Despite their sweet songs and sweeter sounds, the Jayhawks may be the hard-liners of alternative country. Where cohorts like Wilco and the Bottle Rockets gain their cred by drawing from punk and hard rock, respectively, the Jayhawks go their own way. They feel their fondness for tense, burnished harmonies and old-fashioned touches of swelling strings don't need credibility. As a result, their new Tomorrow the Green Grass is a gracious stunner, presenting a true modern country sound that has little to do with that nominal genre. Instead they're the lost cousins of the Byrds and Gram Parsons, working the same promising territory that later went wrong in the hands of the Eagles. The opening track "Blue" is the album's gem, a blast of voices and emotion; what follows--the courtly "Miss Williams Guitar," the dramatic "Nothing Less to Borrow," even a satisfying run at Grand Funk's catchy "Hard Time"--is nothing less than the million-dollar record that justifies spending the months in the studio and hundreds of thousands of record-company dollars. Commerce doesn't always recognize such achievements, however, and the band, not to mention their label's accountants, can't be happy with the record's poor commercial showing. Live, leaders Mark Olden and Gary Louris bring their voices together exhilaratingly. The show's sold out. Friday, 7:30 PM, the Vic, 3145 N. Sheffield; 472-0449.