Some cities in the path of a powerful winter storm headed for the mid-Atlantic could face even more snow than the two feet originally predicted, the National Weather Service said Friday.

The service, which issued updated blizzard warnings for several major cities along the East Coast, said that some parts of Virginia and Maryland could receive up to 39 inches of snow.

The updated forecasts were issued after the storm began dumping snow, sleet and freezing rain across the south overnight, including 9 inches of snow in 10 hours in one part of North Carolina.

The National Weather Service’s radar showed more precipitation falling across a large stretch of the southeast on Friday morning. The storm, which The Weather Channel is calling Winter Storm Jonas, was expected to pummel Washington, Baltimore and Philadelphia later today before arriving in New York, Long Island and southern New England early Saturday morning.

Watches, warnings or advisories were in effect in portions of 22 states from Arkansas to Massachusetts, including blizzard warnings for parts of Virginia, Maryland, Delaware, Pennsylvania, New Jersey and New York and the entire District of Columbia.

Residents in the storm’s path are encouraged to monitor their local weather forecasts.

The storm is expected to hit suburbs of Washington and Baltimore the hardest, with more than three feet of snow possible in those areas. Updated forecasts from the National Weather Service on Friday said 32 inches were possible in Washington and Baltimore could receive 30 inches.

If those totals materialize, they could break snowfall records for those cities.

The National Weather Service said the current three-day mark for Washington is 28 inches, and was set in January 1922. Baltimore had 26.8 inches of snow in three days in February 2003.

Many other cities were expecting double-digit totals.

Blizzard warnings issued for Philadelphia and New York said those cities could see up to 18 and 12 inches, respectively. One-to-two-foot totals were possible in large parts of the nation, and high winds were expected to make travel next-to impossible where the storm was at its worst.

In Washington and Baltimore, the service warned the storm could pack wind gusts of 60 mph in addition to the significant snowfall totals. The Washington Metropolitan Transit Authority is shutting down all subway and bus service on Saturday and Sunday, according to a news release.

All federal offices in the Washington area closed at noon Friday, according to the Office of Personnel Management.

Winds were expected to be lighter in Philadelphia, though the National Weather Service warned that 40 mph gusts and wet, heavy snow could still trigger power outages and block local roads.

While forecasts were saying the worst of the storm had yet to be seen, states from Arkansas to Virginia reported significant snowfall totals overnight. According to the National Weather Service, more than 5 inches of snow fell in Arkansas, Kentucky, Tennessee, Virginia and the Carolinas, including an overnight national high of 9 inches near Waynesville, North Carolina. Parts of Tennessee, Kentucky, and the Carolinas also saw measurable amounts of freezing rain.

Nearly 800 flights into or out of Charlotte Douglas International Airport had been cancelled as of 11:15 a.m. local time Friday morning, according to flight monitoring website FlightAware.com.

The airport is a major hub for American Airlines, which cancelled 789 flights across the country — about 24 percent of those it had scheduled, according to FlightAware. The airline was offering to waive rebooking fees for travelers going through many airports in the storm’s path.

Several states declared states of emergency or preparedness ahead of the storm, urging would-be travelers to stay off the roads and take necessary precautions to prepare for its potential impacts.

The states where the National Weather Service issued watches, warnings or advisories for the storm include Missouri, Arkansas, Louisiana, Illinois, Indiana, Kentucky, Tennessee, Alabama, Mississippi, Ohio, Pennsylvania, West Virginia, Virginia, North Carolina, South Carolina, Georgia, New York, New Jersey, Delaware, Connecticut, Rhode Island and Massachusetts.