Expert Forecast Opinion

526
FXUS63 KDTX 151755
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
155 PM EDT Sat Aug 15 2026

.KEY MESSAGES...

- Gradually increasing chances for showers and possibly some thunderstorms
through tomorrow. Heavy rainfall leading to localized flooding is
possible, mainly along and south of the I-94 corridor.

- Dry early next week before showers return Wednesday.

&&

.AVIATION...

High degree of cloud cover with the moisture advection north of the
activity associated frontal system across the Ohio Valley is
bringing overcast skies at mostly low VFR ceilings. A few scattered
light rain showers lifting Lower Michigan this afternoon warranted at
least a PROB30 mention for later this afternoon into the early
evening. Otherwise, VFR ceilings will become MVFR ceilings late
tonight into tomorrow morning with pockets of IFR ceilings becoming
increasingly likely. Additional potential for showers exists tomorrow
morning with lower ceilings hanging around during the day. Light E
to SE winds today will become more S to SW tomorrow morning into the
early afternoon. Isolated showers and possible thunderstorms again
possible tomorrow afternoon.

D21/DTW Convection... Scattered thunderstorm chances this evening
hold near the Ohio border. Additional window for convection is
possible Sunday morning and afternoon, but overall thunder coverage
is expected to be limited.

.DTW THRESHOLD PROBABILITIES...

* Medium for ceiling 5000 feet or less this afternoon, high tonight
and tomorrow.

* Low for thunderstorms this evening and again Sunday.

&&

.PREV DISCUSSION...
Issued at 300 AM EDT Sat Aug 15 2026

DISCUSSION...

A bit more clarity with the forecast, as the lead shortwave over the
Midwest not as strong as forecasted yesterday and will result in a
flatter wave tracking near or just south of the southern Michigan
border this afternoon/evening. Sufficient instability to support
severe storms is not expected to cross north of the border
(supported by the machine learning). Although, it still is a close
enough call for SPC to maintain the marginal risk for Lenawee and
parts of Washtenaw/Monroe counties. Rain shower are still likely
along and south of I-94, with chances then diminishing as one heads
north. There is still some potential for 500 MB heights to close
off, which would enhance showers and allow for a slower progression
tonight. However, vast majority of solutions still highlight well
under 1 inch of rain.

The second wave coming out of the central Plains looks to be the
stronger one now, moving through southeast Michigan during the
favorable Sunday afternoon period. This should assure a greater
coverage of showers across southeast Michigan, as associated surface
reflection moves right through the middle section of the CWA.
With MLcapes aoa 1000 J/kg and 700 MB dew pts around 8 C, torrential
rain causing localized urban and low-lying flooding is a concern.
However, activity looks progressive enough. Also, weak mid level
lapse rates and 0-6 KM bulk shear values under 30 knots look
to limit severe chances.

Dry weather returns for Monday and Tuesday as large a high pressure
over the western Ohio Valley extends into southeast Michigan
underneath west-northwest upper level confluent flow.

A large upper level low/trough centered over Hudson Bay will direct
a strong Pacific shortwave and strengthening surface low through the
central Great Lakes on Wednesday, per 00z Euro. Cool Canadian air
will follow, with 850 MB temps bottoming out around 6 C by Friday.

MARINE...

Area of high pressure is now centered over the eastern Lakes this
morning. This high should keep the area mostly dry while winds veer
to the east and remain below 15 knots ahead of the next system. A
warm front will lift through this evening with winds responding by
veering southeasterly and increasing with gusts to around 20 knots.
There is a chance of showers and thunderstorms in the late afternoon
across Lake Erie and Lake St Clair, with lesser chances further
north where dry air lingers from the ridge. Increased chances of
precipitation tonight as a weak system works east along the state
line. Higher chances of rain across the whole region on Sunday as a
low tracking through the northern Great Lakes pulls a cold front
through the area. Winds then shift to the northwest on Sunday behind
the front.

&&

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

$$

AVIATION.....AA
DISCUSSION...SF
MARINE.......DRK


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