Tropical Storm Dean, whose heavy rain and winds have churned the Atlantic Ocean for several days, could generate downpours and wind gusts up to 30 miles an hour for the Washington area today.

But the National Weather Service said its forecast could change, given the storm's erratic nature. At 9 last night, the storm was centered 110 miles southeast of Virginia Beach.

Gale warnings were issued along the Atlantic seaboard from Long Island, N.Y., to Cape Lookout, N.C., yesterday and coastal residents were advised to tie down mobile homes, campers and other loose belongings in anticipation of winds close to 60 miles per hour. Officials at military bases in Virginia took steps to protect aircraft and ships from the storm's onslaught.

Described as a strong nor'easter rather than a typical tropical storm, Dean picked up speed as it moved toward the coast, whipping up 40 mile-an-hour winds near the Virginia-North Carolina border. Small craft advisories were posted from Provincetown, Mass., to Jupiter Inlet, Fla.

Weather officials said the combination of the storm and high pressure over New England caused a broad range of gales between Dean and the coast yesterday.

Flooding and power outages were reported along North Carolina's Outer Banks, with water reported over one foot deep on some parts on the coastal highway. Ocean City, Maryland's coastal resort, also got an early taste of the storm, with winds gusting to 30 miles an hour, tides one foot over normal and minor street flooding.

The Norfolk Naval Station, the largest naval base in the world, was on "hurricane condition two" under which ships at pier were prepared to leave in four hours. At the Langley Air Force Base in Hampton, Va., about 50 jets were relocated to inland bases.

Weather Service officials warned of possible beach erosion along the coast, but said it was too early to predict the full impact of the storm.