With television lights aimed at her from the wings and a large, appreciative audience sprawled on the lawn before her, Phoebe Snow turned in a stirring performance at Fort Dupont Summer Theatre last night.

Snow has recorded a broad range of material, but there was no mistaking the funk-fortified sound she wanted to pursue on this occasion. She came strutting on stage to the elastic beat of "Shaky Ground," and in no time her rich contralto gave way to piercing, exultant cries. That joyful sound, and the chorus of screams it invariably generated on the lawn, punctuated virtually every number, including a slyly syncopated version of Paul Simon's "Something So Right" and rhythmically compelling treatments of "Do Right Woman" and "Stir It Up."

Providing those rhythms was a crackerjack quartet that also had the good sense to back off when Snow strapped on an acoustic guitar for "Poetry Man." A few other, more reflective songs were also included, but "party," not "poetry," was the operative word, and on that score Snow and company came through time and time again.

The Young Bucks, a local group, opened the show with an appealing mixture of romantic balladry and hip-shaking soul.

The free concert is to be repeated tonight.