Winds, Heat Threaten to Spread California Fire

Winds that have diminished are expected to pick up later today, causing more fire danger.

Image courtesy: AccuWeather.com

(SANTA BARBARA) - AccuWeather.com reports that although firefighters have been able to reach 70% containment of the fire, aided by a combination of lighter winds and a cooler, moist onshore flow from the Pacific over the weekend, winds are expected to pick up again tonight into Tuesday.

These winds are not expected to be as strong as those of late last week. Winds could become rather strong again late in the week. Temperatures are expected to surge in the Wednesday to Friday period, when humidity levels will drop significantly.

Sundowner winds fueled the destructive blaze in the Santa Barbara, Calif., area late last week. Sundowner winds are similar to Santa Ana winds, in the sense that high pressure interacting with lower pressure offshore sends gusty winds through mountainous and canyon areas of Southern California.

The placement of the high determines whether the winds will be Santa Anas or Sundowners. A high moving into the Great Basin will trigger Santa Ana winds, while a high positioned over the Pacific Northwest will lead to Sundowner winds.

In the Sundowner case, air flows away from the high toward lower pressure off the Southern California coast. The greater the pressure difference, the stronger 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 100s in Santa Barbara last Wednesday and Thursday. Temperatures for the coastal city typically rise into only the lower 70s this time of year.

When temperatures are at their peak values in Santa Barbara late in the afternoon, the pressure of the air is at its lowest level. A significant difference in pressure between the high and the coast will result, causing Sundowner winds to increase.

Source: Accuweather.com