443
FXUS63 KDTX 312242
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
642 PM EDT Thu Jul 31 2025

.KEY MESSAGES...

- Cool and dry with temperatures dropping into the low to mid 50s
  overnight.

- Dry this weekend with below normal temperatures in the 70s
gradually warming to the low 80s by Sunday.

- Rain chances hold off until middle of next week.

&&

.AVIATION...

Hazy conditions persist this evening as Canadian wildfire smoke
lingers. Observations continue to offer a general visibility
restriction within the 4 to 6 mile range and will maintain this
condition going forward into the a portion of the overnight period.
Forecast affords recovery to widespread VFR as smoke vacates the
region by late tonight/Friday morning. Otherwise, notably drier and
more stable conditions will exist this taf period under building
high pressure. Cooler low level northeast flow could support a lower
coverage of lower VFR lake stratus development and inland
penetration overnight, but of limited coverage targeting MBS. Modest
northeast wind prevails into Friday with a standard coverage of high
based diurnal cu for the afternoon.

For DTW/D21 Convection...No thunderstorms will occur through the
duration of the TAF period.

THRESHOLD PROBABILITIES...

* Low in ceilings aob 5000 feet this evening, and then again
  Friday afternoon.

&&

.PREV DISCUSSION...
Issued at 317 PM EDT Thu Jul 31 2025

DISCUSSION...

Rain showers and low stratus have gradually cleared out of SE
Michigan as strong mid-level subsidence slides in from the north,
observed via nearly 50 C 700mb dewpoint depressions in the 12z APX
RAOB. Low level winds backing with height indicate ongoing cold
advection, which combined with NE flow has led to some diurnal cu
development underneath leftover high cloud and hazy skies from
wildfire smoke. All of this represents a pattern shift to seasonably
cool and dry weather that persists into the weekend.

Cool start to the day expected on Friday with lows in the low to mid
50s. There is signal in some of the hi-res moisture fields for
stratus to stream off of Lake Huron in the NE flow regime as early
as 08z (4am). This seems reasonable considering the warm water
temperatures (22-24 C) and cool 850mb temperatures (6-9 C) that keep
profiles well-mixed even overnight. Cloud cover should become more
scattered in nature as diurnal processes ramp up Friday afternoon.
Otherwise, strong high pressure (nearly 1030mb) reaches max MSLP
(per NAEFS) while moisture parameters (i.e. PWAT, specific humidity)
and low level temperatures drop below the 10th percentile. This
equates to comfortable but mild conditions for early August
standards, with highs topping out in the mid-70s.

Mean layer thickness increases as the airmass modifies to support a
modest increase in temperatures each day this weekend back toward
seasonable normals (mid-80s) by early next week. The surface high
will be complemented by upper level convergence on the west side of
the trough axis to maintain an extended dry stretch through the
weekend into early next week. The high eventually drifts into
Ontario middle of next week to reestablish return flow over the
Great Lakes, bringing the next chance for precipitation.

MARINE...

Gusty northeasterly winds remain in place across the region this
afternoon into tonight with gusts reaching near 25 knots which will
lead to elevated wave heights in the nearshore waters. A Small Craft
Advisory remains in effect into the overnight period to account for
these winds and waves. High pressure building into the area today
will continue overnight eventually decreasing the winds and the
headlines will expire. Lighter winds and lower waves will then carry
into, and through the weekend as the high centers itself over the
region.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until midnight EDT tonight for MIZ048-049-
     055-063-083.

Lake Huron...Small Craft Advisory until 4 AM EDT Friday for LHZ421-441>443.

     Small Craft Advisory until 10 PM EDT this evening for LHZ422.

Lake St Clair...Small Craft Advisory until 4 AM EDT Friday for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 4 AM EDT Friday for LEZ444.

&&

$$

AVIATION.....MR
DISCUSSION...MV
MARINE.......DRK


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