textproduct: Detroit/Pontiac

KEY MESSAGES

- Seasonable temperatures through Saturday with mainly dry conditions.

- Increasing chances for showers and storms through next week.

DTW THRESHOLD PROBABILITIES

* Low in ceilings aob 5000 feet through tonight.

PREV DISCUSSION

Issued at 317 AM EDT Fri Aug 28 2026

DISCUSSION...

High pressure will center over the Great Lakes this morning and afternoon, supporting a largely dry forecast. A weak mid-level shortwave will traverse the area early this evening, bringing a very low chance to generate an isolated showers across the Tri-Cities to Thumb. Weak mid-level capping and negligible instability keeps the possibility of this low. High pressure to shift into New England tomorrow as mid-level flow becomes increasingly zonal with little forcing locally. This will support dry conditions through much of tomorrow.

Attention will turn upstream tomorrow night as well established southerly flow across the Plains helps initiate and support sustained convection. This activity will likely progress eastward as an MCS towards the Great Lakes. As is often the case with these systems, convection will encounter little instability and weaker shear with eastward extend, favoring a reduction in both intensity and coverage before reaching SE MI. Some remnant shower or thunderstorm activity could survive into the area Sunday, but confidence in timing and coverage remains low.

Of potential greater consequence through the Sunday to Monday timeframe will be the placement of an increasingly defined low-level theta-e gradient/baroclinic zone across the Great Lakes. Current guidance focuses the stronger isentropic ascent and associated precipitation across northern lower Michigan, clipping portions of the northern portion of the forecast area, leaving much of SE MI dry. This scenario is reflected in the very warm NBM temperature forecast, with temperatures peaking in the mid to upper 80s Sunday and up to 90 in the urban areas by Monday. Confidence in temperatures at this range are considerably lower than these values would suggest as only a modest southward displacement of the projected ascent/precipitation would introduce substantially greater cloud coverage and potentially prolonged rainfall across a larger portion of the cwa. This southward shift could hold portions of the region in the 70s to low 80s Sunday and establish a much sharper north-south temperature gradient on Monday.

There is slightly better convergence between model output of a more northward advancement of the theta-e gradient Tuesday as southerly flow increases warm advection into the Great Lakes which would then favor well above normal temperatures. But overall next week does highlight the potential for a more active period of showers and thunderstorms and increased flood risk should the convergence zone fail to make appreciable northward progress by the midweek period.

MARINE...

High pressure in place through the day maintaining light winds and dry weather. Influence of said high wanes tomorrow as it shifts to the Northeast with the central Great Lakes holding on its westernmost fringe. This allows for modest southwest winds to develop during the day with gusts holding aob 20kts. Active pattern returns by late Sunday as developing low pressure over the northern Plains lifts a warm front through the area ushering in a more humid airmass leading numerous shower/storm chances into the new work week.

DTX WATCHES/WARNINGS/ADVISORIES

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