A TEST OF THE RELATION BETWEEN PRECIPITATION AND SYNOPTIC PATTERNS AT 200 AND 300 MILLIBARS

Abstract

A proposed method of forecasting the occurrence of precipitation by forecasting the field of vorticity advection at 300 mb is tested in this study by verifying the concurrent relationship between the two phenomena. A similar verification is made of the relationship between precipitation and the field of 300-mb height-change advection and 200-mb temperature advection. Better verification is attained by means of the latter two patterns. The principal conclusion reached is that upper level charts do not contain sufficient information to permit accurate forecasting of precipitation without additional information from levels below 300 mb.