Marine Weather and Tide Forecast for Mackinac Island, MI

DISCUSSION
Issued at 159 PM EDT Wed Jul 8 2026

Deep moisture will overspread northern Michigan tonight into Thursday as several mid level shortwaves ride along a quasi- stationary frontal boundary layed out across central Wisconsin into northern Michigan. Enhanced low level convergence along this boundary will provide the potential for locally heavy rains. The front will eventually sag south of the area, setting northern Michigan up for a mainly dry weekend. Significant heat and humidity build early next week as high amplitude ridging strengthens over the center of the CONUS.

A myriad of model solutions tonight, largely influenced by convective evolution during the day and residual boundaries.
Tonight likely features the best combination of moisture and forcing for heavy rain and possibly localized flooding with PWATs surging toward 200% of normal. Forecast soundings show deep moisture through the column, warm layer cloud depths to 12k+ and skinny CAPE - overall a favorable look for heavy rain.
The activity tonight will be a very efficient heavy rain producer and we will have to watch for possible flooding in any areas with antecedent high soil moistures from recent rains (Leelanau County through the Tip of the Mitt). Later tonight into Thursday, a surface low will ride along the boundary draped across the area, further enhancing rain potential and slowing any southward drift of the front. The shower and storm chances continue on Thursday, with a slow southward shift in focus as the aforementioned boundary slowly sinks southward. Although only marginal instability through Thursday, a few stronger storms will be possible with gusty winds the main threat (due to precipitation loading).

A nice summer weekend shaping up for northern Michigan with mainly dry conditions and highs in the 80s. Generally comfortable humidity levels as well, with a slight rise in surface dewpoints by Sunday as moisture begins to work back into the Great Lakes. A washed out frontal boundary on Sunday could be the focusing mechanism for a shower or storm but most of that appears to remain north of our area. More significant heat returns early next week as a large amplitude ridge builds to our west. Rising humidity will accompany the heat, with heat indices likely pushing well into the 90s (or higher). Some of the warmest temperatures for the week may occur early in the week, where the mid level cap will be strongest and convective development limited (much like occurred a week ago). The cap breaks down by midweek and "ridge runner" convective complexes will be possible across the Great Lakes.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
Issued at 159 PM EDT Wed Jul 8 2026

Afternoon cu developing with cloud bases near 3-5kft, with some SHRA expected, esp for CIU/PLN and possibly TVC...expect SHRA/TSRA will pop up this afternoon, esp near APN after 21z.
Visbys likely VFR/MVFR but could go lower in showers/storms, esp tonight. Currently expect a period of IFR/LIFR and DZ/BR across CIU/PLN as a low pressure crosses the Tip of the Mitt, but could break up toward morning instead. Best shot at widespread RA/TSRA will be this evening -- watch for storms over WI to track into TVC/MBL... and think another shot at RA/TSRA toward 9-12z as low strengthens. Winds light and generally vrb; lake breezes this afternoon and land breezes possible tonight at coastal sites, turning more N for CIU/PLN and E for APN toward morning.



APX WATCHES/WARNINGS/ADVISORIES
MI...None.
MARINE...None.