Sarah Vaughan singing a program of Gershwin songs accompanied by the National Symphony in the wooded confines of Wolf Trap Farm - and on live television.

The blend would ordinarily make for some stunning musicmaking. But Saturday night's concert was more of a grand entertaining event than a memorable performance.

In the first of a PBS series of five live telecasts of Wolf Trap performances, Vaughan skipped merrily through 17 Gershwin songs (and a fervent "America the Beautiful"), compartmentalizing them into a segmented medley.The effect was one of great hurry. She hardly stayed with a song long enough to fully explore its contours.

However, in Vaughan's favor it should be said that the evening was uncomfortably sultry and she must have sweated a gallon of perspiration.

From the easy perspective of hindsight, it would have been better if Vaughan had sung half the song she performed - and delivered them in their entirety.

That way she could have offered more exquisite singing, as she did on "A Foggy Day." She slowed the song's tempo from its usual snappy pace, caressed the melodic line and hit some corners in the musical line that are rarely touched.

Vaughan was preceded by pianist Jeffrey Siegel playing Gershwin's "Rhapsody in Blue" and by the symphony performing the composer's "An American in Paris," both conducted by Christian Badea.

Siegel gave the "Rhapsody" a jazz-like flavor greater than that given by most pianists, bending notes and stretching rhythms in an exhilarating manner. "An American," an exuberant tone poem, was given na crisp and intense performance.