Ten years ago, when Antal Dorati was appointed music director of the National Symphony Orchestra, but before he had come here to begin those duties, he was talking in Los Angeles about his goals for the orchestra. "I look forward to the day," he said, "when the orchestra will be able to prepare a symphony from the standard repertoire in a single rehearsal."

Last night Dorati demonstrated to his Kennedy Center audience how far the orchestra has progressed in that laudable direction. Because of the weather, the orchestra had only a single rehearsal plus one hour of overtime, on Wednesday afternoon, to prepare not merely a symphony but an entire program, no concert having been played on Tuesday night.

It was a Brahms evening, with the Tragic Overture, the Alto Rhapsody, and the First Symphony. Most of the rehearsal time went to the first two works since the orchestra has played them much less frequently than the symphony.

With Maureen Forrester and members of the Choral Arts Society, the Rhapsody achieved an enraptured performance. Forrester, as in her matchless Bach and Mahler, sings this music not only "by" but with heart. Hers is the ideal.

Making allowances for certain regged attacks and balances which time had not permitted adjusting, the music was solid, often very beautiful, and in the final movements of the symphony, filled with a welcome energy. The program will be repeated Thursday night and Friday afternoon.