636
FXUS63 KDTX 281758
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
158 PM EDT Sat Jun 28 2025

.KEY MESSAGES...

- Seasonable temperatures in the mid 80s today with dry weather
  expected.

- Warm and unstable conditions return Sunday and Monday with highs on
  Sunday near 90 degrees.

- Another cold front brings chances for showers and thunderstorms on
  Monday.

&&

.AVIATION...

Cumulus field has proven rather formidable early this afternoon,
especially for the northern sites (MBS/FNT) with pockets of MVFR
ceilings still lingering amidst surface high pressure encompassing
Lower Michigan. Favorable diurnal heating should continue to
gradually lift ceilings above 3 kft AGL within the next hour or two,
ushering in an extended period of VFR conditions. Breezy, with
occasional WNW gusts around 20 knots until speeds drop-off this
evening and overnight. Remaining low cloud also dissipates tonight
with just a bit of residual high cirrus as winds trend toward calm.
Can`t rule out a bit of fog, but visibilities should generally hold
VFR, above 5 SM. Any fog that develops will burn off quickly Sunday
morning while limited available column moisture prevents meaningful
low cloud fraction through the end of the TAF cycle. Surface flow
backs south-southwesterly Sunday with speeds below 10 knots.

For DTW/D21 Convection...No thunderstorms expected through the TAF
period.

 THRESHOLD PROBABILITIES...

* Low in ceiling at or below 5000 ft beyond 19Z this afternoon.

&&

.PREV DISCUSSION...
Issued at 417 AM EDT Sat Jun 28 2025

DISCUSSION...

A cooler and less humid post-frontal airmass fills into SE Michigan
this morning, characterized by a sharp surface theta-e gradient
between Metro Detroit (low 70s dewpoints) and the Saginaw Valley
(low 60s dewpoints). Column moisture will decrease significantly for
the entire area this morning as deep isentropic downglide takes
residence, with upstream 00z RAOB observations recording PWAT values
between 0.8 and 1.0" in comparison to 1.94" at DTX last evening.
Deep static stability (above 5.0 kft agl) and dewpoint depressions
exceeding 30 C all ensure a dry forecast for today with minimal
cloud cover.

The parent low pressure system eventually shears out over Quebec,
which orphans the cold front about 100 miles south of the state
line. Upstream conditions remain characteristic of the previous
week`s hot and humid airmass, which return to SE Michigan Sunday and
Monday. Particularly noteworthy is the elevated mixed layer that
advects into lower Michigan Sunday afternoon, boosting mid level
lapse rates above 7 C/km. While remnant subsidence and mid-level
anticyclonic flow should prevent convective development in SE
Michigan, several hi-res solutions show upstream thunderstorm
complexes clipping the Saginaw Valley and Thumb regions before
outpacing the instability gradient. Still do expect most areas to
remain dry on Sunday, with low amplitude ridging rebounding 925mb
temperatures above 20 C and max temps toward 90 degrees.

Low level moisture advection ramps up from the southwest early
Monday morning, and will briefly overlap with the departing elevated
mixed layer to support surface destabilization by late morning.
Model signal latches on to both a pre-frontal wave and the surface
cold front in terms of possible forcing mechanisms for convection.
Lack of mid-level flow in both scenarios should largely prevent
organized convection, although precipitation loaded cores do suggest
an isolated wind threat. The rich theta-e environment will also be
supportive of heavy downpours.

Once the cold front passes through Monday night, a more amplified
pattern develops with broad troughing expected east of the
Mississippi River. This will support a cooler and drier Canadian
airmass as high pressure fills into the region by mid-week. Expect
seasonable temperatures in this pattern.

MARINE...

Lighter winds emerge with drier conditions Saturday as high pressure
fills in. The next low pressure system enters the northern Great
Lakes Sunday night into Monday driving a stronger cold front through
the region providing additional storms Monday and a stronger post-
frontal wind field Tuesday.

&&

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

$$

AVIATION.....KGK
DISCUSSION...MV
MARINE.......MR


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