Anomalous wintertime precipitation in the western United States and related meteorological variables

Abstract

Significant anomalies of monthly precipitation in the western United States are related to (1) anomalies of sea-surface temperatures in the eastern North Pacific Ocean, (2) anomalous flow associated with departures from normal sea-level pressure, and (3) differences in the flux of moisture. Examples are given shewing that large-scale anomalies of temperatures of the ocean surface are coherent, making detection from month to month possible; these anomalies greatly influence the circulation of the overlying atmosphere and, in turn, are influenced greatly by the ever-changing atmospheric flow. The underlying ocean controls the development of large cyclones and anti-cyclones that persist for weeks, months, or even seasons by being a main source of moisture and energy. ...