The storm clouds that hopscotched around the city all afternoon shed only their grace - no rain - on the Philadelphia Orchestra on Friday night at Penn's Landing. Earlier rumbles quieted, clearing the air for patriotic - or at least American - tunes played for an avid crowd.

Just the stage area attracted an estimated 10,000 to 12,000 listeners, according to a spokeswoman for the Delaware River Waterfront Corp., with more eavesdropping on the free, hour-long concert through speakers in other perches near the river. Fireworks followed.

One of the great things about the orchestra's annual appearance here, the group's only full-orchestra concert in its neighborhood concert series this summer, is the audience it draws.

Whoever you think the typical classical listener might be, expectations are bound to be dashed by this crowd. It was diverse in nearly every way imaginable, but generally quite young. The audience listened in diverse ways, too, from an inner ring that hung on every note, to groups on the periphery who seemed aware only that sometimes it was hard to hold a conversation over all that music.

The vast majority stopped in their tracks, however, to take in the soft-edged boy-soprano sound of Bobby Hill, made famous last year when he performed during Pope Francis' visit to Philadelphia. Hundreds of cellphones came out to capture his "God Bless America," footage that has no doubt traveled the social media globe by now.

Lio Kuokman, the orchestra's assistant conductor, was on the podium, making good on another installment of this orchestra's mission to break some kind of record performing the music of John Williams. The film composer famously bridges worlds; where the casual listener hears music that marches and soars, the concert-hall habitué recognizes Elgar and Strauss. The "Throne Room" and "Finale" brought everyone into the single mind-set that something beautiful and important was happening, even if you've never seen Star Wars.

There's not much music written specifically for outdoor use, but the orchestra improvised well, with Tchaikovsky's 1812 Overture receiving a few personalized turns from Kuokman, and a snappy "Hoe-Down" from Copland's Rodeo. Robert Lowden's "Armed Forces Salute" is always good for turning the tables, asking those to stand when the corresponding song from the branch of the military in which they served is played.

Music seemed to interact with nature in the "Pie Jesu" from Andrew Lloyd Webber's Requiem when Hill's sound was backed by piles of clouds lit pink. This is the sort of thing that can happen at an outdoor concert. But only when you get lucky - with the weather, and when the boy soprano in question is as good as Bobby Hill.