By mid-afternoon, the traffic circle in front of National Airport was glutted. The main highway to Maryland's oceanside towns was jammed. And back downtown, more and more secretaries were telling their bosses' callers: "He's [she's] gone for the day."

In short, Washingtonians began observing the Memorial Day weekend one day early with a time-honored ritual: The exodus. Spurred by the sunniest forecast in three weekends, mobs of vacationers were expected to descend on Ocean City, Virginia Beach, Rehobeth and other beach towns.

"It's that old, get-out-of-town policy that Washington always has," said Isaac Riggs, a City Cab taxi driver who knows the policy well, and who started ferrying holiday travelers to and from National Airport on Thursday. "What is it, Veteran's Day?" Riggs asked with a laugh, explaining he hadn't even had time to think about which holiday it was.

The weekend began with the hottest day of the year -- 87 degrees at mid-day -- and temperatures were expected to climb as high as 95 in the next three days, with little chance of rain.

The forecast delighted tourism officials like Ocean City's Gary Fisher, who predicted that sunshine and ocean breezes would lure 210,000 vacationers to the small Maryland town this weekend. Calls to more than a dozen hotels in the area failed to turn up a vacant room.

If the predictions hold true, the crowds in Ocean City would far exceed last year's turnout of 150,655, a figure calculated through "demo-flushing," or the measurement of how much water is flushed into city sewers. Virginia Beach officials said they, too, expect to fill all hotel rooms there.

For those who doubt that Washington is a transient city, yesterday's outbound traffic was a solid rebuttal. Dozens of travelers at National and at Union Station said they were headed for reunions with families and close friends, for weddings, for a quick taste of lives they left behind when they came to Washington.

To accommodate them, the Eastern Airlines shuttle to New York instituted what is known as the "quick turn" -- sending the planes back a little more quickly than normal after they arrive in New York -- and Amtrak officials added cars and extra trains, in addition to preparing for "standees," or passengers who stand part of the way from Washington to New York.

The trains and planes leaving Washington were at least 20 percent fuller than usual on the average, according to Amtrak and airline officials. Yesterday's run of the Southern Crescent, the train that winds through the Carolinas to Atlanta, was 90 percent booked as early as two weeks ago, a spokesman said.

The heavy holiday traffic has apparently inspired some zeal among local police forces and highway patrols. The Maryland State Police announced that their No. 1 priority is to "get the drunk driver off the road," according to spokesman Dan McCarthy. "These people think that just because they're away from home they can take a drink. They let their guard down."

McCarthy said the Maryland police are pulling out all the stops to catch speeders, too, drawing on radar, special computers, aerial patrols and unmarked police cars. Similarly, Dewey Beach, Del., has hired new officers and passed a list of new ordinances to limit public drinking, rowdiness, roaming pets and overzealous partying.

In Ocean City, police plan to cash in on the crowds to demonstrate their dissatisfaction with Mayor Harry Kelley for their proposed 8 percent pay raise. A boardwalk demonstration is planned for today, said Lt. Thomas Hodgson, head of the local Fraternal Order of Police.

Meanwhile, for the thousands left in Washington on the weekend honoring America's war dead, the outlook wasn't so grim. "I'll probably just smoke some dope, drink some beer and lay around the house," said a painter at a downtown construction project.

"Why should I leave?" asked the painter, who identified himself only as Lynn. "If everybody else is gone, it should be pretty nice around here."