textproduct: Detroit/Pontiac

KEY MESSAGES

- Mostly dry and near-normal temperatures this weekend.

- High confidence for above normal temperatures (90+) next week.

- Shower and thunderstorm chances increase during the second half of the work week.

DISCUSSION

Surface high pressure builds into the northeastern quadrant of CONUS today and Sunday under a region of modest mid-level height rises. A seasonable airmass is currently in place with the 12z.KDTX raob observing PWAT of 1.10" and h8 temperature of 14 C, falling within the interquartile range of sounding climatology. This equates to near normal temperatures in the mid-80s today, with a slight warming trend into Sunday. Cloud trends will be the only real forecast challenge this weekend amidst lake moisture influence in the NE flow regime and high cloud streaming in from the Ohio Valley low. The latter becomes less influential Sunday with the low peeling off toward the Atlantic Coast, leaving just localized potential for lake induced stratus/patchy fog development by Sunday morning.

Warming trend peaks during the first half of the week as the 600 dam ridge over the Dakotas/Upper Midwest folds into the Great Lakes. Position of the ridge forces gulf moisture to carve west into the Plains/Rockies before pivoting around the ridge and into SE Michigan, compromising the moisture quality. This does two things for us: 1. keeps dewpoints aob 70 degrees, and 2. keeps thermodynamic profiles capped for the first half of the week. So even as temperatures climb into the mid-90s, heat indices largely look to remain below 100 degrees. Lack of moisture also limits convective chances, with projected soundings appearing too dry and capped for any meaningful rain/storm chances until mid-week.

Back half of the week carries lower predictability in both temperature trends and storm chances. Much of this is related to how the ridge evolves, with the GFS favoring a more persistent, strong ridge than the Euro solution. This ultimately influences how the next Pacific wave behaves, which moves onshore the Pacific Northwest mid-week. Regardless of which scenario verifies, mean wind is forecast to shift to the northwest mid-week and puts SE Michigan within a favored corridor for MCS propagation as we often see in these ridging patterns. So although there are still details to work out, an overall increase in thunderstorm chances is expected from Thursday into the weekend as the ridge breaks down and a more dynamic setup emerges.

MARINE

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

PREV DISCUSSION

Issued at 1248 PM EDT Sat Jul 11 2026

AVIATION...

High pressure centered on the northern Great Lakes maintains NE wind over Lower Mi that is brinGing in air with gradually lower moisture content today and tonight. In the meantime, there is a generous cumulus response to daytime heating as surface Td lingers in the mid 60s this afternoon. This combines with a component of high clouds along the DTW corridor tied to the front stalled in the Ohio valley and these continue west to east over that area. Both the cumulus and cirrus diminish this evening as surface high pressure reinforces a dry NE wind that is projected to carry surface Td down into the 50s during the night. This limits fog potential under otherwise clear sky tonight and Sunday morning.

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

DTW THRESHOLD PROBABILITIES...

* Moderate for ceiling 5000 ft or less this afternoon.

DTX WATCHES/WARNINGS/ADVISORIES

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