Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 290408
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1208 AM EDT MON AUG 29 2016

.AVIATION...

Clear sky other than some thin cirrus debris will contribute to
favorable conditions for continued fog and stratus development
during the night. High pressure shifting from northern lower
Michigan to Lake Huron will line up to direct some marine moisture
inland. Surface moisture conditions are already be favorable for
borderline LIFR/IFR fog and the marine moisture will enhance both
the fog and LIFR/IFR stratus potential through morning. While
prospects are good for restrictions, observational trends will be
required to refine timing and coverage at each terminal location.
Conditions will then follow a standard improving trend through late
morning and lead to clear sky and light wind through afternoon into
Monday evening.

For DTW... Borderline LIFR/IFR restriction in fog and stratus or
obscuration remains likely late tonight through mid morning with
improvement to VFR by late morning/early afternoon. Clear sky and
light wind will then persist into Monday evening.

//DTW Threshold Probabilities...

* High ceiling aob 5000 feet late tonight through mid morning.

* Low for ceiling/visibility below 200 ft or 1/2 sm late tonight
  into early morning.

&&

.PREV DISCUSSION...
Issued at 950 PM EDT Sun AUG 28 2016

UPDATE...

Mid evening surface analysis indicates a healthy gradient of
dewpoint from north to south over SE Michigan, from the mid 60s
in the north to lower 70s Detroit to the Ohio border. This marks
where the surface trough has stalled and will now wash out during
the night in favor of high pressure over the northern Great Lakes,
and even that process will be weak and slow. A combination of fog
and low clouds remain likely at all locations overnight as surface
wind continues to drop off and the sky remains otherwise clear for
good radiational cooling. No headlines will be issued at this
point but locations to the south will be monitored closely for
trends in that direction.

PREV DISCUSSION...
Issued at 259 PM EDT Sun AUG 28 2016

DISCUSSION...

High pressure will settle across the Great Lakes tonight beneath a
building shortwave ridge aloft. Light northeast gradient off of Lake
Huron will result in a shallow inversion that will support inland
development/advection of fog and/or stratus late tonight.

Diurnal deepening of the boundary layer will mix out low cloud
during Monday morning. Very dry column within flat/confluent upper
level flow aloft will support mostly clear skies on Monday and
mixing to perhaps 850mb where temperatures will reside in the mid
teens around the northern periphery of the expansive mid-level high
parked over the eastern 2/3 of the US. Highs will hover just above
average values for the date in the low 80s.

Little change in the local environment through Tuesday. SE Michigan
will still reside safely east of the instability corridor that will
be drawn north over the Northern and Western Great Lakes in response
to height falls associated with a weak cyclone over northern
Ontario. Depression of heights locally will allow for slightly
deeper mixing than observed on Monday, so inherited high temps in
the mid 80s still look good. Theta-e ridge will fold into the area
from the northwest on Tuesday night in advance of a weak cold front.
Nothing more than a chc pop warranted Tuesday night given weak
dynamic forcing and unfavorable nocturnal timing.

Surface cold front will move through the area on Tuesday and
Wednesday. A fairly moist airmass ahead of the front will allow for
scattered showers and thunderstorms to develop over portions of
southeast Michigan. As the cold front passes through on Wednesday,
high pressure builds over the region with cooler/drier conditions to
follow. High temperatures are expected to be in the low to mid 70`s
through Saturday with low to mid 80`s returning for Sunday/Monday.

MARINE...

High pressure building into the central Great Lakes will bring
veering and weakening flow to region overnight into Monday.
Northwest winds will become northeasterly Monday morning and though
winds will be in the 10 to 15 knot range through most of the night,
they will quickly drop off in the morning to less than 10 knots.
Modest southwest winds expected on Tuesday ahead of a weak cold
front tracking through the region.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

AVIATION.....BT
UPDATE.......BT
DISCUSSION...JVC/DE
MARINE.......DRK


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at www.weather.gov/detroit.


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