Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 311040
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
640 AM EDT TUE MAY 31 2016


.AVIATION...

VFR conditions with predominate this forecast period as high
pressure builds across the area today and then continues east
overnight. With a gradual re-positioning of this high further
east, light northerly flow will become more east northeast (and
eventually southeast late in the forecast). Other than cirrus
varying from SCT to BKN during the forecast, only expect a period
of FEW diurnal cumulus with bases in the 5-6kft area this
afternoon.

//DTW Threshold Probabilities...

* Very low for ceilings of 5000 feet this afternoon.

&&

.PREV DISCUSSION...
Issued at 333 AM EDT Tue May 31 2016

DISCUSSION...

Backdoor cold front will slide down across Lake Huron and settle
into the northern Thumb and Saginaw Valley today as upper energy
tracks north of Lake Huron and Canadian high pressure begins to
settle into the area. Upper ridging will meanwhile amplify over
Michigan today and tonight in response to an upper low digging into
the Northern Plains. This should keep dry and stable conditions over
the area as upper levels warm, even as the shallow cold front slides
into the northern and eastern portions of the forecast area. Main
impact from this frontal push will be increased easterly winds and
cooler temperatures. Max temps are still expected to reach into the
low 80s well inland, but much of the thumb will only see temps in
the mid 60s to low 70s with low-level cold air advection and east
winds off the lake. Other forecast issue is determining amount of
high cloud that will move into Michigan today from off convection
upstream early this morning. Building ridge will attempt to dampen
these clouds, but think enough should survive to go with a partly to
mostly sunny forecast.

Warm front will lift into the area mid-day Wednesday as the area of
low pressure lifts into western Ontario. Area looks to stay mainly
dry Wednesday as instability and moisture remain to our west. A few
showers/tstorms are however possible late in the day over the
Saginaw Valley, closer to the approaching cold front which will work
across the area Wednesday night. GFS continues to show H850
dew points pooling to 10C ahead of the front, with frontal forcing
aided by right entrance region forcing from a jet streak. Mid-level
lapse rates around 7 C/km will also support chances for
thunderstorms, and will overall help to increase coverage of
showers/tstorms given only modest lift. Max temperatures on
Wednesday will again be held back by east flow off the lakes, but
still looking for above normal temperatures in the upper 70s to low
80s.

There is some uncertainty as to how long showers will linger into
Thursday as models differ with the speed which the upper low lifts
through Ontario and into Quebec. Will leave some small POPS early in
the day to cover differences, but dry the afternoon out as high
pressure starts to build into the area. Surface high should keep the
area dry on Friday before chances for rain/tstorms return over the
weekend as an upper trough settles in overhead.

MARINE...

A surface high pressure will maintain favorable wind and wave
conditions over all areas through this evening. Light southeast flow
will develop tonight and increase modestly by Wednesday as the high
moves into Quebec and the next low pressure system organizes over
the upper Midwest. Small Craft Advisory conditions remain unlikely.

A notable cold front will cross the region Wednesday night into
early Thursday. This front will bring a chance for thunderstorms and
also the potential for westerly wind gusts around 25 knots Thursday
before high pressure brings a weakening pressure gradient again by
Thursday night and Friday.

HYDROLOGY...

A passing cold front may bring around a quarter of an inch to parts
of the area Wednesday night. These amounts will be most likely over
the Saginaw Valley. Given the generally light amounts expected, and
relatively dry conditions of late, there are no concerns of flooding.

&&

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

$$

AVIATION.....99
DISCUSSION...HLO
MARINE.......DG
HYDROLOGY....DG


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at www.weather.gov/detroit.



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