textproduct: Detroit/Pontiac

KEY MESSAGES

- Light rain across southeastern half of the forecast area this morning and early afternoon.

- Brief period of dry weather Monday.

- Scattered shower and thunderstorm chances Monday night-Tuesday.

- More typical fall weather mid to late week.

DISCUSSION

Moisture associated with the remnants of Isaias is lifting northward into southeast Michigan this morning. The high based cloud cover will transition to thicker lower clouds through the morning and carry through the bulk of the day. While the deeper gulf moisture holds off to the south, rain showers will be supported through the morning hours and be focused generally across the southeast half of the CWA. Rain amounts expected to be light. Overcast skies for most of the area will help keep daytime highs today down in the 60s, though parts of the Saginaw Valley may make a run up into the low 70s as thicker low clouds may not make it that far north as high clouds pull east during the afternoon. Remnant moisture will pull east throughout the afternoon with a period of mid-upper level dry air filtering into southeast Michigan tonight into Monday. Forecast soundings show a developing subsidence inversion tonight with dewpoints lingering in the mid 50s will set the stage for at least some patchy fog development prior to sunrise tomorrow morning.

A low amplitude ridge will take up a short residence time over Michigan tomorrow allowing for a dry period through the afternoon. Passing of the ridge axis early in the day will lead to increasing southwest flow and associated warm advection with temperatures at 850mb climbing to around 15C. This will help daytime highs push into the mid-upper 70s and possibly topping 80 degrees in some locations.

Troughing develops over the Intermountain West Monday and Tuesday with downstream southwest flow increasing atop a frontal zone stretching from the central plains into the Midwest. As larger scale ascent becomes more favorable with help from the increasing LLJ, it will trigger a weak low pressure system along the frontal zone that will move across the western Great Lakes states and drive a cold front through the central Great Lakes on Tuesday. This will bring a stretch of increased precipitation chances Monday night through Tuesday. General thunderstorms chances will exist during this time within a modestly sheared (~40kts of 0-6km bulk shear) and weakly unstable environment (mid-level lapse rates 6-7 C/km) ahead of the approaching cold front.

Cold air advection will ensue behind the front Wednesday night through Thursday as 850mb temperatures drop by about 10C pulling daytime highs back down towards mid-October averages. Expect daytime highs in the 60s with overnight lows in the 40s for the late half of the work week. Periodic chances for lake induced showers will be possible Wednesday to Thursday morning associate with northerly flow that will also cause higher coverage hanging around as a high pressure tracks east across the northern Lakes. Canadian troughing then develops late week a should bring a return of widespread precipitation Thursday night into Friday with a much colder airmass expected over the weekend.

MARINE

Remnants from Hurricane Isaias will move in through the Ohio Valley this morning before departing into New England tonight. Wind speeds around 20 knots across Lake Huron will dwindle through the day as this system exits. Light rain showers will be possible across southern Lake Huron and locations south as this system approaches the southern Great Lakes. A ridge of high pressure will then briefly fill in tomorrow which will back winds to the southwest. Winds stay light for most locations with localized higher gust potential around 20 knots for northern Lake Huron. A low pressure system and subsequent cold front move through Tuesday and Wednesday, bringing the next chance for rain and a low chance for isolated thunderstorms.

PREV DISCUSSION

Issued at 1132 PM EDT Sat Oct 10 2026

AVIATION...

Remnants from Hurricane Isaias will lift across the southern and central Appalachians tonight and Sunday. The northwestern edge of the rain shield is forecast to extend partially into Se Mi on Sunday. Weakening of the ascent will only support light rain. The combination of low level moisture influx and evaporational cooling of the low levels will result in high probabilities for IFR and MVFR ceilings during much of the day Sunday, with the exception of MBS which will remain more entrenched in the drier air. Recent model trends continue to indicate a rapid northward expansion of MVFR and IFR cloud bases from southern Ohio into metro Detroit during the 08Z to 12Z time frame. Upstream observational trends continue to lag the onset slightly, which continues to suggest holding timing of the IFR conditions into Metro Detroit around 13Z.

D21/DTW Convection...No thunderstorms forecast during the period.

DTW THRESHOLD PROBABILITIES...

* High in ceilings aob 5000 feet Sunday.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory until 4 AM EDT early this morning for LHZ441- 442.

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