Endlessly compared to Sarah McLachlan and Vanessa Carlton because, well, she sounds an awful lot like both of those artists, Missy Higgins is a bona fide star in her native Australia, where she’s charted regularly since her next-big-thing emergence five years ago. Her latest album, On A Clear Night, places less emphasis on gentle piano-pop in favor of more tumultuous (but still pretty), “Grey’s Anatomy”-ready guitar pop. Singer-songwriters Eric Hutchinson and Julie Moffitt open for Missy Higgins’ 8 p.m. show tonight at the Turner Hall Ballroom.