Thunderstorm Sequence - August 1, 2002

Late in the afternoon of August 1, 2002, stationary thunderstorms began to form south of Baltimore, Maryland. New storms tended to redevelop to the south and west of the previous storms. Washington, D.C. was directly in the path of the developing thunderstorms. At 6:30 p.m., cumulus clouds formed east of D.C. The clouds moved slowly south while growing larger. Soon, a rainshaft developed. Less than an hour later, lightning began to strike. The storm was almost stationary -- moving very slowly to the south and west. Cloud-to-ground lightning became frequent and heavy rains fell near Alexandria, Virginia. Later in the evening, a flash flood warning was issued for Alexandria and southeast Fairfax, County.

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1) Cumulus clouds form east of D.C. and move south -- 6:30 p.m.

2) Clouds expand -- 6:50 p.m.

3) A rainshaft develops just southeast of D.C -- 7:15 p.m.

4) View looking up at the storm -- 7:55 p.m.

5) The storm grows and remains almost stationary -- 8:00 p.m.

6) The storm expands and produces lightning -- 8:15 p.m.

7) Frequent cloud-to-ground lightning and heavy rain occur south of D.C. -- 8:30 p.m.

8) Lightning within a thunderstorm creates an explosion of light, setting a dramatic backdrop for the Washington Monument -- 9:00 p.m. Photo Credit: Kevin Ambrose