Snow has already fallen in the Great Smoky Mountains, and temperatures in Oak Ridge and Anderson County are expected to dip into the low- to mid-30s through Friday as Hurricane Sandy moves into the mid-Atlantic and brings cold air to the Southern Appalachians, the National Weather Service said Monday.

The NWS said Hurricane Sandy is expected to make landfall along the central New Jersey coast later this evening or tonight, and produce a life-threatening storm surge, hurricane-strength winds, and heavy snowfall in the Appalachian Mountains.

Forecasters have issued a winter storm warning for southwest Virginia and the East Tennessee mountains through 8 a.m. Wednesday. A winter weather advisory is in effect for parts of northeast Tennessee from 8 p.m. Monday to 8 p.m. Tuesday.

Several flights from McGhee Tyson Airport to the northeastern United States have been delayed or canceled today due to the storm.

“This is expected to be the first of many flights inpacted by Hurricane Sandy over the next few days,” the Metropolitan Knoxville Airport Authority said on its website.

National Weather Service forecasters said blizzard conditions are possible at elevations above 3,000 feet in East Tennessee.

The seven-day forecast for Anderson County said rain or snow showers are possible tonight and Tuesday.

The National Weather Service said the heavy snowfall is expected to be dependent upon elevation, with no snowfall or light accumulations in most valleys.

The airport authority said most airlines are waiving flight change fees if passengers rebook by Nov. 4, but each airline is slightly different in this policy “so visit your airline’s site for more specific information.”