A severe storm will slam the eastern U.S. with rain, thunder, wind, snow and possibly a tornado, weekend predictions show. Rough weather will span across 1,200 miles, from the Gulf Coast to Canada, bringing with it the threat of power outages and tree damage, forecasts from CNN and the Weather Channel show. Severe thunderstorms will hit late Saturday morning in the South, which could see hail, strong winds or a tornado, CNN reports. The region bordered by eastern Texas, western Tennessee and northern Alabama could see storms strengthen by Saturday afternoon, the report shows. Up north, snow is…