Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 151742
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1242 PM EST Wed Feb 15 2017


.AVIATION...

Gusty northwest flow, possibly touching 25 knots for a period this
afternoon, will persist through the evening before relaxing some
overnight. Winds will likely still remain above 10 knots through the
overnight before finally falling off on Thursday. Clouds will be a
bit of a challenge as models are much more pessimistic this
afternoon, holding onto the MVFR/low VFR stratus through much of the
overnight before finally breaking up Thursday. Hard to argue too
much with this shift in thinking as we`re looking at a pretty solid
cloud field across the region with very few this spots. Will carry
MVFR into tonight and if drier air can start eroding the low level
moisture sooner, will adjust as needed. Just a few flurries this
afternoon, otherwise forecast will be dry.

For DTW...Northwesterly winds will gust into the 20-25 knot range
into the evening hours before dropping off some overnight. Clouds
will be a challenge as ceilings may lift to around the 3kft level
level, bringing VFR into play. At this point will hold MVFR til obs
show a change is warranted. Cross wind thresholds may possibly be
reached but wind speeds will most likely stay below criteria.

//DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 ft or less today, moderate tonight.

* Low for crosswind thresholds being met this afternoon.

&&

.PREV DISCUSSION...
Issued at 315 AM EST Wed Feb 15 2017

DISCUSSION...

The cold front came through late yesterday evening with limited
precipitation, but wind gusts did briefly peak out in the 30 to 40
MPH range during the passage.

Post frontal/upper wave subsidence this morning has lead breaks in
the cloud cover. None-the-less, brisk northwest flow/cold advection
through the day, leading to 850 mb temps of -12 to -14 C should be
sufficient to generate clouds with steepening low level lapse rates.
Generally unfavorable northwest flow for lake effect and inversion
heights under 5 kft should limit snow shower activity however, but
some modest cape in the 2500-3500 kft level probably be enough to
generate flurries, especially this afternoon.  With the well mixed
boundary layer during the day, should be able to tap into 25-30
knots, and thus gusts around 30 mph expected. With lack of snow
cover, some breaks in the clouds (mainly south), and mild start for
February standards, went with highs predominately in the 30 to 35
degree range, in line with latest guidance.

Majority of models adamant clouds Tonight will be maintained
underneath a strengthening inversion, see 850 mb RH fields, but
regional gem does suggest significant breaks in the clouds
developing, which would potentially send temperatures colder than
currently forecasted (upper teens to around 20 degrees).

Large upper level low slow to exit off the New England Coast on
Thursday, and low level thermal trough over Lower Michigan looks to
persist (925 mb temps of -5 to -7 C), keeping maxes near normal in
the lower 30s.

Big warm-up then commences on Friday as dry warm front lifts through
of southeast Michigan Friday, as pronounced upper level ridge axis
(562-566 DAM at 500 mb) arrives Saturday morning. With good low
level southwest flow developing and advertised 925 mb temps of 9-10
C, confidence is increasing Detroit will reach around 60 degrees,
with solid 50s elsewhere, placing daily record highs in jeopardy.

Record highs for February 18th:

Detroit 62 degrees (1976)
Flint 56 degrees (2011)
Saginaw 53 degrees (1981)

Very weak cold front progged to track through lower Michigan
Saturday evening, with just a modest cooling of the airmass for
Sunday, but still looks supportive of high temperatures in the 50s
with sunshine, as mean 1000-500 mb RH remains dry at or below 40
percent, and no low clouds expected, as 00 Euro indicating 925 mb
dew pt depressions around 15 C.

Increase in heights again on Monday, with an amplified upper level
ridge axis (570-572 DAM at 500 MB) returning. However, surface
warm front potentially getting hung up, and at least clouds draped
across the State, making for a bit more challenging of a high temp
forecast, but still looks like we will be at least in the 50s,
with potential to exceed 60 degrees.

MARINE...

Northwest winds to gales remain possible over much of the central
Lake Huron basin this morning. Reduced stability within arctic
trough axis will maintain winds in the 10 to 25 knot range today.
Issued small craft advisories for all of the nearshore zones that
are not ice covered. Pressure gradient is expected to remain tight
over the central Great Lakes tonight in response to the deepening
Nor`easter near the Canadian Maritimes. Winds will quickly diminish
on Thursday with a ridge of high pressure building into the region.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...Gale Warning until 7 PM EST this evening for LHZ362-363-462.

     Small Craft Advisory until 4 AM EST Thursday for LHZ441>443.

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

$$

AVIATION.....DRK
DISCUSSION...SF
MARINE.......CB


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.



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