756
FXUS63 KDTX 160845
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
445 AM EDT Sun Aug 16 2026

.KEY MESSAGES...

- Scattered shower and thunderstorm chances this morning into early
evening mainly along/south of I-69. Torrential rainfall and minor
localized flooding possible with any storm.

- Additional scattered shower chances mainly north of I-69,
particularly in the Thumb, this evening-early tonight as a cold
front crosses.

- Dry, seasonably average conditions for the early week period.

- Shower and storm chances return Tuesday night into Wednesday with
the arrival of the next cold front.

&&

.AVIATION...

Low clouds (IFR/MVFR) and fog (with a brief dip to LIFR possible)
around the start of the taf period will be replaced by slightly
higher ceilings as showers track across the southern tafs during the
mid to late morning hours. Regeneration of showers is expected for
the afternoon and early evening hours a cold front moves through. A
few embedded thunderstorms are also likely, but confidence remains
too low to include at specific taf sites. Very light southerly winds
to start the day veer to the west for the mid afternoon hours,
generally topping out around 10 knots sustained. Winds will then
shift to the northwest behind the cold front late this evening, with
low clouds at least partially clearing from northwest to southeast
tonight.

D21/DTW Convection...Low chance for thundestorms this morning
through early this evening.

.DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 feet or less today, medium this evening, low
  overnight.

* Low for thunderstorms today.

&&

.PREV DISCUSSION...
Issued at 316 AM EDT Sun Aug 16 2026

DISCUSSION...

Ongoing convection across northern IL/IN is tied to the arrival of a
central Plains shortwave that will slide along MI`s southern border
over the rest of the morning/early afternoon. While the majority of
convection is again expected south of the state where the stalled
frontal boundary resides, reinforcing moisture and modest mid-level
ascent supports scattered AM shower chances over the southern half
of SE MI. Thunder chances during the morning activity will be quite
limited due to the lack of available instability (MUCAPE <500J/kg).
This gradually changes by afternoon however as ongoing moisture
advection pushes surface dewpoints into the the lower 70s allowing
diurnal heating to generate MLCAPE between 1000-1500J/kg. Increasing
instability combined with the modest synoptic support from the
passing shortwave supports scattered convective showers and
thunderstorms through the afternoon, mainly along/south of I-69
given the location of the wave. Severe storms are unlikely as weak
column winds keep shear sub-30kts in addition to abysmal mid-level
lapse aob 6 C/km. PWATs in excess of 2" and warm cloud layers near
15kft however do offer the threat of torrential rainfall. That said,
the progressive nature of any convection plus the dry summer thus
far should keep flooding more localized to the typical floodprone
urban/low lying areas. Storm chances wane by early evening in the
south as the shortwave departs east; though the arrival of a cold
front dropping out of northern MI shifts scattered shower chances
towards the northern half of SE MI, particularly the Thumb, this
evening-early tonight. Late arrival in the diurnal window likely
keeps thunder more isolated.

Passage of the aforementioned tonight ushers in a more seasonably
average airmass as dewpoints and 850mb temps return to around 60F
and lower teens C, respectively. As such, pleasant early week in
store with highs in the lower to mid 80s Monday-Tuesday and sunnier
skies.

Broad Hudson Bay upper trough sends another cold front into the
Great Lakes midweek. Currently, frontal timing and associated
preceding showers favored to work across SE MI late Tuesday night-
Wednesday. Cooler air follows to close out the work week with 850mb
temps hovering around 10C keeping highs slightly below normal by the
latter part of August standards.

MARINE...

As low pressure tracks north of the area it will push a cold front
through the central great lakes region later today and tonight.
Ahead of the front, south winds prevail for much of the day around
10 to 20 knots. Behind the cold front, northwest winds fill in and
increase across Lake Huron, and eventually down through Lake St.
Clair and the Michigan waters of Lake Erie late tonight. The
strongest winds are expected across Lake Huron, especially the Open
Waters with 20-25 knot winds expected late Sunday evening into early
Monday morning. Thus, will need to keep an eye on the wave forecast
and the potential for Small Craft Advisories for nearshore waters
across the tip of the Thumb of Michigan. Showers and thunderstorms
will be possible as this system moves through today through tonight.
The best chance for thunderstorms will be along the cold front later
this evening.

&&

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

$$

AVIATION.....SF
DISCUSSION...KDK
MARINE.......JA


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