(Adds records, Arkansas roads, new quote)
By Ian Simpson
WASHINGTON, March 4 (Reuters) - The eastern and central United States were plunged into a deep freeze on Tuesday, with record low temperatures in the wake of a deadly storm expected to moderate in coming days.
The late-winter storm left behind frigid temperatures after pushing freezing rain, sleet and snow from the Mississippi Valley to the Atlantic and Gulf coasts.
Temperatures this week will be "below average east of the Rockies, as it has been for a good part of the winter," said Bob Oravec, a National Weather Service meteorologist in College Park, Maryland.
The icy front sent the mercury plunging to minus 1F (minus 18C) at Washington Dulles International Airport, tying a monthly record, the weather service said.
Baltimore; Scranton, Pennsylvania; Morgantown, West Virginia; Zanesville, Ohio; and Flint, Michigan all set or tied record lows.
The latest in a series of arctic weather systems to grip the winter-weary eastern United States, the cold front stretched from the Canadian border to southern Texas, where freezing rain was forecast.
Arkansas Governor Mike Beebe called National Guard units to help rescue motorists stranded on icy Interstate 40 in the eastern part of the state. The storm dumped snow, sleet and freezing rain on much of Arkansas late on Sunday, leaving it nearly paralyzed.
The severe cold and icy roads prompted the federal government to open its Washington offices with a two-hour delay after being closed on Monday. Schools, colleges and local governments throughout the region were closed or opening late.
The cold is expected gradually to lift to normal March temperatures this week, first in the U.S. midsection and then in eastern states, Oravec said.
The storm was blamed for at least six deaths, most of them from traffic accidents on slippery roads. A woman in Bowie, Maryland, died on Monday from a likely heart attack after shoveling snow, a spokesman for the Prince George's County fire department said.
About 730 U.S. flights were canceled and about 2,700 delayed on Tuesday in the wake of the bad weather, according to airline tracking site FlightAware.com. About 8,000 flights were canceled or delayed on Monday. (Additional reporting by Suzi Parker in Little Rock; Editing by Scott Malone, Bernadette Baum and Nick Zieminski)