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.
The wind has been north-northeast at Grand Haven, just strong enough for upwelling to occur. That was not been the case as of this morning at the other locations.
The South Haven buoy shows warm water down to about 40 feet. The water temp. at 36 feet at the buoy is 75.5°. At 43 feet, the water temp. is 58.6° and the water temp. at 56 feet is 46.6 feet. There’s some pretty cold water under the warm layer and anytime we get an offshore wind, we have a chance of upwelling.