As storms roiled outside the Long Center on Friday, the Austin Symphony and pianist Orion Weiss whipped Rachmaninoff’s Piano Concert No. 3 into a musical cyclone.


Those in attendance had no way of gauging how the weather fared outside the hall. They were too mesmerized by the rare experience of witnessing the transcendent “Rach 3” played live — and extraordinarily well.


The stage was set, however, by Johannes Brahms by way of Arnold Schoenberg.


Brahms’ Piano Quartet in G minor is a friendly face on the concert stage. In 1938, Schoenberg transcribed it for orchestra.


Oddly. While staying true to Brahms’ composed notes, Schoenberg brings in all sorts of other orchestral sounds, including instruments that Brahms did not use.


It seemed that, in the first movement, the orchestra, led by Peter Bay, hunted for the piece’s ponderous course, finding it the second movement with its lighter, more playful mood. They brought gusto to the big-footed march in the third movement, and unlocked the full powers of the ensemble in the triumphant fourth.


Not in love with it, sure, but I’m glad I finally saw this atypical piece in performance.


Many Americans know Rachmaninoff’s concerto mainly through “Shine,” the 1996 Australian movie about an emotionally troubled musician, played by Geoffrey Rush, pushed over the edge by his attempt to ascend Rach 3. We hear only snatches of the concerto in the movie, so don’t judge the music based on that memory.


The concerto is fiendishly difficult to perform and almost impossible to watch without becoming concerned about the state of pianist’s shoulders, arms and hands.


From the precious opening notes, Weiss’ fingers rarely rested for what must have been 40 minutes. They were configured — almost always in rapid motion — in ways I’ve never seen before.


Technical virtuosity was not enough for Weiss.


He found the soul in Rachmaninoff’s barest, most heart-rending tunes, expanding the feeling out into the harmonies and his partnership with the orchestra, toying with the contrapuntal, almost jazzy back and forth over the keyboards, earning his way at last to a finale that took off like a spaceship.


Bay’s regulars were ready to partner. Especially the strings, at first, but then also the brass, woodwinds and percussion.


What could have been a night of mere amazing mechanical craftsmanship became a deeply moving musical experience.


Thoroughly cheered, Weiss returned to the stage with the ideal answer to the weight of the concerto — Debussy’s “The Girl with the Flaxen Hair” done simply, delicately, impeccably.