As millions of Americans hunker down for a massive winter storm sweeping the country, new maps are offering updated forecasts of snow and ice accumulations.

A winter storm already spreading snow across the Southeast will strengthen rapidly into a bomb cyclone with hurricane-force wind gusts over the next 24 hours.

The storm could ultimately impact more than 1,000 miles of the Atlantic coastline, but its worst conditions are likely from Georgia up to southern Virginia and southern New England.

Get ready. Snow is on the way. A significant winter storm will pummel Upstate New York Sunday through Monday, with forecasters predicting most areas will see between 10 and 20 inches of snow.

Upstate New York could see several more inches of lake-effect snow through Saturday morning, with the heaviest totals focused near Lake Ontario.

The region is expected to receive between 7-12 inches of snow Saturday and into Sunday, with higher amounts possible, the National Weather Service said.