Sundowner winds fueled the destructive blaze in the Santa Barbara, Calif.,area late last week. Sundowner winds are similar to Santa Ana winds, in thesense that high pressure interacting with lower pressure offshore sends gustywinds through mountainous and canyon areas of Southern California.The placement of the high determines whether the winds will be Santa Anas orSundowners. A high moving into the Great Basin will trigger Santa Ana winds,while a high positioned over the Pacific Northwest will lead to Sundownerwinds.
In the Sundowner case, air flows away from the high toward lower pressureoff the Southern California coast. The greater the pressure difference, thestronger the winds. The air travels down the Santa Ynez Mountains to the coast,warming in the process. This warmed air sent temperatures soaring into the 100sin Santa Barbara last Wednesday and Thursday. Temperatures for the coastal citytypically rise into only the lower 70s this time of year.
When temperatures are at their peak values in Santa Barbara late in theafternoon, the pressure of the air is at its lowest level. A significantdifference in pressure between the high and the coast will result, causingSundowner winds to increase. Winds will continue to gust strong through thenight before subsiding some the following morning.
These winds will continue to blow into Thursday night. This could threatento spread any existing fires or fan any new ones that ignite.
Story by AccuWeather.com Senior Meteorologist Kristina Pydynowski
