The Australian import THE ROAD WARRIOR, George Miller's imposing futuristic sequel to his sensational first feature "Mad Max," is scheduled for sneak previews this Sunday, anticipating openings in the Washington area next Friday. The remake of I, THE JURY remains firm for August 20, but the new doomsday thriller THE SOLDIER has dropped back to September 3.

Another medieval adventure melodrama, THE BEASTMASTER, shot on location in suburban Simi Valley, California by Don Coscarelli, the amiable young perpetrator of "Phantasm," suddenly materializes on the 20th. Marc Singer, appealing earlier this year in "If You Could See What I Hear," plays hero to the heroine of Tanya Roberts, the erstwhile Charlie's Angel.

Meanwhile, the R-rated high school farce ZAPPED, in which Scott Baio goes telekinetic, now rebounds from the fall schedule for an August 27 opening. At the moment Franklin Schaffner's YES, GIORGIO with Luciano Pavarotti, and Fred Zinnemann's FIVE DAYS IN SUMMER with Sean Connery appear to be the first major releases of the fall, currently being depleted by most distributors in order to stack the winter. Both films are supposed to arrive on September 24.

The Key begins a two-week revival of WOODY ALLEN films today, and the AFI Theater launches its final summer programs, a NOEL COWARD retrospective and a renewal of the ever-popular CULT MOVIES, on Monday. Remember, the cult parlay to end them all is scheduled for showings on August 27 & 28 -- BEYOND THE FOREST with Bette Davis plus QUEEN BEE with Joan Crawford. On the 28th the AFI will also host the free novelty of independent filmmaker Jon Rubin's FLOATING CINEMA, a presentation of drifting images back-projected onto a pair of screens mounted on barges which will cross the Potomac. The performance, designed to be discernible from the shoreline between Key Bridge and the Kennedy Center, shoves off at nightfall.

E.T., still maintaining an average box-office gross of $3 million a day but finally showing signs of slowing to about $2 million over the next several weeks, should pass the $200 million milestone in accumulated gross receipts this weekend. It's also the weekend STAR WARS returns for another end-of-summer revival. "E.T." would have roughly another $200 million to go before overtaking "Star Wars" as the modern box-office champ.

SHELDON TROMBERG, the local pioneer of the screenwriting seminar, hopes to renew private, flextime tutorial sessions for aspiring or stymied amateur screenwriters in the fall. If you're interested in a collaborator or script doctor for a screenplay-in-progress or in the back of your mind, consult Tromberg at 244-1818 and see if you make sense to each other.

Two local companies, Mypheduh Films and Positive Productions, have combined to organize an independent film series devoted to black directors and African themes at the Takoma Theater this fall. The program is dominated by the work of HAILE GERIMA, an Ethiopian who has lived and worked in the Washington area for the last several years. The series opens with his short 1972 feature, CHILD OF RESISTANCE, on September 18 and 19 and closes October 30 and 31 with the premiere of a new two-hour feature, ASHES AND EMBERS. Detailed information on the series may be obtained by calling 529-0220.

The Smithsonian Resident Associates will offer a six-part series devoted to recent Soviet features starting September 16. John Glad, director of the Kennan Institute for Advanced Russian Studies, will join Soviet ambassador Anatoly Dobrynin to introduce the opening selection, a 1979 Estonian melodrama about the closing months of World War II called A NEST IN THE WIND. Sergei Bondarchuk will be represented by THE STEPPE, a 1978 adaptation of a Chekhov story. Showings will be held in Carmichael Auditorium. Subscriptions are $10 for Smithsonian Resident Associates or AFI members and $13 for nonmembers..