Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 260655

Area Forecast Discussion
National Weather Service Marquette MI
255 AM EDT Wed Jul 26 2017

.SHORT TERM...(Today and tonight)
Issued at 254 AM EDT WED JUL 26 2017

Lingering showers and thunderstorms have bisected Upper Michigan
this morning. One wave moving across the eastern half
associated with 700mb moisture transport, and a second wave
moving into the western half associated with deeper moisture
transport just ahead of a cold front that continues to push east
across the Arrowhead of Minnesota and towards Upper Michigan. Over
the last hour or so, additional convection has developed across west
and central portions of the area as the previously mentioned deeper
moisture arrives and the main shortwave begins to dig over
northern portions of Lake Superior.

The main forecast concern is the development of widely scattered
showers and thunderstorms this morning, that will produce moderate
to heavy rain at times, and a high swim risk for the northern
shores of Lake Michigan. Ahead of the the above mentioned cold
front, south-southwest winds of 20 to 30 knots across Lake
Michigan will allow dangerous currents to be in place throughout
the day today. Deep moisture pooling ahead of the cold front has
also allowed PWATs to approach the 2.0 inch mark, this moisture
should work well with the favorable entrance region of a 100 knot
upper- level jet tracking across Lake Superior to produce a fairly
widespread area of showers and embedded thunderstorms this
morning. With plenty of elevated instability over the area as
MUCAPES remain around 1000-2000 J/kg, a few embedded thunderstorms
could get pulsey through the morning hours; however, effective
shear is 30 knots at best, which does not bode well for
maintaining a persistently organized updraft. As we progress into
the mid- morning to afternoon hours, the surface cold front will
continue to push eastward across the area and allow precipitation
chances to diminish from west to east. The best chance for seeing
lingering showers and thunderstorms throughout the afternoon hours
will be across the eastern and south central portions of the area
as the front will be slowest to vacate those areas. A few of the
high- res models are a bit slower with the fronts progression this
afternoon and regenerate another round of showers and storms
along the cold front in the south central portions of the area,
which is possible as the speed of the front will slow this
afternoon as it becomes more west to east oriented. Confidence is
not high that these storms will develop, but if they can get going
later this afternoon they would be strong at best as the better
instability will be push well south of the area.

As the front continues to push south of the area overnight, we
will begin to try out across the area and cloud cover will thin
from west to east.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 412 PM EDT TUE JUL 25 2017

Fairly quiet long-term forecast expected as a surface ridge builds
across the area. Near normal temperatures expected.

As a cold front sinks southeast of the area Wednesday evening, the
best chances for showers and thunderstorms will slide out of the
U.P. A deeper shortwave will slide across the area Thursday
afternoon, which will lead to diurnal CU along with a small chance
for isolated showers and maybe a thunderstorms or two. Moisture will
be limited as the wave moves across, so coverage should be isolated
to scattered at best. A surface ridge will build across the area
through much of the rest of the extended keeping conditions mainly
dry trhough the extended. At this point will stick with a consensus
of the models through the extended, bringing little to no chances of
precipitation until Monday into Tuesday.

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 122 AM EDT WED JUL 26 2017

Cluster of thunderstorms moving towards KIWD ATTM while convection
continues to spread toward KCMX. With better moisture and
instability to the south of KCMX have trended a bit more
conservative on TSRA chances there, but still cannot preclude it
with the approaching front extending across MN. As this as front
moves through the region through the day, shower and thunderstorm
activity to gradually diminish from west to east with all three TAF
sites expected to be VFR before Noon. There should be a brief period
where MVFR cigs approach IFR with the frontal passage, but cigs will
recover fairly quickly shortly thereafter. VFR conditions to prevail
through the remainder of the forecast.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 254 AM EDT WED JUL 26 2017

A cold front will push east across the lake today with the
strongest winds expected to be ahead of this front generally
across the eastern half of the lake, with speeds of 25 to 30 knots
at times through the mid-morning hours. Across the west half of
the lake this morning winds will be around 10 to 15 knots as the
pressure gradient is a bit more relaxed in the vicinity of the
front. Throughout the day winds across the east half will relax
and increase across the west half, overall winds of 15 to 20 knots
are expected this afternoon into the overnight hours. By Thursday
morning, winds will relax further to around 10 to 15 knots. As
high pressure settles into the region for the end of the week and
weekend, expect the winds to remain around 10 to 15 knots through
the weekend and even linger into early next week.


Upper Michigan...
  Beach Hazards Statement through this evening for MIZ014.

Lake Superior...
Lake Michigan...


SHORT TERM...Ritzman
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