Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 242014
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
314 PM EST Tue Jan 24 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 304 PM EST TUE JAN 24 2017

A lee cyclone continued to develop and deepen across the high
plains of Colorado/western Kansas early this afternoon as a deep
longwave trough continues to lift out of the western CONUS. Water
vapor imagery shows additional upper-level energy location in
southern Manitoba, where a cutoff low continues to slowly spin.

As the above mentioned surface low lifts northeast across the Mid
Mississippi River Valley and eventually across southern Wisconsin
tonight through tomorrow, expect the main system precipitation to
remain just south of the area where the best lift will occur. Later
tonight/early tomorrow morning, there will be the potential for
freezing drizzle in locations that see below freezing
temperatures tonight as the low stratus thickens, but will not be
cold enough to support ice crystals. Some minor ice accumulations
are possible and may lead to a slick morning commute. This
freezing drizzle may hold on through the day in portions of the
interior west where temperatures are expected to remain around
freezing, but expect the freezing drizzle to transition over to
drizzle and/or light snow. Immediately downwind of Lake Superior,
expect enhanced lift due to onshore northerly flow with resulting
increased precipitation amounts. Not expecting much in the way of
snowfall accumulations given the poor thermal profiles, but a few
locations could pick up around or just over 2 inches of snow.

Further south where system precipitation is expected, forecast
soundings hint towards a seeder-feeder scenario. Therefore, it is
possible that the transition over from drizzle to snow may hold off
longer than reflected in this forecast depending on how long it
takes mid levels to moisten tomorrow morning/afternoon. As discussed
above, the main system snow looks like it will clip the region
and/or just just south of the area. However, still could see
around 2 inches across far southern portions of Menominee County. Elsewhere
across southern and eastern portions of the area expect anywhere
from a trace of snow to one inch. Closer to Lake Michigan could
see rain mix in with the snow, allowing for lower snowfall
totals.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 256 PM EST TUE JAN 24 2017

Nam shows a closed 500 mb low over se WI 00z Thu with another over
northern Ontario. The Ontario low helps to dig a trough into the
upper Great Lakes Thu and into the lower Great Lakes on Fri. Looked
at both NAM and GFS bufkit soundings for Wed night and Thu and
temperatures aloft stay well below zero and feeling is that the pcpn
will start out as rain/snow mix with rain in the east Wed night
turning over to all snow rather than any freezing rain or sleet Wed
night. Overall, did not make too many changes to the going forecast.

In the extended, GFS and ECMWF show a broad 500 mb trough over most
of the U.S. except there is a ridge in the western U.S. with 850 mb
temperatures over Lake Superior down to -13C to -15C 12z Sat. A
shortwave digs south into the upper Great Lakes 12z Sun with
temperatures dropping to -17C to -18C over Lake Superior. This
shortwave digs into the lower Great Lakes 12z Mon. Another shortwave
moves into the upper Great Lakes 12z Tue. Temperatures will be near
normal this forecast period.
&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1226 PM EST TUE JAN 24 2017

Visibilities have improved across all terminals, but IFR ceilings
continue this afternoon. There may be a brief break in the IFR
ceilings at KIWD early this afternoon, but expect the lower ceilings
to fill back in. Tonight into tomorrow, conditions will deteriorate
across all terminals as low pressure lifts north towards the region.
Expect some drizzle/freezing drizzle tonight and then eventually
transition over to snow into the early morning hours at KIWD/KCMX.
Further to the east, the transition at KSAW is expected to occur
around/after midnight.
&&

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 522 AM EST TUE JAN 24 2017

With a weak pressure gradient overhead, winds below 20 knots will
continue through this evening and into the overnight hours. However,
expect north-northwest winds to increase Wednesday morning as the
pressure gradient increases with an area of low pressure traverses
southern Wisconsin/northern Illinois. With the largest isallobaric
component and strongest surface pressure gradient should remain
south of the area Wed-Thur, not expecting winds to increase to
gales. Rather expect the north winds to ramp up to around 25 to 30
knots late Wednesday through the overnight hours. Thursday winds
will maintain speeds of 25 to 30 knots, but north winds will back
to the northwest. Expect these winds to maintain themselves
through Friday and Saturday as the surface pressure gradient
responses to shortwave energy moving through the area.

&&

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

$$

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


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