236
FXUS63 KDTX 071958
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
358 PM EDT Fri Jun 7 2024

.KEY MESSAGES...

- Decreasing wind this evening and decreasing clouds tonight into
Saturday morning.

- Showers return quickly mid to late Saturday afternoon and spread
across the area Saturday night. A rumble of thunder is possible
south.

- A stray shower is possible Sunday with a weak cold front leading
to slightly below normal temperatures Monday.

- Cool early week conditions are followed by a warming trend back
into the 80s by late week.

&&

.DISCUSSION...

Breezy and cool conditions continue for the balance of today and
this evening around the south flank of broad northern Ontario low
pressure. Afternoon radar and satellite data indicate a favorable
tendency for light showers toward the Tri Cities and northern Thumb
but still just spotty coverage. This is associated with a smaller
scale wave sliding across Lower Mi providing localized forcing along
with peak daytime heating within the larger scale mid level cold
pool. Model analysis fields also show a mid level short wave ridge
across the Midwest set to follow across the Great Lakes late tonight.
A rapid subsidence transition then leads to decreasing clouds with a
weak surface high pressure reflection through Saturday morning.
Westerly surface wind holds around 5 knots to prevent full
radiational cooling for low temperatures around 50 by sunrise,
slightly below normal for early June.

An equally rapid transition back to a pattern of showers occurs
later Saturday through Saturday night as Plains low pressure moves
into the Midwest and Great Lakes. Today`s 12Z models are in good
agreement on a plume of mid level moisture returning into Lower Mi
ahead of the surface wave with slightly faster onset timing Saturday
afternoon rather than by Saturday evening compared to earlier
forecast cycles. The faster timing is tied backing flow ahead of the
mid level wave and associated DCVA driving increased isentropic lift
and theta-e advection, although with still anemic instability for low
thunderstorm potential. The 12Z HREF run exhibits both near zero
surface based and MUCAPE as the surface wave and weak cold front move
across the region and exit eastward by sunrise Sunday morning.

The Saturday night wave transitions the large scale mid level
pattern away from the uncommon west to east configuration to more of
a trough-ridge-trough set up Sunday into Monday. This results in
reinforcement of cool air into the Great Lakes with another front
moving down from Canada Sunday afternoon and night. The latest model
data is again in reasonable agreement on mid afternoon timing which
allows temperatures a chance to rise into the lower 70s before
clouds thicken with a stray shower late in the day. The inherited
borderline slight/chance POPs are preferred and maintained in this
forecast cycle. The bulk of the cool air reinforcement then arrives
Sunday night in time to start Monday out with another round of below
normal readings in the 60s.

&&

.MARINE...

Winds weaken overnight to generally below 20kts as broad low
pressure over northern Ontario shifts further east. Weak low
pressure swings into the southern Great Lakes Saturday bringing
widespread showers though little to no increase in westerly flow is
expected. Winds shift northwesterly following this system as
deepening low pressure over western Quebec results in tightening of
the local gradient. Wind gusts between 20-25kts likely over the bulk
of the central Great Lakes throughout the day Sunday. Areas of
potential overachievement with gusts potentially nearing 30kts are
the Saginaw Bay due to the warmer waters and subsequent more
unstable thermal profile, as well as northern Lake Huron given the
favorable fetch. Lighter winds (10-20 knots) then arrive by Monday
as high pressure builds overhead. This high remains in place for the
first of half of the work week.

&&

.PREV DISCUSSION...
Issued at 122 PM EDT Fri Jun 7 2024

AVIATION...

VFR conditions prevail today as SE MI resides under a cooler airmass
due to the influence of a low pressure system located over the
northeast portion of Michigan. The cooler air has allowed mixing
depths to tap into stronger winds aloft, which will bring sporadic
westerly wind gusts on the order of 25-30 knots through the daylight
hours. Otherwise, an isolated shower cannot be ruled out for the
remainder of the day, but the bulk of shower activity is expected to
hold over the Thumb. Wind gust and the low shower potential will
wane after sunset. Generally clear skies expected overnight along
with lighter winds.

For DTW/D21 Convection...Thunderstorms are not expected.

 DTW THRESHOLD PROBABILITIES...

* Low for exceeding crosswind threshold this afternoon and evening.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...Small Craft Advisory until 8 PM EDT this evening for LEZ444.

&&

$$

DISCUSSION...BT
MARINE.......KDK
AVIATION.....AM


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