Additionally, strong winds may knock out power lines in the Midwest, especially in areas where heavy snow fell last week and is already weighing down tree branches.Snow could fall as far south as Jackson, Mississippi, Memphis and Nashville in Tennessee and even Birmingham, Alabama, on Thursday.In anticipation of what will be a week of travel nightmares, United, American, Delta, Southwest and Jet Blue have issued travel waivers for dozens of airports across the country from the South to the Northeast, because in addition to snow covering roadways, low visibility could make air travel dangerous.The storm is expected to reach the pressure equivalent of a Category 3 hurricane as it reaches the Great Lakes, with the weather service describing the strength of the low a “once-in-a-generation” event.Blizzard warnings are in effect for parts of the Dakotas, Montana, Minnesota, Iowa, Indiana and Michigan – where travel conditions will become difficult to impossible as the storm peaks Thursday into Friday."