Marine Weather and Tide Forecast for Bay Port, MI

DISCUSSION
Issued at 1219 AM EDT Thu Apr 16 2026

Pattern Synopsis:

Active southern stream pattern to carry through Friday, albeit with some caveats for northern Michigan. Strongest low level jet dynamics will remain downstate, suppressing the concentration of instability and moisture pooling downstate and points south tonight. Well- defined convectively driven shortwave currently across western Iowa will ride the corridor of SWerly subtropical jet flow, with associated surface low pressure riding the stalled frontal boundary draped across Michigan. Result will be a return of scattered thunderstorms into the day Thursday, particularly across northern lower Michigan. In the wake of this shortwave, a brief window of ridging folds overhead as surface high pressure and subsidence aloft passes over the region, bringing a brief reprieve. This will be short lived as a potent northern stream trough currently over the Pacific northwest will make an eastward advance, forcing ridging and surface high pressure east of the Great Lakes, resulting in the return of more rain and thunder Friday night into Saturday. The backside of this system will deliver a sharply colder airmass with a polar surface high building to start next week, with a seasonable moderating trend commencing with time.

Details:

Current boundary position generally from Frankfort to Rogers City, with little northward advancement expected over the next 36 hours.
This does induce some changes from previous forecast cycles, with deeper moisture content overlapping instability suppressed south.
There is potential now for far northern areas of northern lower to completely miss out on rain showers through Friday morning, which is some welcome news for flooding impacts. Light rain showers set to prevail for M-32 and south the rest of tonight and into Thursday.
Though if the southern trend in guidance continues, this line may be suppressed as far south as M-72. Lack of instability will limit thunder potential for most... but south of M-55, just enough instability may be present to drive some convection and thus higher rainfall rates, especially closer to Saginaw Bay. As far as additional rainfall through Friday morning is concerned... looking at a general 0.10" or less north of M-72. For those south of M-72, looking more like 0.25-0.50", with localized 0.75"+. The area with the best shot to see upwards of 1.50" of rain is Gladwin and Arenac counties... though that may also get suppressed to the US 10 corridor. So still some monitoring to be had regarding ongoing flooding.

The other story tonight will be the prevalence of fog across the region away from the steadier rain to the south. This in itself may limit instability for this afternoon, especially north of the frontal boundary
Otherwise
a break in the action Friday as high pressure moves overhead.

Next item of interest will be the system passing through Friday night into Saturday. Occluding and closing off surface low moving eastward across the US / Canada border to our NW will lead to the reinvigoration of the low level jet into the Great Lakes, with another Gulf moisture tap ahead of an advancing cold / occluded frontal boundary. Global models are admittedly struggling with this process... and pattern recognition says this does favor showers and thunderstorms with heavier rainfall across the region. Will have to see how transient this is... orientation of the boundary parallel to the strongest 850mb flow makes me skiddish on saying this will be a fully transient feature. And with potential for heavy rain producing thunderstorms, this needs to be watched closely. Overall, most places probably see an additional 0.25-0.75" of rain Friday night through Saturday night, with localized totals exceeding 1.50". The other issue this system presents is that this time, rainfall may actually make it into eastern upper, a region still nursing a surprisingly resilient snowpack. So hydro concerns may quickly ramp up for our Yooper friends. Beyond this system, a pretty stellar cold intrusion makes an appearance into Sunday with highs falling back into the 30s for the most part... with snow shower chances. Heading into next week, we do slowly moderate back to more seasonable temperatures.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
Issued at 656 AM EDT Thu Apr 16 2026

LIFR grunge continues this morning with light/vrb winds and fog.
Scattered rain showers possible thru midday esp for TVC, mbL, APN with slight improvements to IFR possible as winds turn subtly N/NW this afternoon. Lake breezes possible at APN/TVC. Expect cigs to SCT at CIU and PLN around 16-19z with largely MVFR-VFR conditions this afternoon, and closer to 19-21z for TVC/APN; will be slowest to reach mbL. Things likely to fog in to LIFR conditions again tonight as winds go light/vrb again. Winds will eventually turn around to the S/SE and increase to 5-10kts toward 12z.

APX WATCHES/WARNINGS/ADVISORIES
MI...Flood Watch through Sunday morning for MIZ086>088-095-096.
Dense Fog Advisory until 10 AM EDT this morning for MIZ086>088- 095>097.
MARINE...None.