Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 200739

Area Forecast Discussion
National Weather Service Marquette MI
339 AM EDT Thu Jul 20 2017

.SHORT TERM...(Today and tonight)
Issued at 339 AM EDT THU JUL 20 2017

Pretty quiet morning as complexes of showers and thunderstorms have
stayed well to the south of Upper Michigan along stationary front
and northern edge of much greater instability. As of 3 am EDT, bulk
of lightning is affecting southern MN into southern WI (where
there has been heavy rain and flooding reported) with a few isold
strikes only as far north as Oshkosh WI. A couple of showers have
drifted across the Bay of Green Bay early this morning and also
over eastern Lk Superior but that is about it. Have isold pops
over far scntrl and east through daybreak but went dry otherwise.
Sfc trough upstream over northwest MN will sweep across western
cwa this morning then over rest of the forecast area early to mid
aftn. Still warm and humid ahead of this front so went for another
warm day with readings into the upper 70s to even upper 80s,
warmest over scntrl with downsloping NW winds. Even as the front
runs into lingering warmth and moisture in low- levels, subsidence
in wake of convection this morning leads to atmosphere that will
be too dry to support any additional shra/tsra during peak
heating. Could be some pop up fair weather cu clouds but that is
all. Most areas should see temps warm quickly this morning with
mostly sunny skies, but expect temps to fall back some this aftn
along Lk Superior into the upper 60s to lower 70s with developing
onshore NW-N flow.

High pressure builds across tonight. Based on upstream temps this
morning in south central Canada vcnty of the high, think interior
areas have shot to drop below 50 degrees tonight which will be quite
refreshing. Temps near 60F will hang on close to the Great Lakes
though as proximity of warmer nearshore waters tempers the cooling.

.LONG TERM...(Thursday night through Wednesday)
Issued at 349 PM EDT WED JUL 19 2017

Thursday night through Friday night: A shortwave is progged to slide
through the area during this time period, especially Friday
afternoon and Friday evening. There will be enough forcing and
moisture, mainly over the southern portions of the U.P., to touch
off a few showers and thunderstorms across the area. The main
shortwave track will be just south of the U.P., which again will
keep the main focus over WI, with a few showers and maybe a
thunderstorm or two nosing into southern areas. High temperatures
will be above normal Friday with highs warming into the upper 70s
and low 80s, except cooler along the Great Lakes shorelines.

Saturday through Sunday: Unsettled weather can be expected again for
the upcoming weekend as an area of low pressure and a couple upper
level troughs/shortwaves are progged to slide into the Upper Great
Lakes region. Although there is still some timing uncertainty, the
initial band of showers with WAA and deep layer q-vector convergence
ahead of the initial shortwave late Friday night into Saturday.
Saturday night into Sunday, the stronger shortwave axis will slide
directly overhead as wrap-around moisture flows into the area on the
northwest side of the surface low. The low will continue to shift
slowly to the east through Sunday night. Again, with the low
remaining nearby and another disturbance sliding through the area
aloft, the rain showers will continue acorss much of the U.P.
through Sunday night. Temperatures will be above normal for Friday,
with highs in the 80s; however, with more unsettle weather over the
weekend, expect high to cool off a bit to more seasonable readings,
in the 70s.

Rest of the extended: High pressure is expected to move into the
area, allowing for mainly dry conditions for Monday into Tuesday.
Models are hinting at a cold front pushing through the area
Wendesday; however, with this being toward the end of the forecast
period, exact timining and placement will be difficult to pin down.
It does look like there will be and increased chance of showers and
thunderstorms for Wednesday and will stick with a consensus of the
models for that time period with scattered showers and
thunderstorms. Again, temperatures should remain near to slightly
below normal through the remaining extended forecast.

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 206 AM EDT THU JUL 20 2017

VFR conditions are expected to prevail thru the fcst period at
KIWD/KCMX/KSAW, though there may be occasional ground fog at IWD
early this morning. There is a small potential that shra could
still develop and affect KSAW overnight. If shra do occur,
conditions could fall to MVFR or lower for a short time.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 339 AM EDT THU JUL 20 2017

Expect winds 15 kts or less late this week into Sat. Next chance for
stronger winds from the N-NE over 20 kts will be on Sun in wake of
low pressure system crossing the Upper Great Lakes. High pressure
builds back over region by early next week with winds mainly 15 kts
or less.

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


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