481
FXUS63 KDTX 131840
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
240 PM EDT Sun Jul 13 2025

.KEY MESSAGES...

- After a dry early week period, showers and thunderstorms return
Wednesday through Thursday.

- An uptick in heat and humidity occurs Tuesday as high temperatures
reach around 90 Tuesday afternoon.

&&

.DISCUSSION...

Last vestiges of moisture axis/cold front roughly along ADG-PHN line
still just enough to touch off isolated showers with weak low level
convergence around. Dry mid levels will tend to inhibit development
and should prevent EQL from reaching -20 C isotherm as MLcapes are
hovering around 500 J/kg, higher on Canadian side. Surface dew pts
started the day around 70 degrees but in the process of slowly mixing
down as dry air over Western Great Lakes (see 12z GRB sounding)
moves east over southern Lower Michigan tonight into Monday. Modest
500 MB height rises into Tuesday (591 DAM) with deep moisture then
ramping up/returning for mid week period, as PW Values push to 2
inches on Wednesday. A couple of waves of moisture/disturbances
moving through Tuesday night-Friday morning time-frame will support a
few rounds of showers and thunderstorms. Euro ensembles now
indicating 24 hr QPF probability of half an inch or more around 40
percent. Bulk of stronger westerlies/0-6 KM bulk shear looks to be
over the northern Great Lakes during the mid weak period, thus
prospects for any severe storms looks low, but there is some
indications MLcapes exceeding 1500 J/kg which would put isolated
severe into play with the average mid level lapse rates. Regardless,
those decent capes will be conducive to localized heavy rainfall
within the moisture rich environment.

&&

.MARINE...

A stray shower or rumble of thunder is possible this afternoon and
evening near Lake St Clair, western Lake Erie, and far southern Lake
Huron. Otherwise, dry conditions and light winds prevail today and
through the early week period as high pressure builds over the Great
Lakes. The next chance for showers and thunderstorms will enter
Wednesday and Thursday as a prefrontal trough and cold front move
across Michigan. This will bring the potential for some localized
stronger wind gusts with any thunderstorm activity.

&&

.PREV DISCUSSION...
Issued at 111 PM EDT Sun Jul 13 2025

AVIATION...

Diurnal cumulus will continue through the afternoon and early
evening with SCT-BKN heights eventually getting to 4k-5k feet. With
the character of the CU early this afternoon and the 12z model
suite, a few isolated showers will form around Detroit late this
afternoon. Therefore will have a vicinity shower in the Detroit area
TAFs. Otherwise...west-southwest winds will continue below 10kts.

Those winds diminish to generally a light and variable wind tonight
and Monday morning. The CU will also dissipate early this evening
leaving a BKN deck of high Altocu or low circus for the early part
of the night. Skies will then become mostly clear late tonight
through much of Monday.

The haze from the Canadian wildfire smoke should remain without much
change over the next 24 hours based on the smoke models and thus the
visibilities in the TAFs are also rather consistent too.

For DTW/D21 Convection...No thunderstorms expected this TAF period.

THRESHOLD PROBABILITIES...

* Moderate for ceiling at or below 5000 ft through 00Z today.


&&

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

$$

DISCUSSION...SF
MARINE.......AM
AVIATION.....RBP


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