san angelo doppler weather radar in motion

San angelo doppler weather radar in motion verification#

On, several supercells developed over central Texas near San Angelo during VORTEX. Unfortunately, the examination of the Garden City supercell is only one case study, and its evolution may not be representative of other tornadic supercells. Wakimoto and Liu (1998) and Trapp (1999) suggest that this mechanism could have triggered tornadogenesis in the larger-scale mesocyclone. Rotunno (1984) has shown that this vortex can be unstable to three-dimensional perturbations accordingly, subsidiary vortices can form in an annular ring that surrounds the downdraft.

This downdraft has been referred to as the occlusion downdraft by Klemp and Rotunno (1983) and results in a two-celled vortex ( Rotunno 1984). This downflow terminates in low- level radial outflow that turns vertical in an annular updraft at an outer radius. Both studies arrived at the same conclusion: intense rotation within the low-level mesocyclone prior to tornadogenesis results in a downward-directed perturbation pressure gradient that induces a downdraft near the central axis of the mesocyclone. 1994) using two different airborne platforms.

San angelo doppler weather radar in motion verification#

Wakimoto and Liu (1998) and Trapp (1999) examined the Garden City, Kansas, mesocyclone during the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX Rasmussen et al. 1998 Trapp 1999 Wakimoto and Cai 2000 Dowell and Bluestein 2002a, b). Moreover, improvements in radar designs combined with increased skill in flying near these destructive storms has produced datasets that are able to resolve supercell structure in greater detail than was previously possible and also has raised a number of new questions concerning the processes that lead to tornadogenesis (e.g., Wakimoto et al. 1998 Wakimoto and Liu 1998 Wakimoto and Cai 2000 Ziegler et al. The introduction of airborne Doppler radars has provided a unique opportunity to place these mobile platforms in close juxtaposition with severe storms (e.g., Wakimoto et al. This type of tornadogenesis has not been previously shown. The unusual aspect of this tornado is that it appeared to develop outside of the low-level mesocyclone. No occlusion downdraft was resolved during this latter period. The mesocyclone evolved through a second period of intensification that produced a weak tornado that was visually apparent from the aircraft. The present study supports this hypothesis and provides the first quantitative view of the vertical structure of this downdraft. Recent studies have suggested that cold downdrafts inhibit the formation of tornadoes. An occlusion downdraft formed but was primarily driven by negative buoyancy rather than a downward-directed perturbation pressure gradient. The end of the first period of intensification did not lead to the formation of a tornado. The mesocyclone accompanying the storm went through two periods of intensification. The superposition of the Doppler wind syntheses with the cloud pictures provides a unique view of the relationship between the low-level mesocyclone and the developing lowered cloud base. Airborne radar analysis combined with cloud photogrammetry of a supercell that formed on near San Angelo, Texas, is presented.