459
FXUS63 KDTX 081100
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
700 AM EDT Sat Jun 8 2024

.KEY MESSAGES...

- Dry to start the day with showers arriving mid to late afternoon
and spreading across the area this evening.

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

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

&&

.AVIATION...

VFR conditions will prevail through the early afternoon with
increasing mid cloud as a shortwave approaches from the west. This
shortwave will bring light rain showers that will spread across KMBS
shortly after 18Z and then spread south over the next few hours.
Lower level dry air should keep these as VFR showers to start before
better lower level saturation occurs bringing periods of MVFR
conditions starting around 00Z this evening. Lower clouds linger for
parts of the overnight with a decreasing cloud trend throughout the
early morning hours. Winds throughout the period will be
predominately out of the west to northwest at 5-10 knots.

For DTW/D21 Convection...There will be very little instability with
the short wave this afternoon and evening, thus thunderstorms are not
expected.


 DTW THRESHOLD PROBABILITIES...

* Low for ceilings aob 5000 feet this afternoon. Moderate this
  evening.

&&

.PREV DISCUSSION...
Issued at 334 AM EDT Sat Jun 8 2024

DISCUSSION...

Modest height rebounds are ongoing early this morning as a mid-level
shortwave ridge squeezes in between the departing upper low moving
into southern Quebec and the next wave emerging out of southern
Manitoba/western Ontario. This is driving the localized high
pressure and window of clear skies over Lower Michigan as subsidence
maintains control through the morning. Clouds will quickly increase
through the day as the next wave induces a pattern of moisture
advection and isentropic ascent ahead of it. Early day sun and
burgeoning southwest wind will boost temps to the upper 70s across
the south, while lower 70s are expected for a high across the north
where clouds will make an earlier arrival.

Showers will spread in from the west after noon - first across the
Tri-Cities and Thumb along an elevated warm front, then spreading
south and east as fgen lights up along the weak surface reflection
as it tracks through during the evening. Warm and stable mid-levels
will prevent much if any instability from developing - less than 10
percent of 00z NBM and HREF members show >100 J/kg of SBCAPE - so
thunderstorms are not expected. Showers will depart east during the
late evening with overnight lows settling into the 50s. Rainfall
amounts are forecast to be on the order of 1 to 3 tenths of an inch.

Troughing will dominate local conditions on Sunday as an upper low
deepens over eastern Canada and sends additional shortwave energy
across the Great Lakes. A cold front will sink south across the area
during the afternoon bringing increasing clouds and about a 10 to 20
percent chance of light showers given relatively shallow moisture
and forcing. Temps ahead of the front will reach the mid to upper
70s for much of the area before the cold advection commences. Lower
70s will be more likely north of I-69. 850mb temps fall steadily
toward the 3 to 7 C range by Monday morning, setting us up for a
cool start to the work week.

The upper troughing and cyclonic flow sticks around into Monday and
may present another low chance for afternoon sprinkles/showers if
enough moisture can hold in place, but have left out of the forecast
for now. With the thermal trough also overhead, high temps will be
limited to the low end of normal in the mid 60s to around 70. The
trough finally releases to the east by Tuesday, allowing a ridge
axis and surface high to build into the Great Lakes with sunny and
milder conditions expected. A more zonal upper flow pattern takes
shape Wednesday into the late week, with a much warmer air mass
arriving from the west to bring highs back into the 80s. There look
to be periodic chances for showers and storms during this period as
several shortwaves pass over the region.

MARINE...

Weak area of low pressure swings into the southern Great Lakes today
bringing widespread showers, particularly over the southern two-
thirds of the region. 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
into Sunday night. Areas where 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, less
than 20kts, then arrive Monday as high pressure builds overhead.
This high remains in place for the first of half of the work week.

&&

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

$$

AVIATION.....AA
DISCUSSION...TF
MARINE.......KDK


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