Saginaw, MI 48609 Weather

Key Messages

- The potential exists for dense fog development each of the daybreak periods through Monday. Any fog that will develop is expected to dissipate or lift by 10 am.

- Mild and dry through the middle of next week.

Discussion

Ridging aloft and at the surface continue to dominate the region and will provide several more days of quiet weather around the Great Lakes. The rex block will remain mostly intact the next couple days before slowly breaking down as the book end troughs break down in favor of a more zonal pattern by the middle of next week.

The last few night fog has been the main concern in the forecast as is usually the case with ridging and flow off the Great Lakes this time of year. Ample moisture with longer cool nights brings areas of fog across the state, heavily influenced by wind direct deciding which locations get the fog and how dense. As the center of the surface drifts southward from southern Quebec toward the east coast of the conus, the surface flow will change from northeasterly to southeasterly today as we become positioned on the west side of the high. The change in flow will lead to the fog likely shifting from the Thumb and Saginaw Valley down to the state line with the flow coming off Lake Erie. Will keep the entry level patchy fog mention in for now and look more at it this afternoon.

The upper level ridge axis will cross the area Saturday night. This will increase the southwesterly flow into the region allowing for a boost in temps Sunday. After slowly moderating upward through the mid 60s to end the week, Sunday could support highs in the 70s for at least part of the area. Looking into next week, a developing low tracking across Canada looks to send a weak backdoor cold front into the region. The airmass is very dry with ridging across the SW conus blocking any moisture return, the front will offer some cooler temps as 850mb temps fall from the upper single digits C, down to just above 0C behind the front with the next surface ridge.

Marine

High pressure centered over Quebec migrates south into New England today. Light easterly winds generally hold AOB 10 knots over the central Great Lakes, veering southeasterly by this afternoon. Winds then turn southerly over the weekend with a slight uptick in speeds as the surface ridge maintains control from the east. The stretch of tranquil and mainly dry conditions largely continues into next week, although an approaching cold front could briefly stall out over The Straits on Sunday. Should the active front make it to the northern waters of Lake Huron, a few showers would be possible. The decaying front then works across the rest of the basin Sunday night into Monday leading to a northerly wind shift, and perhaps a few opportunities for a stray shower.

Prev Discussion

Issued at 1150 PM EDT Thu Oct 22 2026

AVIATION...

Steady expansion of very low stratus will continue across southeast Michigan during the early morning hours, as light northeast low level flow draws better moisutre off lake Huron into the area. A rapid decline into LIFR will occur with cigs hovering in the 300 to 400 ft range based on latest observational trends. Expectation for some lowering of this cloud base closer to daybreak, offering a greater potential for some degree of fog formation as well. Potential does exist for a period of dense fog to develop, with visibility below 1/4 mile. A gradual improvement in conditions late morning as daytime heating works to lift and clear any lingering low stratus and fog. VFR conditions with a limited diurnal cu production for the remainder of Friday.

D21/DTW Convection... Thunderstorms are not forecast through the TAF period.

DTW THRESHOLD PROBABILITIES...

* Low for cigs/vsby to fall below 200 ft and/or 1/2SM late tonight.