700-mb warm air advection as a forecasting tool for Montana and northern Idaho

"The purpose of this report is to describe and show synoptic weather patterns and case histories in which 700-mb level warm air advection was one of the important tools in forecasting precipitation over Montana and northern Idaho. Because of the mountainous terrain, it is felt that the 700-mb chart represents more clearly the temperature advection, wind field, and available moisture than either the 8S0-mb or SOO-mb charts. In this report three ideal 700-mb flow patterns with wind direction from the southwest, west, and north wiII be shown. A case study wiII be presented for each flow pattern and wiII show the 12-hour synoptic trend at the surface and 700-mb levels, usually 12 to 24 hours prior to the onset of precipitation. From the 12-hour synoptic trend, a basic criterion is established to be used as a guide in the forecasting of warm air advection precipitation"--Introduction. Norris Warner. Includes bibliographical references (page 6). 1971 NWS (National Weather Service) WR (Western Region) Library Public Domain 1931