More than a few Washingtonians may lunch today on the unused contents of yesterday's picnic hamper. Among them, no doubt, are some of the 50,000 who might have attended the National Symphony Orchestra's Labor Day concert on the west lawn of the Capitol were it not for the scraggly edges of an indecisive storm named Dennis.

Early Sunday afternoon, when the outer reaches of the storm were buffeting the area, the orchestra decided to move the outdoor concert to the Kennedy Center, the first time in more than a decade that the popular event has been rained in. The Concert Hall was packed with a crowd still looking a bit outdoorsy, with baseball caps, cameras and kids in tow.

Moving alfresco music indoors gives it a very different frame. A program of Sousa marches and movie tunes is like champagne in a Dixie Cup, just the thing if the skies are clear, the weather balmy and the crowd fully recumbent. But the audience and musicians were undaunted at this turn of events. Conductor in Residence Anthony Aibel had assembled a program that rewarded the stern gaze of the Concert Hall and that worked, when needed, as a rousing sing- and clap-along.

His choices looked on paper like a crazy quilt, but there was an evening-length dramatic logic to it, and some wry humor. Juxtaposing Rimsky-Korsakov's "Flight of the Bumblebee" with Vaughan Williams's Overture to Aristophanes' "The Wasps" is a bit of a stretch; the former is all naturalistic buzzing and humming, a good workout for the violins, but breezy music when set beside Vaughan Williams's more substantial curtain-raiser to the classic Greek comedy. But any excuse for presenting the Vaughan Williams--which seems to argue what Plato's "Symposium" makes clear, that Aristophanes was not only the funniest but also the most lyrical of his Athenian circle--is welcome. The orchestra played it with genuine engagement and warmth.

Gershwin's "Promenade" preceded Dvorak's "Carnival" Overture, a strange succession that worked very well as a segue into intermission. Both had their moments, especially principal clarinetist Loren Kitt's slithery tone in the Gershwin. The Dvorak reminded one that this composer, who produced so much empty symphonic bombast, could also produce symphonic bombast of the first class.

More familiar and pulse-raising works were reserved for the second half. Tchaikovsky's "Marche Slave" was one of the best performances of the evening, a progression from the grim to the maudlin to the triumphant. Gounod's macabre little strut, the "Funeral March of a Marionette," raised knowing chuckles from fans of Alfred Hitchcock's old television series, for which it served as theme music. John Williams's music from "Star Wars" was unsettling, inspiring in the listener vaguely self-important thoughts about heroic deeds never committed.

The program also included the world premiere of Ellen Taaffe Zwilich's "Upbeat." World premieres are a rarity on popular programs, but Zwilich has produced new music to suit the occasion.

The Pulitzer Prize-winning composer cobbles together (sometimes a bit chockablock) familiar riffs and themes culled from other works and styles, and spreads them over menacing and rhythmically angular intrusions that propel the music along, despite its hodgepodge of melodic material. It is well crafted and clever and, unfortunately, a bit leaden and awkward.

CAPTION: Glenn Garlick, the NSO's assistant principal cellist, answers a question from young Matthew Faulkner, at last night's concert with his baby sister and family friend Jim Phillips.

CAPTION: An usher directs the crowd for what normally is an outdoor event to line up inside the Kennedy Center yesterday evening. Left, Anthony Aibel conducts the NSO in its Labor Day concert.