Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 062247
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
547 PM EST Sat Mar 6 2021


.AVIATION...

Other than a few patches of scattered cumulus early in the forecast,
expect clear conditions into Sunday morning as high pressure builds
further into the area. Cirrus will increase later in the forecast,
but VFR conditions will remain. Wind gusts will ease quickly early
this evening with north-northwest winds under 10 knots overnight
into Sunday.

.DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 355 PM EST Sat Mar 6 2021

DISCUSSION...

Large amplitude, longwave trough/ridge dipole is in place over North
America this afternoon with Southeast Michigan residing within the
transition zone between high and low geopotential heights. A notable
temperature gradient exists over the region with 850mb temperatures
of roughly -14C over Huron County and -4C across the southern Lake
Michigan basin. The change to setup tonight is that a daisychain of
vort maximums will dig southward through Lower Michigan/Lake Huron.
The vort max this evening will be accompanied by midlevel cold pool
which will drive secondary 925-700mb cold air advection down into
the state. Plan view perspective of system relative progs show
renewed isentropic downglide and support for subsidence. Good signal
for calm/nil wind setting up Sunday morning north of I 69. Despite
loss of snowcover did go fairly aggressive with low temperatures
with single digits across the northern cwa (supported by very low
dewpoints this afternoon). Heart of the surface ridge axis will pass
over Southeast Michigan during the day on Sunday. High confidence
neutral temperature advection during the day. Coming off of a cold
morning, sided with a persistence forecast.

Shortwave ridging over the region early Monday with shortwave
passing across Lake Superior will ratchet up the southwest flow over
Southeast Michigan. The questions for Monday simply comes down to
how high mixing heights will attain for much of the southern cwa and
behavior of warm to cold frontal boundary after shortwave passage.
Forecast soundings continue to show extreme static stability up to
2.5 kft to start the morning. Evolution of forecast soundings show
this inversion and stability becomes a problem during the late
afternoon. The north is a questionmark as the NAM is showing a
solution that causes initial warm front to stall out and even sink
southward some near Saginaw Bay late in the day. The forecast is in
ok shape for the southern cwa which is some 5 degrees above
guidance. Low confidence exists in the temperature forecast Monday
for the northern cwa.

Ridging will then push across Lower Michigan lead to warmer
temperatures Tuesday and Wednesday. Temperatures are expected to
reach and exceed 60 degrees both of the day. Tuesday will be the dry
and nicer of the two with clouds and moisture/precipitation finally
pushing into the cwa by Wednesday. Models suggests a colder airmass
for end of the week and next weekend.

MARINE...

Conditions will continue to improve through the evening and
overnight as a ridge of high pressure centered over Ontario builds
southward. The center of the high will become positioned over the
Great Lakes by Sunday afternoon. Winds have generally dropped below
25 knots this afternoon across the region while still out of the
northwest with a further decrease on Sunday to less than 15 knots
with the high overhead. Winds will become southwesterly by Monday
morning as the axis of the ridge pushes just east of the area. Winds
will increase but will be much warmer and more stable limiting gust
potential.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

AVIATION.....DG
DISCUSSION...CB
MARINE.......DRK


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