Southeastern US daily temperature ranges and predictability with El Niño Southern Oscillation

The diurnal temperature ranges (DTRs) in the Southeastern United States have a wide distribution of magnitudes, and patterns in this distribution are witnessed on both spatial and temporal scales. DTRs on the upper-tail of the distribution can exacerbate thermal stress on animals or tax a power grid; therefore an accurate seasonal prediction of these climate-driven fluctuations will be helpful for the equestrian, cattle, and energy industries. It is hypothesized that DTRs vary with respect to the climatological phase of the El Niño Southern Oscillation (ENSO). ENSO has well documented impacts on temperatures in the Southeast US, especially in the winter months. A 50-year record of quality-controlled temperature observations collected from the National Weather Service's Cooperative Observing Network (COOP) is being used for analysis. Probability distribution functions (PDFs) are applied to show that DTRs vary in response to El Niño or La Niña with statistical significance. These varied responses will be presented both temporally and spatially across the region. Results show that DTRs are extreme, above 30 degrees Fahrenheit, with a higher probability during the La Niña phase compared to the mean, particularly during seasonal transitions. The converse is true for the El Niño phase. These results may allow seasonal predictability of the extreme DTR events depending upon the current (or expected) phase of ENSO.