A rapidly strengthening storm is expected to develop off the Southeast coast this weekend amid a deadly cold outbreak, bringing a high likelihood of snow and strong winds to parts of the Carolinas and southern Virginia - just days after a historic winter storm blasted large parts of the East Coast.

That uncertainty is not unusual at this early stage. Forecasters rely on a blend of weather models — computer simulations used to predict future conditions — and they are more confident in a forecast when most of those models are consistent with one another. The closer the storm is, the more confident forecasters become.

At least 13 people have died and hundreds of thousands across the US are without power as a winter storm sweeps through the country.

TOLEDO, Ohio — The term "bomb cyclone" has become a staple of winter weather headlines, but for meteorologists, it describes a specific and powerful atmospheric process rather than just a heavy snowstorm. As a significant weather system moves toward the ...