The Tulia outbreak storm: mesoscale evolution and photogrammetric analysis
Rasmussen, Erik Nels
Supercell thunderstorm structure and evolution is examined on several length and time scales using evidence from the 28 May 1980 Tulia Outbreak storm. Conventional meteorological data are combined with storm intercept team observations and photographic data to perform this analysis. New motion picture photogrammetry techniques are described and used for tornado analysis, and errors arising in photogrammetry are determined. It is found that the storm was triggered by a surface dryline, developed in a favorable environment, and intensified in an area of strong surface temperature gradients. After the storm collapsed it showed cyclic variations in intensity which corresponded to stages in cyclic tornado evolution. The photogrammetry results include a number of new findings. The three-dimensional flow structure is revealed and axial asymmetries are documented. In addition, time variations in tornado morphology, translation, and strength are documented.