Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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000
FXUS63 KDTX 301131
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
631 AM EST Wed Nov 30 2016

.AVIATION...

Cloud trends the issue today in advance of a cold front.  Elongated
area of low stratus now over west Michigan will push toward the
region through the latter half of the morning.  A mixed signal
across the model guidance on it`s potential survival, but will lean
in favor of some MVFR type restrictions entering all locations by 14-
15z.  Window for this restriction appears confined to a 3-4 hour
period, before drying commences by mid afternoon.  Light southerly
flow will see an uptick inmagnitude as direction shifts to
southwesterly with the frontal passage this afternoon. Higher
confidence in lowering ceilings tonight as a large plume of low
level moisture now over WI/IA pivots into the region. Extensive MVFR
stratus likely overnight, with the potential for some light
rain (brief SN mix?) during this time.

For DTW...Window for low stratus /15-18z/ to emerge in advance of a
cold front through early afternoon.  Low confidence in both duration
and coverage.  Light south wind becomes southwesterly and increases
this afternoon.

//DTW Threshold Probabilities...

* Medium for ceilings aob 5000 feet today, then high tonight.

&&

.PREV DISCUSSION...
Issued at 303 AM EST Wed Nov 30 2016

DISCUSSION...

WV and IR imagery reveal shear max of interest positioned along the
eastern flank of the broad trough centered over the central US.
Inflection point noted in the southern plains, and given away by
expanding clouds in TX/OK will be the focus of synoptic scale lift
as it lifts northeast into SE Michigan today. Relatively deep layer
of 925-700mb conditional instability will reside over the forecast
area, but the 00z progs all indicate that the weak northward
moisture surge associated with this wave will mainly take place to
the east. Trimmed pops back to chc over far eastern areas where
forcing, diurnal heating, and moisture will be most favorably
superpositioned. Steepening lapse rates west of US-23 beneath the
encroaching cold core aloft will be offset by lack of moisture. An
isolated shower possible, but nothing worth an explicit wx mention.
Cold front currently hung up along the Lake Michigan shoreline will
release east as large scale support translates over Lower Michigan
this aftn. Highs a few degrees colder than yesterday, near 50,
especially further west where cold fropa will occur in early/mid
aftn.

Lake Michigan activates tonight 0-1km theta-e lapse rates fall to a
modest -3 to -5C/KM. Broad scale ascent and descent moisture quality
will support deepening convective depths emanating off the lake,
particularly as an embedded shortwave tracks across the area after
06z tonight. Deepening saturated layer during this time will favor
lake effect rain and snow showers becoming likely north of M59 late
tonight into Thursday morning. No accumulation. Cool cyclonic flow
and prevalence of lake clouds will ensure temps near average through
the end of the week.

MARINE...

Modest southerly flow will continue across the region through the
daylight period.  Winds will then increase from the southwest this
evening as cooler air begins to funnel over the lakes.  Gusty
southwest winds will persist tonight and Thursday.  While the gust
magnitude will largely remain just shy of cold season small craft
conditions /<30 kts/, a favorable trajectory across Saginaw Bay will
build waves sufficiently to warrant a small craft advisory across
the outer bay and along the tip of the thumb.  These conditions will
likely persist into early Thursday night before easing.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...Small Craft Advisory from 10 PM this evening to 10 PM EST Thursday
     FOR LHZ421-441.

Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

AVIATION.....MR
DISCUSSION...JVC
MARINE.......MR


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