A March storm, its eyes set on Washington, D.C., broke a snowfall record in Chicago and prompted the cancellation of more than 1,000 flights for Wednesday.
The system was expected to dump up at least 4 inches in Pittsburgh beginning Tuesday evening as it moved toward the District of Columbia and Baltimore, which braced for potentially significant accumulations, according to the National Weather Service.
Chicago's O'Hare International Airport had 6 inches of snow by Tuesday afternoon, besting a 1999 record for the date by 2.2 inches. It was the first 6-inch snowfall in the Windy City since the Groundhog Day blizzard of 2011, the National Weather Service said.
United Airlines said about 650 flights systemwide for Wednesday were canceled, most to and from Dulles International Airport near Washington.
"They will try to get as many aircraft out of Dulles today (Tuesday) as possible so they are not sitting in a snow storm," United spokeswoman Megan McCarthy told CNN. "This helps speed up the resumption of flights after the storm is passed. "
U.S. Airways reported 350 cancellations for Wednesday, and American Airlines called off 20 flights, down from 360 on Tuesday.
Southwest Airlines said it made no major adjustments for Wednesday. Delta Air Lines reported 120 cancellations on Tuesday.
Airlines advised passengers to check their flight status before heading to airports.
O'Hare canceled 900 flights on Tuesday and reported delays, while Chicago's other major airport, Midway, canceled 240 flights, according to the city's aviation department.
The storm deposited heavy snow on portions of the Ohio Valley and upper Midwest on Tuesday.
By midafternoon Tuesday, Lake City, Minnesota, had been blanketed with 11.5 inches of snow since Sunday morning. New Hampton, Iowa, had 8.6 inches and the level stood at 15 inches in Langdon, North Dakota.
The storm will intensify in the mid-Atlantic and parts of the Northeast on Wednesday, said CNN meteorologist Dave Hennen, with a rain-snow line from Washington to Boston. West of the line will see significant snowfall, particularly in the higher elevations of Virginia, Maryland and West Virginia.
One weather model predicts that the snow won't make it to the District of Columbia, said CNN meteorologist Ivan Cabrera. Another says Washington, Philadelphia and Boston could see a foot of snow.
The Washington suburb of Alexandria, Virginia, is prepared to deploy scores of trucks and snow plows, CNN's Weather Center said. Washington and Baltimore were under a winter storm warning Tuesday evening.
Arlington National Cemetery put in place inclement weather plans for Wednesday.
Amtrak said it expected to operate as scheduled Wednesday.
Interstate 95, connecting the capital with Philadelphia, could see heavy snow, the weather service warned.
Severe weather hit Gordon County, Georgia, on Tuesday afternoon, more than a month after a fierce system caused widespread damage in the area. Officials reported downed power lines, trees and damage to homes, said Cpl. Andrew York of the county's dispatch center.
About 10 homes were damaged, officials told CNN. No injuries have been reported so far.