Abstract:
Previous research based upon examinations of previous weather events speculates that the El Nino/Southern Oscillation affects severe weather in the United States. However, in this study, thermodynamic and kinematic parameters associated with severe weather are calculated from rawinsonde data to explore differences in the atmospheric stratification during the El Nino, La Nina, and Neutral ENSO phases. The soundings used in this investigation are taken over the southeastern United States during the winter season. Two separate datasets are examined: one of soundings from severe weather events and another of all 00UTC soundings. Surface-3km Storm Relative Helicity, Surface CAPE, and Surface-6km Bulk Shear are analyzed for the severe weather dataset, and results show that severe weather occurs under the same atmospheric conditions regardless of ENSO phase. For the dataset of all weather soundings, three thermodynamic parameters (Mean Layer CAPE, Surface Convective Inhibition, and Mean Layer 300mb Lifted Index) and three kinematic parameters (Surface-6km Bulk Shear, Surface-1km Storm-related Helicity, and Surface-3km Storm-Related Helicity) are examined. The results from this analysis reveal that the thermodynamic parameters favor storm development during the La Nina ENSO phase and that the dynamic parameters favor the El Nino and Neutral phases for severe thunderstorms.