Santa Ana associated offshore fog : forecasting with a sequential model.

Abstract

Aircraft measurements made offshore during a coastal fog sequence by R.A. Markson are analyzed . Fog occurrence and areal extent are determined using aircraft, ship and shore station obs ervations obtained during the Cooperative Experiment in West Coast Oceanography and Meteorology--1976 along with analyzed satellite visual and iril’ra-red imagery. The offshore conditions are compared with those at the shore stations using selected fog indices. Photographs of special features observed are included . The offshore conditions are classified into phases by assigning limits within the specified fog indices used in the modified Leipper fog model. The sequence of observed fog events is compared to the ideal sequence. The trends in the sequence are analyzed and a general relationship between the phase sequence and the local offshore flow is indicated . The Leipper indices, the Sari Dieg~ . raob and the sequential fog model appear to ‘be useful in fog prediction for the nearshore oceanic region from San Diego to Point Conception.