Relationships between the pacific/north american teleconnection patterns and precipitation events in the south‐eastern USA

Abstract

AbstractPrecipitation event attributes, defined as the amount, duration, and frequency of individual rainstorms, vary considerably from place to place and season to season. Event variability is caused by a combination of large‐scale and local climate processes. Correlations of seasonal time series show that the Pacific/North American (PNA) teleconnection pattern and local rainfall event attributes are significantly related in specific areas of the south‐eastern USA in some seasons. Shifts in the zonal/meridional flow over North America affect both the number of events and the event size. The total number of events in some regions changes by as many as 10 to 12 events per season with shifts in continental‐scale circulation. An analysis of attribute distributions shows that the percentage of total events falling into selected intensity categories may also change by as much as 10 per cent between flow regimes. Relationships have both temporal and spatial patterns. Shifts in continental‐scale circulation affect event attributes most strongly in winter, with more events occurring in zonal years. Events with greater amounts and durations are found east of the Appalachians in meridional years and west of the mountains in zonal years.