Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 230517

Area Forecast Discussion
National Weather Service Marquette MI
117 AM EDT TUE AUG 23 2016

.SHORT TERM...(This evening through Tuesday)
Issued at 338 PM EDT MON AUG 22 2016

Mid-level clouds and a couple of showers across the Keweenaw late
this morning associated with a narrow region of mid-level WAA has
shifted to the NE this afternoon. Subsequent capping advecting in
at around 6kft has suppressed any widespread cumulus formation.

A second pocket of WAA within a layer of higher moisture between 800
and 700hPa has been evident by patch of alto-cumulus drifting NE
across western WI this afternoon. As this area spreads across the
west half of the CWA this evening, convergence on the nose of a
developing LLJ around 800hPa should initiate at least some
convection. Given the shallow layer of moisture, confidence is low
on the coverage of any precip. So, have maintained slight chance
PoPs across the central mid evening into the early overnight hours,
and chance PoPs across most of the east half late evening through
most of the overnight. MuCAPE for parcels forced from the
aforementioned layer will be around 750j/kg, so elevated thunder
will be possible with any precip formation.

For Tuesday, capping will result in mostly sunny skies across the
area. 900hPa temps around 20C and winds up to 30 knots will support
sfc temps well into the 80s and gusty SW winds to 25mph,
respectively. Would not be surprised to see a few downslope
locations along Lake Superior approach 90 late in the afternoon.
Lastly, with the recent rain of at least an inch across all of
Upper Michigan, fire wx concerns are minimal.

.LONG TERM...(Tuesday night through Monday)
Issued at 434 PM EDT MON AUG 22 2016

Upper trough over the northern plains slowly crosses the Upper Great
Lakes late this week. At the sfc, low pressure crossing the Northern
Plains on Tue aftn will shift a warm front across the Upper Great
Lakes Tue night into Wed. Though the U.P. will be in the warm sector
on Wed, lowered temps to the low-mid 70s as consensus is increasing
that lead shortwave slides across WI and Upper Michigan spreading
area of clouds and showers from southwest to northeast. Dprog/dt of
models indicates trend toward keeping majority of rain over central
and eastern cwa on Wed so nudged forecast in that direction with
likely pops south central and east. Southwest winds ahead of the sfc
low could stay strong/gusty Tue night into Wed, especially from
northern Lk Michigan across the eastern cwa and over the eastern
portions of Lk Superior. Gusts to 30 mph are likely.

Some chance of tsra as the showers move across per SI/s that are
slightly negative as fairly compact low-level system crosses the
area. No severe storms are anticipated. Once the shortwave crosses
subsidence behind the wave should keep conditions mostly dry Wed
night. Secondary cold front bringing in H85 temps down to 6-7C moves
in for Thu. Just a small chance of showers as the next push of
cooler air arrives. Soundings indicate dry airmass so that should
limit extent of showers. A breezy day is expected on the Keweenaw and
near Lk Superior as winds shift to the west at 20-30 mph. Lighter
winds on Fri as pressure gradient weakens. Daytime temps Thu and
Fri within the trough aloft should be in the upper 60s to lower 70s.

Rest of forecast will be influenced by high building across late in
the week which could bring cooler nights inland Thu Night and Fri
night. As the high moves east, return flow kicks in for the weekend.
Sat should be mostly dry but rain chances return into Sun. Seems to
be better chance of thunder as ml and elevated mucapes climb toward

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 117 AM EDT TUE AUG 23 2016

Shra/tsra that have been affecting KSAW during the evening have
shifted e of the terminal with no new development expected
overnight. As a result, VFR conditions are expected thru this fcst
period at KIWD/KCMX/KSAW. Low-level jet over the area will result in
LLWS at all terminals for the remainder of the night. Winds will
become gusty today, especially at KSAW.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 338 PM EDT MON AUG 22 2016

South to southwest winds of 15 to 25 knots are expected through much
of Wednesday as a low pressure trough over the Plains tracks toward
the Upper Great Lakes while high pressure exits to the east.
However, a brief period of winds to 30 knots will be possible
overnight tonight. The trough will cross Lake Superior Wednesday
afternoon and evening, then usher in west winds of 15 to 25 knots
Wednesday night and Thursday. High pressure will then bring SW to NW
winds less than 20 knots through Saturday.

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


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