Fierce Santa Ana winds continue to fan Southern California fires

A strong Santa Ana wind event continues over Southern California, fanning two major fires that have caused over $100 million in damage near Los Angeles. Wind gusts up to 76 mph were clocked early this morning at Camp Nine near the Sylmar fire, which is burning in the mountains about twenty miles north of downtown Los Angeles. Yesterday, winds gusted to 72 mph near the Montecito Hills fire in Santa Barbara County. A Fire Weather Warning continues for the Los Angeles area, and high wind warning for winds of 25 to 45 mph with gusts to 60 mph have been posted for surrounding mountain areas. A strong high pressure system has built in to the north and east, and the clockwise flow of air around this high pressure system will drive strong east-to-west offshore winds from the mountains to the ocean over the Los Angeles metropolitan area through Sunday morning. As air drops out of the mountains, it will warm due to compression as its pressure increases. The warm winds have caused several record highs to be set, including 91° in Burbank yesterday. Very low humidities in the 5-10% range have contributed to the dangerous fire conditions. Fire conditions will ease on Sunday as high pressure weakens, allowing winds to slow down. However, winds are not forecast to reverse direction and blow moist air inland from the ocean until Tuesday.


Figure 1. Visible satellite image from NASA's Terra satellite taken on Saturday, November 15, 2008 at 10:45 am PST. Smoke from the Sylmar fire 20 miles north of Los Angeles has drifted out over the Catalina Islands. A smaller plume of smoke from the "Freeway Fire" in Orange County is also visible.

Tropical update
In the tropics, there are no threat areas to discuss, and none of the reliable models are calling for tropical storm formation over the next seven days. However, it is possible that an extratropical low expected to form south of the Azores Islands on Monday will be able to gradually acquire tropical characteristics during the week, and could become a subtropical storm late next week. Such a storm is not likely to threaten any land areas.

Jeff Masters