247
FXUS63 KDTX 102250
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
650 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...

Unsettled pattern within cyclonic west/northwest flow will maintain
periods of lower VFR cigs into tonight, but with some scattering out
in time. A stray shower may encroach on KMBS, but coverage seems too
low to add to forecast at this time. An additional diurnal component
should then lead to a period of BKN cigs again Sunday. Westerly flow
will drop to 10 knots or less tonight with gusts to 20 or more knots
by midday Sunday with better mixing.

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

DTW THRESHOLD PROBABILITIES...

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

&&

.PREV DISCUSSION...
Issued at 301 PM EDT Sat Aug 10 2024

DISCUSSION...

Water vapor imagery this afternoon shows the well-defined upper low
spinning across the Upper Great Lakes and Ontario this afternoon,
with multiple lobes of vorticity rotating about the main
circulation. This upper low will slowly move southeast across
Ontario and into Quebec over the rest of the weekend. As a few lobes
of vorticity and the pocket of cooler air aloft move over portions
of southeast Michigan on Sunday, showers are possible from mid-late
morning and into the afternoon hours. High-res guidance show better
coverage and a higher potential for numerous showers up across the
Thumb region, with more isolated to scattered showers further south.
So not everyone will see shower activity on Sunday.

As the main upper level trough continues to move towards the
Northeast on Monday, large-scale troughing lingers through much of
next week as a series of weaker shortwaves dig across the region.
Given this pattern, the pocket of cooler air over Michigan will be
slow to modify. Thus, expect a warm up back to near-normal (mid-
upper 70s) for Monday and then warming a few degrees each day as we
head through the end of the week. Precipitation chances for next
week are challenging given the numerous shortwaves moving through
the region and uncertainty regarding their strength and timing.

MARINE...

Broad area of low pressure remains spread across Ontario and Quebec
while reaching southwest through the Great Lakes. The upper low has
several stronger troughs rotating around it, the next which will
swing through the region later tonight. This may help to keep a few
stronger gusts around later into the night but we`ll continue to
monitor observations to see if an extension to the current Small
Craft Advisories will be needed. This will be competing against the
nocturnal minimum for mixing depths as well as a weakening gradient
owning to the area of high pressure sliding up from the south.
Expectations are for gusts to continue tonight with occasional gusts
to 25 knots possible, then holding more around 20 knots on Sunday.
Expansive ridge then builds across the Great Lakes Sunday night and
persists through the start of the week.

&&

.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.....DG
DISCUSSION...JA
MARINE.......DK


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