Washington is particularly rich in choral resources as well as in its variety of outstanding pipe organs. Both of these factors are reflected in the coming season, for which these seven area choruses recently received grants from the National Endowment for the Arts: the Cathedral Choral Society, Choral Arts Society, Columbia Pro Cantare, Paul Hill Chorale, Oratorio Society, Washington Bach Consort and Howard University Choir. And next June the American Guild of Organists will bring to town around 3,000 organists for its biennial convention.

The shape of musical things to come in Washington is determined months and years in advance of any season. Our popular galleries, the National and the Phillips, the Smithsonian and the Library of Congress, where many concerts are presented free, are deluged years ahead of time by artists anxious to perform in this intensely musical center.

Our big musical organizations like the National Symphony, the Washington Opera, the WashingtonPerforming Arts Society and the presenters of the many series that so greatly enrich the area's musical offerings -- such as the National Institutes of Health in Bethesda, the Jewish Community Center in Rockville, and the Chamber Music Series at the Adult Education Center at the University of Maryland -- must sign up artists seasons in advance if they want to secure the finest and most attractive soloists and ensembles.

Without benefit of the gift of prophecy, here are just a few of the events coming up in the next four months, some of which are sure to give audiences the special thrills that make a good season memorable.

September

Every night through Sept. 27, except Mondays, the Bernstein "Mass" plays in the Opera House, with matinees on Saturdays and Sundays. Tonight at 8:30 in the Kennedy Center, the National Symphony salutes the center's 10th birthday with Leonard Bernstein playing and conducting Mozart's Concerto in G, K. 453, and Mstislav Rostropovich conducting the Second Symphony of Brahms.

The NSO's opening concert is on Sept. 15, with Rostropovich conducting and the Choral Arts Society singing Stravinsky's Symphony of Psalms. Also on the 15th, the Terrace Theater concerts open with Erick Friedman and Michel Block. These concerts will include soprano Judith Blegen on the 16th; Sept. 17, pianist Richard Goode; Sept. 19 and 22, Peter Serkin and David Soyer, piano and cello; Sept. 23, composer/pianist Ned Rorem; and Sept. 24, pianist Anton Kuertti.

On Sept. 20, Jean Langlais, French organist/composer, will perform in a concert of his organ and choral music at the Shrine of the Immaculate Conception. The National Symphony will observe the 75th birthday of Dmitri Shostakovich on the 22nd through the 25th, with the composer's son conducting, the composer's grandson as pianist, and cellist Rostropovich.

October

The brilliant young tenor Robert White appears in the Terrace Theater on Oct. 1. The Philadelphia Orchestra performs with Ormandy and violinist Peter Zazofsky in the Kennedy Center Concert Hall Oct. 5. The Juilliard Quartet opens its Library of Congress concerts Oct. 8 and 9 with baritone William Parker.

On the 10th, the Philip Glass Ensemble is at the Pension Building, and on the 14th, Alberto Ginastera in the composer series at the Terrace Theater. Laurie Anderson will be in "United States III & IV" at the Pension Building Oct. 17. And on the 31st, the Tokyo Quartet plays with pianist Tedd Joselson at the University of Maryland's Adult Education Center.

November

On the 3rd, the National Symphony with Rostropovich and Leventritt-winning pianist Cecile Licad; on the 4th, at the Kennedy Center, a George London Gala with opera stars Joan Sutherland, Marilyn Horne, Tatiana Troyanos, Leonie Rysanek, Evelyn Lear, Carol Neblett, Catherine Malfitano, Nicolai Gedda, James McCracken, Cesare Siepi, Simon Estes, Richard Stilwell, Rockwell Blake and others.

On Oct. 6 to 8, a Handel Festival takes place at the University of Maryland and the Library of Congress, with choral and instrumental concerts and lectures. The Washington Opera opens its season Oct. 7 with "Boheme," and follows during November with "Macbeth," "Magic Flute" and "The Rake's Progress."

On the 8th, the 20th Century Consort is at the Hirshhorn, with Lucy Shelton, soprano; on the 14th and 15th, the Mahler Eighth Symphony will be performed at the Washington Cathedral, with the Cathedral Choral Society, Choral Arts Society, boys and school choirs, soloists, Paul Callaway, conductor, celebrating the Choral Society's 40th birthday.

Previn and the Pittsburgh Orchestra perform in a two-program British festival on the 21st and 22nd; the Aeolian Chamber PLayers are at the University of Maryland's Adult Education Center on the 21st; MusicCrafters appear on the 24th at the Library of Congress, in Busoni, Holst, Debussy, Knussen. Winding up the month are the French National Orchestra with Leonard Bernstein in a French program on the 28th, and pianist Rudolf Serkin on the 29th. .

December

The month opens with the Kennedy Center Honors on the 6th, followed by the Philadelphia Orchestra, with conductor Charles Dutoit and pianist Peter Serkin, Dec. 7. The American Boychoir and 20th Century Consort are in Baird Auditorium, with The Ceremony of Carols, "King David," and a Crumb Christmas suite on the 21st. And on the 26th, the Washington Opera revives its brilliant "Barber of Seville."

You can also be sure of vast quantities of Christmas music all through December. Remember that many of the finest concerts all around the Washington area are free.