United States

By Alex Sosnowski, Expert Senior Meteorologist

September 16, 2012; 4:40 AM

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Water rushes down the steps of the Lincoln Memorial in Washington, D.C., on Thursday, Sept. 30, 2010, during a downpour. The storm, spanning Sept. 29 and Oct. 1, ended up bringing about 5 inches of rain to the city. (AP Photo/Jacquelyn Martin)

Drenching downpours with beneficial rain for some people and urban flooding problems for others will affect the Appalachians and the Atlantic coast this week.

A storm system that recently brought flash flooding to the Southwest will continue to take a slow path across the South Central states this weekend, and will then wash slowly northeastward reaching the mid-Atlantic and New England I-95 corridors by late Monday and Tuesday.

The system brought some much-needed rain to portions of Texas, Oklahoma, Missouri and Arkansas, with some areas receiving around two inches of rain.

As the system moves farther east, topography, increasing atmospheric dynamics and moisture from the Gulf of Mexico will be joined by Atlantic Ocean moisture.

According to Expert Meteorologist and Senior Vice President, Dr. Joseph P. Sobel, "There is the potential for 2 to 4 inches of rain in parts of the Tennessee Valley, the Appalachians and the upper East Coast with this event."

While the benefits of rain in portions of the Mississippi, Tennessee and Ohio valleys are obvious with drought ongoing in many areas, flash and urban flooding issues could take center stage around the Appalachians and major cities.

"Some small streams could rapidly fill, and disruptions to outdoor activities, roadway commutes and flights are possible as the blinding downpours move slowly along," Sobel said.

Timing of the most prolific downpours would be from Monday afternoon into Monday night in Atlanta, late Monday into Tuesday in Charlotte, N.C., from late Monday night into Tuesday afternoon in Washington, D.C., throughout the day Tuesday in New York City and Tuesday afternoon into Tuesday night in Boston.

The heaviest rain could stay over the mountains north of Atlanta and northwest of Charlotte and may also pass south of major Ohio River metro areas of Louisville and Cincinnati. However, some problem-causing rain may reach the Laurel Highlands southeast of Pittsburgh, and many locations in the South will still be on the receiving end of a few downpours.

Folks will want to check on their local AccuWeather.com forecast and radars before venturing out as the system advances.

Beforehand, a cool front swinging rapidly eastward from the Midwest will bring spotty thundershowers that quickly leave the Northeast during the first part of the weekend as well as another breath of autumnlike air.