Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 281747

Area Forecast Discussion
National Weather Service Marquette MI
147 PM EDT Fri Oct 28 2016

.SHORT TERM...(Today and tonight)
Issued at 419 AM EDT FRI OCT 28 2016

Broad upper level ridge from the rockies to the Central Plains
flattens today as strong jet stream pushes across the northwest
Conus. Sfc low over southern Saskatchewan to the western Dakotas
slides to north of Lk Superior by this evening. It is very dry to
south and southeast of low but this strong warm air advection regime
/00z h85 temps varied from 17-18c at BIS/ABR to 9c at MPX to -1c at
GRB/ has led to developing shield of isold light rain showers/sprinkles
working across MN arrowhead and now into western Upr Michigan. Some
light rain/drizzle could occur this morning over much of northern
Upper Michigan, then as shortwave arrives this aftn expect better
chance of light rain over eastern Lk Superior and into east cwa. Any
rain will remain quite light though. Despite the clouds and rain
chances, shear advection of warm air back to the southwest this
morning will lead to highs topping out well into the 50s across the
cwa. With any breaks in clouds over west, could see a few 60 degree

Main issue today will be strong S-SW winds, especially over the
eastern cwa with 925mb winds 40-45 kts overhead. Soundings show
increasing low-level stability but that will be offset somewhat by
pressure falls over and north of Lk Superior this aftn tied to the
approaching low pressure system. Expect winds 20-30 mph with gusts
35-40 mph. Strongest gusts should occur at downslope areas from
Munising to Grand Marais. Think setup does not favor needing wind
advy with abundant cloud cover and stable profile holding down
mechanical mixing of higher winds aloft. Strongest winds will occur
mid to late aftn with during the more ideal isallobaric component to

This evening and into tonight, even as mid level moisture departs
the low level moisture deepens and there remains some lift as sfc
trough moves through. Drizzle or very light rain seems possible
tonight and included both in the forecast. Later tonight as winds
turn to the west behind low pressure system/sfc trough, chance of
light drizzle or light rain will become focused over higher terrain
of western cwa. A mild night as cold air will lag this trough by a
good margin. Lows will only drop into the upper 40s to lower 50s
degrees, which is at or above normal highs for this time of year.

.LONG TERM...(Saturday through Thursday)
Issued at 340 AM EDT FRI OCT 28 2016

NAM shows a shortwave over the upper Great Lakes 12z Sat with a
closed low off the Pacific NW. This low moves a trough onshore of
the west coast on Sat and ejects a shortwave out of the trough that
ends up in the northern plains 12z Mon. Looks pretty quiet for this
forecast with slight chance pops only. Overall, did not make too
many changes to the going forecast.

In the extended, GFS and ECMWF show a 500 mb trough in the western
U.S. 12z Mon with a broad ridge over the ern U.S. A shortwave moves
through the upper Great Lakes 12z Tue and moves over the top of the
ridge that now positions itself over the sern U.S. This ridge
amplifies more over the sern U.S. 12z Wed as a trough amplifies in
the western U.S. Another shortwave moves through the upper Great
Lakes Wed night and brings a cold front through the area Thu
morning. Temperatures look to stay above normal for this forecast

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 146 PM EDT FRI OCT 28 2016

A low pressure system over the area will drag a cold front across
the area tonight. Low level moisture and upslope flow behind the
front will bring conditions down tonight. conditions will stay low
or gradually improve early Sat.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 419 AM EDT FRI OCT 28 2016

S-SW winds increase substantially today as low pressure system over
the northern Plains moves to north of Lk Superior by this evening.
Winds of 20-30 kts are expected over all of Lk Superior but will
reach gales to 35 kts this aftn and early this evening on eastern
sections. As the low continues east late tonight, winds will shift
to the NW to 20-25 knots with strongest winds over north central and
eastern Lk Superior. Winds will remain less than 20 kts into Sun and
Sun evening then another round of S winds to 20-30 kts are expected
on Mon out ahead of low pressure tracking across the northern
Plains. Gale gusts may occur over eastern sections Mon afternoon
into Mon evening. The low will cross Lake Superior by Tue morning
shifting the winds to W 20-25 kts.

Upper Michigan...
Lake Superior...
  Gale Warning until 11 PM EDT this evening for LSZ249>251-266-267.

Lake Michigan...
  Gale Warning until 2 AM EDT Saturday for LMZ221-248-250.



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