706 Evolution of summer thunderstorms in the Baltimore-Washington, DC metropolitan area

Wednesday, 26 January 2011
4E (Washington State Convention Center)
Cassie A. Stearns, Howard University, Washington, DC; and E. Joseph, A. E. Reynolds, G. M. Heymsfield, D. Venable, and B. B. Demoz

Summer thunderstorms are a common phenomenon in the Baltimore-Washington, DC Metropolitan Area. While most of the storms originate in the Ohio River Valley and strengthen over the Blue Ridge, the development of the storms once they enter the region varies dramatically. While many dissipate when entering the corridor, some storms remain strong or intensify such as the storms on July 25 and August 5, which left 250,000 people and 120,000 people without power for several days. Furthermore, the behavior has often been observed to be inconsistent along the line: the system will fall apart over the Baltimore Washington corridor, while remaining strong in Baltimore and south of DC.

During the summer of 2010, a joint study took place between NASA Goddard Space Flight Center and Howard University to understand the characteristics and evolution of thunderstorm lines in the Washington-Baltimore metropolitan area. The purpose of this study is to better understand how local conditions such as topography, land use and moisture distribution affect the development of local convective systems.

A unique and unprecedented mix of atmospheric observation systems were employed over the region to investigate factors that may determine the evolution of these convective systems particularly those related to land attributes. Convective systems were observed using a combination of instruments. Storm tracking and climatology was derived from Nexrad WSR-88D (1988 Doppler) Weather Surveillance Radar data, while storm structure was identified using the vertically pointing EDOP radar at Goddard Space Flight center. Antecedent conditions prior to the line passage were recorded from rawinsondes, Raman, and wind lidars, microwave radiometers, wind profiler and surface flux measurements from the Howard University Beltsville Research Campus. The information gained from this study can be used in the future to improve forecasts of storms in the area, and be applied in the design of future expansion.

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