for Wednesday and toward the end of the

Wednesday through Wednesday night: The upper level trough will
continue to flatten through this time period as southerly flow kicks
up ahead of a cold front approaching from Ontario. This will allow
850mb temperatures to warm to around +4C to +6C by Wednesday
afternoon. That, along with partly cloudy skies, will allow daytime
highs to warm above average briefly, with many locations expected to
reach the the upper 30s to low 40s. There is a shortwave progged to
slide through or just south of the area Wednesday, but soundings are
very dry, keeping precip chances to a minimum. Late Wednesday night,
the cold front will approach the U.P. from the northwest. Most
locations will remain dry through this time period with the only
noticeable changes being a shift in winds to the north and
increasing cloud cover.

Thursday and Friday: Increasingly colder air to near -20C is
expected to move across the Upper Great Lakes by Thursday night in
the wake of Wednesday night/Thursday morning`s frontal passage. This
will for better chances for nw flow lake effect snow especially late
Thursday into Thursday night. However, extensive ice cover on Lake
Superior and large scale anticyclonic flow should keep snow
accumulation light. The eastern U.P. would have the better chances
as it looks like there is still an decent area of open water.
Additionally, shallow moisture, below the dgz, may lead to some very
light frdz, late Wednesday night into early Thursday morning. Flow
backing west by Friday afternoon will confine any additional lake
effect accumulation to the Keweenaw.

The rest of the extended: At this point, will stick with a consensus
of the models through this time period, which shows fairly steady
troughing over the eastern CONUS into the first part of the weekend.
This will bring occasional waves through the area, giving
intermittent light snow showers, mainly over the Keweenaw and Lake
Superior as winds are expected to be south to southwest. This would
also support continued below normal temperatures for that time
period. Models diverge on the track of an approaching system for the
last half of next weekend into early next week; however, they do
have a trend of keeping the system just west of the U.P. If that
does occur this would lend support to warmer southerly flow into the
area, with temperatures possibly warming to above normal again late
in the weekend into the next week.

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1227 PM EST TUE FEB 13 2018

VFR ceilings will give way to some clearing this afternoon, along
with increasingly gusty winds at all terminals. Tonight, low-level
wind shear will develop at KSAW as the axis of a low-level jet
tracks across central Upper Michigan. This increase in the low-level
wind fields may also reflect down towards the surface and allow for
intermittent gusty winds through the overnight hours at all
terminals. Low-level moisture will be on the increase tonight, but
given the breezy boundary layer winds not confident that we will see
impacts to ceilings and visibilities.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 452 AM EST TUE FEB 13 2018

Southwest gales to 35 knots are expected this afternoon into Tuesday
night across central and eastern Lake Superior. These will be the
strongest winds for this forecast period with several other periods
getting up to 30 knots, but remaining below gales.

Upper Michigan...
Lake Superior...
  Gale Warning until 1 AM EST Wednesday for LSZ266-267.

  Gale Warning from 7 PM this evening to 7 AM EST Wednesday for

Lake Michigan...


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