Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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000
FXUS63 KDTX 261227
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
727 AM EST Sun Feb 26 2017

.AVIATION...

A ridge of surface high pressure will continue to slide east of
Lower Michigan during the morning and carry low clouds out of the
region. This will leave strong southwest wind to redevelop ahead of
low pressure moving through the northern Great Lakes during the
afternoon. Mid level clouds will thicken ahead of the system and
virga will be indicated by radar with this moisture. Light snow with
this system is expected to remain north or just brush MBS with some
flurries leaving the wind as the primary concern for aviation into
early evening. Afternoon gusts are expected to reach the upper 20s
to lower 30 knot range by mid afternoon. The wind will then diminish
during the evening as the trailing cold front settles into central
Lower Michigan and dissipates overnight.

For DTW... Southwest wind will increase during late morning and gust
near 30 knots during the afternoon, however the 230 direction is
expected to be steady for minimal impact on operations.

//DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 345 AM EST Sun Feb 26 2017

DISCUSSION...

Today will turn out a little warmer than Saturday, at least on the
thermometer, as it will feel just as harsh due to windy conditions
persisting. Wind gusts around 20 mph during the morning will return
into the 30 mph range around noon and could reach 40 mph in the Tri
Cities and northern Thumb by mid afternoon. The southwest direction
will bring in some warmer air and help lift temperatures to around
40 across the area while feeling more like 20. A warming trend then
remains on track to quickly get underway to start the week.

The strong wind field today will be supported by a wave of low
pressure moving quickly through the northern Great Lakes up against
expansive high pressure centered over the SE states. The resulting
compression of the surface pressure gradient will keep the wind
elevated and gusty as boundary layer depth builds through the day.
The SE states surface high will extend into Lower Michigan during
the morning before being directed eastward by afternoon. Early
morning satellite imagery shows this process being effective at
sweeping out the low clouds along and east of the ridge axis. The
cloud edge is a reasonable representation of the low level thermal
trough departing the area as well. The ensuing southwest flow
between the systems will then continue to supply warmer and much
drier air through the low levels. This will be important in
determining how much if any snow might occur as the northern stream
wave moves through the region. Prospects look slim as model
depictions of mid level isentropic lift/theta-e advection occurring
ahead of the wave continue to appear weak and moisture-starved.
Model soundings indicate the dry air holding through the low levels
supporting no more than a low chance POP for trace amounts of snow
reaching the ground in the Tri Cities area. Expect mid level clouds
to return and virga to show up on radar over the rest of the region.

The cold front trailing this system will wash out over central Lower
Michigan tonight in favor of renewed high pressure by Monday. This
will be the result of a rebound in the 500 mb height pattern between
the departing northern stream wave and a new long wave trough
developing out west, the continued development of which will
accelerate the warming trend in the Great Lakes Monday into Tuesday.
Surface low pressure development in the lee of the Rockies through
the Plains will direct persistent southerly flow into Lower Michigan
during this time. The temperature trends look solid as they are
being governed by large scale features. Timing the next round of
precipitation has lower predictability due to the dependence on
short wave energy arriving from the long wave trough Monday night
into Tuesday. The good news here is that, even if faster solutions
verify, surface temperatures are expected to be above freezing at
southern locations that have a chance POP prior to 12Z Tuesday
morning. There is then a time window for readings to warm above
freezing at points north Tuesday morning before moisture arrives
there. This would be followed by another generous helping of
rainfall across the area Tuesday through Wednesday as the primary
low pressure system moves along the surface front stalled over the
region. Colder air will then fill back in over the Great Lakes on
the heels of this system to finish the week.

MARINE...

A gale warning remains in effect today through this evening for
Saginaw Bay and central Lake Huron with small craft advisories in
effect for the remaining marine areas. Moderate westerly flow during
the morning will become southwest and increase again during the
afternoon into this evening as low pressure moves through the
northern Great Lakes. The associated cold front will settle over
Lower Michigan and central Lake Huron tonight and dissipate in favor
of high pressure by Monday morning. Favorable marine conditions in
the form of light south wind and milder air will then continue
through Tuesday. The next low pressure system is projected to arrive
Wednesday on a track through the central Great Lakes followed by
colder air on moderate northerly wind for the end of the week.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.

Lake Huron...Gale Warning from 10 AM this morning to 10 PM EST this evening for
     LHZ362-363-421-422-441-462.

     Small Craft Advisory from 10 AM this morning to 7 PM EST this
     evening for LHZ442-443.

Lake St Clair...Small Craft Advisory from 10 AM this morning to 7 PM EST this
     evening for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory from 10 AM this morning to 7 PM EST this
     evening for LEZ444.

&&

$$

AVIATION.....BT
DISCUSSION...BT
MARINE.......BT


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



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