Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 280806

Area Forecast Discussion
National Weather Service Marquette MI
406 AM EDT Fri Apr 28 2017

.SHORT TERM...(Today and tonight)
Issued at 405 AM EDT FRI APR 28 2017

Water vapor imagery shows deeper wrap around moisture, associated
with the system that lifted north across the area yesterday,
continuing to slowly lift across southern portions of Canada this
morning. Much of the precipitation associated with this system has
come to an end, with the exception off the Keeweenaw Peninsula where
onshore, upslope flow and cold air advection have allowed light snow
to linger through the morning hours.

Expect the light snow to linger across the Keweenaw Peninsula
through the morning hours before gradually tapering off as drier air
begins to advect southeast across the area, along with increasing
upper-level subsidence as the left-rear quadrant of an upper-level
jet will lift across the area. Elsewhere, expect clouds to linger
through much of the day. Towards the afternoon hours, we could see a
few peeks of sunshine as clouds should become more broken, opposed
to overcast. With the pocket of cold air still lingering overhead,
expect winds to get a bit gusty this afternoon given the steep low-
level lapse rates and 20-30 knot 925-850mb flow. High temperatures
will be tricky today given cloud cover, cold air advection, and
downsloping westerly winds across portions of the area. The warmest
locations look to be across the south central portions of Upper
Michigan, where downsloping flow will aid in adiabatic warming.
Tonight, cloud cover will diminish into the early morning hours with
lows dropping below freezing.

.LONG TERM...(Friday night through Thursday)
Issued at 357 PM EDT THU APR 27 2017

Main weather concern in the extended will be below normal
temperatures along with a stronger system possible with a wintry mix
Sunday through Tuesday.

Friday night through Saturday: A surface ridge and drier air is
expected to build into the area during this time period allowing
skies to become partly cloudy with only minor chances for rain and
snow showers, again, the main focus would be early in the day Friday
over the Keweenaw Peninsula. Temperatures are expected to be
slightly below normal through this time period.

Saturday night through Tuesday: Low pressure is expected to develop
over the Southern Plains late Saturday night and slide through the
Upper Great Lakes Sunday through Tuesday. Models are coming into
better agreement on the details of the system as it slides through
the area; however, some timing and placement differences continue
with the solutions. The GFS/Canadian have similar tracks and timing;
however, the GFS is deeper with the surface low and upper level low.
Each of the models each have the low moving out of the area Tuesday
afternoon. The latest run of the EC is keeping the surface low and
850mb low farther west, taking the low over the western U.P. If the
GFS/Canadian are correct there could be substantial accumulating
snowfall across portions of the west half of the U.P.; however, if
the EC solution is correct, then most areas may end up seeing mainly
rain with maybe even some dry slotting expected over the east half.
850mb temperatures are progged to be as high as 8 to 9C with the EC,
while the GFS/Canadian have 850mb temperatures over the west half
as low as -4 to -5C. Until better sampling occurs with this
system it is likely that there will continue to be variances in
the models, with improvement expected by Friday as the wave of
energy is better sampled. Consensus is still the way to go at this
point in the extended due to the reduced confidence in the system
track. This will give a continued mix of rain and snow central,
rain changing to snow west and mainly rain east.

Tuesday night through the extended: High pressure and drier air will
slide into the area Tuesday night through Wednesday, which will
allow skies to become clear to partly cloudy and temperatures to
slowly moderate to near or slightly above normal. A weak system may
slide through the area Thursday; however, moisture looks to be
fairly limited only bringing isolated rain showers to the area.

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1212 AM EDT FRI APR 28 2017

Snow showers will linger a bit longer at KCMX under cyclonic
upslope westerly flow. Otherwise expect MVFR cigs to linger  into
Fri morning with improvement to VFR at all sites by Fri afternoon
as drier air filters in from the west.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 405 AM EDT FRI APR 28 2017

West winds of 20 to 30 knots are expected today. Locations west and
north of the Keeweenaw Peninsula will see the strongest winds as
west winds back slightly west-southwest, allowing for flow to
accelerate as it gets funneled along the coastline. By Saturday
morning, winds will become northerly and decrease to 10 to 15 knots
as high pressure moves across the region. By Sunday, the pressure
gradient will start to increase once again as winds become east-
northeasterly 15 to 25 knots. Sunday night through Monday, east-
northeast flow will increase to gales of 35 to 40 knots across the
west and central portions of Lake Superior. As low pressure tracks
northeast across the Upper Great Lakes, winds will back to the north
20 to 30 knots into Tuesday morning. Wednesday and Thursday, winds
will be less than 20 knots as high pressure builds across the

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


SHORT TERM...Ritzman
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