A cold front moved farther south than anticipated Sunday, possibly taking with it much of the heavier snow forecast across the southern part of Pennsylvania into today, according to the National Weather Service.
Michael Kennedy, senior meteorologist at the weather center's Pittsburgh regional office, said the city will now probably receive about 4 inches of snow, far less than the 6 to 8 inches forecast earlier Sunday.
The weather service had been calling for 6 to 8 inches of snow across the southern quarter of the state, with lesser amounts farther north, except for higher elevations like the Laurel Mountains in Western Pennsylvania and the Poconos in the east. Now, most areas of the state could receive less than first predicted -- perhaps a little more than half, Mr. Kennedy said.
Despite that, a winter storm warning remained in effect across the state's southern counties, where it was expected to end at 1 p.m. today in the Philadelphia area.
"The trend has been to pull the front south, everything has just gone south," Mr. Kennedy said.
Dire forecasts from a few days ago, which predicted the storm would drop up to a foot of snow on some parts of southern Pennsylvania, were based on an expected one-two punch of snow, Mr. Kennedy said.
The first band arrived in Western Pennsylvania as predicted, though a bit sooner than originally thought, as snow began falling in Pittsburgh and surrounding areas about dawn Sunday. That system tapered off in the afternoon in Western Pennsylvania, and was expected to bring freezing rain turning to snow farther east as night fell.
A second band of snow was expected to hit Western Pennsylvania after midnight Sunday and dump more snow into this afternoon as it moved through Philadelphia. But it now appears that second system will move farther south, either missing southern Pennsylvania or dropping far less snow than originally predicted, Mr. Kennedy said.
"That's the main difference in how the forecast has really changed: The second wave is not going to be as significant as first thought," Mr. Kennedy said.
While Pittsburgh and southwestern Pennsylvania were spared, Washington, D.C., and other cities along the Atlantic coast braced for the storm, which was expected to dump up to a foot of snow on parts of the East Coast.
In the latest blast of a harsh winter, forecasters said, a layer of ice and 8 to 12 inches of snow was possible by the end of today in Washington and the mid-Atlantic region. Nearly a foot of snow was expected in parts of New Jersey.
"I'm over it," said Yasmon Hanks, 24, of Hampton, Va., echoing thoughts of many who have been cooped up inside this winter. Ms. Hanks visited the Martin Luther King Jr. Memorial on the National Mall in Washington with her husband, Lynwood, and two young children. She was happy to be able to get outside, she said, because "I thought it was going to be way worse."
Elsewhere on the Mall, joggers were out in shorts and T-shirts, families flew kites and tour guides led groups around landmarks such as the Washington Monument and Lincoln Memorial. Cherry blossom trees were growing new buds for the spring.
But much can change in a matter of hours. More snow and ice, perhaps as much as 2 inches falling every hour, were on the way ahead of today's morning commute. By late Sunday afternoon, rain was moved into the Washington area, temperatures dropped and the city had declared a snow emergency beginning early today.
On Sunday night, the federal government announced that its Washington-area offices will be closed today. The U.S. Office of Personnel Management, which sets leave policies for 300,000 federal workers in the region, says non-emergency personnel are granted excused absences for the day.
A round of wintry precipitation moved across much of the nation Sunday, bringing a mix of freezing rain and heavy snow to central and eastern states. Authorities warned of possible power outages and flight disruptions from weather that could affect millions.
Ken and Linda Mokry of Chicago took advantage of the 54-degree temperature in Washington to visit as many monuments as possible before the storm.
"You've got grass! We don't even have grass to see at home yet," Linda Mokry, 66, said. "We had our first snow right at the end of November ... and we've had snow ever since then, so we've had a long, long winter -- way too long."
Ken Mokry noticed the cherry blossom trees are forming tiny buds, making him wish spring would arrive sooner so they could see the trees blossom in pink and white.
"I hope this cold snap doesn't hurt anything," he said. "We were really hoping that we would be able to see them. Maybe next time."
Meanwhile, back in Pittsburgh, officials weren't taking chances.
Mayor Bill Peduto said crews were pretreating bridges, hills and curves on busy roads, and some 24 snow plows were waiting to be deployed if the second wave of snow makes that necessary.
"The forecast and the storm can change quickly and the Department of Public Works remains at the ready for a much larger snow event should the city receive one," Mr. Peduto said in a statement.
Philadelphia Mayor Michael Nutter declared a snow emergency as of 10 p.m. Sunday and canceled trash collection for today. Four to 8 inches of snow was forecast in and around the city.
The Southeastern Pennsylvania Transit Authority planned to begin alerting commuters to weather-related detours and delays of bus and train service by 4 a.m. today. And Amtrak announced it would operate on a modified snow schedule in the Northeast today, including fewer trains providing Keystone Service from Harrisburg through Philadelphia to New York City.