“Raw power,” “emotional complexity,” and “vibrant,” are words that have been used to describe Ana Popovic’s sound.  She’s a singer and guitar slinger and she’ll be at the Iron Horse tonight.  Big Blues Bender says, “Popovic is one of most exciting Blues performers you’ll witness with a universal expression of joyous abandon and ecstatic pleasure.” Well okay, then. Check her out. Tickets are $25. Iron Horse,  20 Center St., Northampton.