A threat of heavy rain, along with an increased threat of severe thunderstorms, is expected on Wednesday. While the main threat of heavy rain and severe weather is expected south of Interstate 20, a few strong storms may occur north of the interstate as well.   While a few storms may become strong by mid morning, mainly across the East Texas Lakes and Toledo Bend area, the bulk of the adverse weather can be expected in the afternoon hour. A few storms may linger into the early evening across mainly north central Louisiana, the threat will rapidly diminish by later in the evening.