"THE WASHINGTON DC TORNADO OF 24 SEPTEMBER 2001: PRE-STORM ENVIRONMENT AND RADAR PERSPECTIVES PLUS A PRELIMINARY LOOK AT THE 28 APRIL 2002 LA PLATA MARYLAND F4 TORNADO "
During the peak of afternoon rush hour on 24 September
2001, an uncommonly strong tornadic supercell thunderstorm traveled across
heavily populated portions of the Washington DC metropolitan area. This
supercell produced an F3 tornado that tracked across the University of
Maryland College Park campus killing two students and injuring 55 others.
Damage produced by tornadoes generated by this supercell have reached $100
million. No tornado rated F3 or higher had struck within the Washington
Capital Beltway in more than 75 years. Also noteworthy: this supercell,
produced an F1 tornado which passed within 0.5 km or less of the Pentagon,
the Jefferson Memorial, and the Washington Monument. Earlier this same
afternoon, another supercell produced an F4 tornado (the ““Rixeyville””
tornado), in north-central Virginia, southwest of Washington, DC. These
two supercells combined to produced a total of five tornadoes with path
lengths ranging from 10 to 30 km long and rated F3 (MD area) and F4 (Rixeyville).
Both supercells were classified as ““low-topped”” (less than 12 km in vertical
depth).
This talk focuses first on the meteorological environmental
factors that led to development of supercell thunderstorms on 24 September
2001. Second, radar analysis of the tornadic supercell that tracked across
the Washington DC region will be provided. Of particular interest in this
case is the importance of rapid tornadogenesis due to the apparent interaction
of a narrow band of rain showers with the supercell. Finally, factors involved
in the warning decision-making process will be briefly reviewed.
Also, on 28 April 2002, a devastating long-track tornado
struck the southern Maryland counties of Charles and Calvert. This tornado,
which killed three people, was rated F4 as it tore through La Plata,
Maryland. A brief look at pertinent meteorological data, including radar,
will be presented.