Large-Scale Factors Influencing the Extent and Location of Stratocumulus Clouds along the California Coast

Stratocumulus are thin low-level clouds that are important to coastal meteorology and forecasting, as well as to earth’s radiation budget. Previous studies have examined their relation to sea surface temperatures, which influences the strength of the marine boundary layer inversion and the moisture and cooling within that layer necessary for their formation (Sandu, Stevens, & Pincus, 2010). This project analyzed the short-term impacts of sea surface temperature and other meteorological variables’ influence on status cloud formation and distribution along the California coast for typical flow patterns. The summers of 2014, 2015, and 2016 exhibit a progression of warmer than average to more average sea surface temperatures, thus changes in stratocumulus extent and location over these years may represent impacts of sea surface temperature and its feedback on low-level flow patterns. Conditions of characteristically cloudy, clear, offshore cloudy, and onshore cloudy days are analyzed for changes over the 3 year time period. These changes are then related to differences in marine boundary layer structure and flow that result in stratus formation or clearing as a consequence of the different sea surface temperatures over the three years.