Lakes Superior and Lake Michigan are currently six degrees colder than last year. If the water continues to remain colder than normal, it could have an impact on Michigan’s winter in several ways.
The average water temperature on Lake Superior and Lake Michigan is currently colder than both last year and the long-term average.Mark Torregrossa
Currently Lake Superior has an average surface water temperature of 47.6 degrees. Last year on this date Lake Superior was at 53.7 degrees. The long-term average water temperature on Lake Superior for October 11 is 51.1 degrees.
So Lake Superior is 6.1 degrees colder than this time last year, and 3.5 degrees colder than normal.
Lake Michigan has an average surface water temperature of 56.0 degrees, while last year at this time it was 62.1 degrees. The long-term average water temperature on Lake Michigan for October 11 is 58.4 degrees.
Lake Michigan is also 6.1 degrees colder than this time last year, and 2.4 degrees colder than average.
Lake Huron is 5 degrees colder than last year, and only 1.5 degrees colder than normal.
This map above shows current surface water temperatures on the Great Lakes. Lake Superior has a large area of water with temperatures in the 40s.
He goes on to talk about the effects this might have on winter:
A warmer Lake Superior and Lake Michigan can really have a modifying effect on bitter cold temperatures. For example, in an early season cold outbreak, Green Bay, WI may have a temperature of 20 degrees. Traverse City, on our side of Lake Michigan, may hold in the mid 30s for temperatures. I usually figure there is a 10 to 20 degree warming effect from Lake Michigan, and also Lake Superior.
But if the lake temperatures continue at this colder pace, cold air will have an easier time moving into Michigan.
So the first impact of cold water could be earlier cold temperatures in November and December.
If the lakes continue through winter colder than normal, freezing over of the lakes would happen earlier.