Here’s water temperatures taken this morning: Ludington 67°, Mears 68°, Duck Lake 78°, Muskegon 76°, Grand Haven 52°, Port Sheldon (buoy) 74.5°, Holland 74°, S. Haven (buoy) 76.8°. Reeds Lake, an inland lake in East Grand Rapids) is at 81°. Pic. is from the buoy – you can see the cumulus clouds over the land and a few passing cirrus clouds. The lake has no effect on those higher level clouds.
What happened at Grand Haven? The water temperature there was 70° yesterday and it was 52° this morning. The answer is upwelling. Upwelling occurs when an offshore wind pushes the warm, surface water out toward the middle of the lake. Colder water moves to the surfact to take its place.