BY THE TIME Seamus Egan was 16, the young Philadelphian had already won all-Ireland competitions on flute, tenor banjo, tin whistle and uillean pipes, and his 1985 debut album of traditional Celtic music reflected a prodigy's proficiency. Egan's now 20, and his long-awaited second album, "A Week in January," is a bold, mature project that more than fulfills his early promise. No longer just a dazzling technical musician, Egan now has something to say with his music and the vision to take Celtic music in new directions.

The all-instrumental album uses various musical casts to bring out different sides of Egan's talent. Egan establishes his Irish roots firmly on pieces like "Fermoy Lasses" and "Tim Hobins" as his flute dips, darts and flutters like an acrobatic bird above the bodhran drum of Ireland's Tommy Hayes. When he explores the Canadian branch of Celtic music on "Cape Breton Set," guitarist Dave MacIsaac and pianist Hilda Chiasson from Cape Breton join in.

The album's liveliest track is "Bird in the Tree," a traditional Celtic fiddle tune given an old-timey Appalachian arrangement. Egan plays Irish tenor banjo against Dick Powell's five-string banjo, and Mick Moloney plays Irish rhythm guitar against Joe Fusco's electric guitar and Saul Brody's harmonica.

Egan's willingness to push the Celtic tradition into new and productive territory is evident throughout the album, but never more so than on the two slow airs he wrote himself, "Weep Not for the Memory" and the title tune. Playing tres (a small Latin guitar), flute and whistle, he is joined by former Trapezoid member Michael Aharon on piano, bass and cello. Together they create a chamber-folk music of such tenderness and palpable feeling that they mark Egan as a major talent of the '90s. SEAMUS EGAN --

"A Week in January" (Shanachie). Appearing with Michael Aharon, Dave MacIsaac and Hilda Chaisson at the Washington Irish Folk Festival, held from noon to midnight Sunday in Glen Echo Park. Call 543 -- 4474 or 217-3673 for schedule.