textproduct: Gaylord

KEY MESSAGES

- Shower/thunderstorm chances along a passing cold front Saturday

- Cooler with some small rain chances Sunday

- More substantial rain event arrives Monday night/Tuesday; heavy rainfall potential.

DISCUSSION

Issued at 309 PM EDT Fri Sep 11 2026

Primary Forecast Concerns:

Shower/thunderstorm chances along a passing cold front Saturday: Surface cold front lying across northwest Ontario/northwest Minnesota/southeast North Dakota at early afternoon is forecast to propagate east through tonight...into the upper Great Lakes Saturday morning...and across northern Michigan Saturday afternoon/evening. Narrow theta-e ridge runs ahead of the front...which will be the source for low level moisture/instability for the front to work with. Not a lot of moisture in a relative sense (dry above 700mb) so raises some questions as to precipitation coverage being limited by dry air entrainment into updrafts that probably won't be all that robust to begin with (there may be some low clouds (high based Sc) at the start of the day to inhibit heating/destabilization). Overall a light precipitation event at best at this point...minimal probabilities for rainfall exceeding 0.25 inch during the day Saturday. Rain chances expected to wind down from west to east by Saturday evening.

Cooler with some small rain chances Sunday: Will be watching a short wave trough dig into the Lake Superior basin Sunday along with an associated jet streak. Can't rule out a few light showers as this feature passes through mainly Sunday afternoon/evening but this also looks pretty minimal. After highs into the 70s and possibly some lower 80s Saturday...cold advection in the wake of Saturday's frontal passage expected to drops highs down into the 60s (lower 70s in downslope areas adjacent to Saginaw Bay).

More substantial rain event arrives Monday night/Tuesday; heavy rainfall potential: Monday itself is expected to be dry as a short wave ridge and surface high pressure cross the Great Lakes. In the wake of this ridging deep layer southwest flow develops Monday night...with a strong low level jet ahead of a cold front that will make slow inroads into the upper Lakes as it parallels the flow aloft. Thermal/moisture advection ahead of this front expected to bring rain and some embedded thunderstorms back into northern Michigan Monday night and into Tuesday...though may see a drying trend Tuesday afternoon especially the farther north you go. Given the deep layer unidirectional flow QPF potential will be much greater than anything that falls this weekend: 1 inch/24h rainfall probabilities (ending 0000Z Wednesday exceed 50 percent north of the M-72 corridor...with probabilities around 25 percent of exceeding 2 inches/24 hours across eastern Upper. Thus the slight Excessive Rainfall Risk across Upper Michigan for Monday night. Things to watch for beyond Tuesday will be how far front the cold front can sink...if it lingers closer to the US-10 corridor will be facing a more substantial heavy rain threat across the southern portion of the forecast area.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1208 PM EDT Fri Sep 11 2026

VFR conditions are expected to continue across northern Michigan for the vast majority of the issuance period. High clouds will begin to spread over the area later this evening and tonight ahead of an approaching cold front. CIGs may lower close to MVFR thresholds by 18Z Saturday, especially across the eastern U.P., but thought is that best chances for MVFR CIGs will hold off until after the end of the issuance period. Otherwise, southwest winds around 5-10 kts will gradually turn to south winds this evening, and then back to southwest Saturday morning ahead of the aforementioned front. Gusts to 15-25 kts will be possible by late morning/early afternoon on Saturday.

APX WATCHES/WARNINGS/ADVISORIES

MI...Beach Hazards Statement from Saturday morning through Saturday evening for MIZ025-031-096-098. Beach Hazards Statement through Saturday evening for MIZ095. MARINE...Small Craft Advisory from noon to 8 PM EDT Saturday for LHZ345>347. Small Craft Advisory from 8 AM to 8 PM EDT Saturday for LMZ323- 342-344>346. Small Craft Advisory until 8 PM EDT Saturday for LMZ341.