While a storm system moving up from the South will be past peak, the system may pack enough punch to bring locally severe thunderstorms and flash flooding part of the Ohio Valley and East Coast into Tuesday night.
**Flash flooding occurred in the Gaithersburg and Germantown, Md. area during the midday Tuesday. Flash flooding expanded to multiple areas north and west of Washington, D.C. and Baltimore during the afternoon. Thunderstorm winds damaged homes in the Anderson, S.C. area during the morning Tuesday.**
According to Severe Weather Expert Henry Margusity, "As an upper-level disturbance associated with the storms system lifts northward the right conditions could develop to produce a few thunderstorms with high wind gusts, hail and even a short-lived tornado."
The violent storm risk area extends from eastern Kentucky to much of West Virginia and central and southern Ohio and southwestern Pennsylvania during Tuesday.
Cities that could be impacted by the storms include Cincinnati, Dayton and Columbus, Ohio; Lexington and London, Ky.; Charleston, Huntington and Morgantown, W.Va.; and Pittsburgh, Pa.
Key to the potential of the storms is how much daytime warming occurs.
"If these areas remain cloudy much of the day, there may not be enough energy and rising air to get severe thunderstorms going," Margusity said. "Provided the storms do develop, atmospheric conditions indicate a fair amount of wind shear, which can lead to damaging wind gusts and perhaps a couple of tornadoes."
Because of cloud-cover issues, an large outbreak of severe weather is not expected, but rather only isolated severe storms.
Some of the storms bringing the severe weather may not have a great deal of lightning strikes associated with them and may sneak up on some locations as a result.
Other thunderstorms will affect the Atlantic Seaboard during Tuesday and a couple of these storms could be heavy and gusty in the I-95 swath from Florida to New York and part of the I-81 corridor farther west.
By heavy and gusty we mean there is not only the potential for damaging wind gusts, but also incidents of flash and urban flooding.
"These areas will be the warmest within the storm system's reach, but the main wind energy will be directed northward toward the upper Ohio Valley, rather than toward the East Coast," Margusity added.
While the storm system is weakening, it will have enough energy and moisture to bring areas of rain into the Northeast into Wednesday.
Big changes are on the way for parts of the Western and Central states late this week and into this weekend.
Similar to the days prior to Thanksgiving, the worst weather will focus on the days prior to Christmas as millions of travelers take to the roads and skies in the U.S. and southern Canada.
Despite a brief warmup in Chicago, wintry conditions will span the weekend.
Warm air is forecast to surge into much of the eastern half of the nation by the weekend and will be accompanied by heavy rain and flooding risk in some locations.
Thunderstorms in parts of the South this weekend may become strong enough to threaten lives and property.
Tune in weekdays at 7 a.m. EST for the latest edition of AccuWeather LIVE.
SW Arkansas (1967)
A 200 mile wide tornado killed people along its 15 mile path from Waldo to near Bueana Vista. People from one house were carried 250 yards and cars were said to have been carried 600 yards.
Philadelphia, PA (1991)
High of 30 degrees; only 5th day in 1991 with a high below freezing.
Riverside RS (Yellowstone Park), WY: -59 degrees, lowest U.S. temp in December.