Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 270803

Area Forecast Discussion
National Weather Service Marquette MI
403 AM EDT Tue Jun 27 2017

.SHORT TERM...(Today and tonight)
Issued at 402 AM EDT TUE JUN 27 2017

Fairly dry weather is expected over the next 24 hours with building
ridge heights and sfc high pressure dominating.

Building ridge heights should ensure mostly sunny skies and mainly
dry conditions across most of Upper Mi today. However, will
continue to include slight chc pops for isolated rain showers that
may develop over the se and eastern U.P. during afternoon heating
and convergence along lake breeze boundaries as some models
continue to show MLCAPE values in the 200-300 j/kg range. The
increased sunshine will help temperatures to rebound closer to
normal for this time of year with most locations warming into the
lower to mid 70s.

High pressure will continue to dominate tonight keeping conditions
dry. There will be an increase in mid-level clouds late tonight from
the west ahead of the next approaching system from the Plains but
the arrival of any pcpn should hold off until after 12z Wed. Expect
min temps mainly in the lower to mid 50s, although a few upper 40s
could be possible over the typical cold spots of central and eastern
Iron County.

.LONG TERM...(Wednesday through Monday)
Issued at 340 AM EDT TUE JUN 27 2017

An active pattern with multiple waves traversing the area will keep
rain chances in the forecast through at least the weekend with
temperatures running 5 to 10 degrees below normal. The best chance
for widespread moderate to heavy rain will be Wednesday into
Thursday, then precipitation chances will be periodic into early
next week. Early next week, temperatures will gradually return to
near normal.

Widespread moderate to heavy rainfall is expected to develop on
Wednesday and push east across Upper Michigan into Thursday morning
as low pressure tracks across the area. Expect the rain showers to
move into western portions of Upper Michigan during the late
morning/early afternoon hours on Wednesday, and then gradually push
east across the central and east into the afternoon and evening
hours. With a warm, moisture rich air mass overhead, PWATs will
increase to around 1.5+ inches, along with deepening of the warm
cloud depth. These ingredients, coupled with increased lift along
the warm front as it lifts across the area will allow for high
rainfall rates. Right now, the highest rainfall totals are expected
to be across the central and east, where 1-2`` of rain looks
possible. There may be some isolated thunder embedded within the
widespread rain, but the threat for any severe thunderstorms will
remain well south of the area. Into early Thursday morning, as
moisture transport lifts northeast into Ontario, the threat for
heavy rain will wave, but with upper-level energy will still linger
overhead, so cannot rule out scattered showers through the day on
Thursday, but depending on the speed of the wave exiting the area
and track of the surface low, things could dry out a bit sooner than
currently reflected on Thursday. Thankfully, the band of moderate to
heavy rain looks to remain fairly progressive as it moves across the
area. However, given the antecedent wet conditions across the area,
and rivers and their respective tributaries running high flooding
may still be an issues in some locations, especially those that
see the highest rainfall rates.

Friday through the weekend, a number of upper-level waves are
progged to move across the Great Lakes region bringing additional
chances for showers and perhaps a few rumbles of thunder. With a
leading shortwave lifting north out of the middle Mississippi Valley
and up into the western Great Lakes Friday afternoon, expect showers
to become a bit more widespread. Progressing into Saturday, a more
potent upper-level wave will pivot across Upper Michigan and allow
precipitation chances to linger through the day on Saturday and into
Sunday. Right now, it certainly looks like the end of the weekend
will be much drier than the beginning.

Early next week, there may be a slight chance for rain showers as
another shortwave digs south across the area, but behind this
exiting wave it looks like we may start to dry out and warm up a
bit. By Monday afternoon/evening, the GFS and ECMWF have increasing
large-scale subsidence across the area with surface high pressure
moving overhead. Also, with ridging progged to build across the
Plains, this may allow the jet stream to shift a bit further north
and the return of more seasonable weather.

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 138 AM EDT TUE JUN 27 2017

All TAF sites will be VFR through the period as dry air moves in.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 402 AM EDT TUE JUN 27 2017

Winds should remain blo 20 knots through Wed morning as sfc high
pressure continues to dominate the area. By Wed afternoon and Wed
night se to e winds could increase to 20 to 25 knots over the east
half of Lake Superior as a low pressure system lifts across the
Upper Great Lakes. Winds will then decrease to 20 knots or less
towards the end of the week and weekend as the pressure gradient
relaxes once again.

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


LONG TERM...Ritzman
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