One of the most popular symphonies of our time will receive its local premiere this weekend. Though written in 1976, Henryk Gorecki's Third Symphony was only "discovered" two years ago when the CD featuring Dawn Upshaw and the London Sinfonietta hit the classical best-seller chart. Its enormous appeal probably can be attributed to its solemn mysticism and gentle yet unwavering political stance: one can readily empathize with Gorecki's lament for his native Poland and for the loss of innocence. Subtitled "Symphony of Sorrowful Songs," the half-hour minimalist incantation includes in each of its three movements a simple, agonizing song (in Polish), using texts from a medieval monastic chant, a prayer by a Gestapo prisoner, and a 19th-century folk song, respectively. The soloist for this performance will be veteran soprano Benita Valente; her voice may not have the purity and radiance of Upshaw's, but it's still an impressive instrument. As an antidote to Gorecki's lulling spirituality, Mozart's vivacious "Exsultate jubilate" is also offered on the program. Valente, a true-blue Mozartean, ought to bring forth a delectable variety of ways to sing the title phrase. Mussorgsky/Ravel's Pictures at an Exhibition rounds out the bill. The conductor is Japanese-born Eiji Oue, a Leonard Bernstein protege who now heads the Minnesota Orchestra. Saturday, 8 PM, and Sunday, 7 PM, Petrillo Music Shell, Grant Park, Columbus and Jackson; 819-0614.