The Influence of the El Nino-Southern Oscillation and North Atlantic Oscillation on Wintertime Weather in the Ohio and Tennessee Valleys
Standard deviations and averages were calculated for each station and weather variable in the study region. Preliminary results for NWS Louisville's area of responsibility (central Kentucky and southern Indiana) indicate that a combined La Nina/Positive NAO pattern has the greatest impact, with warmer than normal temperatures, above average precipitation, and below average snowfall for the December-January-February period. Results also show that the most significant cold, dry winters occur during an El Nino/ Negative NAO pattern. Preliminary findings for all NWS offices in the Ohio and Tennessee Valleys will be discussed. Near future work will concentrate on other types of statistical analyses and using similar procedures on other weather phenomena.
This multi-faceted study will allow forecasters to identify upcoming seasonal trends to facilitate a Weather-Ready Nation by answering customer questions as they prepare for unique cyclical weather challenges. In addition, forecasters will be better equipped to anticipate day-to-day weather patterns and storm behavior based on ENSO and NAO phase combinations to enhance user decision support.