Weather may hinder holiday travel

PHILADELPHIA (NBC) -- No major travel problems to report for the second half of the weekend, but that could soon change.

It was smooth sailing at airports and train stations across most of the country.

Airports in Philadelphia and Atlanta were crowded, but most flights were running on time Sunday.

But a major winter storm dumping steady rain and snow on the Sierra Nevada Mountains promises a white Christmas and travel headaches for a wide swath of the country.

Forecasters warn that roads could become treacherous Christmas Day and Christmas night from western Kansas eastward into Arkansas and the mid-Mississippi valley.

The storm is expected to reach the northeast Wednesday, bringing gusty winds and widespread precipitation.