460
FXUS63 KDTX 071722
AFDDTX

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

.KEY MESSAGES...

- Breezy today with westerly wind gusts of 25 to 35 mph and high
temperatures topping out around 70 degrees. Scattered showers mainly
across the Thumb.

- Showers are likely (50-70%) to spread across the area Saturday
afternoon into Saturday evening. A rumble of thunder is possible
south.

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

&&

.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.

&&

.PREV DISCUSSION...
Issued at 407 AM EDT Fri Jun 7 2024

DISCUSSION...

Moist cyclonic flow around the upper low tracking across Georgian
Bay maintains a breezy, unsettled almost fall-like forecast today.
Isolated to scattered showers will develop through the day, likely
most pervasive over the Thumb where moisture depth and stream of PV
aloft will align favorably. 850mb thermal trough will be directly
overhead at 5 to 6 C, limiting high temps to the upper 60s to around
70, roughly 1 sigma below normal for June 7. Meanwhile, a belt of 20
to 30 kt wind within the boundary layer will result in another
breezy day with gusts in the 25 to 30 mph range during the
afternoon. Any higher gusts to around 35 mph will be most likely
along/south of I-94. Winds then begin to subside during the evening
as surface heating/mixing tapers off.

The upper low moves off into southern Quebec tonight, allowing a
shortwave ridge to build into the Great Lakes through early
Saturday. This quickly crests overhead by midday, sending a warm
front into the area during the afternoon as low-level wind shifts
from the southwest. At the same time, the next upper low begins to
sink south across Lake Superior with difluent flow ahead of it
forming a weak frontal low over the Midwest that moves in during the
evening. The resultant fgen will bring an area of showers that
spreads southeastward across the area from the late afternoon
through the evening. Models across the board offer very little
instability with this setup given weak lapse rates in part from
strong mid-level capping. The best chance for any thunderstorms
would be within the warm sector south of M-59, if capping is weaker
and surface dew points are high enough to overcome the lapse rates.
Otherwise, just expect around a quarter inch of rainfall from the
showers before they move out overnight.

Added a slight chance of light showers on Sunday, mainly north of I-
96, as a lobe of PV and mid-level moisture sink across the region
while the aforementioned upper low tracks southeast across Georgian
Bay into Quebec. Additional shortwaves rotate around the low Sunday
night into Monday, driving a cold front south across the region.
This brings a cool start to the week with high pressure then
beginning to build in from the west as the resident low-amplitude
trough over eastern North America begins to amplify over New
England. The high pressure maintains quiet conditions through
Tuesday but is quickly followed by the next trough and opportunity
for showers by Wednesday. A substantial warm-up is likely by the
late week with zonal flow helping advect a warm Plains air mass
eastward.

MARINE...

Cooler air has filtered into the Central Great Lakes this morning,
leading to low level profiles a bit closer to neutral. Overall,
winds above the surface look slightly weaker compared to yesterday,
and thus expecting winds to mostly hold in the 20-25 knot range
today. Lake Erie stands the best chance of exceeding 25 knots due to
the warmer water temperatures.

Lighter winds (10-20 knots) arrive over the weekend before high
pressure center settles overhead on Tuesday and brings light and
variable winds.

&&

.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.

&&

$$

AVIATION.....AM
DISCUSSION...TF
MARINE.......SF


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