Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 222303
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
703 PM EDT Tue Aug 22 2017

.NEAR TERM...(Tonight through Wednesday)
Issued at 312 PM EDT Tue Aug 22 2017

...An early fall type airmass...

High Impact Weather Potential:  Beach hazards likely for parts of
the area through Wednesday. Waterspouts possible later tonight
into early Wednesday - mainly Lake Huron.

Pattern Overview:  High amplitude and anomalously strong upper
trough (for August) deepening across the Great Lakes through
midweek. Several pieces of embedded shortwave energy pinwheeling
around the main upper low over Quebec.  Tight pressure gradient
between departing area of low pressure to our east and large
Canadian high pressure building into the upper midwest.

Details: A few sprinkles possible over northwest lower through
late afternoon as a weak wave slides across the area. Otherwise,
we should see decreasing cloudiness once we lose the diurnal cu
field. Deep layer cyclonic flow and an uptick in mid level
moisture later tonight, combined with increasing delta t`s into
the mid teens, likely evokes a lake response in the form of
cloudiness and possibly some sprinkles/light shower (is this
August?). This scenario maintains itself into the day on
Wednesday, with cool and somewhat moist cyclonic flow producing
northwest lake clouds and possibly a few sprinkles/showers. Breezy
day expected once again with gusts 20-30 mph. A very chilly
August day, with highs generally in the 60s (record low max
temperature in Gaylord is 60 degrees - which we likely won`t
break). These high temperatures are a solid 10 to 12 degrees
below normal.

&&

.SHORT TERM...(Wednesday Night through Friday)
Issued at 312 PM EDT Tue Aug 22 2017

...Cool...

High impact weather potential...None.

High pressure initially over Manitoba, will build gradually se-ward,
and will be dead overhead on Friday. This will keep our wx cool and
mostly quiet. However, a prominent spoke of energy rotating around
the stacked low in Quebec will rotate into the region Wed night/Thu.
Cloud cover will be highest during these periods, and there is some
potential for some associated showers, with the lakes assisting.

Delta Ts will top out in the mid teens Wed night/Thu morning, as a
850mb thermal trof accompanies the shortwave and somewhat deeper
moisture. A north 1000-850mb fetch is not ideal for much of the
forecast area (including all of eastern upper MI). But would expect
at least a few showers in the Gd Trav Bay region, and skirting the
ne lower MI coastline south of Rogers City. Will continue and/or add
to small pops in those regions late Wed night into Thu morning.

Once that passes, considerable and deep subsidence/drying will be
seen with the approaching high. Cloud cover will diminish from n to
s Thu afternoon, and Friday looks very sunny and pleasant (after a
cool start).

Min temps will be mainly in the 40s, closer to 50 along the coasts.
Would not be surprised to see a few upper 30s in interior cool spots
Thu night. Max temps mid/upper 60s Thu, with a few degrees of 60f
Fri.

.LONG TERM...(Friday night through Tuesday)
Issued at 312 PM EDT Tue Aug 22 2017

High Impact Weather Potential...Cool overnight lows heading into
the weekend.  Even some patchy frost a possibility.

Very quiet weather for the extended period with dry air and high
pressure over the Great Lakes region through Monday. Said high
pressure will provide northern Michigan with a light wind regime,
cooler than normal temperatures (in the low to mid 70s), and rain
free weather through at least the weekend. Models then hint at a
weak area of low pressure developing over the western Great Lakes
region with some associated moisture that may trigger hit and miss
showers over the southern forecast area late Monday into Tuesday.
Lows will be chilly once again Saturday morning (possible frost??),
with the remainder of the forecast period in the 40s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 703 PM EDT Tue Aug 22 2017

Deep cyclonic flow combined with ample low level moisture and
ongoing CAA will generate lake enhanced clouds across much of
Northern Lower Michigan by Wednesday. Scattered showers will
impact locations across NW Lower Michigan targeted by W/NW
flow...mainly locations between PLN and TVC. In the meantime...
skies will remain mostly clear thru most of tonight. W/NW winds
gusting to 15 to 25 kts will diminish to around 10 kts after
sunset...but will strengthen to 15 to 20 kts again on Wednesday.

&&

.MARINE...
Issued at 312 PM EDT Tue Aug 22 2017

A tight gradient behind an exiting cold front will result in gusty
winds across the northern Great Lakes through the day on Wednesday.
This will result in widespread advisory headlines, with low end
Gales expected in Whitefish Bay and through Presque Isle light for
this evening.  Increasing overlake instability with cold air
advection will result in scattered lake effect rain showers as well.
Waterspouts will also be possible later tonight into early Wednesday
on Lake Huron.  High pressure builds into the Great Lakes for the
end of the week, resulting in much lighter winds.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT through Wednesday afternoon for MIZ016-
     019>021-025-031.
LH...SMALL CRAFT ADVISORY until 6 PM EDT Wednesday for LHZ345-346-349.
     GALE WARNING until midnight EDT tonight for LHZ347-348.
LM...SMALL CRAFT ADVISORY until 6 PM EDT Wednesday for LMZ323-341-342-
     344>346.
LS...SMALL CRAFT ADVISORY until 6 PM EDT Wednesday for LSZ322.
     GALE WARNING until midnight EDT tonight for LSZ321.
&&

$$

NEAR TERM...JK
SHORT TERM...JZ
LONG TERM...TL
AVIATION...MR
MARINE...JK



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