Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 131024

Area Forecast Discussion
National Weather Service Marquette MI
624 AM EDT Fri Oct 13 2017

.SHORT TERM...(Today and tonight)
Issued at 232 AM EDT FRI OCT 13 2017

Early this morning, a trailing cold front continued to push eastward
across the Arrowhead of Minnesota. With moisture lacking, along
this cold front, precipitation failed to develop early this
morning. However, head of this front, southerly flow has brought
additional low-level moisture northward across Upper Michigan this
morning, resulting in areas of extensive cloud cover, and drizzle
and/or light rain at times. This light precipitation was observed
across the far east where frictional convergence off of lake
Michigan aided in localized enhanced lift, along with areas that
saw upslope conditions due to southerly winds.

Today, as the cold front continues to push east across the area, due
to the enhanced low-level moisture, we could see scattered light
rain showers and/or pockets of drizzle develop. Overall, the deeper
moisture is expected to remain well south of the area, so not
expected much in the way of rainfall accumulations. Temperatures are
expected to remain rather seasonable today with lingering cloud
cover out ahead of the cold front. Once the front passes through,
much drier air will work into the region and allow for skies to
gradually start to clear across the west by the late afternoon
hours. Winds will be breezy at times today, especially closer to the
Great Lakes and across the Keweenaw.

Tonight, skies will continue to clear across the central and eastern
portions of the area as the cold front drop south of Upper Michigan
and the above mentioned drier air continues to filter eastward.
Surface high pressure will quickly fill in behind the exiting cold
front, which will provide the appropriate conditions for a crisp
fall night, especially across the west and central, as light winds
and clearing skies will give way to ample radiational cooling. Some
locations across the interior west and central could see
temperatures drop down in the lower 30s.

.LONG TERM...(Saturday through Thursday)
Issued at 245 AM EDT FRI OCT 13 2017

500 mb ridge over the sern U.S. and a trough in the Rockies 12z Sat.
Trough moves into the upper Great Lakes 12z Sun and remains through
Sun night. Nam shows some 850-500 mb q-vector convergence 00z Sun
through 12z Sun with deeper moisture moving through the area. Pops
will be high as this moves through and have qpf amounts from 0.50
inch to 1 inch of rain expected with this system. Overall, did not
make too many changes to the going forecast.

In the extended, the GFS and ECMWF show a 500 mb ridge across the
southwestern U.S. 12z Mon with a trough in the ern U.S. There is
also a shortwave over northern Alberta and northern Saskatchewan and
this heads east Mon night into Tue and pushes a cold front through
the area. This is followed by a shortwave ridge that moves into the
upper Great Lakes 12z Wed and ridging builds into the ern U.S. 12z
Thu. Troughing moves out into the plains and western U.S. 12z Fri.
Above normal temperatures will continue this forecast period.

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 623 AM EDT FRI OCT 13 2017

Ceilings this morning range from IFR to MVFR across all terminals as
low-level moisture remains in place across Upper Michigan, ahead of
a cold front expected to arrival later today. Once the cold front
arrives, drier air will push west to east across all terminals, with
KCMX/KIWD first, allowing ceilings to rise and eventually scatter
out. Precipitation wise there could be some light rain showers, but
with coverage expected to be fairly scattered opted to leave
mentions out for now. Look for breezy winds after the front arrives
at KCMX.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 232 AM EDT FRI OCT 13 2017

...Northeast to North gales possible on Lake Superior Saturday night
through Sunday...

Today as a cold front traverses the lake, winds of 20 to 30 knots
are expected. Tonight, winds will decrease in speed from west to
east across the lake as high pressure quickly tracks across the
region. However, the surface pressure gradient will increase from
west to east late Saturday through the end of the weekend as a
strengthening low pressure system lifts northeast across the Western
Great Lakes. Initially winds will be out of the east-northeast by
late Saturday at speeds of 20 to 30 knots. As the above mentioned
system lifts northeast into Ontario by Sunday morning, winds will
switch around to the north, with gales up to 35 to 40 knots.
Thankfully, this system is progged to exit the region rather
quickly, and the gales should subside from west to east through
the day Sunday. We will see a brief lull in the winds as speeds
lessen to around or less than 20 knots by Monday. Winds will ramp
back up to 20 to 30 knots Monday night into Tuesday as a system
rapidly digs just east of Lake Superior across Ontario and
enhances the surface pressure gradient. It is not out of the
question that we could see a few gale force gusts during that time
period as well. Otherwise, through the middle/end of next week,
winds will subside to be around or less than 20 knots.

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


SHORT TERM...Ritzman
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