textproduct: Detroit/Pontiac

KEY MESSAGES

- Much warmer today with temperatures in the upper 70s.

- Next chance of rain arrives Sunday, focused over the southeasternmost areas, tied to the remnants of Isaias.

- Very mild, dry again Monday with highs in the upper 70s to 80.

- Scattered shower chances Monday night-Tuesday tied to a passing cold front. This front brings a return to a more typical fall pattern for the mid to late week period.

DTW THRESHOLD PROBABILITIES

* None

PREV DISCUSSION

Issued at 317 PM EDT Sat Oct 10 2026

DISCUSSION...

Main weather story of today is the landfall of Isaias last evening and its ongoing extratropical transition. While SE Michigan is spared of the bulk of this system, the shield of high cloud outside represents its northern edge. While moisture quality is expected to degrade as the gulf moisture stream cuts off, models are still generating light rain potential Sunday with a thickening cloud deck aloft. Diabatic cooling leads to a cooler day Sunday with temperatures in the cloud shield holding below 70 degrees. Slightly warmer temperatures expected further inland as the remnants of Isais pivot east into the mid-Atlantic by Sunday afternoon. Much drier air then fills into the Great Lakes Sunday night-Monday, which currently stretches from the southern Plains to the Upper Midwest. Strong subsidence signature observed in 12z soundings (e.g. TOP/LMN/OUN) should be the airmass that advects into SE Michigan Sunday night, which combined with a moistened boundary layer/longer mid-October nights could result in fog development Monday morning.

Drier day than expected Monday as brief ridging slides overhead. Winds shift to the southwest with the passage of the ridge axis, quickly leading to warm advection into SE Michigan Monday. Highs thus warm into the upper 70s with highs possibly breaking 80 degrees Tuesday. The catch to this is another opportunity for rain beginning late Monday night and lingering through mid-week. This comes as moisture pools along the deformation axis to our north, while return flow sets up to the south. Increasing LLJ winds Monday night bring in the initial wave of mid-level moisture, followed by increasing synoptic support through the day Tuesday as the LLJ, surface low/cold front, and finally a strong ~110 knot upper level jet work into SE Michigan. While moisture depth is not overly impressive on its own, multiple lift mechanisms through the day will compensate for this at least partially to keep rain chances going. Thermodynamic profiles show a strong elevated mixed layer (mid level lapse rates ~7.0 C/km), so cannot rule out a few rumbles of thunder particularly as the front comes through during peak heating. SWODY3 has designated General Thunder for most of the state.

Passage of the cold front establishes strong cold advection across the region between 00z Wed thru 00z Thu. For reference the 10.06z ECMWF has h8 temps dropping from 15 C to 7 C. This brings surface temps back toward normal values for mid-October by mid-week (mid-60s highs and mid 40s temps). This cooler airmass is likely to keeping cloud cover and possibly lake induced showers around through Wednesday given still warm lake temperatures in the teens and N/NW flow. High pressure will eventually erode moisture ahead of a strong low that draws even cooler temperatures into SE Michigan by next weekend.

MARINE...

Remnants from Hurricane Isaias has strengthened the pressure gradient across the Great Lakes, resulting in breezy southeast flow that will continue into tonight. Gusts 20 to 25 knots are expected through south and central Lake Huron, sporadically peaking around 30 knots over north-central Lake Huron where the fetch is more favorable. Small Craft Advisories remain in effect from Port Austin to Port Sanilac with the elevated wave heights in effect. Sporadic gust to gales will be possible across north-central Lake Huron, however, confidence in achieving gales remains very low noting high stability over the lakes which will greatly hamper or nullify any mixing of stronger winds aloft.

Breezy conditions will subside through tomorrow as a ridge of high pressure fills in. Remnant moisture from the tropical system will also bring the chance for rain showers overnight. On and off rain showers and some low-end storm chances will be possible through next week as a couple of systems moves through.

DTX WATCHES/WARNINGS/ADVISORIES

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

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