Many ingredients are required for the formation of severe weather in the central and eastern parts of the United States. One of these factors, which is most difficult to forecast, is the timing and location of the return of warm, moist, unstable air from the Gulf of Mexico. This research is part of a larger National Oceanic and Atmospheric Administration (NOAA) led project which seeks to improve understanding of the modification of cold air outbreaks as they move over the warm Gulf waters. Of particular interest are the nature of this airmass modification and the factors which control it. A combined modelling and observational approach is planned including a small field program. Observational systems will include the NOAA P-3 research aircraft, supplemental soundings from National Weather Service (NWS) upper air stations and satellite data. Four Cross-chain Loran Atmospheric Sounding Systems (CLASS) from the National Science Foundation sponsored National Center for Atmospheric Research will be used to improve the spatial density of the sounding information available from the NWS sites. Three of these systems will be placed in the Gulf of Mexico -- two aboard research vessels and one on an oil drilling platform. The data collected from this ensemble of instrumentation will be the most complete to date on airmass modification over the Gulf.
