The Pacific Decadal Oscillation (PDO), El Nino-Southern Oscillation (ENSO), and the North Atlantic Oscillation (NAO) have produced conditions favorable for monthly extreme temperatures and precipitation. These climate modes produce teleconnection patterns that favor regional droughts, floods, heat waves, and cold spells, and these extremes impact agriculture, forestry, and transportation. The above sectors prefer the worst (and sometimes the best) case scenarios. To ease prediction of these extremes, one should know the teleconnections, including upper atmospheric wind and height anomalies, that influence these events. This study examines the worst and best case scenarios for each phase and the combination of phases that produce the greatest monthly extremes.

This study examines extreme monthly temperature and precipitation for each phase of the three climate modes. Data from stations in Canada, Mexico, and the United States are gathered from the Global and United States Historical Climate Network, and 55 years from these stations bootstrapped to produce larger time series. All stations share the same list of bootstrapped dates to maintain consistency. The bootstrapped data are sorted, and the first, tenth, ninetieth, and ninety-ninth percentiles will be analyzed. After that, these extremes are analyzed against bootstrapped gridded upper atmospheric data obtained from NCEP-NCAR reanalysis data. It is expected that the upper air patterns in these extreme percentiles differ from the means. The upper data are used to analyze teleconnections between the climate modes and the extreme monthly temperature and precipitation events.