The National Weather Service has issued a winter storm warning for parts of West Virginia, the first warning issued in advance of Winter Storm Jonas.

The warning, issued by the NWS office in Charleston, West Virginia, includes nine counties in the higher elevations of the state east of Charleston. Elkins and Snowshoe are among the locations in the winter storm warning, which goes into effect at 7 p.m. Friday and continues through 1 a.m. Sunday. The Weather Channel forecast calls for 15 to 20 inches of snow across much of the warning area.

Earlier in the day, the National Weather Service issued the first watches ahead of Jonas, including a blizzard watch for the Baltimore and Washington, D.C., areas. That blizzard watch remains valid from Friday afternoon through Saturday night.

Winter storm watches are in effect in a swath from eastern Arkansas to northern New Jersey. The winter storm watches and blizzard watches include about 47 million Americans. Winter weather advisories for the early stages of Winter Storm Jonas are in effect for another 4.6 million people from southern Nebraska through parts of Kansas and Missouri, including the Wichita and Kansas City areas.

For winter storms, including blizzards, a watch means hazardous winter weather is possible; a warning means hazardous winter weather is occurring or imminent.

Stay with The Weather Channel and weather.com for continuing coverage of Winter Storm Jonas.