Authors: Robert Rohli*, Louisiana State University, Stephen P Caparotta, Louisiana State University
Topics: Climatology and Meteorology, Coastal and Marine, United States
Keywords: Severe Weather, Gulf of Mexico, Gulf Coast Cyclone, Madden-Julian Oscillation
Session Type: Paper
Start / End Time: 3:05 PM / 4:45 PM
Room: Buchanan, Marriott, Mezzanine Level
Presentation File: No File Uploaded
While much scholarly attention has been devoted to interannual and long-term trends in severe weather, intra-annual variability is often overlooked. Previous research has identified a connection between the Madden-Julian Oscillation (MJO) and intra-annual patterns related to tropical cyclogenesis, extratropical nor’easters, and other features of North American weather such as precipitation, temperature, extreme precipitation, tornadoes, and atmospheric rivers. Moreover, ongoing work is focusing on the relationship between the MJO and cyclogenesis and precipitation variability in the Gulf of Mexico. This research continues that theme by analyzing severe weather in the Gulf of Mexico region by MJO phase. Cool season reports of tornadoes, hail, and strong/damaging winds were analyzed for the 1979-2014 period, for the box bounded by 19-33°N and 100-80°W. The data used for the analysis were obtained from the National Centers for Environmental Information (NCEI) Storm Events Database (https://www.ncdc.noaa.gov/stormevents/ftp.jsp). Results of Monte Carlo simulations suggest that MJO Phases 7, 8, and 1 support active severe weather, while MJO Phases 4, 5, and 6 are associated with more tranquil conditions. Analysis of composite geopotential height anomalies and 300 mb wind anomalies reveals that the MJO influence is likely tied to modification of the Rossby wave train. These results could be helpful in weather forecasting of events that are likely to endanger life and property in a vulnerable region.