Ag Weather Forum

A blast of cooler air and a storm system will move into the Great Lakes and Ohio Valley this weekend. The cooler air could lead to widespread snowfall with lake-effect snow likely for areas downwind of the Great Lakes as gusty northwest winds sweep across the warmer air of the lakes.

The lake-effect snow could lead to measurable snowfall across much of Michigan, northern Indiana and Ohio. Lake-effect snow becomes more frequent in the late fall and winter across the Great Lakes because of cool air moving across the warmer lakes.

For lake-effect snow to develop, cooler air from Canada will drift south across the open waters of the Great Lakes. The water temperatures are often higher than the air temperature and any warmth and moisture from the lakes can get transported to the lower parts of the atmosphere. The warm, moist air will eventually rise and condense into clouds that can produce snow.

As of Nov. 3, water temperatures across the Great Lakes spanned between 45-60 degrees Fahrenheit. Some of the warmest waters are located across southern Lake Michigan and Lake Erie. Lake Superior is the coolest with water temperatures generally below 55 degrees F.

This weekend, cooler air from Canada is expected to drift over the lakes. You can read more about how this cooler airmass develops here: https://www.dtnpf.com/…. Saturday morning's low temperatures could approach the 20s F in Michigan's Upper Peninsula. Mid 30s F are possible across central Michigan. By Sunday morning, low temperatures could approach the low to mid 30s F for northern Illinois with widespread low to mid 20s for portions of Wisconsin, northern Iowa and Minnesota. One of the main ingredients for lake-effect snow will be present this weekend with the cooler air sweeping across the warmer lake water.

Model guidance has now been hinting at a widespread lake-effect snow event developing across the Great Lakes since earlier this week. Some of the heaviest lake-effect snow bands could develop in western Michigan, northern Indiana and northeast Ohio.

A low-pressure system is expected to move across the Great Lakes and northern Ohio Valley Saturday night through Sunday morning. Cooler air on the northern side of the low could lead to spotty snow showers in southern Minnesota, southern Wisconsin, and northern Iowa before becoming more widespread across lower Michigan. Scattered rain showers are expected farther south.

After the low-pressure system passes to the east, cooler air from Canada and gusty northwest winds will begin producing lake-effect snow showers across the Great Lakes later Sunday into Monday. The northwest winds will aid in producing bands of lake-effect snow as it blows cooler air across the bodies of water and this allows the warm, moist lake air to condense into clouds and eventually produce snow.

From Nov. 8-10, a swath of 4-8 inches of snow could fall across the lower half of Michigan. On the east and south sides of Lake Michigan as well as the south side of Lake Erie, some of the lake-effect snow showers could lead to isolated snowfall totals exceeding 6-10 inches in some spots. However, the exact spots where heavier snow will fall remain uncertain as models continue to resolve the exact track of this weekend's low-pressure system. Slight shifts in the center of the low could cause heavier snow to shift north or south.

To find more weather conditions and your local forecast from DTN, head over to https://www.dtnpf.com/….

Teresa Wells can be reached at teresa.wells@dtn.com

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