Title: “Continuing Studies of Cool- and Warm-Season Precipitation Events over the Northeastern United States”

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2005
• Subjects: Pacific; North Atlantic; North Atlantic oscillation
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.666.3957; http://cstar.cestm.albany.edu/CSTAR_docs/CSTAR+10-21-05.pdf

Past research has indicated that reconfigurations of large-scale flow regimes can alter regional weather patterns due to shifts in storm tracks and associated eddy transports of heat, momentum, and vorticity. Conventional wisdom also suggests that high-impact weather events tend to occur during large-scale regime transitions. Motivated by these considerations, this research investigates relationships between large-scale regime transitions and Northeast precipitation in the cool season (November–April) from a statistical and synoptic perspective. In this study, a regime transition is defined as a two-standard-deviation change centered on zero in the North Atlantic Oscillation (NAO) index or Pacific/North American (PNA) pattern index over a seven-day period. To identify regime transitions, a 56-year database (1948–2003) of daily NAO and PNA indices was generated from the National Centers for Environmental Prediction (NCEP)–National Center for Atmospheric Research (NCAR) reanalysis dataset. A daily precipitation anomaly database for the Northeast was derived from the Unified Precipitation Dataset (UPD) for the same 56-year period. Key statistical results indicate that transitions from positive to negative NAO regimes and from negative to positive PNA regimes are associated with enhanced precipitation in the Northeast.