AccuWeather.com

By Alex Sosnowski, Expert Senior Meteorologist

Mar 12, 2010; 7:45 PM ET

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Streams and rivers already rising from melting snow and spotty rain into Friday will surge markedly over the weekend, leading to significant flooding in low-lying, unprotected areas.

The storm at hand this weekend is the latest in a series of storms during the winter of 2010 to foil plans, slow travel, disrupt power, cause damage, and tax budgets.

While it appears a disaster similar to that of January 1996 may be avoided in most areas, a few locations could approach those conditions as the weekend progresses.

Two prime areas of concern lie in the Catskills and the Alleghenies, where the snow cover is deep and loaded with water.

In the Alleghenies, rivers approaching flood stage Friday at midday included the Tygart, Youghiogheny and Monongahela.

Other rivers in the mid-Atlantic, including the Delaware, Ohio, Mohawk, Potomac and Susquehanna, were beginning to rise.

Inland interests in the Northeast should be prepared for a minor to moderate flooding event of streams and rivers from the Virginias to southern New York state and southern New England.

This concern is valid, even in areas without snow cover, as the expected 2 to 4 inches of rain on soggy ground alone can lead to significant flooding of low lying and urban areas along the Interstate 95 corridor from Washington, D.C. to New York City, Boston, and Portland, Maine. Strong winds and tidal flooding are another threat in coastal areas with this storm.

The bulk of the rain will fall late Friday night into Sunday morning. However, some rain will linger into Monday morning. Snow will be melting and running off through this time over many of the mountains.

Snow to the Rescue?

While some folks may not want to hear this, wet snow and colder air could come to the rescue in parts of the Appalachians.

There is potential for a change to wet snow in the Alleghenies, Endless Mountains, Poconos, Catskills and perhaps the Berkshires Saturday night into Sunday. If this changeover occurs, snow could pile up over the ridges.

The falling wet snow instead of rain would slow the runoff, as would temperatures in the middle 30s as opposed to temperatures in the 40s and 50s.

Northern New England Spared

Somewhat less rain and melting of snow are now expected over northern New England and should minimize or prevent flooding altogether in this instance. Other storms later in the month could track farther north and lead to flooding problems in these areas.

Be Prepared

There is potential for a few locations to receive double the general 2- to 4-inch rainfall. Where this happens, flooding may be rapid and severe in a small area, and is impossible to forecast hours in advance.

Have a plan of action in place in case floodwaters arrive quickly.

If your area is prone to flooding in the spring or during any episodes of heavy rain, now is the time to take precautionary action. Make sure the downspouts have not become dislodged around your home over the winter. Move valuables out of your basement. Park vehicles on high ground.