The National Weather Service has issued blizzard warnings for Washington D.C. and Baltimore, marking the first blizzard warnings issued in advance of Winter Storm Jonas, a system now developing over the Plains states and expected to turn into a powerhouse winter storm by the time it reaches the East Coast Friday and Saturday.

The blizzard warning goes into effect at 3 p.m. Friday in the nation's capital and 6 p.m. Friday in Baltimore. The warnings also include the surrounding suburbs of both cities in Maryland and northern Virginia, as well as a narrow strip of higher terrain paralleling Interstate 81 in north-central Virginia.

Snowfall totals of 18 to 30 inches and sustained winds greater than 30 mph are expected across this region late Friday through early Sunday. The combination of heavy snow and high winds will create near-zero visibility in whiteout conditions. Major highways will likely be forced to shut down during the height of the storm.

More than 70 million Americans are under watches, warnings or advisories in the path of Winter Storm Jonas, which has already produced more than 9 inches of snow in parts of Nebraska and Kansas. The worst of the storm is expected to target the Mid-Atlantic states Friday through early Sunday.

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