LENOX — It takes more than a mighty tempest to ruin a hallowed, 70-year tradition — Tanglewood on Parade, the nine-hour party showcasing the Boston Symphony, Boston Pops, Tanglewood Music Center Orchestra and the Boston University Tanglewood Institute's middle- and high-school age musicians.

And mighty it was, a supercell thunderstorm that blew through the grounds just after 5 on Tuesday, forcing patrons into designated storm shelters as 60 mile-an-hour winds toppled several parking-lot trees, complete with lightning strikes, hail and a monsoonal deluge.

Sadly, the result was a hardy but diminished crowd of only 7,000 for the evening gala concert, normally attended by 10,000 or more. Tanglewood, dependent on a robust lawn audience to augment the 5,000-seat Shed, has suffered too much from this summer's abysmal weather.

But artistically, the concert offered a cornucopia of pleasures — no surprise given the cast including distinguished pianist Kirill Gerstein and a parade of conductors: Living legend John Williams; Keith Lockhart, in his 24th year as Pops leader; the TMC's conducting program chief and artist-in-residence Stefan Asbury; and Bramwell Tovey, a more frequent guest maestro with the BSO since his appointment last year as director of orchestral activities for Boston University's School of Music.

Gerstein, who richly deserves his designation this summer as Koussevitzky Artist, performed Gershwin's Rhapsody in Blue with the Pops and an attentive Lockhart as a headlong rush through the score's supercharged, jazz a la mode sections — though they dialed back the energy for the romantic, lyrical big tune.

The Boston Pops (mostly the BSO) was in full big-band mode, with bluesy riffs by Thomas Martin, the associate principal clarinetist, fine solo work by Tamara Smirnova, the BSO's first associate concertmaster, and a brass section in full cry. A sensational performance, making the oft-heard rhapsody sound as if had been composed yesterday. As a curtain-raiser to the concert's second half, Lockhart led a lively traversal through the overture to "Nice Work If You Can Get It," a 2012 Broadway musical featuring some of George and Ira Gershwin's greatest hits.

Tovey opened the evening by leading the BSO through a capable run-through of Tchaikovsky's "Romeo and Juliet." The TMC Orchestra, led by Asbury, followed with Ravel's Daphnis et Chloe Suite No. 2 — raucous energy, but a lack of delicacy during the hushed Pantomime.

Later came the hero's welcome for Williams, a spry-looking 86, leading an especially appealing trio of selections from his most recent "Star Wars" contributions.

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Bookended by "The Adventures of Han" from last spring's "Solo: A Star Wars story" and "The Jedi Steps and Finale" from "The Force Awakens" — reimagined samplings of his familiar series themes — a new concert arrangement, "Adagio," adapted from cues from that 2015 film also known as "Episode VII" was seriously, stunningly beautiful.

Conducting with remarkable vitality, Williams was obviously pleased to be back at Tanglewood, which he described to me as the "spiritual center" of music in America during an August 2012 interview for The Eagle.

Concluding the nearly two and a half hour concert came the obligatory "1812 Overture," conducted by Tovey. Tchaikovsky denigrated the nationalistic potboiler as "unsuitable for any but Russian concert halls." Little did he know.

In 1976, BSO Music Director Seiji Ozawa began the tradition here and, with one exception, it has endured as an annual tour de force for the combined BSO and TMC orchestras — the audience demands nothing less. Fireworks ensued, both musical and literal, echoing through the nearby hills and dales. For a few moments, all seemed right with the world.

Clarence Fanto can be reached at cfanto@yahoo.com, on Twitter @BE_cfanto or at 413-637-2551.