544
FXUS63 KDTX 101804
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
204 PM EDT Sat Aug 10 2024

.KEY MESSAGES...

- Below normal temperatures this weekend with breezy west winds into
this evening and then again on Sunday.

- Dry or mainly dry weather, with just a slight/low chance of brief
showers on Sunday, and sporadic brief times next week.

- Near normal temps expected next week.

&&

.AVIATION...

SCT-BKN VFR cumulus this afternoon is being supported by the cooler
air associated with troughing over the Great Lakes. Ceilings are
sitting around 5,000 feet at press time with potential for ceilings
to settle slightly higher throughout the afternoon. Mixing depths
are tapping into stronger flow aloft and bringing wind gusts out of
the west to around 25 knots. Wind gusts at times may achieve the 30
knot mark. Gusts subside after sunset with some degree of clouds
holding through the overnight with the trough overhead. It remains
possible for a stray shower towards MBS, but will keep mention out
given the low probability.

For DTW/D21 Convection... No thunderstorms are expected.

DTW THRESHOLD PROBABILITIES...

* Low for cigs at or below 5000 ft this afternoon and evening.

&&

.PREV DISCUSSION...
Issued at 250 AM EDT Sat Aug 10 2024

DISCUSSION...

Large upper level low/trough encompassing Central Canada south into
the Midwest/Great Lakes region, with at least 3 distinct upper level
waves/mid level cold pools rotating around. Once such wave is
tracking off to the northeast, north of Lake Huron. Thus, just a
glancing blow of cold air to move through today. 00z Green Bay raob
indicated an 850 MB temps of 7 C, but some modification is expected,
with 850 MB temps of 7.5-10 C suggesting highs today in the 70 to 75
degree range. Deep boundary layer mixing with 30 knots of flow at
850 MB will be supportive of westerly gusts around 30 mph this
afternoon. Lots of strato-cu development, but looks like showers
will be hard pressed to develop, except perhaps in and near Saginaw
Bay. Better chance of showers, but still low, tonight and tomorrow.
The shortwave along the northern North Dakota border swings through
tonight, with the main trough axis extending from the parent 500 MB
low tracking through on Sunday. 700 MB cold pool (-2 C to perhaps
-4 C) looks to be tracking through Lake Huron, which suggests the
best chance of showers will be over the northern Thumb region with
the west-northwest low level flow.

Upper level northwest confluent flow/subsidence Sunday night gives
way to ill defined pattern as some shortwave energy/upper level PV
over the Dakotas attempts slide through early next week. NBM came in
with pops 10 percent or less, but 00z Euro certainly argues for
having at least slight chance pops Monday-Tuesday based on the
strength and northward position of the shortwave tracking through
the Central Great Lakes. Moisture remains on the low side, with up
to 6 g/kg of mean specific humidity in the 850-700 MB layer.

Resumed northwest confluent flow/modest shortwave ridging for the
middle part of the week then expected, with temperatures near
normal.

MARINE...

Low pressure remains over Ontario today but will slowly pull off to
the northeast. Increased cold air advection today combined with a
tightening gradient, due to high pressure to the south, will bring
gusty winds today. Winds ramp up this morning reaching 25 knots
across all marine zones and possibly up towards 30 knots across
Saginaw Bay and Central Lake Huron. Small Craft Advisories are in
effect for all marine zones this morning through this evening. Will
reassess to see if Saginaw Bay needs to be extended further into the
overnight. Wind do look to decrease back below 25 knots for Sunday
as high pressure starts to build back in from the south.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 10 PM EDT this evening for MIZ049.

Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ421-422-
     441>443.

Lake St Clair...Small Craft Advisory until 10 PM EDT this evening for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 10 PM EDT this evening for LEZ444.

&&

$$

AVIATION.....AA
DISCUSSION...SF
MARINE.......SF


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