Children across parts of the US Northeast will stay home on Monday as a powerful winter storm forced school closures and pushed offices and transit systems onto emergency schedules, with officials across the region warning of heavy snow, strong winds and dangerous travel conditions.The storm has already snarled travel along the East Coast from Washington to New England, with airlines canceling thousands of flights and officials urging people to stay off the roads. Winter weather in the Northeast may also slow the processing, transport and delivery of mail and packages, the US Postal Service said.For all the latest headlines follow our Google News channel online or via the app.New York City, the nation’s largest school district, ordered all public school buildings closed for a traditional snow day, with no remote instruction and all after-school programs canceled.Mayor Zohran Mamdani declared a state of emergency and ordered non-essential vehicles off city roads from Sunday night to