Fierce winds fueling California's firestorm to ease as air quality worsens this weekendnews AccuWeather
As winds subside, smoke and poor air quality from wildfires may linger in Southern California this weekend.
Major fires have forced hundreds of thousands to evacuate this week and schools to close in Southern California this past week, according to ABC7.
A motorists on Highway 101 watches flames from the Thomas fire leap above the roadway north of Ventura, California, on Wednesday, Dec. 6, 2017. (AP Photo/Noah Berger)
Locally gusty winds, dry air and dry brush will continue to cause problems for firefighting efforts through this weekend and into next week.
Wind speeds will fluctuate this weekend. At times, winds may be nearly calm. At other times, a breeze will be active.
"We expect northeast winds to ease up substantially but not completely drop off into Sunday," according to AccuWeather Meteorologist Evan Duffey.
On average, northeast winds of 8-15 mph are expected through Sunday. A few gusts may reach 25 mph through some of the canyons during this time.
Relative humidity levels dipped below 5 percent in parts of Southern California at midweek. Humidity levels are expected to remain at low levels this weekend but not quite as low as much of this week.
"As winds lighten up and some moisture extends inland from the Pacific Ocean, the risk for the rapid spread of existing fires and new blazes igniting will ease, but smoke may remain a problem and may get worse in some areas." Duffey said.
Smoke from the Thomas fire hangs over Ventura, California, as the sun rises on Wednesday, Dec. 6, 2017. (AP Photo/Noah Berger)
During light wind situations, a temperature inversion usually sets up at night and lingers into the morning hours. These conditions may develop this weekend.
A temperature inversion occurs when cool air collects near the ground, but a layer of warm air remains a few hundred to a few thousand feet above the ground.
When a temperature inversion exists, a warm column of smoke cannot rise past the beginning of the warm layer of air. The smoke spreads out under that layer and fills the space below as a result.
The temperature inversion tends to trap the smoke in the valleys and lowest levels of the atmosphere.
"Some fires will continue to burn or smolder and produce smoke," Duffey said.
"Due to light winds and the temperature inversion, overall air quality may be at its worse during the nighttime and early morning hours starting this weekend."
Only where thick smoke was being carried downwind in recent days may air quality improve a bit.
Outside of the fire risk areas and smoky conditions, blowing dust will diminish as winds subside this weekend.
While a weak storm may spin toward Southern California next week, it is unlikely to bring enough moisture to bring any rainfall to the region.
According to AccuWeather Lead Long-Range Meteorologist Paul Pastelok, the next chance for rain may occur around Dec. 20.
Winds may kick up again next week but perhaps not to the levels of this past week.