151
FXUS63 KDTX 141049
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
649 AM EDT Fri Aug 14 2026

.KEY MESSAGES...

- Showers and thunderstorms return late Saturday into Saturday
night. Heavy rainfall leading to localized flooding is possible,
particularly along and south of the I-94 corridor.

- Additional showers and thunderstorms likely on Sunday before
dry weather returns early next week.

&&

.AVIATION...

Greatest low level moisture holds across the Detroit terminals this
morning supporting MVFR cigs and patchy fog. Still some model signal
for a shot at a few showers to develop near the start of the
forecast period so have keep VCSH mentions. Improvement to these
lower ceilings occurs over the course of the morning as convective
debris cloud vacates allowing diurnal heating to promote SCT skies.
Surface high pressure maintains lighter E/NE winds today through
tonight.

D21/DTW Convection...No thunderstorms anticipated during the taf
forecast period.

.DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 feet or less early this morning, low by late
  morning.

* Low for visibility restrictions of 1/2sm or less or ceilings at
  less than 300 ft.

&&

.PREV DISCUSSION...
Issued at 301 AM EDT Fri Aug 14 2026

DISCUSSION...

A tropical airmass is in place across the Midwest, as the 00z KDVN
RAOB reported an extreme 700 MB dew pt of 11 C. Southeasterly
trajectories beneath an upper-level ridge axis over the northern
Mississippi River Valley will keep the deep moisture south of the
Michigan border today. A strong upper-level wave coming out of
eastern Colorado early this morning will pool another round of deep
moisture (PW values 2.25 to 2.5 inches), which will make a run
toward- and at least impact locations near-the southern Michigan
border by Saturday evening. Several hi-res model solutions hold the
instability gradient just south of the Michigan border. However, The
notable exceptions are the NAM and Canadian models, which are
stronger and farther north with the shortwave/MCV. This would
present a heavy rain threat with MUcapes over 1000 J/kg. 700 MB dew
pts are seen rising to around 10 C, which is near record high from a
climatological prospective. However, with the warm and most airmass
in the mid-levels, mid-level lapse rates are weak. Local
probabilistic guidance suggests NAM is an outlier with the amount of
instability and excessive rainfall. Most solutions indicating
rainfall amounts generally under 1 inch, except perhaps right near
the southern Michigan border. 18z Euro ensemble members suggest a 10-
20 percent chance for 24-hour qpf to reach or exceed 1 inch across
all of southeast Michigan. However, the 00z UKMET is also bullish on
heavy rainfall, indicating a swath of 2+ inches of rain across the
south half of the CWA/Detroit Metro area. The SPC day 2 outlook has
highlighted a marginal risk of severe for Lenawee and parts of
Washtenaw/Monroe counties. If a stronger circulation and
corresponding enhanced 0-6 KM bulk shear verify, then damaging winds
and even a tornado would be possible. Obviously, a good deal of
uncertainty exists this far out.

Assuming low clouds and/or any fog this morning dissipate by mid-
morning and a canopy of higher clouds from storms over the Ohio
Valley is not too impactful, highs in the mid 80s seem reasonable
today. Similar temperatures are expected for Saturday as clouds
thicken up during the day and potential showers arrive by day`s end
with light southeasterly flow at the surface.

Modest height falls for the second half of the weekend into early
next week will bring modest troughing over the Great Lakes region
extending east into New England. It looks like a cold front tracking
through Sunday into Sunday evening will be support numerous showers
and strong thunderstorms before dry weather returns for Monday and
Tuesday as large high pressure over the Western Ohio Valley extends
into southeast Michigan.

MARINE...

High pressure is building across the Great Lakes and Ontario leading
to generally quiet conditions across the region. The high will be
slowly shifting eastward eventually reaching the eastern lakes by
Saturday morning. The stalled frontal boundary is still lingering to
the south but convection also should remain to the south of the area
today. Once the high pushes off to the east Saturday, the next low
will be developing to the west and should pass through the area in
the evening and overnight. Light and variable winds will become
northeasterly today and increasing to 10 to 20 knots across southern
Lake Huron. Winds then turn southerly late Saturday and increase to
around 20 knots ahead of a cold front Saturday night. Winds then
shift to the northwest on Sunday behind the front.

HYDROLOGY...

Deep tropical moisture characterized by precipitable water values
rising to between 2.0 and 2.5 inches will pool along and near the
Michigan/Ohio border Saturday afternoon into Saturday night. This
anomalously moist airmass will support high rainfall efficiency,
with heavy rain rates of 1-2 inches per hour in any robust
convection. While the model consensus keeps the primary axis of
heaviest rainfall just south of the state line, a few models have
trended farther north. Thus, concern for heavy rainfall leading to
localized flooding, particularly along and south of the I-94
corridor. However, confidence is not high enough for a Flood Watch
at this time.

&&

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

$$

AVIATION.....KDK
DISCUSSION...SF
MARINE.......DRK
HYDROLOGY....SF


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.