Upper level structure of Oklahoma tornadic storms on 2 May 1979, Pt. 1 Radar and Satellite observations

This paper discusses the observational characteristics of the upper level structure of severe tornadic storms in Oklahoma on May 2, 1979, during SESAME. The data analyzed consist of limited-scan GOES-East and -West visible, IR (11- mu m), and stereo statellite data, dual-Doppler radar observations, and special storm-scale soundings. The time histories of stereo cloud top height, minimum equivalent blackbody temperature (T sub(B) sub(B) ), and radar reflectivity are followed for three severe storms over a several-hour period; two of the storms were tornadic. Cloud top IR growth rates and vertical velocities of the storms were computed and found to have maxima within Adler and Fenn's severe storm classification. For one of the storms, an interesting coupling occurred between cloud top parameters and low-level radar echoes; the other tornadic storm showed no unique relationship. Hail damage began shortly after tropopause penetration by these storms. Two major IR cold areas associated with the leading downwind storm (i.e., Lahoma storm), were both similar to 10 degrees C lower than the minimum (tropopause) temperature in an upwind sounding. One was displaced upwind similar to 15 km from the visible cloud top and the inferred updraft position from radar; the other was located similar to 15 km to the south of the visible cloud top. A V pattern of lower T sub(B) sub(B) with embedded higher temperature (warm areas) developed after tropopause penetration by the Lahoma storm. Composites of stereo height contours on IR images indicate that T sub(B) sub(B) was not uniquely related to height. The warm areas are deduced to be of two types: one, called the close-in warm area, was located similar to 10-20 km downwind of the cloud top of the Lahoma storm, and the other, called the distant warm area, was similar to 50-75 km downwind. The close-in warm area had a motion similar to that of the storms and appears to have been dynamically linked to the leading storm. A model is proposed to explain this warm area, based on mixing processes and subsidence near cloud top. The distant warm area advected with a direction similar to the 9-14-km upper level winds, but with a speed 10-20 m sec super(-) super(1) lower. This appears to have been anvil cirrus material. However, the T sub(B) sub(B) in this area were several degrees warmer than the stratospheric environmental temperatures at the anvil top. Stratospheric above-anvil cirrus (Fujita) explains neither the V shape nor the intern