textproduct: Detroit/Pontiac

KEY MESSAGES

- An extended period of dry and generally seasonable weather continues through early next week.

DTW THRESHOLD PROBABILITIES

* None

PREV DISCUSSION

Issued at 352 AM EDT Thu Sep 24 2026

DISCUSSION...

A rex block continues to drift over the eastern Great Lakes today with broad surface high pressure anchored over southern Quebec providing strongly subsident and stable conditions. Easterly wind persists through the day but with slightly lower magnitude than yesterday given a weakening gradient. This advects a drier air mass in with PWAT slated to fall below 0.50", bringing lots of sunshine. High temperatures are forecast to land within a few degrees on either side of 70 degrees. Another clear, crisp fall evening is in store with lows tonight falling well into the 40s outside of the urban core.

By Friday the rex block evolves into a coastal low but leaves longwave ridging in control of the Great Lakes. A weakening upper shortwave brings increasing coverage of high clouds late tonight into Friday which dampens high temps a few degrees compared to today, but highly stable and dry conditions in the mid and low levels ensure dry weather. As the coastal low drifts northward toward New England this weekend, deep layer subsidence settles back in across SE Michigan. This favors mainly clear skies and light wind with high pressure established overhead. A good amount of sun and air mass modification will facilitate a gradual warming trend through the weekend. This stagnant patterns looks to hold through Monday before the coastal low finally begins to release east.

The next opportunity for more active weather targets the local area between late Tuesday and Thursday as a Pacific wave treks through. There are a subset of solutions that carve out a cutoff low over the Four Corners, leaving a disorganized frontal system to track through the Great Lakes. Other solutions carry a more amplified 500mb wave directly across the region, producing a more dynamic surface low with potential for thunder and/or stronger wind. For now, a chance PoP will be advertised for this broader mid-week period until details come into focus.

MARINE...

A moderate pressure gradient responsible for brisk east to northeasterly flow will ease through the morning and afternoon hours. This will diminish wind speeds through the day, leading to light winds by tonight. High pressure will slowly build in from Quebec and Ontario and will center over the Great Lakes by Friday. This will bring an extended period of quieter weather that will sustain light winds and dry conditions through the weekend.

DTX WATCHES/WARNINGS/ADVISORIES

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