Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 291051
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
551 AM EST Tue Nov 29 2016

.AVIATION...

Lingering MVFR stratus through mid morning, before rapidly exiting
to the northeast.  VFR then expected through at least early tonight.
Gusty southwest winds ease with time through the day, before
gradually backing to southeast again tonight.  Moisture will
increase again overnight, but some uncertainty remains as to
potential coverage and ceiling heights.  Northeast trajectory of
this moisture out of Missouri may favor lower cigs initially working
into MBS/FNT.  Light showers with an accompanying reduction of
visibility will be possible overnight.

For DTW...Lingering low stratus in place through mid morning will
rapidly vacate the airspace 14-15z leavning plenty of clear sky
below 5000 ft for the remainder of the daylight period.
Intermittently gusty southwest wind will ease through the day,
holding at this trajectory through sunset.

//DTW Threshold Probabilities...

* High for ceilings AOB 5000 feet through 14z this morning, then
  clearing.

* Low for ceilings falling below 5000 ft tonight, medium Wednesday.

&&

.PREV DISCUSSION...
Issued at 255 AM EST Tue Nov 29 2016

DISCUSSION...

Dynamically forced convection oriented along the occluded front and
within the corridor of greatest height falls will lift out of the
area to the northeast prior to daybreak. Strong westerly wind field
will provide potential for wind gusts of 40 to 50 mph on an isolated
based on upstream observations so far this morning. Elevated dry
advection surged into the area hours ago and will continue to
descend through the column during the morning. Low-level moisture
axis supporting clouds as far west as Indiana should slowly erode as
clouds work through the southeast half of the CWA and dewpoints fall
into the low 40s by this aftn. Ongoing warm advection pushing 850mb
temps into the mid single digits and better insolation through a
partial coverage of aftn mid-level clouds will support highs in the
mid 50s...perhaps touching 60 in a best case scenario.

Uncertainty increases markedly by Wednesday as the large cyclone to
the west nudges east and an elongated shear max propagating through
the eastern periphery of the trough lifts through the area. Lower
static stability supports potential for deepening low pressure to
foster a blossoming precip shield overhead. SUNY Stony Brook PC
analysis suggests the bulk of variability among the ECMWF ensemble
members is due to intensity outcomes. An ever-so-slightly flatter
00z solution appears to limit PV advection and favor a weaker
solution. This also falls in line with the op GFS and the vast
majority of GEFS members. Although this increases confidence that
Wednesday will not be the washout that some NWP has suggested, there
remains plenty of potential for afternoon shower development. Will
retain the west-east pop gradient on Wednesday but will refrain from
making a call by raising or lowering pops until NWP spread shows
signs of collapsing toward a solution. With no airmass change from
Tuesday, increased clouds and potential for rain suggest max temps
in the low to mid 50s.

Maturing cold conveyor will finally push through the forecast area
Wednesday night as the low is shoved into Quebec by the continued
surge of Pacific jet energy. Moist cyclonic flow and embedded
shortwaves propagating overhead support a chc mention of ra/sn
showers on Thursday, but nothing impactful due to marginal lake
instability and borderline temperatures.

MARINE...

Ongoing south to southeast gales this morning will ease through the
day as winds become south-southwesterly.  Modest southerly breeze
will hold across all marine areas tonight and Wednesday, maintaining
more favorable wind and wave conditions through this time.  There
will be a period of stronger southwesterly flow Wednesday night and
Thursday as colder air funnels back into the region.  At this time,
gusts are expected to remain below gales.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...Gale Warning until 4 PM EST this afternoon FOR LHZ363-421-422-441-
     462.

     Gale Warning until 10 AM EST this morning FOR LHZ361-362-442-443-
     463-464.

Lake St Clair...Small Craft Advisory until 10 AM EST this morning FOR LCZ460.

Michigan waters of Lake Erie...Gale Warning until 7 AM EST this morning FOR LEZ444.

&&

$$

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


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at www.weather.gov/detroit.



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