Virginia Republican Wyatt B. Durrette and Democrat Gerald L. Baliles closed their long, expensive campaigns for governor yesterday as each candidate pressed for support they hope will help bring them victory in today's election.

Durrette, trailing Baliles in the polls, hoped to rally Republicans as he visited the Oval Office for a brief meeting with President Reagan.

"His support in what I expect to be a close election Tuesday is yet another major boost for my campaign and an important signal for the people of Virginia," Durrette told reporters on the White House lawn. "The fact that he thought enough of this race and enough of me to initiate the invitation to come here and meet with him today -- that message will not be lost on the voters of Virginia."

Baliles, appearing increasingly confident of victory, traveled across the state for rallies in Roanoke, Norfolk, Richmond and Northern Virginia, where he joked about the weather and his opponent's meeting across the Potomac.

"The president is waiting for better weather before he comes back to Virginia, so we decided to come back here to help Wyatt stay on the other side of the river," the Democratic nominee told 100 supporters at the Arlington Courthouse.

In addition to the governor, Virginia voters today will pick a lieutenant governor, state attorney general and 100 legislators and will fill numerous local offices. In Fairfax County voters will decide the fate of a $135 million road bond issue, the largest such proposal in the state's history.

District voters will vote on a rent control referendum and elect five members to the Board of Education. In Maryland residents of several communities will elect local officials.

The Baliles Arlington rally had to be moved inside because of yesterday's rain, but the mood of the candidates and Gov. Charles S. Robb was upbeat.

"We know what the sunlight is going to look like tomorrow," Baliles said to cheers.

Robb, who broke the Republicans' 12-year hold on the governor's office in Virginia, has said the Democrats, whose ticket includes the first black and the first woman nominated for a state office by the party, is facing a "rendezvous with destiny."

Officials from both campaigns in Virginia were keeping one eye on the weather as officials were warning that flooding from several days of rain would force them to set up temporary polling places in some areas of Southwest Virginia.

Portions of the state near Roanoke appeared hardest hit by the heavy rains as hundreds of local residents fled their homes and businesses, and Gov. Robb declared a limited state of emergency for the area, which activated units of the state's National Guard and other emergency agencies, according to Michael La Civita, director of the Office of Emergency Services.

The registrar's office in Salem, a city near Roanoke, was flooded yesterday and officials took to rowboats to reach the office and retrieve election files while other communities reported roads blocked and felled trees as the rains inundated the area.

The National Weather Service said up to 20 inches of rain had fallen over parts of Virginia during the past four days, and the forecast for today called for more rain tapering off late in the day.

Election and campaign officials were uncertain how the rain would affect turnout. There are 2.6 million registered voters in the state and officials had been expecting a turnout of about 60 percent, the same level as in the 1981 gubernatorial election, when 1.4 million voters went to the polls.

Durrette, 47, a former Fairfax County legislator, said yesterday he told the president that the GOP campaign had growing momentum, but he said neither he nor the president mentioned polls during a meeting that Durrette said lasted "about three or four minutes."

The GOP nominee began the day campaigning under an umbrella in Springfield where he greeted commuters at a parking lot and later at the Pentagon Metro stop in Arlington. He was joined by Rep. Frank R. Wolf, Sen. John W. Warner, and John F. Herrity, chairman of the Fairfax County Board of Supervisors.

Durrette's running mates, state Sen. John H. Chichester of Stafford County, running for lieutenant governor, and Del. W.R. (Buster) O'Brien of Virginia Beach, who is seeking the office of attorney general, campaigned elsewhere. So did their Democratic opponents, state Sen. L. Douglas Wilder of Richmond, who is opposing Chichester and is attempting to become the first black elected to a major state office in the South, and Del. Mary Sue Terry of Patrick County, who is O'Brien's opponent.

Baliles, 45, a former state attorney general, ended his day in Richmond, where 300 supporters descended on his home for a barbecue supper. A power outage occurred during the meal. "Everybody's walking around in the dark eating barbecue and brunswick stew," said Chris Bridge, Baliles' press secretary. "We're using some old pumpkins for light."

In Roanoke, where Baliles began his day, he complimented Durrette, who he has said is unqualified to be governor and who has been the subject of negative TV ads.

"I also want to pay tribute to Wyatt Durrette. He may be my opponent, but he is not my enemy," Baliles said. Then he joked: "But I can be thankful that all of his [seven] children are not old enough to vote."