Posted: Aug 4, 2020 / 12:48 PM EDTUpdated: Aug 4, 2020 / 03:18 PM EDT
The water temperature of Lake Michigan along the Michigan shore has taken tumble! Check out the water temperatures this morning at the Lake Michigan beaches and buoys: Ludington 49°, Mears 53°, Hoffmaster S.P. 54°, Holland St. Park 50°, Port Sheldon buoy 54°, Saugatuck 61°, South Haven buoy 56°. What happened??!! The answer is upwelling.
The prevailing wind in the summer in West Michigan is west to southwest. It’s seldom that we have a north, northeast or east wind for a longer period of time. That allows the surface water to warm up. But…when we do get a prolonged period of northeast or east winds…we can get upwelling. Warmer surface water is pushed toward the Wisconsin and Illinois shores and colder water rises to the surface from below. Here’s a graph of the surface water temperature at the South Haven buoy over the past several days:
At the end of last week, the surface water temperature at the South Haven buoy was running 75° – 77°. It’s been a warmer than average summer and a sunnier than average summer. We’ve also had relatively light winds. So, the surface water was able to really warm up.
Now, we’ve had a period of north-northeast winds and that has pushed the warmer surface water away from shore and toward the other side of the lake. The water temperature today is 73° in Chicago and 72° at Michigan City, Indiana.
When the wind goes back to the west, the warmer surface water will return to the Michigan shore. In the meantime, if you want to go swimming, you might want to choose a warmer, inland lake. The water temperature of Reeds Lake was 78° at midday. That may go down a few degrees with the cooler air, but you won’t see temperatures crash like they have at Lake Michigan.
Here’s a picture of the South Pier (actually a breakwater) today (Tuesday). There are a lot of fishermen on the pier. That’s because fish will come close to shore when the water is cold. There’s also fewer people at the beach and fewer still actually in the water.
Here’s a picture of the North Pier at South Haven. Note that there is no one on the pier with the cold waves crashing over the pier. You can see cumulus clouds over the land, but not over the colder water.
At noon, the air temperature was 67° in Grand Rapids, but only 57° at the Muskegon Beach. This is the coolest 4-day period since June 12-15. Over the first 3 days of August, Grand Rapids had 27% of possible sunshine and that’s the cloudiest period of weather since May 17-19.
Here’s a look at the water temperatures of Lake Michigan, with the colder water near the Michigan shore.