Brave the windchill, or just reserve a weekend suite at the Blackstone Hotel, where Chicago’s unsinkable Marshall Vente has assembled a promising lineup for his second annual jazz festival. The pianist, composer, bandleader, and DJ–best known for his 9-to-12-piece band Project Nine–last year added concert promotion to his resume, and the 1994 model follows the blueprints for its predecessor: three days of music featuring several of the bands Vente leads, as well as groups headed up by various Vente sidemen. This year, Vente has placed the emphasis on showcasing new projects–several of which will premiere this weekend. These include saxophonist Jeff Newell’s New Trad Octet, a unit in the style of the Crescent City’s traditional street bands (Friday); the Chip Gdalman Woodwind Ensemble, led by Vente’s longtime baritone saxist and featuring five reeds plus rhythm section (Saturday); and Vente’s own Limited Edition Jazz Orchestra, a 19-piece unit that satisfies Vente’s long-held desire to write for a true big band (also Saturday). Other highlights: a tribute to Dizzy Gillespie by another Vente unit, the Afro Caribbean combo Tropicale (Friday); and for the finale (Sunday), the big band led by pianist Frank Mantooth with two special guests: Kansas City vocalist Kevin Mahogany, whose debut CD made several of last year’s top-ten lists, and west-coast saxist Pete Christlieb. (See listings for complete schedule.) Friday and Saturday, 6:30 PM to 12:30 AM, and Sunday, 1:30 to 5 PM, Joe Segal’s Jazz Showcase, Blackstone Hotel, 636 S. Michigan; 427-4846.