It has long been a tradition in jazz to "tell a story" on your horn. The messages tumbling out of Al Cohn's tenor saxophone last night at Blues Alley were of such eloquence and urgency that were he running for office, the nomination would be his for the asking.

As guest artist with Mike Crotty's Sunday Morning Jazz Band, Cohn's big tone and Lesterian flow began to swagger on the opening notes of "Green Dolphin Street," his initial feature. The 18-piece orchestra had already acquitted itself splendidly on a half-dozen numbers before the veteran tenorist took his place, but he gave a lift to it that nearly amounted to levitation. A spellbinding "Well, You Needn't," laced with references from 15 other Thelonious Monk compositions, concluded the set.

Highlights of the first half, before Cohn took to the hustings, included the windy ensemble on a riff pattern of "Love To" and the explosive "Softly as a Morning Sunrise" with its bright trumpet by Marc Weigel. Alto, bass and C flutes and bass clarinet lent interesting colors to "A Certain Smile" and the limping rhythms of Paul Morawski's piano introduction to "Lunarcy" presaged the later "Bartlett's Quotations" of Monkish themes.

Cohn and the Sunday Morning Jazz Band return to Blues Alley this evening.