Analysis of a California Catalina Eddy Event

Abstract

During the period 26?29 May 1968 a shallow cyclonic circulation, known 1ocally as a Catalina eddy, developed in the offshore waters of southern California. A synoptic and mesoscale analysis of the event establishes the following: 1) the incipient circulation forms on the coast near Santa Barbara downwind of the coastal mountains, 2) cyclonic shear vorticity appears offshore in response to lee troughing downstream of the coastal mountains between Vandenberg and Pt. Mugu, California, 3) mountain wave activity may be aiding incipient eddy formation in association with synoptic-scale subsidence and the generation of a stable layer new the crest of the coastal mountains, 4) a southeastward displacement and offshore expansion of the circulation occurs following the passage of the synoptic-scale ridge line, and 5) dissipation of the eddy occurs with the onset of a broad onshore flow.