Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 261955

Area Forecast Discussion
National Weather Service Marquette MI
355 PM EDT Mon Jun 26 2017

.SHORT TERM...(This evening through Tuesday)
Issued at 355 PM EDT MON JUN 26 2017

Finally some dry weather in the short-term forecast after showers
end over the far eastern U.P. late this afternoon into this evening.

As the shortwave that brought all of the rain over the past 24 hours
shifts east of the U.P., heights will begin to rise from west to
east. This ridging aloft along with a surface high building into the
Upper Great Lakes region, will allow the precipitation to come to an
end and allow for clear skies across the area. This will allow
temperatures to cool off tonight, with many locations inland cooling
to the low 40s tonight. Actually, with ideal radiational cooling,
its not out of the question that a few of the typically cooler
locations may see a few upper 30 degree readings. The dry weather
and clear skies will continue into Tuesday; however, there is a very
small chance that some isolated rain showers may develop over the
eastern U.P. during afternoon heating/lake breeze boundaries. The
increased sunshine will help temperatures to rebound closer to
normal for this time of year with many locations warming into the
mid 70s.

.LONG TERM...(Tuesday through Sunday)
Issued at 405 AM EDT MON JUN 26 2017

The main forecast highlights will be the brief arrival of near-
normal temperatures with a mostly dry day on Tuesday, but then
towards the middle of the week through the weekend, chance for rain
return as multiple systems are expected to track across the area.
The heaviest rain is expected to fall on Wednesday through Thursday
morning. With much of Upper Michigan seeing above normal rainfall
over the last week or two, heavy rain may bring flooding concerns.

Tuesday, expect much of the area to remain dry as high pressure
drops south from the northern Plains into the Ohio River Valley.
With ample diurnal heating expected through the day, expect lake
breezes to develop off of Lake Superior and the northern end of Lake
Michigan. Converging lake breezes across eastern portions of the
Upper Michigan may provide enough lift for a few isolated afternoon
showers, and perhaps a thunderstorm or two. Otherwise, expect much
of Upper Michigan to remain dry, with diurnal cumulus developing
downwind of lake breezes.

Tuesday night into Wednesday, surface low pressure will eject out of
the northern Rockies and track across the northern Plains as
shortwave energy traverses north central portions of the CONUS. The
combination of low pressure to our west and the above mentioned area
of high pressure slowly tracking towards the Mid-Atlantic states
should allow moisture-rich air from the Gulf of Mexico to funnel
northeast towards the Upper Great Lakes region. This increase in
moisture will allow PWATs to climb to around 1.5+ inches and
increasing warm air advection across the area will allow the warm
cloud depth to increase, setting the stage for efficient, heavy
rain. The medium range models have diverged a bit on the track and
speed of the system across the area, but they remain consistent with
Upper Michigan riding along the nose of the best moisture transport,
which should allow fairly widespread precipitation to start from
west to east through the day on Wednesday. Instability looks very
limited, but cannot rule out a few rumbles of thunder especially
closer to the Wisconsin/Michigan border. Wednesday night into
Thursday, as anomalously strong 850mb flow becomes enhanced, with a
50 knot low-level jet ramping up across Wisconsin, expect the focus
for heavy rain to shift east into Thursday. It is difficult to
pinpoint what areas will see the highest rainfall totals Wednesday
through Thursday, but given the antecedent wet conditions across
much of Upper Michigan, areas that see heavy rains may see hydro
concerns increase. Even though the system will be exiting the area
on Thursday, lingering upper-level vorticity and wrap-around
moisture may still allow for lingering rain showers through the day.

Friday through the weekend, the upper-level pattern across the
medium range models begins to diverge, but with multiple shortwaves
expected to track across the area periods of showers will be

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 355 PM EDT MON JUN 26 2017

All TAF sites will see improving conditions to VFR through this
evening. KSAW will see some lingering low clouds early this
afternoon before drier air moves in from the northwest and the main
area of moisture shifts to the southeast. Skies will clear tonight
and wouldn`t expect too much more than some fair weather clouds to
pop up tomorrow afternoon with daytime heating.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 355 PM EDT MON JUN 26 2017

Winds of 10 to 15 knots are expected to continue through the first
half of next week as the pressure gradient decreases and high
pressure builds into the area. Towards the middle of the week, winds
will start to increase to around 20 to 25 knots as a low pressure
system lifts across the Upper Great Lakes. Winds will then decrease
to around or less than 15 knots towards the end of the week and next
weekend as the pressure gradient relaxes once again.

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


LONG TERM...Ritzman
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