On Friday at 5 p.m., mammoth sheets of rain ripped into skyscrapers, and blasts of thunder obliterated the sounds of the city.

One hour later, Francis Coppola's much-awaited "Apocalypse Now" had its first screening in finalized form, for an invited audience that walled away from the surrealistic two-and-a-half-hour Vietnam epic as if exiting a funeral. The fadeout was followed by little applause, ubiquitous ashen faces and plenty of canceled dinner plans.

The screening was the first of several to be made this week, culminating in the film's premiere here Wednesday. (It opens in Washington in October.)

There were few recognizable faces in the audience - some of the film's actors, rock musician Bruce Springsteen, Vitenam veteran and author Ron Kovic - but this was primarily for members of the press and other Hollywood mailing-list types.

Whatever festivities usually surround these silly movie junkets were quickly obliterated by the mental agony of the movie.

"I couldn't go to my free dinner after the screening," said one Midwestern film critic. And even by Saturday morning, when Coppola held a press conference, the gathered scribes still seemed like shell-shocked veterans of My Lai.

Coppola spent four years and $31 million making the film - about two years and $20 million more than originally planned. In the process: Coppola fired actor Harvey Keitel and had to reshoot three weeks of scenes; central character Martin Sheen had a heart attack; the sets in the Philippines were destroyed by a typhoon; and Coppola's marriage was decaying. Apocalypse Now became Apocalypse Forever, and the director became the Ayatollah Coppola.

"I've got this thing," Coppola said Saturday, "about my personal life being spread out like a sheet of butter: Being asked am I nuts, what have you. When I was making the picture I felt the press took a lot of unfair shots at me. I'm so sick of this movie now. I don't have any project now. I'm an unemployed director. I've never had a vacation in my life. Maybe I should just go for a while without a project if that's possible for me."

The film will have to do enormous business even to break even. There has been speculation that the success of Vietnam themes in "The Deer Hunter" and "Coming Home" at this year's Academy Awards may hurt Coppola's chances for big grosses and awards.

"I didn't worry at all," the bearded director said, "that any of the other films being made could be at all like the film I was making." Indeed, it is an intensely personal vision, inspired by Joseph Conrad, but ultimately a mental map of the internal struggles Coppola perceives to exist in Vietnam.

"You know how I made this movie," he said. "I had a list of things that made the Vietnam war: use of helicopters, use of drugs, black guys, young guys in the front lines...and I checked them off as I conceived of scenes."

Of Oscars, Coppola said, "I'm not interested in them. I have several." During preproduction of the film, when several actors, including Robert Redford and James Caan, had turned down parts, Coppola threw his five Oscars through a window in his Napa Valley home. Four of them broke.

Coppola previewed the film several times in four cities and asked audiences to resond on a three-page criticism form. Directors then re-edited parts of the film. A "work in progress" was presented this spring at the Cannes Film Festival, where it shared the Best Film award. Coppola says that this final cut had 67 changes since Cannes. The 70-millimeter, quadraphonic print here has no credits, but rather a printed program listing credits distributed after the film. The 35-millimeter stereo prints will have a 4 1/2-minute credit sequence at the end, the titles superimposed on infrared footage of bombs bursting in air.

The only comic relief of the weekend came from actor Dennis Hopper, who plays a demented photojournalist in the lash half hour of the film. At the press conference, Hopper would regularly interject his comments which tended always to be a slurred "I think this is a great movie." He also suggested that Marlon Brando is "great" and added "I think of Martin Sheen as Alan Ladd in "Shane."

"Look," said Hopper. "This is the best film I've ever seen. But besides "Gone with the Wind," what can you talk about?" CAPTION: Picture 1, Actor Robert Duvall and Director Francis Coppola, by Donal F. Holway for The Washington Post; Picture 2, Francis Coppola at post-premiere press conference, by Donal F. Holway