Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 150704

Area Forecast Discussion
National Weather Service Marquette MI
304 AM EDT Sun Oct 15 2017

.SHORT TERM...(This evening through Sunday)
Issued at 358 PM EDT SAT OCT 14 2017

Lakeshore flooding and strong winds are the primary hazards in the
short term, so focused most on those.

Utilized the higher-res guidance (NAM, CMC, NCEP WRFs) for winds
through Sunday. These models are in very good agreement with the
strength/timing/track of the SFC low, while the GFS/ECMWF are
similar track but faster and a little weaker. Expect NE winds to
increase this evening into Sunday morning. Peak gusts will be over
and near S-central Lake Superior late tonight through late Sun
morning with shorelines gusts up to 45-50mph. Have issued a wind
advisory as a result. This will also generate large waves, large
enough to cause beach erosion along all of our Lake Superior shores.
Waves will be highest from Marquette County east at up to around
15ft, with the largest waves expected late tonight into early Sun
afternoon. The height and NE-N direction of these waves will lead to
flooding of Lakeshore Blvd in Marquette in addition to other exposed
locations. Have issued a Coastal Flood Advisory for Marquette, Alger
and Luce Counties. Other concern for lakeshore flooding is US-41
between Baraga and L`Anse due to potential for NNE winds coming
right down the bay for around 12 hours and elevated lake levels. Not
nearly as certain in that area given lack of known cataloged
flooding cases there.

Of course, plenty of rain is expected. Widespread rainfall amounts
around an inch, with localized amounts near or greater than 1.5
inches expected. No significant impacts are expected from the precip.

.LONG TERM...(Monday through Saturday)
Issued at 303 AM EDT SUN OCT 15 2017

Overall, the weather through the extended looks quiet with a warm up
on the way through the middle/end of the week, with the next best
chance for rainfall chances returning later next weekend. Therefore,
the main forecast concern will the magnitude of this warming.

Monday, forecast soundings show just enough lingering cold air and
low-level moisture to foster the development of diurnally driven low
clouds. This cloud cover and lingering cool air aloft will promote
seasonable temperatures. Monday night into Tuesday, a weak shortwave
is progged to dig across the Upper Great Lakes, pushing a weak cold
front across the region. Not expecting any precipitation to develop
along this frontal boundary, but the surface pressure gradient will
become enhanced allowing for breezy winds. These breezy winds should
lessen the impacts of radiational cooling a bit, and allow
temperatures to only drop down into the upper 30s and 40s.

Tuesday through Friday, the weather is expected to remain dry and
with above normal temperatures as warm air advection increase across
the region. Right now it looks like temperatures will climb into the
60s each day, with a few pockets of lower 70s in locations that see
downsloping winds. Overnight low temperatures will remain fairly
mild, generally drop into the 40s and 50s.

The next best chance for precipitation will arrive next weekend as
de-amplifying longwave troughing tracks across the region. There is
some disagreement among the medium range models, with the ECMWF and
GFS bringing the next system across the region Saturday night
through Sunday; whereas, the Canadian is much faster with this
system as it tracks east across Upper Michigan on Saturday.
Depending on the arrival of this system, it will not only impact
precipitation chances, but also how warm temperatures will get.
Ahead of the cold front, if the GFS and ECMWF solutions come to
fruition, temperatures in the current forecast package would need to
be adjusted upwards. Even though mixing to around 850mb may be
challenging this time of year, the potential will still be there for
temperatures to climb nearly 15 to 20 degrees above normal for this
time of year.

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1233 AM EDT SUN OCT 15 2017

With low pres tracking from southern WI to northern Lower MI by
daybreak, shra will continue overnight, and winds will increase.
Cigs will settle into the MVFR category at KIWD/KCMX. At KSAW, ideal
upslope flow should support IFR cigs. Winds will generally gust to
20-30kt thru the morning, but there will be higher gusts upwards of
35kt at KSAW. Conditions will improve quickly from w to e this
aftn/evening as the low quickly departs. All 3 terminals will be VFR
by evening, if not sooner.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 358 PM EDT SAT OCT 14 2017

Winds will increase to gales tonight into Sunday as winds become
north-northeasterly. A few storm force gusts are possibly over
eastern Lake Superior late tonight into early Sunday afternoon. As
the system exits the region, winds will briefly diminish to around
15 knots Sunday night; however, expect the winds to ramp back up to
20 to 30 knots Monday into Tuesday. Wednesday through the end of the
week, winds look to remain around or just below 20 knots.

Upper Michigan...
  Wind Advisory until 2 PM EDT this afternoon for MIZ005>007.

  Coastal Flood Advisory until 8 PM EDT this evening for MIZ006-

  Coastal Flood Advisory until 8 PM EDT this evening for MIZ005.

Lake Superior...
  Gale Warning until 8 PM EDT this evening for LSZ248>251-265>267.

  Gale Warning until 11 AM EDT this morning for LSZ244-245-264.

  Gale Warning until 11 AM EDT /10 AM CDT/ this morning for LSZ162-

Lake Michigan...
  Gale Warning until 5 PM EDT this afternoon for LMZ221-248-250.



LONG TERM...Ritzman
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