Saint Ignace, MI Weather

Key Messages

- Areas of dense fog tonight, particularly northeast lower MI.

- Mild through the weekend, slight chance for showers Sunday.

- Cooler, but likely seasonable, early next week.

Discussion

Issued at 140 PM EDT Fri Oct 23 2026

Another night, another round of fog as sfc high pressure remains off to our east. South to southeast low level flow will advect moisture off Lake Huron, resulting in the best chance for fog near Saginaw Bay. Seems it could travel inland as well across the interior, and leak into eastern upper as well. Patchy fog possible elsewhere. Other than that, southerly flow and increasing heights on Saturday will lead to rising temperatures, and the start of a truly nice weekend for the end of October.

Above normal heights aloft, as has been the case, will remain over northern MI this weekend with southerly transport winds. Consequently, temperatures rise into the 60s to near 70 degrees each afternoon this weekend. Ridging gets beat down some by impressive upper trough across Ontario, and subsequent boundary will leak down into northern MI. Thus, as the energy to the north continues east, the cold front and cooler airmass slowly push into northern MI early next week. This feature will produce showers as well, particularly on Sunday and across eastern Upper Michigan, but leakage down into northern lower possible as well (light rain for those "lucky" enough). That being said, this cool down will feel cooler than it really is, with progged high temps hovering around normal for this time of year (upper 40s to lower 50s most areas).

Pretty energetic from Tuesday and through the rest of the week as multiple short waves/upper lows track from the Pac NW/Desert SW across the Upper Midwest. Meanwhile, the northern stream remains active as well. How these features interact and how far south any northern stream piece of energy digs will tell us how cool, or warm, it may get. Current ensemble guidance means are generally more warm (or above normal) than cool (or below normal) as the vast majority of guidance keeps the main troughing and subsequent seasonably cold air to the north. Additionally, light precipitation chances are possible, starting Tuesday into mid week as an upper low tracks into the Upper Midwest. How far west this feature tracks will determine how much precip we get. Farther west and we lose the influence, farther east, and more moisture and synoptic forcing produce more in the way of scattered showers. Latest GEFS prob for 24 hour precip >0.1" is generally low (10-40%) with higher probs across Upper Michigan, perhaps indicating that a farther west trajectory, at least initially, may be the preferred solution.

Aviation

Issued at 630 PM EDT Fri Oct 23 2026

Expect most sites to fog back in again after sunset, or at least, within a few hours. CIU may be tricky given they have stayed IFR all day today; think there's a chance they could stay IFR cigs with little to no visby restrictions, at least initially. Most sites should drop to IFR or LIFR; least certainty in persistent LIFR visbys will be TVC/MBL where the fog could be a little more transient and cigs could rise to VFR at times with mid/high clouds slowly creeping in. Slow improvement to VFR again in the morning, closer to 14-17z. Winds tonight should remain light/vrb to slightly SE...but think offshore winds could develop again at APN, TVC, MBL in particular...and will pick up a bit more again from the S/SSE during the day.

Apx Watches

MI...None. MARINE...None.