The grounds of Wolf Trap were suffused with rain Thursday night but an eager crowd turned out anyway to hear Renee Fleming in one of her rare Washington area performances. Not surprisingly, it stayed to cheer. Fleming may be the most celebrated American soprano before the public right now, with her fresh, lustrous voice of rare opulence, her warm stage presence that seems both queenly regal and "girl next door," and her magnificent way with a song.

It was a generous program, including arias by Handel, Massenet (both "Manon" and "Thais"), Verdi (the Bolero from "Les Vepres Siciliennes," which Fleming sang in public for the first time, with brilliance) and others, as well as songs by Richard Strauss, Cole Porter and Richard Rodgers. The National Symphony Orchestra was conducted by Patrick Summers, and very well indeed: Overtures to Act 3 of Wagner's "Lohengrin" and "Vepres" were presented not as mere bonbons but as though they were in fact going to precede some substantial music drama, with that elusive mixture of gravity and momentum a proper overture performance needs. And Rodgers's "Carousel Waltz" sounded just as grand, in its decidedly American way, as the great dances from Tchaikovsky's "Eugene Onegin": They don't make many such melodies.

Right now, I should probably put in the obligatory critical paragraph about outdoor concerts, their pluses and minuses. No, you can't obtain the sound quality of the best auditoriums -- great acoustics need walls. Yes, Fleming was forced to use amplification. And yes, it was a little disconcerting to hear the Virginia crickets all but drown out the hushed, radiant opening to Strauss's "Morgen." (Imagine if the cicadas were still aboveground!)

Still, there is something to be said for listening to music in the open air, even on such a humid day as Thursday. A finer evening would have brought more people out on the lawn, but the Filene Center itself was packed to capacity and the event took on a welcoming informality that would have been hard to duplicate indoors.

I was not especially happy with the arrangements Fleming used for the pop selections -- "You'll Never Walk Alone" sounded uncomfortably like the "Liebestod" from "Tristan und Isolde," as the orchestration tended to puff up the song's openhearted directness into something that, given a less tasteful interpreter, could easily have veered into camp. And "Shenandoah" seemed more of an excuse for exquisitely shaded vocalizing than an expression of wracked homesickness: It was sweet on the ears but it can be so much more.

The three concluding selections found Fleming at her best -- deft pyrotechnics and a luscious trill in the "Vepres" Bolero; a pained, "am-I-losing-my-mind?" intensity to "Ebben?" from Catalani's "La Wally" and, sandwiched in-between, "O mio Babbino caro" from Puccini's "Gianni Schicchi."

In its original context, "Babbino" is a little flash of pure lyricism within a broad, gruff and deeply likable comedy that doesn't otherwise lend itself to dicing up. In the midst of byzantine family squabbles the melody arrives as if on wings, is beautiful, and is gone. In the past couple of decades, however, "Babbino" has become one of Puccini's most popular arias, and a tendency has arisen to drag it out, as though to milk every last lovely nuance of what remains a very short piece. Not surprisingly, Fleming's tempo was a slow one -- probably too slow for incorporation into a staged performance of this quicksilver opera, in which everything else moves so fast. Still, on a wet night at Wolf Trap, at the crescendo of this lush, nervous summer, her performance had the healing tenderness of a balm.

Soprano Renee Fleming sang a program at Wolf Trap that showcased her lustrous voice, and Patrick Summers led the NSO in complementing it.