594
FXUS63 KDTX 121935
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
335 PM EDT Fri Jun 12 2026

.KEY MESSAGES...

- Warm and dry during the day on Saturday, then showers and
thunderstorms move in Saturday night into early Sunday.

- Drier and cooler conditions early next week before another active
pattern commences midweek.

&&

.DISCUSSION...

Post-frontal airmass characterized by surface dewpoints falling into
the 50s and a 10C reduction in 850 mb temperatures have led to more
seasonable conditions across Southeast Michigan. Column winds
organize out of the west while geopotential heights rise aloft,
ensuring continued subsidence and dry weather. 12.12Z KDTX RAOB
revealed a deep layer of dry air from 0.5-8.0 km AGL, with a max
dewpoint depression of 46C near 4.5 km AGL. Broad 1016 mb surface
high pressure rolls eastward from The Plains into the lower Ohio
Valley by this evening backing winds WSW. Afternoon gusts of 25-30
mph drop off after the boundary-layer decouples by nightfall. Clear
skies tonight with lower dewpoints allow for efficient longwave
cooling, with lows dropping into the 50s by Saturday morning.

Low cloud fraction to start and backing southwesterly Gulf-modified
flow within the low levels will culminate in Saturday being the
warmest day of the forecast period. 850 mb temperatures rebound into
the teens with ample insolation lifting 2 m temperatures into the
mid-upper 80s. A quasi-Rex Block pattern emerges over the eastern
half of CONUS with southern Lower Michigan residing near the
stronger kinematics within the unified jet axis. Favorable mixing
profile leads to another day of diurnal gustiness, generally
southwesterly at 25-30 mph. An enhanced low-level jet response over
The Thumb and Tri-Cities could favor gusts approaching 40 mph at
times before sunset.

A medium wavelength trough of Pacific origin digs into the Upper
Midwest, phasing with an embedded shortwave revolving around the
Ontario upper low. This leads to a packet of height falls moving
through the Great Lakes late Saturday into Sunday. As the composite
wave works through aloft, it forces a cold frontal passage overnight
into Sunday morning. Pre-frontal theta-E advection will be present
helping to destabilize the frontal slope with steepening mid-level
lapse rates resulting in MLCAPEs in excess of 1 kJ/kg. However, 0-6
km bulk shear will be falling during the evening and overnight hours
as the front arrives, limiting the overall intensity of convection,
while instability weakens. At this time, a mix of gusty showers and
a few thunderstorms are most likely to progress through the region
following some pattern of linearity with low potential for
hazardous/severe wind.

The progression of overnight convection should slow, thus, lingering
decaying showers could remain over some eastern locations Sunday
morning. Once the front finishes clearing out, noticeable cooler air
backfills into the forecast area through the rest of the day. Highs
top out in the 70s with dewpoints eventually retreating into the 40s
by the end of the day. Dry, cool, and breezy weather persists Monday
and into Tuesday morning with a zonal flow configuration aloft. The
next chance for rainfall returns for the second half of Tuesday with
the next speed max. A much stronger wave could impact Lower Michigan
mid-late week with strong geostrophic flow and upper level
divergence.

&&

.MARINE...

High pressure is building across the southern Lakes today while the
next cold front starts moving toward western Lake Superior. This
will help keep a fairly tight pressure gradient in place across the
region today. Winds will remain elevated from the southwest offering
a period of gusts to 25 to 30 knots for Saginaw Bay and the tip of
the Thumb during the afternoon Saturday so we`ll issue a Small Craft
Advisory. The front then sweeps east by Sunday morning. Winds will
stay elevated around 20 knots, but out of the northwest Sunday.

&&

.HYDROLOGY...

Showers and thunderstorms move through from west to east Saturday
night into Sunday ahead of a cold front. Total basin rainfall
amounts of quarter to a third of an inch expected. No widespread
flooding concerns exist, although heavy downpours with rainfall
rates up to an inch per hour may be possible. Localized flooding of
low-lying or poor drainage areas possible.

&&

.PREV DISCUSSION...
Issued at 335 PM EDT Fri Jun 12 2026

AVIATION...

Increasing mixing depths allowing winds to gusts above 20 knots this
afternoon. Upper level wave/cold pool tracking through northern
Lower Michigan could allowing for some passing mid clouds (5+ kft)
this evening and tonight, higher confidence over the northern taf
sites. Southwest winds ramp up tomorrow ahead of a cold front, with
gusts of 25-30 knots expected in the afternoon.

D21/DTW Convection...Thunderstorms are not expected.

.DTW THRESHOLD PROBABILITIES...

* None.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory from 10 AM to 10 PM EDT Saturday for LHZ421-
     422-441.

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

$$

DISCUSSION...KGK
MARINE.......DRK
HYDROLOGY....KGK
AVIATION.....SF


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