Mike Chesterfield, Lead Meteorologist, The Weather Channel

Feb. 4, 2010 1:29 am ET

A storm system currently developing in the western Gulf of Mexico promises to leave quite a legacy across the South and East by the time it exits the country late Saturday.

Moderate to heavy rain will move out of eastern Texas into the Mississippi Valley today. The rain will reach the Southeastern US and Tennessee Valley by tonight.

Ice-covered trees and power lines may result in sporadic power outages by Friday morning.

While the South will begin to dry out by late Friday, attention will turn to a significant snowstorm taking shape across Ohio Valley into the Mid-Atlantic.

A band of moderate to occasionally heavy snow will develop later this afternoon around the Saint Louis area then stretch eastward reaching the Indianapolis area tonight then as far east as Pittsburgh by Friday.

This area of real-estate will end up with four to as much as eight inches of snow by the time the snow ends Friday night.

As impressive as these forecasted snowfall amounts may be they will pale into comparison to what is going to fall in Northern Virginia, Maryland, Delaware and southeastern Pennsylvania.

Over a foot of snow is likely to fall in the Beltway of Washington and Baltimore by Saturday evening.

Heavy snow will extend as far north as Philadelphia where six to nine inches of snow is possible by the time all is said and done.