Spatial Variability of Warm Season Echo Activity as a Function of Two Stability Indices Computed from the Yucca Flat, Nevada, Rawinsonde

Abstract

A radar echo survey for two warm seasons is used to determine the spatial variability of the relative frequency of occurrence of an echo day in six selected areas. These areas include the Las Vegas Valley, Lake Mead and the Spring Mountains, all located in extreme southern Nevada. Also included are the Tonopah and Nevada Test Site areas as well as the Cedar City, Utah, area. The occurrence of an echo in these areas is related to both the K and Z indices, calculated from the Yucca Flat, Nev., 1200 GMT sounding. The relative frequency of occurrence of an echo was determined for various categories of K and Z. The resulting charts should have practical value for estimating the probability of the occurrence of moist convection over mountainous terrain.