Brace yourself, Baltimore. The storm that was coming — then wasn't — is back to full strength, heading our way with a major coating of snow predicted for Sunday and blizzard-like conditions in the Northeast.
Meteorologists anticipate between six and 10 inches of snow falling across the region before the system passes, and the storm could curtail shopping for the day after Christmas if families hunker in their homes and delay gift returns and new purchases until skies clear.
Gov. Martin O'Malley declared a state of emergency late Saturday night in advance of the storm, a move that allowed him to activate National Guard units if needed.
Those units "are prepared to assist local emergency managers and first responders around the state," the governor said in a statement.
Some organizations late Saturday began canceling events for Sunday in anticipation of the storm. The Maryland Zoo in Baltimore said it would be closed to the public Sunday due to the weather forecast.
Jared Klein, a meteorologist with the National Weather Service, said the metropolitan region could expect winds of 15 to 25 miles an hour starting Sunday afternoon and evening, with sharper gusts up to 40 miles an hour by night.
"You don't want to go north," said Andy Woodcock, also a meteorologist with the National Weather Service.
Interstate 95 could serve as a divide, he said, with areas east of the highway getting more snow and areas west seeing less. As the storm heads north, some projections showed the New York City region getting about a foot, with wind-whipped precipitation holding the potential to shut down highways.
Some flakes — part of a different event — began falling on Christmas morning, dusting cars and shrubs. By Saturday afternoon, the region had experienced a light covering of snow.
But the real action is to start Sunday morning.
The weather service issued a winter storm warning for central Maryland from 4 a.m. Sunday through 6 a.m. Monday.
With the plans of untold numbers of motorists returning from holiday visits hanging in the balance, transportation officials across the region are preparing their crews.
Maryland's State Highway Administration had been preparing for the possibility of snow as early as Tuesday, when equipment was tested and stockpiles of gas and salt were evaluated.
"We want to get ahead of this the best we can," said Kellie Boulware, a highway department spokeswoman.
The agency was closely monitoring weather reports to determine how to deploy resources, and was urging motorists to delay their travel plans in the case of significant snowfall.
Airline passengers across the Mid-Atlantic should prepare for cancellations Sunday, according to Accuweather.com. The best time to travel to and from southern New England Sunday should be Sunday morning, since conditions are expected to deteriorate later in the day.
Continental Airlines announced Saturday evening that it was canceling 250 flights departing from Newark Liberty International Airport outside New York City.
Continental and United Airlines issued a news release on Saturday saying that weather conditions would likely force delays and cancellations at United's hub at Washington Dulles International Airport and at other northeastern airports between Saturday and Monday. Those carriers and others are waiving fees for one-time changes in affected areas and urged passengers to make changes through their web sites.
As the storm moved through the South, airlines canceled hundreds of flights, including at the busy Hartsfield-Jackson Atlanta International Airport, a hub for Delta. Delta said it would decide on possible additional Sunday cancellations later.
An airline spokesman said people with travel plans through Baltimore, Washington, Boston, New York and Newark, N.J., on Sunday or Monday can change flights without a penalty as long as they travel by Dec. 29.
Jonathan Dean, a spokesman for Baltimore-Washington International Thurgood Marshall Airport, said that no schedule changes had been made Saturday afternoon, but he warned travelers to check with their airlines before traveling Sunday.
Travelers "should check with their airline to give them the most updated information," he said. Changes often "depend on the airline and its operation," Dean said, saying that the storm could affect flights in a number of cities, further causing delays.
Amtrak canceled some of its Virginia routes for the weekend and into Monday morning, and Cliff Cole, an Amtrak spokesperson, said the company will continue to monitor the snowfall throughout the day on Sunday to determine train schedules.
"I'm fairly certain there will be other adjustments we will have to make," Cole said. The Virginia cancellations were "the first round," he said.
In the Washington area, the Metro subway system had workers on standby to remove snow from rail station entrances and platforms if necessary.
Metro says that it will operate a very close to normal rail schedule in snowfall of up to six inches. But if snow reaches a depth of eight inches Metro may suspend rail service above ground.
People throughout the region had been bracing for a storm, but the path had been unpredictable for the past week.
As recently as Friday, prognosticators were saying that the region would get no snow. But the models began to shift late Friday and into Saturday. So what looked like a total miss suddenly became a prediction of several inches, conjuring memories of a year ago, when a major December storm was followed by historic twin blizzards in February.
The storm that started in California blanketed sections of the Midwest and hampered motorists there on Friday, before dipping south. Winter weather advisories were in effect Saturday afternoon from western Tennessee to the Carolinas and from West Virginia to Alabama.
In Baltimore, Miriam Havard looked out her window Saturday morning and knew that ominous weather was on the horizon.
"I kept hearing that the weather was going to be bad," she said. "I looked outside and said, 'That's a sky that says storm to me.'"
Havard, a soup kitchen volunteer, ventured from her apartment building near the Safeway supermarket in Charles Village for some grocery staples — just in case.
"I didn't want to get snowed in without chocolate," she said with a laugh. "Chocolate, bread, and paper towels were the real important things to me."
The threat of snow didn't appear to affect Landmark Theatres Harbor East, which was bustling for most of the day.
"We've heard a lot of different things," said manager Jamie Guntner, who balanced monitoring weather reports with making sure the business ran smoothly on its busiest day of the year. "Before there was a 50 percent chance of snow. Now they're saying it is going to snow tonight. We'll be open no matter what."
After last winter's record-breaking storms, Guntner said she and her staff was more than ready to deal with a couple of inches.
"Harbor East does a good job making sure that the snow is cleared, but we have salt and the ushers will mop up the floors if things get wet and messy," she said.
Ginny Rajnes, a Locust Point resident who works in marketing, was unaffected when she learned about the possibility of snow. She and her family, who were visiting from out of town, had just finished watching "The King's Speech" and were heading home to eat Christmas dinner.
"I'm not at all worried," she said.
Her mother, Elaine Rajnes, chipped in: "She has the shovel and the salt ready."
Mellissa Lozano, a Baltimore resident who was also at the theatre with her out-of-town relatives, worried that the snow might affect her plans Monday to visit museums in Washington.
Ann Miller, a Philadelphia resident who was visited family in her native Baltimore, originally planned to watch two movies. But the news of the looming snow appeared to throw a hiccup in her plans.
"Now I'm only going to see one movie," she said, as she waited in for her film to begin. "I don't want to get caught in the snow."
Guntner, who planned to monitor weather reports more frequently as the evening progressed, added: "A little bit of snow is okay. Just as long as no one gets hurt, and the guests are happy, I'm happy."
Baltimore Sun reporters Yeganeh June Torbati and Jessica K. Anderson and the Associated Press contributed to this article.