445
FXUS63 KDTX 131730
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
130 PM EDT Sat Jun 13 2026

.KEY MESSAGES...

- Showers and a few embedded strong thunderstorms work through
  southeast Michigan this evening into Sunday morning.

- Dry Monday, but showers and possible storms return Tuesday
  afternoon and late Wednesday/Wednesday night.

- Heaviest rainfall looks to be Wednesday night, with the potential to
  exceed 1 inch.

&&

.AVIATION...

Well mixed conditions will persist through the balance of the
daylight hours - supporting gusty southwest winds. Otherwise, just
some scattered fair weather cumulus - especially north of the
Detroit terminals.

Showers are expected to develop late this evening across west and
central Lower Michigan in advance of a cold front. The initial
development will be capable of producing a few thunderstorms
- which may affect the Saginaw and Flint airspace around midnight.
Overall, a scattered shower pattern will remain in place in the
vicinity of the slow moving front, including after frontal passage
as rather deep moisture will remain in place through the end of the
forecast window.

Ceilings will lower late tonight and remain MVFR through much of
Sunday.  The southwest winds this evening will become variable
around the front - then take on a north/northeast direction early
Sunday - before becoming northwest later Sunday.

D21/DTW Convection... chances for a thunderstorm within the showers
late tonight into Sunday are low.

.DTW THRESHOLD PROBABILITIES...

* Low for a thunderstorm after 08z Sunday.

&&

.PREV DISCUSSION...
Issued at 356 AM EDT Sat Jun 13 2026

DISCUSSION...

Mostly clear skies start the day, but regional radar showing a
cluster of showers upstream over the Midwest highlights what`s to
come later this evening as a cold front moves in. Dry conditions
prevail locally today as Ohio Valley high pressure and zonal flow
aloft maintain stable conditions, but there is a low probability for
some showers in the northern Saginaw Valley and Thumb midday as a
surge of low-level theta-e arrives from the south. Low to mid-level
southwest flow strengthens as the high migrates toward the
Appalachians and the cold front approaches from the Midwest. High
temps are forecast to reach the mid to upper 80s with the southwest
wind becoming gusty to 20 to 30 mph by mid-late afternoon. Parts of
the Saginaw Valley and Thumb could see gusts up to 35 mph as daytime
mixing taps into higher momentum within a LLJ passing across
northern Lower MI.

A spoke of vorticity rotating around the closed low over northern
Ontario induces a period of gradual height falls this evening,
causing the cold front to sink southward into the area. This will
trigger a broken line of showers with embedded thunderstorms late
this evening. The highest coverage looks to set up north of I-69
where a feed of marginal instability will be directed and CIN will
be lowest. A window for isolated strong to severe storms and briefly
heavy rain exists between 11pm to 4am while overlap exists between
frontal forcing, marginal SBCAPE, and deep layer wind shear of 35 to
40 kt. Primary threat appears to be wind gusts of 45 to 60 mph given
the storm mode and available momentum in the column. Signal among ML
severe weather probability tools corroborates the SPC Day 1 Marginal
Risk for the area. Showers with embedded thunder will continue
overnight as the front progresses southward and weak low pressure
develops along it.

A flare-up in shower activity is forecast Sunday morning as PVA and
divergence aloft spread in ahead of the mid-level shortwave arriving
from the Midwest. Frontogenetical forcing will contribute to some
enhancement of lift on the cool side of the front and some areas may
see multiple rounds of moderate showers. Coverage will then
gradually taper off through the afternoon with post-frontal
temperatures much cooler in the upper 60s near the lakeshore and 70s
elsewhere.

Longwave troughing aloft dominates the Great Lakes early next week
with temperatures remaining on the cool side of average. Dry
conditions are favored Monday, then showers and storms reenter the
picture Tuesday through Thursday as a series of shortwaves traverse
the region. There is a signal for a more vigorous wave to track
through late Wednesday into Thursday, with potential for heavy
rainfall and/or severe weather in the region as divergence aloft and
strong kinematics accompany the wave. LREF grand ensemble data
indicates a 30% chance for portions of the area to exceed 1" during
this period.

MARINE...

High pressure has expanded across the southern Lakes while a cold
front over the northern Lakes starts drifting south reaching Central
Lake Huron this evening. This will help keep a fairly tight pressure
gradient in place across the region today with southwesterly winds
gusting to around 30 knots over Saginaw Bay and the tip of the Thumb
this afternoon. A Small Craft Advisory is in effect through 10pm to
account for the wind and waves. The front will also offer a round of
showers and thunderstorms affecting northern Lake Huron through the
day, and the rest of the area through the night. The front then
sweeps east by Sunday morning. Winds will stay elevated around 20
knots, but out of the northwest Sunday.

HYDROLOGY...

Scattered to numerous showers and storms are expected tonight
through early Sunday as a slow moving cold front tracks southward
across the area. Most areas are forecast to receive a quarter inch
or less of rainfall. Localized areas that see repeated rounds of
moderate showers/storms may receive in excess of 1 inch and ponding
of low-lying or poor drainage areas is possible.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ421-422-
     441.

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

$$

AVIATION.....Mann
DISCUSSION...TF
MARINE.......DRK
HYDROLOGY....TF


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at www.weather.gov/detroit.