Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 181946

Area Forecast Discussion
National Weather Service Marquette MI
346 PM EDT Wed Oct 18 2017

.SHORT TERM...(This evening through Thursday)
Issued at 345 PM EDT WED OCT 18 2017

...Windy into this evening then again on Thu...

Surface low over northern Manitoba down to 973mb at 19z/4-5 standard
deviations below mid October mean is resulting in warm and windy day
across much of Upper Michigan. Temps over portions of western U.P.
have reached over 20F above normal in the middle 70s. Warm spot as
of 3 pm in Upper Michigan is on the Keweenaw near the Upper Entrance
of the Portage Canal. Houghton Co Airport not far behind at 75F.
Pretty warm for mid to late October. Should note the record high for
today in the Houghton area is 80F set in 1910.

Dry airmass ahead of the low and associated cold front is leading to
just a batch of mid clouds over northern Ontario into western Upper
Michigan. Cold front crosses region late tonight with winds shifting
from southwest to west. Based on RAP soundings showing mixed layer
winds over 35 kts/40 mph, current obs and pressure falls crossing
north of Lk Superior into early this evening, expect wind gusts over
40 mph from north central into eastern forecast area. Issued special
weather statement into early evening to cover the strong winds.

West winds ramp back up on Thursday behind the cold front. Strongest
wind gusts 30-40 mph will be across Lk Superior and Keweenaw
Peninsula but 15-30 mph gusts could also occur over rest of forecast
area. Even with cooler airmass compared to today, temps on Thursday
will top out in the low to mid 60s, which is still well above
normal. Min RH values will bottom out in the 20-25 percent range so
fire weather concerns may be elevated especially given the recent
stretch of warm/dry weather.

.LONG TERM...(Thursday through Tuesday)
Issued at 311 AM EDT WED OCT 18 2017

Upper level ridging moves into the upper Great Lakes on Thu and
lasts into Fri. Troughing moves into the Rockies and plains Fri
night. Did not make too many changes to the going forecast with
above normal temperature continuing.

In the extended, GFS and ECMWF show a 500 mb trough over the western
half of the U.S. and a ridge along the east coast 12z Sat. The
trough moves into the central U.S. 12z Sun with a sfc cold front
moving through the area. More upper level troughing moves in for 12z
Mon with the trough digging into the eastern U.S. 12z Tue along with
some colder air. Troughing remains over the eastern part of the U.S.
into Wed. Temperatures stay above normal through Monday and then
colder air moves in for Tue and Wed where temperatures return to
near normal. Best chance for rain is on Sun when a cold front moves
through the area.

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 121 PM EDT WED OCT 18 2017

Only aviation concern will be gusty winds from the southwest this
afternoon...which should subside with loss of heating by early
evening. Some marginal low level wind shear possible...though
winds will be shifting this evening to the west with passage of a
cold front. VFR conditions expected through Thursday morning.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 345 PM EDT WED OCT 18 2017

South to southwest winds to 30 kts with a few gale gusts to 35 kts
over eastern sections will continue into the evening. Cold front
crossing tonight will shift winds to west and these may gust to 30
kts late tonight into early Thu aftn and once again there may be
gale gusts to 35 kts over east half. Overall, expect winds to stay
25 kts or less Thu night into early next week. Winds could increase
to 30 kts late Fri night into Sat though as pressure gradient
briefly tightens up ahead of low pressure tracking across south
central Canada.

Upper Michigan...
Lake Superior...
  Gale Warning until 11 PM EDT this evening for LSZ250-251.

  Gale Warning until 8 PM EDT this evening for LSZ248-249.

Lake Michigan...
  Gale Warning until 11 PM EDT this evening for LMZ248-250.



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