Monthly climatological charts of the behavior of fog and low stratus at Los Angeles International Airport

Coordinates of arrival time and ending time are used to chart the monthly climatology of fog as well as very low stratus clouds at Los Angeles International Airport. Nineteen years of record and special observations are charted by seasons and months in two categories: Fog (less than 200-foot ceiling and/or visibility less than 1/2 mile) and low stratus (ceilings 200 feet through 500 feet and visibilities of 1/2 mile or more). A variety of chart symbols are used for cloud or fog conditions to indicate the origin, how it subsequently changes to another category, its duration, and repetitions within categories. From the 24 monthly charts and 7 seasonal charts which are reproduced, patterns are discernible which should be useful to forecasters and flight operations personnel who have to make decisions about the immediate behavior of these marginal-type weather conditions. Some rather distinct patterns are apparent. A comparison of fog frequency between the years 1952-1962 and 1963-1971 shows a significant reduction in fog in the recent period. This is tentatively attributed to extensive land development and expansion of the airport westward toward the ocean. Donald M. Gales. Includes bibliographical references (page 9). 1972 NWS (National Weather Service) WR (Western Region) Library Public Domain 1931