Lake-effect snow can dump heavy snow on communities: We explain how, where it forms
A major lake-effect snowstorm brought record-breaking amounts of snow to the Great Lakes region, especially areas downwind of Lakes Erie and Ontario. The storm caused multiple road closures, including Interstates 90 and 86, along with power outages, school and business closures, and other travel delays.
Some areas of New York state had around 5 feet of snow over the past week, while parts of Pennsylvania, Ohio and Michigan had 3 feet or more. Erie, Pennsylvania, experienced its snowiest day on record Friday with 22.6 inches of snow, beating its previous record of 21.8 inches in 2017.
Into the first week of December, the coldest air of the season will continue to move southward across the Midwest, Ohio Valley, and Northeast, according to AccuWeather.
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How weather patterns guide lake-effect snow to Great Lakes region
Large-scale weather and climate patterns, guided, in part, by the jet stream, play a major role in the storms and cold outbreaks that define winter weather across the Great Lakes.
How lake-effect snow forms
Lake-effect snow, which can last for only a few minutes to several days, develops from narrow bands of clouds that form when cold, dry arctic air passes over a large, relatively mild lake.
As the cold air passes over the unfrozen "warm" waters of the Great Lakes, warmth and moisture are transferred into the lowest portion of the atmosphere, the National Weather Service says. The air rises, and clouds form and grow into narrow bands that produce 2 to 3 inches of snow an hour or more.
These snows typically occur only in the fall or early winter, before the lakes freeze over. (But if the lakes don't freeze, lake-effect snow can occur throughout the winter and into the spring.)
This story was updated to add new information.
CONTRIBUTING John Bacon and Doyle Rice
SOURCE NOAA, National Weather Service, University Corporation for Atmospheric Research and AccuWeather