Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 150811

Area Forecast Discussion
National Weather Service Marquette MI
311 AM EST Wed Feb 15 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 418 PM EST TUE FEB 14 2017

WV imagery and RAP analysis indicated an amplified pattern with a
mid/upper level ridge from the western CONUS into
Alberta/Saskatchewan and a trough from Hudson bay into the northern
Great Lakes. At the surface, a cold front extended across central
Upper Michigan from low pressure northeast of Lake Superior. A
shortwave moving into wrn Upper Michigan combined with daytime
heating supported an increase in snow showers across the area.
However, with 850 mb temps only to around -11C and Spring-like
warming over the land, the snow showers were more cellular and
disorganized resulting in little or no accumulation.

Tonight, expect that the snow showers will increase in intensity and
coverage this evening as the disruption from daytime heating
diminishes and low level conv increases across most areas of nrn
Upper Michigan favored by strong nnw flow. The LES will continue
overnight but should diminish over the west where subsidence and
850-700 mb drying is strongest behind the shrtwv. Although the
snow is later to develop than expected, 1 to 3 inch amounts are
still possible. Locations east of Marquette should still see
additional acumulations in the 2 to 4 inch range. The strongest
isallobaric component and gustiest winds are expected this evening
with some gusts to around 40 mph. The stronger winds overnight
are expected to shift into the ern cwa.

Wednesday, nnw winds will continue with 850 mb temps remaining
around -14C. This should be enough to keep light to moderate LES
going over mainly the east, downstream from the longer fetch.
Otherwise, inversion heights dropping to around 3k ft will result in
only light LES over the west.

Even with little snow this afternoon, the winter weather advisories
were retained as conditions are expected to deteriorate this
evening, especially in locations exposed to the stronger winds.

.LONG TERM...(Thursday through Tuesday)
Issued at 311 AM EST WED FEB 15 2017

Nam shows a 500 mb ridge over the Rockies 12z Thu that moves into
the northern Plains 00z Fri. This ridge moves into the upper Great
Lakes on Fri and Fri night. Basically, pretty quiet for this
forecast period.

In the extended, GFS and ECMWF show a closed 500 mb low over the
southern plains 12z Sat with a shortwave over the upper Great Lakes.
A 500 mb ridge moves into the plains 12z Sun and this ridge moves
into the upper Great Lakes on Mon. A shortwave moves into the upper
Great Lakes Mon night with more shortwave energy moving into the
area for Wed. Temperatures will be above normal for this forecast
period and the pcpn will be mostly rain for late Mon into Mon night.

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1158 PM EST TUE FEB 14 2017

While cold air mass flowing across Lake Superior will yield MVFR
cigs thru this morning at KIWD/KCMX/KSAW, influx of drier air will
result in diminishing -shsn that will be affecting mainly
KCMX/KSAW, but KSAW more so. Vis in -shsn should mostly be MVFR.
As drier air continues to push into the area today, -shsn will
diminish and/or end. While KIWD should break out to VFR this aftn,
MVFR cigs will likely persist at KCMX/KSAW.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 418 PM EST TUE FEB 14 2017

Winds will increase to gale force late this afternoon over most of
Lake Superior as a strong upper disturbance slides into the Upper
Great Lakes and tightens the pressure gradient through tonight.
Since colder air will be arriving at the same time, heavy freezing
spray warnings were hoisted for tonight and Wednesday for most of
Lake Superior. Winds will gradually diminish from Wednesdy afternoon
into Wed evening.

Upper Michigan...
  Winter Weather Advisory until 7 AM EST this morning for MIZ006-

Lake Superior...
  Heavy Freezing Spray Warning until 7 PM EST this evening for

  Gale Warning until 1 PM EST this afternoon for LSZ266-267.

  Gale Warning until 7 AM EST this morning for LSZ264-265.

Lake Michigan...


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