On "Ah Mary," the opening track on Grace Potter and the Nocturnals' THIS IS SOMEWHERE, the chorus erupts in a radio-ready pop-rock blast, complete with cranked guitars and a singalong chorus. This might seem to indicate a change in Potter's roots-oriented, country-blues approach, and THIS IS SOMEWHERE does have its share of pop garnish, but Potter never loses sight of tradition. Emotive and soulful, Potter still takes a page from Bonnie Raitt and Lucinda Williams, and manages to remain authentic and folksy even when her overall sound gets gussied up for the city.