Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 220522

Area Forecast Discussion
National Weather Service Marquette MI
122 AM EDT Sat Oct 22 2016

.SHORT TERM...(This evening through Saturday)
Issued at 328 PM EDT FRI OCT 21 2016

A ridge of high pressure currently over the western CWA will
continue to diminish lake effect rain and snow showers that are
mainly over central Upper MI. Last precip should be around 00Z this
evening. The upper trough over the Great Lakes right now will shift
east while an upper ridge moving in behind it. Between those two
features, the upper jet will arc into the area tonight, which will
force some precipitation aloft. That precip is not expected to reach
the ground over land and only maybe over the western lake due to dry
low levels. This should lead to cloud cover that will cover much of
the area tomorrow morning before slowly dissipating/moving out.

Lows tonight will be in the 20s away from the shores. Since cloud
cover will move in from the west, the coldest area will be interior
central Upper MI in the low 20s.

.LONG TERM...(Saturday night through Friday)
Issued at 341 PM EDT FRI OCT 21 2016

Saturday night: A weak ridge will be in place Saturday evening
before slowly sliding off to the east of the area late Saturday
night. This should keep the area mainly dry through this time
period; however, increasing moisture on the back side of the
departing ridge and ahead of and approaching shortwave/surface low,
will allow cloud cover to steadily increase through the overnight
hours. Temperatures will be warmer than Friday night due to the
aforementioned increased cloud cover/WAA.

Sunday through Monday: The shortwave is progged to slide from
Southern Manitoba into the Upper Great Lakes region through the day
Sunday as a low pressure system slides through or just south of the
U.P. The combination of these two features along with increased
moisture will lead to chances of rain showers throughout the day.
This can be seen by overlaying deep layer Q-conv and 1000mb-500mb
RH. Colder air will filter in over the east half of the U.P. Sunday
night into Monday as another shortwave dives through the eastern
half of the area. This will allow 850mb temperatures to drop into
the -5C to -6C range. This cooler air aloft, along with lake surface
temperatures around 10-11C will allow for delta-T values in the 15
to 17C range. This combination will provide continued lake effect
cloud cover and lake effect rain showers over mainly the east half
of the U.P. as winds will be out of the northwest and that area is
under the shortwave as it slides through. Even though deeper layer
moisture will slide east, the increased fetch on the northwest flow
will keep enough lake modified air in place to keep the rain showers
around for Sunday night into Monday morning. 850mb temperatures will
modify through the day Monday as the trough slips eastward and a
surface ridge builds into the area. This should effectively diminish
any lake effect rain potential across the U.P.

Monday night and Tuesday night: The high pressure ridge will linger
through the day Tuesday; however, moisture will steadily increase
through the day Tuesday as an upper level 500mb trough moves into
the Plains. This will help to develop a low pressure system over the
Central Plains Tuesday evening. This low is progged to slide to the
east-northeast into late Tuesday night. As this happens, cloud cover
will continue to increase from across the area, with the thickest
cloud cover and a few showers possible late Tuesday night near the
WI border. Otherwise, most of this time period should remain fairly

Wednesday through the extended: The aforentioned low is progged to
stay to the south of the U.P., along the Northern IL-Southern WI
border, which will keep the bulk of the precipitation south of the
area. There will still be some showers and cloud cover, but the
significant rain will remain across WI for Wednesday into Wednesday
night.  Models differ for Thursday into Friday as the EC has a deep
trough over the eastern CONUS while the GFS maintains zonal to
slight ridging across the area. At this point, will stick with a
consensus of the models for this time period.

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 117 AM EDT SAT OCT 22 2016

VFR conditions will prevail at KIWD/KCMX/KSAW thru this evening with
cloud bases no lower than 4000-5000ft at times thru the morning hrs.
Sfc high pres ridge will mostly dominate, resulting in light winds.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 328 PM EDT FRI OCT 21 2016

No significant low pressure systems are expected to move through the
Upper Great Lakes in the next several days. Winds will remain below
gales through the period. A tightening gradient between a deep low
pressure system moving through Quebec and a high pressure ridge
building into the Plains could lead to a period of NW winds to 30
knots over north central and eastern Lake Superior late Sunday into

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


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