There was a classic case of upwelling along the east shore of Lake Michigan from Thursday to Friday. Look at what happened to the water temperature at Grand Haven State Park! The water temperature there on Thursday was a pleasant 70°. Just 24 hours later, the water temperature had fallen to 45° – a drop of 25°. Water that cold can be dangerous. You might not know the water is that cold. It’s can be tempting to jump off a pier or jump from a boat. If you jump into water that cold, it’s quite a shock to your body. It’s also easy to get hypothermia.
Upwelling occurs when an offshore wind (NNE, NE, E, SE) blows the surface water away from the nearshore area, allowing colder water to rise from the bottom of the lake to the surface. This process can happen quickly. Even after a warmer than average summer in mid August, we can see 45-degree water come to shoreline areas. The water will warm up again when the wind goes west and brings back the warmer surface water…though it’ll be tough to recover back to the mid 70s.
SATURDAY AM Water Temperatures : Ludington 70°, Duck Lake S.P. 56°, Muskegon S.P. 60°, Grand Haven 56° (up 11° from Friday), Holland S.P. 69°, Saugatuck Oval Beach 48°, S. Haven buoy 59°. Reeds Lake in East Gr. Rapids was 76° – that will likely fall a degree or two this (Sat.) afternoon with the rain and cool temps.
Upwelling can be good for Lake Michigan fishing. The cold water can bring the fish back to the shore.
The high temperature Saturday 62°. The last time we had a day with a high temperature of 62° was May 23rd. Saturday we had the coolest high temperature in August since 2015.