textproduct: Detroit/Pontiac

KEY MESSAGES

- Dry and near-normal temperatures today.

- Above normal temperatures (90+) starting tomorrow.

- Shower and thunderstorm chances increase Thursday onwards.

DISCUSSION

The early to mid-week period will feature an extended period of dry weather along with increasing temperature trends that will yield well above normal readings.

For today, a strong region of surface high pressure will hold across Michigan, producing mostly sunny skies with temperatures peaking in the mid 80s. The strong heat dome anchored over the Intermountain West and Rockies will fold into the Midwest and Great Lakes tomorrow into Tuesday as a series of mid-level waves traverses the central and southern Canadian provinces. This will greatly enhance subsidence as an anomalously warm thermal ridge builds overhead. Highs at or above 90 become likely as early as tomorrow, initially favoring the interior of northern Michigan and south into the Tri- Cities where the core of the low-level warmth initially arrives. Tuesday looks to be the peak of the heat with 850 mb temperatures approaching 24C over central lower Michigan by 18Z, around the 99.5th percentile of climatology, and closer to 22C over metro Detroit. Guidance continues to highlight the hottest potential in the Saginaw Valley due to the lower terrain coupled with the weak downsloping southwest flow. Latest NBM guidance paints the potential for some isolated 100 degree readings in this corridor (along with the urban Metro corridor). While triple digit heat remains a climatologically rare outcome for SE MI and confidence in this specific number is low, the overall signal supports widespread mid to upper 90s across the cwa. Warm overnight lows holding in the upper 60s to lower 70s are also expected Tuesday and Wednesday morning.

A very modest step down follows Wednesday as the thermal ridge pivots slightly south with 850 mb temperatures of 18-20C holding from Port Huron to MI/OH border, and slightly lowered values holding north. This will still bring the potential for temperatures aoa 90 degrees for a high, most favorable outside of the Thumb region. Heights will slowly erode Thursday into Friday as the flow aloft takes on a more northwest to southeast orientation, increasing potential for upstream convection and/or associated cloud debris to progress into SE MI late Thursday through Friday. This will likely temper temperatures, especially with any precipitation. Lower end chances for unsettled weather continue into the weekend.

MARINE

Broad area of high pressure will continue to allow for quiet marine conditions through the weekend. This high pressure will gradually strengthen going through Sunday. Lighter northeast winds will continue to variable as the high passes overhead.

PREV DISCUSSION

Issued at 1101 PM EDT Sat Jul 11 2026

AVIATION...

High pressure over the northern Great Lakes will ensure VFR conditions throughout the TAF period. This will bring limited clouds through tonight with a generally light northeast wind. Mostly clear skies tonight, but a drier airmass is expected to limit fog potential during the early morning hours. VFR conditions expected to hold through Sunday afternoon with mostly clear skies. An isolated diurnal cumulus response looks very limited if at all with northeast winds 5 to 10 knots during the afternoon. Northeast winds veer begin to veer east-southeast Sunday evening as surface high pressure settles further east.

D21/DTW Convection...No thunderstorms are forecast today through Sunday.

DTW THRESHOLD PROBABILITIES...

* None.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None.