Marine Weather and Tide Forecast for Grand Rapids, MI

DISCUSSION
Issued at 328 AM EDT Sat Apr 19 2025

Amplified longwave pattern across the CONUS continues over the weekend. The longwave trough that brought the recent bout of storms is not finished, as the southern end has cut off and makes a run at Lower Michigan later this weekend.

Showers move southeast this morning then fair and cooler behind the cold front with temperatures steady or falling today. The fair weather lasts through Sunday morning then moisture returns as the cut off low across the Southern Plans moves northeast with rain expected by Sunday afternoon through Sunday night. Instability is limited but some elevated thunderstorms are possible at times late Sunday.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
Issued at 144 AM EDT Sat Apr 19 2025

The initial focus is on convection for the first few hours, and then shifts to low clouds for much of the day.

Scattered to numerous showers and thunderstorms are in place SE of the KMKG terminal. These are all ahead of the cold front dropping through the area. There is a good chance that each terminal SE of KMKG will see at least VCTS, if not a full tsra. They will gradually push out of the area, most likely by 10z.

Immediately behind the front, the winds will shift to become from the WNW, and low clouds will arrive at each terminal. Model guidance indicates that KMKG will see BR also, likely due to the proximity of Lake Michigan. These low clouds will slowly improve through the day as they lift, and eventually scatter out late this afternoon and this evening.

MARINE
Issued at 328 AM EDT Sat Apr 19 2025

The SCA is cancelled, Winds and waves will diminish today then increase Sunday night into Monday and a SCA will be needed.

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