Inclement weather prevailed for about half of the four-day Wolf Trap Jazz Festival. But attendance remained at capacity, boding well for the future.

There was some fluff and concessions to commercialism, and one entire area of jazz - the avant-garde - was conspicuous by its absence. Some of the Olympians, however, were present and in good form.

Count Basie introduced "Wind Machine" Saturday evening with a single note. On "Booty's Blues" he provided some rolling boogie, and on that same piece trombonist Booty Wood got down and dirty with plunger mute. Trumpeter Paul Cohen lyricized on "I Can't Get Started." Drummer Butch Miles was flamboyant and flashy but impeccably precise and brilliantly swinging.

Carmen McRae transformed melodies, scatted and emulated a variety of instruments, all of this in a voice broad in range and harmonically sophisticated. "Someone Like You' displayed her forte in a New York State of Mind" was a vehicle for wry social commentary.

Earl 'Fatha' Hines led off his set on Sunday with a solo medley of materials he recorded 50 years ago. Later, on "St. Louis Blues," he combined his "trumpet-style" right hand with a modified stride in the bass and then switched, his right sustaining a tremolo while his left carried the melody and quoted from other pieces.

Marva Josie, Hines' vocalist, can do almost anyhting with her classically trained voice. Her song "It'll Never Be Over For Me" was full of swoops, glides, bends and full-throated cries.

Dividing his time on stage about equally between trumpeting and clowning. Dizzy Gillespie ripped apart a funked-up "St. Louis Blues," then regaled the audience with an anecdote about his coaching of Jimmy Carter on how to sing "Salt Peanuts." He later returned for a wordless vocal effort with Buddy Rich's Orchestra.

Rich's current band is polished and swinging and his pyrotechnics are fun to observe even if sometimes tedious. His tenorist Steve Marcus got off an impressively frenzied free solo.

Grover, Margret & Za Zu Zaz's swing era vocal gymnastics culminated in a medley tribute to royalty, "Three Kings," for Ellington, Basie and Hines.

Ghosts emerge from the playing of Mary Lou Williams even when she is not consciously evoking the past. And last night, as always, those shadows became her.

Stratospheric brass virtuoso Maynard Ferguson's big band rock machine rolled over everything in sight - and sound. Subtle they ain't but electric they are as they demonstrated on their "jazz/rock/gospel/march," "Gabriel."