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000
FXUS63 KDTX 172357
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
757 PM EDT Wed Apr 17 2024

.KEY MESSAGES...

- Next round of showers move through Thursday night.

- Drier and cooler weather Friday and into the Weekend.

&&

.AVIATION...

The earlier line of thunderstorms have pushed well east of the
terminals with predominately VFR ceilings in the post frontal
environment. Only a few locations near the southeast Michigan
terminals are experiencing MVFR ceilings at press time. Expect the
more widespread MVFR ceiling to develop by around 06Z and hold
through the morning. Winds will persist out of the W-SW at around 10
knots through tonight. Will see a clearing of lower clouds tomorrow
afternoon with increasing coverage of high clouds into the evening
ahead of the next chance for rain tomorrow night.

.DTW THRESHOLD PROBABILITIES...

* High for ceiling aob 5000 ft through Thursday morning.

&&

.PREV DISCUSSION...
Issued at 234 PM EDT Wed Apr 17 2024

DISCUSSION...

Severe thunderstorm watch remains in effect until 7 PM, but the line
is moving through at a good clip, and watch will likely be canceled
early.

Surface dew pts have mostly topped out around 60 degrees, and
MLCapes have risen to 1000 J/kg but coming up short of 1500 J/kg
(except right along the southern Michigan border). A few discrete
cells in the line have been rotating with effective bulk shear in
excess of 30 knots. Theses storms have produced large hail (Ingham
county) and damaging winds (Williams county), but the bulk of line
just has just produced non-severe wind gusts of 40-50 mph thus far.
Isolated tornadoes remain possible, especially over the southern
counties.

Sharp convergence line, with southerly winds ahead of the front,
followed by breezy westerly winds behind the front this evening as
the surface low (998 MB) over northern Wisconsin slowly weakens and
heads off to the northeast.

Westerly winds look to remain somewhat elevated tonight, around 10
knots, with cold advection through the night as 925 MB temps lower
into the low single numbers by 12z Thursday. Even so, low clouds
likely hold min temperatures in the 45 to 50 degree range.

Large and elongated (west-east) upper level trough/low over south
Central Canada extending back into the northern Rockies will slowly
wobble off to the east, with the trough axis passing through the
Central Great Lakes on Saturday. Before this occurs, a surface low
and deeper Gulf of Mexico and Pacific moisture will become absorbed
in the deepening southwest flow and race off to the northeast
tomorrow and tomorrow night. PW values reaching 1 inch late tomorrow
over southeast Michigan, with the sharp moisture gradient setting up
over Central/Eastern Great Lakes Thursday night. Good low level FGEN
should support widespread rain moving through southeast Michigan.
But even this rain shield looks progressive, and total amounts under
half an inch expected.

Much drier air to follow for Friday and into the Weekend,
supporting dry and cooler weather (slightly below normal).

MARINE...

Weakening low pressure continues to slide towards the Straits this
evening as its attendant cold front sweeps through the central Great
Lakes. A line of showers and thunderstorms will precede this front
with some storms being strong to severe with both large hail and
>34kt wind gusts possible- mainly from southern Lake Huron/Saginaw
Bay south. Winds back to westerly behind the front tonight with the
loosening gradient allowing flow to weaken to aob 25kts. Brief
period of ridging sets up for Thursday supporting favorable marine
conditions across the region. A second cold front then sags south
into the area late Thursday night into the first half of Friday
offering another shot at widespread showers and perhaps a few
thunderstorms mainly focused over the southern Great Lakes. Cooler
westerly flow follows the fropa supporting an uptick in wind
strength latter half of Friday into this weekend- peak gusts
generally topping out between 20-30kts.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Gale Warning until midnight EDT tonight for LHZ361-362.

     Small Craft Advisory until midnight EDT tonight for LHZ421-422-
     441>443.

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

$$

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


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