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.
A tropical wave is likely to become the Atlantic Basin's next tropical storm as it approaches or crosses the Caribbean Sea later this week.
Bouts of wet weather will soak the northeastern United States during the last full week of September.
Typhoon Megi will threaten lives and property across Taiwan and eastern China into the middle of the week.
Gusty winds will accompany a push of chilly air across the Great Lakes through Tuesday.
The final day of September will bring a rare lunar event that hasn’t occurred since March of 2014, a Black Moon.
Following some rain and gusty winds on Tuesday, a strong storm will target the United Kingdom on Thursday.
New England (1816)
"Black Frost" over all New England killed still unripened corn.
Georgetown, GA (1822)
Hurricane killed 125 people.
South Carolina Coast (1893)
1,000 to 2,000 people died when hurricane battered coast.