Porgy and Bess lives in the American ear with all the familiarity of a far-off train whistle. Everyone knows the sound when they hear it — “Summertime,” for instance. But it takes an encounter with the entire work to get its full genius. And then Porgy and Bess fills you with nothing less than awe.

Audiences this weekend are able to hear, if not the entire opera, a great deal more than the usual stray song or two. With an excellent cast and chorus, the Philadelphia Orchestra Thursday night wove scenes from Porgy and Bess into a cohesive and thrilling half-evening (to be repeated Saturday night).

The concert was led by Marin Alsop, who told the Verizon Hall crowd that the program followed an American melting pot theme.

The first half had the Morgan State University Choir conducted by director Eric Conway in a glowing setting by Nolan Williams Jr. of the spiritual “Done Made My Vow to the Lord.”

Escaramuza, inspired by music of Andean Peru, was the curtain raiser. The springy, dance-like work, a decade old, is by the orchestra’s new composer in residence, Gabriela Lena Frank, and the piece bodes well for this formidable musical personality as her influence here begins.

Jessie Montgomery’s Coincident Dances, from 2017, aimed to capture the multicultural fabric of New York City, and indeed the piece passed before us like an audio postcard. Principal double bassist Harold Robinson started with a solo, bouncy woodwinds happened by, and then four percussionists took over. It was exhilarating music, racing and gathering energy the way Sibelius can, until the winds ended like a flock of birds moving into the distance.

The melting pot moved to Catfish Row — Charleston, S.C. — for Porgy and Bess, presented here in selected scenes and performed concert-style (no sets, no costumes, or even choreographed movement). It was fascinating to once again hear this piece, with George Gershwin’s music and a libretto by Ira Gershwin and DuBose Heyward; it was haunting as ever, but perhaps more so today as our cultural lens continues to evolve.

Conductor Marin Alsop
Conductor Marin Alsop

These performances of Gershwin are being recorded for the Pentatone label (the release date has not been set), and the hour or so of music is an assemblage of great strengths. The familiar songs are here (“Summertime,” “I Got Plenty of Nothin’”) and, as Bess, soprano Angel Blue has got it all. Her voice is rich and powerful and full of subtle expressive devices.

Baritone Lester Lynch and bass-baritone Kevin Short were both exceptionally strong. Tenor Chauncey Packer had the role of Sportin’ Life, putting him at an advantageous starting point for charisma. But he also heightened the part with some vivid and nuanced acts of vocalism.

It would be hard to overstate the emotional boost the Morgan State voices brought to this performance. Angel Blue was wonderful in “Summertime,” but the hushed women of the chorus lifted it to another level.

What’s most striking about this packaging of highlights is being able to hear the music with all its connective tissue and in a larger context. In that scene where Bess is telling Porgy that she can’t resist the powers of Crown and must go off with him, the orchestra darts in and out with commentary — a tender flute, poignant violins.

Gershwin is such a supreme melodist, it’s almost easy to overlook what he does with the orchestra. Alsop underlines it, expressively so. This recording should be the whole package.

Additional performance: Saturday at 8 p.m. in Verizon Hall, Broad and Spruce Streets. Tickets are $10-$174. 215-893-1999, philorch.org.