An intensifying weather system was expected to bring heavy snow and rain to parts of the US Midwest, the Appalachians and the Northeast on Tuesday, with more than 50 million Americans under a winter storm advisory.
Up to a foot of snow is forecast to fall across the Ohio Valley, Pennsylvania, upstate New York and into New England, with some areas getting up to an inch an hour, said Ashton Robinson Cook, a forecaster at the National Weather Service's Weather Prediction Center.
"If you don't have to be on the roads today, stay home," Cook said. "In areas of heavy snow, it's best not to travel. But if you have to go out, give yourself a lot of extra time."
Light to moderate snow was already falling from western Pennsylvania to central New England on Tuesday morning, he said, Reuters reported.
Hundreds of school districts from Cincinnati and western Pennsylvania to New Hampshire and Maine announced school closures or delayed openings.
The snow is expected to miss some areas east of Interstate 95, a major north-south corridor that hugs the Atlantic Coast, but residents can expect rain and freezing rain in Washington, New York City and Philadelphia, where temperatures will hover above the freezing point.
The weather in Boston might toggle between snow and rain later on Tuesday, Cook said.
In addition, some areas along the central and southern Appalachians will see freezing rain and slick roads.
The snowfall is likely to linger into early Wednesday for parts of New England.
