Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 231140

Area Forecast Discussion
National Weather Service Marquette MI
740 AM EDT Wed Aug 23 2017

.SHORT TERM...(Today and tonight)
Issued at 419 AM EDT WED AUG 23 2017

This morning, Upper Michigan was situated between high pressure over
the Northern Plains and low pressure southeast of the Hudson Bay.
Upstream of the area, a weak shortwave began to dig south across
Lake Superior and usher in better cold air advection southward. With
a lingering enhanced pressure gradient and increasing cold air
advection across the region, quasi-breezy winds lingered across
inland areas and especially near the shores of Lake Superior.

The arrival of better cold air advection and remnant upslope flow
will allow ongoing cloud cover to linger and likely become more
widespread this morning as we start to see diurnal heating pick up.
A few areas of light rain/sprinkles are possible early this morning,
but as dry Canadian air continues to drop south, clouds will begin
to dissipate through the afternoon hours from north to south. As the
above mentioned area of high pressure begins to work it`s way into
Upper Michigan later today, breezy winds will subside through the
afternoon and evening hours from west to east. The strongest wind
gusts are expected to be along the shores of Lake Superior, which
will create a high swim risk today for the beaches of Marquette and
Alger Counties. Temperature wise today, it will be a battle between
increased insolation and cold air advection, and in some locations
downslope warming as well. Overall, afternoon high temperatures
should climb into the 60s, with the warmest temperatures expected
across the south central. Given the increasingly dry air mass this
afternoon, wouldn`t be surprised if a few locations reach the 70
degree mark.

Tonight, the combination of dry air, ample boundary layer
decoupling, and mostly clear skies will result in strong radiational
cooling through the overnight and early morning hours. Right now it
is still looking like patchy to widespread frost will be possible
across the interior west early Thursday morning. There is the
potential for mid-level clouds to slow the rate of cooling overnight
along the Wisconsin border as a shortwave digs south across the
Upper Mississippi Valley, but the majority of the thicker clouds are
expected to remain south of the area.

.LONG TERM...(Thursday through Tuesday)
Issued at 507 AM EDT WED AUG 23 2017

Models suggest that a slowly progressive pattern will prevail with
the trough from ern Canada into the Great Lakes giving way to a
ridge from the wrn Great Lakes to Hudson bay by late Saturday. As
the wrn CONUS ridge again builds into wrn Canada, a mid level
trough from nw Ontario into the upper MS valley will gradually
slide to the east bringing showers chances back into Upper
Michigan from Sunday into early next week.

Thursday, cool dry weather will prevail with sfc high pressure
dominating the area under confluent nw mid/upper level flow. Under
mostly sunny skies with only a few/sct cu and 850mb temps around 5c,
highs will remain in the mid 60s. With PWAT values down to 0.25 inch
and favorable radiational cooling conditions, temps will again drop
into the lower 30s (and even some upper 20s for isold typical
cold spots), over the inland areas of both west and cntrl portions
of the cwa, where patchy frost is expected.

Friday into Saturday, dry conditions will continue as the high
slowly builds to the east and mid level ridging bloecks the eastward
progress of the shrtwv and pcpn over MN. highs will climb from the
upper 60s Friday to the lower 70s Saturday.

Sunday through Tuesday, Shower chances will increase over the west
half of Upper Michigan Sunday into Sunday but may dwindle from
Monday into Tuesday as the mid level low drops to the south toward

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 740 AM EDT WED AUG 23 2017

Ceilings are ranging from LIFR to VFR this morning and will continue
to fluctuate over the next couple of hours across all terminals, so
amendments may be needed. Clouds will scatter out, before clearing
later this afternoon from west to east as drier air pushes into
Upper Michigan. Northwest winds will be gusty through much of the
day, but the winds will relax from west to east through the
afternoon and evening hours. Tonight, high pressure will come
overhead and winds will become light.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 419 AM EDT WED AUG 23 2017

Today winds will start off gusty, at speeds of 20 to 30 knots across
much of the lake, and then gradually weaken to around 10 to 20 knots
from west to east later this evening and tonight as high pressure
drops into the Upper Great Lakes region. This area of high pressure
is expected to linger across the region through the end of the week
and weekend. Therefore, expect winds to be less than 20 knots.

Upper Michigan...
  Beach Hazards Statement through this evening for MIZ005-006.

Lake Superior...
Lake Michigan...


SHORT TERM...Ritzman
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