© CNNThe mid-Atlantic and Northeast U.S. could see combinations of rain, sleet and snow on Christmas Eve and Christmas Day.
Delta Air Lines has pre-emptively canceled approximately 500 Christmas Day flights, a company spokesman said, as it and other U.S. airlines work to get ahead of a storm that's threatening the East Coast.
Morgan Durrant, a Delta spokesman, said Friday that the airline has canceled roughly 300 flights in and out of Atlanta and 200 more elsewhere around the country.
Delta also has joined Continental, United and AirTran in waiving penalties for travelers who have to reschedule their trips over the weekend.
The mid-Atlantic and Northeast could see combinations of rain, sleet and snow, with the heaviest amounts of precipitation in highest elevations, CNN meteorologists said.
It's too soon to say how serious the storm system will become, forecasters say, adding that by Saturday morning the scenario will be clearer.
Comment: From USGS website: