Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 150815
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
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.

&&

.PREV DISCUSSION...
Issued at 1153 PM EST Tue Feb 14 2017

AVIATION...

A secondary surge of NW flow will follow the evening cold front and
continue through the night with gusts returning to around 25 knots
across the area. Intervals of MVFR will also be possible in this
pattern as colder air moves into the region, although the wind
direction is more favorable for a low end broken coverage of VFR
across the terminal corridor. The best potential for restriction
will be with snow that could brush the MBS to FNT area while moving
through the Thumb region before sunrise. Gusty wind conditions are
projected to last through afternoon with low end VFR ceiling and
possibly some flurries during peak heating. Some modest clearing
and reduced gustiness is then expected during Wednesday evening.

For DTW... Wind remains the primary concern during the night as
lighter northwest wind becomes gusty again before sunrise and then
lasts through the day. Otherwise, just some intervals of MVFR and
flurries within a broken sub 5000 ft VFR ceiling.

//DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 ft or less during the night, moderate
  during the day.

* Moderate for exceeding NW cross wind threshold before sunrise
  through afternoon.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...Gale Warning until 11 AM EST this morning for LHZ362-363-462.

     Small Craft Advisory until 4 AM EST Thursday for LHZ421-441>443.

Lake St Clair...NONE.
Michigan waters of Lake Erie...Small Craft Advisory until 4 AM EST Thursday for LEZ444.

&&

$$

DISCUSSION...SF
MARINE.......CB
AVIATION.....BT


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



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