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Area forecast discussion 
National Weather Service Detroit/Pontiac Michigan
601 am EDT Friday Oct 21 2016


Cold airmass in place over Southeast Michigan, with northerly flow
off Lake Huron helping to sustain high MVFR/low VFR ceilings through
the day. The northerly winds look to be gusting in excess of 20
knots wit deep daytime mixing. Scattered light showers expected,
with ptk standing the best shot to see one. Winds diminishing this
evening and shifting a bit more to the northwest, which is
expectedto allow for clearing this evening/tonight, but transient
streamers/clouds (2500-3500 feet) will remain possible. High
MVFR/low VFR clouds are expected to quickly reform by late Saturday

For dtw...northerly moisture push from Lake Huron should sustain
high MVFR/low VFR clouds through the day, slight chance of a light
shower passing through. Northerly wind gusts in excess of 20 knots,
to possibly as high as 25 knots today.

//Dtw threshold probabilities...

* high confidence in ceilings aob 5000 feet today, low tonight,
medium by late Saturday morning.


Previous discussion...
issued at 335 am EDT Fri Oct 21 2016


Steady expansion of high amplitude troughing into the region today.
The ensuing reduction in mean thicknesses will translate into a step
downward in the thermal profile relative to recent days. Cold air
advection under prevailing north-northeast flow will sustain a
favorable environment for inland penetration of moisture off Lake
Huron. This will supplement the existing 3000 to 4000 ft of
moisture depth tucked beneath a Stout inversion based near 850 mb.
Given the advective component and increasing mid level cyclonic
flow, this should support renewed expansion in shower coverage
through the afternoon hours. Highest precipitation chances
certainly allocated for The Thumb region, but recent hi res
guidance points to the potential for inland penetration as far
west as the Flint-Howell corridor. Limited insolation potential
given the extensive cloud cover will contribute to a notably
cooler day, as will a firm and intermittently gusty north wind.
Highs in the vicinity of 50 degrees.

Upper trough axis exits to the east tonight, with a backing low
level flow eventually pivoting the Lake Huron moisture plume largely
offshore. With that said, some perpetuation of the existing stratus
may continue well into the night given the existing low level
thermal troughing. This lends some uncertainty as to the potential
nocturnal cooling response. In addition, surface ridging is
displaced too far to the west to yield a more favorable light wind
field. Thus, continue to favor a low temperature distribution
that leans on the warmer side of the model guidance spectrum. This
places the coldest locales in the mid 30s.

Deep west-northwest flow Saturday as upper heights slowly begin
to recover. Eastward propagation of a residual ribbon of Lake
Michigan moisture augmented by diurnal heating likely translates
into a solid expansion in stratocu. Limited overall diurnal
temperatures response despite a modestly mixed profile and at
least partial sun. Temperatures a touch warmer relative to
Friday, with highs 50 to 55.

Solid pattern of warm air advection emerges for Sunday, as low level
southwest flow briefly takes hold immediately downstream of the next
inbound short wave and cold front. This process will nudge readings
back up to around 60 degrees. Limited moisture availability and
simply a glancing shot of forcing seemingly translates into
minimal potential for rainfall with this frontal passage Sunday
night. A dry Post-frontal airmass will then tilt on the cooler
side of normal early next week.


Much colder airmass in place over the Great Lakes region, with
strong northerly winds between 20 and 30 knots today and tonight
as low pressure deepens along the mid Atlantic and northeast
coast. Small craft advisories remain in effect for nearshore waters
of Lake Huron. Winds will remain strong tomorrow but will be out of
the northwest, with frequent gusts to around 30 knots over the open
waters. If the low over New England is a bit farther west and
stronger, gale force winds could develop with the deep mixing.
Winds look to slowly diminish Saturday night ahead of the next weak
low which moves through on Sunday...allowing for winds to drop at or
below 15 knots.


DTX watches/warnings/advisories...
Lake Huron...Small Craft Advisory until 4 am EDT Sunday for lhz441>443.

Small Craft Advisory until 10 PM EDT Saturday for lhz421-422.

Lake St Clair...none.
Michigan waters of Lake Erie...none.



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