Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 142007
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
307 PM EST Tue Feb 14 2017

.DISCUSSION...

Mild afternoon within moderate west southwest flow in advance of
approaching cold front. Temperatures have reached the 40s over the
whole forecast area and would not be surprised to see a few 50
degree readings over the southern portion of the region before
heating top out. Aforementioned cold front will bring a quick end to
this though as it sweeps south through lower Michigan between 8 pm
and midnight.

Scattered rain and snow showers will accompany this frontal boundary
with the best concentration most likely over the Thumb where best
forcing/convergence along the front will exist (nearer the low as it
drops southeast along Georgian Bay). While these showers will change
to snow pretty quickly, especially over the northern forecast area,
do not expect anything more than a dusting in some spots. Winds will
also be a bit breezy, but not nearly as much as the previous cold
front a few days ago. Wind gusts will peak more in the 25 to 30 mph
range within cold air advection in the wake of the front.

Much colder weather will settle into the area behind this cold front
for the next several days as the low pressure continues on to the
New England area where it rapidly deepens and leads to a very
amplified upper trough over the northeast CONUS. Expect highs to
range in the upper 20s/lower 30s Wednesday and Thursday with lows in
the teens and 20s. Scattered snow showers/flurries from lake effect
activity can be expected on Wednesday. A moderating airmass from the
west will then squelch this activity by Thursday, even as
temperatures at the surface remain similar to Wednesday.

Warming trend will begin on Friday as a broad upper level ridge sets
up over the Great Lakes through the weekend. Under the ridge dry,
mild conditions will stay in place through Monday. With 850 mb temps
approaching 10 C on Saturday high temperatures will surge well into
the 50s and possibly near 60. Above normal temperatures look to
remain in place into early next week before the next storm system
brings a chance for rain to SE Michigan.

&&

.MARINE...

Models continue to highlight a sharp thermal trough feature crossing
northern Lake Huron as low pressure drops southeast along the shores
of Georgian Bay and drags a strong cold front through the area. This
should lead to local compaction of the pressure gradient field. This
will be enhanced further by the interaction with coastal convergence
effects over Lake Huron. These factors are expected to compensate
for a rather lackluster environmental wind profile and allow for a
period of gale force gusts over parts of the open waters of Lake
Huron overnight into Wednesday morning. Hence, the Gale Watch will
be upgraded to a warning with this forecast package.

&&

.PREV DISCUSSION...
Issued at 1146 AM EST Tue Feb 14 2017

AVIATION...

Probabilistic wind information continues to supports gusts exceeding
15 knots with at least a moderate confidence in reaching 25 knots as
well. Given the fact that gusts have already reached the 15-20 knot
range, will maintain gusts up to 25 knots, both in WSW flow this
afternoon and also NW flow tonight in wake of passing cold front.
Stratus/strato-cumulus field associated with this system remains a
bit chaotic, but generally should see a trend to MVFR as the cold
cyclonic northwest flow regimes becomes established tonight. Would
also expect at least scattered rain/snow showers in advance of the
front this evening the dynamic nature of the parent shortwave.

For DTW...Winds will veer to WSW this afternoon and then NW late
this evening as strong cold front passes. Will maintain TEMPO group
this evening for rasn showers, but lack of moisture should keep this
activity rather scattered in nature. Wind gusts should range between
20 and 25 knots at times.

//DTW THRESHOLD PROBABILITIES...

* Moderate in ceilings below 5000 ft tonight.

* Low in crosswind thresholds being exceeded this evening.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...Gale Warning from 1 AM to 11 AM EST Wednesday for LHZ362-363-462.

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

$$

DISCUSSION...DG/JD
MARINE.......DG
AVIATION.....DG


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