A surprisingly perfect role for two-time Academy Award winner Emma Thompson (Sense & Sensibility, Howards End), the Brian Kirk-directed Dead of Winter centers on Thompson’s grounded, realistic portrayal of a working class, Minnesota woman, Barb (accent and all), understandably mourning the recent loss of her longtime husband, Karl (Paul Hamilton), in the middle of an ice-cold, snow-covered midwestern winter (hence the title). Extraordinary in her obvious ordinariness, Barb has spent all — or most of — her adult life surviving Minnesota’s harsh, unforgiving winters, making her unexpectedly prepared for an inadvertent run-in with an unnamed, middled-aged couple identified in the credits only as Purple Lady (Judy Greer, impressively persuasive as Barb’s eventual antagonist) and Camo Jacket (Marc Menchaca), when she ventures far into the…