Regionalized correlations between atmospheric teleconnections and tornado frequency in the United States
While in a typical year, approximately 1,000 tornadoes occur within the contiguous United States, the number is highly variable from 700 to almost 1200. This variability is not easily forecast on a yearly basis. ,Through the application of teleconnection patterns such as the El Nino/Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), and Pacific-North America Pattern (PNA), it is shown that relationships exist between the phase of these large-scale atmospheric circulation anomalies and tornado frequency in different regions of the United States. Correlation analysis for each phase of the different patterns show that regionality exists when considenng the pattern's correlations with tornado frequency. These patterns are reasonably explained through the use of NCEP/NCAR Reanalysis data. The most interesting result from this study is that the NAO and PNA patterns yielded similar stateby-state correlation patterns, suggesting that the two patterns may be linked as has been suggested by prior research.