Gusty Santa Ana Winds Zap SoCal Mountains
UPDATED 6:15 AM PST, November 6, 2013
UPDATED By WeatherBug Meteorologist, Seth Carrier
Bursts of gusty Santa Ana winds will continue to whip across southern California today. Combined with low humidity, the fire danger will remain elevated.
Peak wind gusts could reach 40 mph across the mountains of southern California again today. On Tuesday, winds in southern California reached 63 mph at Pleasants Peak, 58 mph at Fremont Canyon and 49 mph at Sky Valley. Other mountain locations recorded gusts ranging from 35 to 45 mph.
Sustained winds in the mountains will be in the 20 to 30 mph range, with the Los Angeles basin seeing 15 to 25 mph sustained winds. Gusts will reach 45 mph.
The high winds are also causing the humidity to drop. The combination of gusty winds, low humidity, and persistent drought will produce conditions that can spread wildfires. Red Flag Warnings continue across the mountains north of Los Angeles through this afternoon. Red Flag warnings are issued when conditions like high winds and low humidity create ideal conditions for wildfires to develop.
In addition to the fire risk, these high winds could trigger sporadic power outages. Driving across the higher passes in the region will be dangerous for high profile vehicles. Residents should heed travel warnings issued by local officials.
The Santa Ana wind occurs when high pressure develops over the Great Basin or Mountain West, a common occurrence in autumn and early-winter. The clockwise wind flow around this high pressure system brings a northeast-to-southwest wind to the Desert Southwest.
As these winds surge towards the California coastline, they flow down the Sierra Nevada, San Gabriel and the San Bernardino mountains. In addition to an increase in forward speed, the winds traveling down these mountain ranges are compressed and warmed.
With the compression and warming, much of the moisture is removed from the fast-moving air mass. The relative humidity within these winds often drops below 20 percent, helping to dry out vegetation in the path of the winds.
The high pressure causing the gusty winds will move into the Plains Thursday while a fresh low pressure takes aim at the Northwest Coast. This will allow the pressure gradient to relax, ending the threat for Santa Ana winds.
Follow the gusty winds in southern California with WeatherBug. Check for updates to the wind advisories and get the latest updates anywhere on Twitter.
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