Forecast Problems in the Western Region of the National Weather Service: An Overview

Abstract

The western United States is a preferred location for persistent midtropospheric long-wavelength ridges at the planetary scale. This greatly affects the character of synoptic-scale disturbances that move through the region, and results in an increased importance of mesoscale process and their interaction with the complex terrain of the area. This article discusses some of the important large scale, synoptic-scale, and mesoscale factors as background for the following series of papers on specific western United States terrain-influenced forecast problems.