Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 170241
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1041 PM EDT Sat Mar 16 2024

.KEY MESSAGES...

- A surge of cold air follows tonight and Sunday which is then
reinforced Monday through Thursday next week. Temperatures around or
below normal can be expected during this timeframe. Chance of
flurries/light snow showers at times as well.

&&

.AVIATION...

There will be some residual showers during the overnight as short
wave energy pivots around the large upper low to the north of the
lakes. Some intervals of clearing in the wake of the earlier frontal
passage allowed enough nocturnal boundary layer cooling to drop wind
speeds/gusts in most locals, although post frontal cold air
advection should support some semblance of low level mixing which
will likely hold westerly winds in the 8 to 14 knot range into the
morning. Based on model soundings and considering a deepening mixed
layer through cold air advection tonight, ceilings are expected to
remain predominately VFR.

For DTW...Model soundings and upstream observations suggest a range
in ceilings through the morning. While they will remain VFR, there
is likely to be some intervals where they cross the 5000 foot
threshold.

.DTW THRESHOLD PROBABILITIES...

* Moderate in ceilings aob 5000 feet through the TAF period.

&&

.PREV DISCUSSION...
Issued at 316 PM EDT Sat Mar 16 2024

DISCUSSION...

Mid-upper trough continues to dig south across the Great Lakes this
afternoon with its attendant surface cold front beginning to work
into NW lower MI at press time. In advance, deep layer SW flow
supported by mostly sunny AM/early afternoon skies, at least south
of I-69, has allowed temps to warm well into the 50s with some lower
60s in the far south. Conversely, persistent alto-cu/stratocu
demarcating the base of the trough has held northern areas,
particularly the Thumb, some 5-10 degrees cooler. Leading baroclinic
zone works NW to SE across SE MI the rest of today offering light
rain chances for portions of the area. Lackluster moisture quality
(PW aob 0.5") has and will continue limit light shower/drizzle
coverage across the Tri-Cities/Thumb/Flint areas this afternoon to
isolated in nature. For areas south, roughly along/south of an Ann
Arbor-Port Huron line, slightly better coverage (scattered to
numerous) is possible after ~20Z into the early nighttime hours.
This is thanks to a combination of a developing jet streak within
the base of the upper trough over southwestern Great Lakes as well
as a ribbon of enhanced theta-e being drawn in from the mid-
Mississippi valley. Surface cold front clears the area early tonight
bringing an end to further shower chances as well as ushering in a
noticeable pattern shift for the new week.

Longwave upper trough settles over the Great Lakes Sunday into
Monday allowing a colder Canadian airmass to likewise settle
overhead dropping 850mb temps to around -10C. With persistent NW CAA
below the lingering trough, periods of light lake effect snow
showers are possible throughout Sunday and Monday. Only minor
accumulations ranging from a dusting to a couple tenths expected. A
clipper system is then progged to slide across the central Great
Lakes Tuesday offering another window for more widespread snow
showers and slightly better accumulation potential. This wave also
draws a reinforcing surge of arctic air south to close out the work
week. Long range models advertise 850mb temps falling into the
negative mid to upper teens with highs struggling to break out of
the 30s.

MARINE...

A strong low pressure system centered just north of Lake Superior
will continue to track southeast into southern Quebec tonight.
Strong southwest winds ahead of the associated cold front have
reached near 30 knots across the eastern Lakes thus a small craft
advisory is in effect through this evening. The cold front will pass
to the east by later this evening with winds then turning more
westerly. A weakening pressure gradient and weak cold air advection
will allow winds and waves to fall to just below small craft
advisory levels and remain through much of Sunday. A second cold
front then passes southward through the region Sunday evening which
will bring in a colder airmass and decreased stability so waves will
likely ramp back up to small craft criteria for parts of Saginaw Bay
and a portion of the nearshore waters of Lake Huron. Cold air
lingers over the region to start the week with another clipper
dropping through on Tuesday.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory from 4 PM Sunday to 4 PM EDT Monday for LHZ421-
     422-441.

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

$$

AVIATION.....SC
DISCUSSION...KDK
MARINE.......DRK


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