Despite long lines and early closings at filling stations, gasoline appeared to be somewhat easier to find yesterday than had been expected as the Washington area entered the Fourth of July holiday week.

Today, gas is expected to be considerably scarcer, according to energy officials and gas dealers.

Nevertheless, Maryland and the District of Columbia have taken steps to assure motorists that at least 26 service station will be open this morning in the District and Prince George's and Montgomery counties [see box on Page B3]. Prospects for fuel in northern Virgina appear bleaker.

"I don't know of any [filling station] that will be open", said Roy Page, president of the Northern Virginia chapter of the Virginia Gasoline Retailers Association. Some officials previously estimated that about 3 percent of Northern Virginia's gas stations may open at some point today, but no list of such stations has been made public.

The uncertainties of the fuel shortage left a deepening imprint on the lives of Washingtonians and tourists yesterday, as holiday outings declined and many motorists began their week-end in blocks-long gasoline lines. Tourism was reported to have dropped off at such vacation spots as the Eastern Shore, Colonial Williamsburg and the Kings Dominion amusement park.

Even Angelo's Pizza on Arlington County's normally heavily traveled Wilson Boulevard has been jolted by the gas crunch. "Fast-food business in the whole area has gone down 19 percent", said Angelo's manager, Charles Abdo. He pointed to the only four customers in his restaurant. "We can see it [the decline] right now."

Clear evidence of at least a slight easing of fuel scarcities yesterday was provided by Prince George's Country officals.

Steve Hannestad, deputy director of the country's emergency preparedness office, noted that his office listed 65 service stations open yesterday as compared with 30 on the previous Saturday. In addition, he said, three stations agreed to stay open after 6.p.m for the first time in recent weeks. "Today started off with much better gas availability than last weekend," Hannestad said.

D.C. Energy Unit director Chuck Clinton and Northern Virgina retailers president Page also said they believed more stations pumped gas yesterday than on previous Saturdays, although they said no statistics were available. Page noted that he had opened his Hunter Exxon station on Interstate Rte. 95 near Backlick Road yesterday -- the first time he had Stayed in operation on a Saturday in recent weeks.

Officals said several factors appear to have led to the increase in the number of stations operating yesterday as compared with pervious Saturdays. These include recent deliveries to gas dealers of emergency fuel supplies from state "setaside" allotments as well as dealers' expectations that they will start getting their scheduled July shipment this week.

Clinton said he hopes the increased Saturday openings also reflect a response to repeated requests by local government officals that gas dealers voluntarily stagger their operating hours. "I would hope we would begin to see this kind of opening up now," he said.

Most of the stations expected to open today in the Washington area have received special "setaside" allotment from emergency supplies regulated by the Maryland and D.C. governments, but government officals said they expect a few additional dealers to operate voluntarily today.

The District also has announced plans for 10 stations to open during Wednesday's July 4 holiday and for eight other dealers to provide gas during evening hours on Monday, Tuesday, Thursday and Friday. On Monday, Washington-area service stations have been asked to the begin displaying special flags, noting the availability of gasolines. A green flag will means leaded and unleaded gas are available. Yellow means only leaded gasoline can be purchased. Red signifies that a station's pumps are shut down.

The impact of the gas shortage could be measured yesterday in statistics and in changing behavior. Traffic across Maryland's Chesapeake Bay Bridge, the main route to Eastern Shore resorts, was reported to have dropped to 2,000 cars an hour compared with about 2,500 a year ago. Police said 40,499 autos crossed the span Friday, a substantial decline from about 48,000 a day last year.

In Washington, Ruth Colbert, a retired nurse, stayed up all night to get the first spot in line at an Amoco station on Rhode Island Avenue NE.

In an interview, she said she had played bingo until midnight. Then she washed clothes and did housework to help stay awake. At 4.35 a.m. she drove to the service station and parked her car at the pump. Four hours later, she was in her auto, eating bacon and eggs and waiting for the station to open at 10 a.m. "I think it's a damn shame," she said.

Tourist attractions in Washington continued to report light crowds, reflecting an apparent decrease in out-of-town visitors. "This weekend , in particular, is shocking. There's just no one out there," said U.S. park ranger Bob Dodson, after surveying the Lincoln and Jefferson memorials and the Washington Monument.

At Kings Dominion near Richmond, officials posted a listing of 58 nearby gas stations. The chart is intended to tell tourists which stations are open and pumping gas. "People are very inhibited about going anywhere," said marketing director Ron Trepanier, noting that attendance has fallen because of the shortage, "and it doesn't look too good for the future." CAPTION: Graph, Holiday Gasoline Guide, The Washington Post