%0 Journal Article
%T Analysis and Forecast of a Tornadic Thunderstorm Using Multiple Doppler Radar Data, 3DVAR, and ARPS Model
%A Edward Natenberg
%A Jidong Gao
%A Ming Xue
%A Frederick H. Carr
%J Advances in Meteorology
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/281695
%X A three-dimensional variational (3DVAR) assimilation technique developed for a convective-scale NWP model¡ªadvanced regional prediction system (ARPS)¡ªis used to analyze the 8 May 2003, Moore/Midwest City, Oklahoma tornadic supercell thunderstorm. Previous studies on this case used only one or two radars that are very close to this storm. However, three other radars observed the upper-level part of the storm. Because these three radars are located far away from the targeted storm, they were overlooked by previous studies. High-frequency intermittent 3DVAR analyses are performed using the data from five radars that together provide a more complete picture of this storm. The analyses capture a well-defined mesocyclone in the midlevels and the wind circulation associated with a hook-shaped echo. The analyses produced through this technique are used as initial conditions for a 40-minute storm-scale forecast. The impact of multiple radars on a short-term NWP forecast is most evident when compared to forecasts using data from only one and two radars. The use of all radars provides the best forecast in which a strong low-level mesocyclone develops and tracks in close proximity to the actual tornado damage path. 1. Introduction Doppler radar observations became more widely used as an analysis tool since the 1970s, by mapping polar coordinate radial velocity data to a Cartesian grid space. Results in Brandes [1] showed the evolution of a supercell including an intensifying mesocyclone and development of the rear-flank downdraft (RFD), as observed by a dual-Doppler analysis. Additional study was done using this technique in Brandes [2] where the airflow within a tornadic thunderstorm was compared with the observed tornado damage path. Brandes [2] also found that, at the beginning of the tornadic phase of a supercell thunderstorm, an increase in radial flow near the tornado was observed in the radar data analysis. This helped determine that there was a strongly convergent flow beneath the mesocyclone during this time. Another major development in the use of Doppler radar was the discovery of a unique Tornado Vortex Signature (TVS), that coincided with the development of low-level rotation and tornadogenesis in the 1973 Union City tornado [3]. The development of this signature was closely linked to the mesocyclone structure model found in Lemon and Doswell [4]. With the frequent use of dual-Doppler analysis and increased resolution of storm scale models, data assimilation has become an important area of research that integrates observations into a numerical weather
%U http://www.hindawi.com/journals/amete/2013/281695/