The Suppression of Deep Moist Convection near the Southern Great Plains Dryline

Abstract

Abstract Deep moist convection failed to initiate over the Texas Panhandle on 6 May 1995 despite expectations to the contrary by the forecasters for the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX). The National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis is used to identify a midlevel migratory short-wave ridge propagating across the area during the time of maximum diurnal heating. Subsidence values of 1.0 × 10−3 hPa s−1 for a period exceeding several hours were associated with the ridge and led to substantial (∼3 K) warming in the midlevels and to the formation of a strong inversion around 600 hPa. A number of independent observations are examined to corroborate the hypothesis that the passage of the midlevel short-wave ridge at the time of maximum diurnal heating is ultimately responsible for the absence of deep moist convection. Twelve-hour forecasts of the 1995 NCEP operational model suite and the Pennsylvania State ...