Severe weather is expected to stretch from coast to coast Tuesday, with more than 100 million people under some sort of winter watch, warning or advisory; nearly 25 million people under threat of flooding; and more snow on the way in Seattle.
Up to 4 inches of snow, followed by a coating of ice, was expected throughout the Northeast -- including in Philadelphia, New York and Boston -- into the morning on Tuesday, before turning into rain.
More than 600 flights into and out of John F. Kennedy and LaGuardia international airports in New York had been canceled as of Tuesday morning, according to FlightAware. More than 1,480 flights were canceled across the country.
A winter storm watch is in effect throughout Massachusetts through Tuesday night. Tuesday's evening commute could be a tough one for Bostoners, as the few morning inches of snow turn into heavy sleet and eventually rain.
Cities including Des Moines, Chicago, Detroit and Buffalo could also see dangerous travel conditions as a band of sleet and ice is expected to cover roadways Tuesday.
A band of heavy snow also will set in Northern Iowa, Wisconsin and Michigan, where residents could shovel away up to 12 inches of snow Tuesday morning.
Ohio Valley flood threat
Widespread rain will continue to soak the Ohio Valley from Arkansas to Ohio on Tuesday, bringing as much as 4 inches of rain.
Nearly 25 million are under a flood or flash flood watch. Cities including Nashville, Little Rock, Louisville, Lexington and Cincinnati could see flooding.
More snow in Seattle
Seattle, despite breaking its snowfall record for February not even halfway into the month, hasn't seen the end of its white days. A few inches of snow are possible around the area Tuesday, with heavy snowfall expected just west of town.
Further south, the Sierra Nevada mountain tops in California can expect to continue to be pounded with snow over the next few days. Extreme winds are also forecast in the Sierra, with gusts of more than 100 mph.