Melissa McCarthy, a comedian best recognized for her full-throated and dim-witted style, stays close to home and character in “Tammy,” a Midwestern road trip that provides comic relief in a summer season largely dominated by apocalyptic action. Co-written with her husband, Ben Falcone, who also makes his directorial debut, the film tells the story of McCarthy’s Tammy, a coarse fast-food worker who loses her job, car and husband in an evening, and rashly takes off on a road trip with her hard-drinking grandmother Pearl, played by Susan Sarandon.
