A large lake like one of the Great Lakes can really change the weather. The picture above is the South Haven Beach late this afternoon. It was cloudy, snowing and 21.2°. The wind was northwest at 27 mph with a peak gust of 37 mph.
This picture was taken just after sunset in Chicago. Here, the sky was clear and the temperature was 12°.
Here’s sunset Thu. evening at Alpena MI. Here the NNW wind didn’t cross enough open water (the North Channel is ice-covered) to generate lake-effect clouds and snow.
The temperature at 5 pm CST was 9° at both Milwaukee and Green Bay, where skies were clear to partly cloudy. Lake Michigan had a water temperature today of 33.3° at Holland MI.
So, Lake Michigan warmed the air by a good 10° – it also generated lake-effect clouds and lake-effect snow showers.
Here’s a satellite pic. of Lake Superior taken Thu. PM. As the cold air from Canada crossed Lake Superior, it picked up moisture. The very cold air (near 0°F) also warmed a little over the open water and the air lifted to produce lake-effect clouds, which tended to form “streets”. You can see lake-effect clouds forming over northern Lake Michigan, too. Most of Lake Superior is open water. There is ice in some of the bays (Black Bay, Nipigon Bay, Duluth Harbor and Chequamegon Bay in Wisconsin). You can see Isle Royale and Michipicoten Island toward the upper right.