Update, 10:30 a.m., Monday, Aug. 17:  Firefighters made significant progress on the Jerusalem Fire over the weekend, despite hot temperatures and gusty winds, and now have it 90 percent contained, according to Cal Fire officials.

But the agency is “not letting our guard down, nor should anybody in that area,” said Cal Fire spokesman Scott McLean. The fire has grown to 25,118 acres.

On Saturday, an evacuation order was lifted, allowing about 150 residents to return home, said McLean.

He pointed out that most of the smoke that drifted into the Bay Area over the weekend was not from the Jerusalem Fire, but from two forest fires burning in Humboldt and Trinity counties.

Here’s the statewide update from Cal Fire:

Over 13,000 firefighters are battling 19 active wildfires across California. After today, temperatures will decrease back to a more seasonable normal level. Winds in many parts of Northern California will continue at lighter speeds early in the week with very low humidity. In Southern California westerly winds of 15 to 25 mph with gusts to 40 mph will surface across the Tehachapi Mountains, Antelope Valley, and Banning Pass. While temperatures will begin to be cooler statewide, very warm and dry conditions will maintain an elevated threat for large fire across the foothills and mountains.

Update, 10:30 a.m., Friday, Aug. 14: Cal Fire officials say they have the Jerusalem Fire 52 percent contained but remain very concerned about triple-digit heat and strong winds forecast for the weekend.

“If things go south, there’s still a lot of assets up here and we’ll hit it as hard as we can,” said Cal Fire’s Steve Swindle. More than 2,200 firefighters remain on the scene, with crews focused on the eastern flank of the blaze, which has now burned more than 24,555 acres.

Temperatures are expected to climb into the 90s today, says Swindle.

Update, 7:05 a.m., Thursday, Aug. 13: Cal Fire’s morning update reports that containment has doubled on the Jerusalem Fire, burning in southeastern Lake County at the border with Napa and Yolo counties. The agency says the blaze has burned 23,500 acres and that firefighters have thrown control lines around 33 percent of the fire’s perimeter.

The big concern today and tonight: much windier weather that will threaten control lines on the fire’s eastern edge. Read on for details.

Update, 10:35 p.m., Wednesday, Aug. 12: Cal Fire’s latest report on its progress against the Jerusalem Fire in Lake County: The fire increased in size by 4,000 acres during the day to 20,500 acres, or 32 square miles. Crews increased containment on the blaze from 6 percent to 16 percent.

The fire agency also says the force fighting the fire has grown to more than 2,000, including some crews transferred from the adjoining Rocky Fire — which burned nearly 70,000 acres between July 29 and the end of last week.

Progress containing the Jerusalem Fire came as the meteorologist and fire behavior analysts assigned to the incident issued a forecast for critical fire conditions with winds expected to gust as high as 30 mph Thursday afternoon. The forecast warns that the gusty westerly wind, aligned with ridges and canyons in the area, will make it more difficult to stop the fire’s spread on to the east.

Winds are supposed to be calmer after midnight Thursday with another windy period Friday evening. The next weather challenge for firefighters will come from temperatures that may reach triple digits over the weekend along with critically low relative humidity.

Update, 7:55 a.m., Wednesday, Aug. 12: Here’s our semi-daily acreage update from Cal Fire: The Jerusalem Fire has grown to 16,500 acres, or 26 square miles, and is 6 percent contained.

The agency’s latest public fire map, depicting conditions about 9 p.m. Tuesday, shows the main growth of the fire during the day Tuesday was to the east and northeast, crossing the northwestern border of Yolo County and the extreme northeastern edge of Napa County. While crews managed to more or less hold containment on the north, west and south borders of the fire, the blaze burned across Knoxville-Berryessa Road, which managers had hoped to hold as the eastern edge of the fire. Their new goal is to keep the fire west of Blue Ridge, just west of Highway 16 and the northern end of the Capay Valley.

Update, 11:55 p.m., Tuesday, Aug. 11: Earlier this evening, Cal Fire updated its estimate of the acreage burned in the Jerusalem Fire, which started in Lake County on Sunday afternoon, to 14,000 — roughly 22 square miles. Containment is 5 percent.

That’s a lower rate of growth — 2,000 acres since early Tuesday — than had been seen on the fire since it broke out. But the agency said it’s facing several big challenges in getting a handle on the blaze, which started just as crews gained the upper hand on the Rocky Fire that had threatened communities at the southeast end of Clear Lake last week.

The agency says it’s had trouble getting at the blaze due to a lack of roads in the fire zone. And, as with the Rocky Fire, the fire is burning fiercely through areas with a heavy cover of drought-stressed brush. The advance of the fire Tuesday caused crews to pull back from a section one main route into the hills of southeastern Lake County, Morgan Valley Road and prompted local officials to order new evacuations in the area.

One advantage for firefighters Tuesday and Wednesday: Cooler temperatures and higher humidities, especially at night. Warmer, drier weather is expected by the weekend.

Cal Fire now says it has about 1,700 personnel fighting the Jerusalem blaze. Full containment is estimated by next Monday.

Update, 11 a.m., Tuesday, Aug. 11: Cal Fire says the Jerusalem Fire, burning in Lake County south of the sprawling area scorched last week by the Rocky Fire, doubled in size overnight to 12,000 acres (18.75 square miles). The firefighting agency continues to give a 0 percent containment figure for the fire — though on its northern edge it’s moving toward an area already burned by the Rocky Fire, which should limit its spread in that direction.

The blaze, now in its third day in the hills northeast of Middletown, threatens about 50 homes. Cal Fire says it has shifted some firefighting crews from the Rocky Fire, which started July 29, burned just under 70,000 acres and is reported to be 88 percent contained. Crews on that fire have been completing containment lines, mopping up smoldering areas around the perimeter and beginning the job of repairing damage caused by the heavy equipment brought in to limit the fire’s spread.

About 1,100 firefighters are battling the Jerusalem Fire.

Update, 4 p.m. Monday, Aug. 10: Cal Fire announced Monday that law enforcement officers had made an arrest on one count of arson and allegedly starting a backfire, but the incident was not tied to the cause of the Jerusalem Fire.

Juan Ramos Silva was booked in Lake County jail Sunday evening on suspicion of starting a backfire, Cal Fire reported in a news release, making him the fifth individual to be arrested on arson-related charges in two weeks.

Officials with the Lake County Sheriff’s office did not immediately return calls seeking comment, but the Los Angeles Times is reporting that deputies suspected Silva of attempting to stage a small controlled burn, to protect marijuana plants from being scorched by the nearby Jerusalem Fire.

“Especially now with the dry conditions from the drought, we will absolutely not tolerate arson of any type,” said Chief Ken Pimlott, Cal Fire director.

Investigations into the cause of both the Rocky Fire and the Jerusalem Fire are ongoing.

Original post, Aug. 10:

Just as fire crews managed to gain control of the massive Rocky Fire, which whipped through Lake County last week, a new wildfire is sweeping through the same area. As of Monday morning, the Jerusalem Fire had already scorched 5,000 acres.

All Rocky Fire evacuation orders had been lifted as of Saturday. But the relief didn’t last long. The Jerusalem Fire prompted a new round of evacuations, in some cases affecting some of the same residents who had just weathered the impacts of the Rocky Fire.

“We’ve got 150 people that have been evacuated out of 50 homes,” Cal Fire spokesman Paul Lowenthal told KQED’s Guy Marzorati in an interview. In many cases, “These people have been through it now twice, where they were evacuated and then re-evacuated for a new fire.”

Lowenthal said a nearby high school had been opened as an evacuation shelter.

The Jerusalem Fire was at zero percent containment and moving to the east and southeast, Lowenthal added, and 545 firefighters had been deployed to fight the blaze, with more on the way. Some crews were diverted from the effort already in place to fight the Rocky Fire, which was at 85 percent containment as of Sunday night. The Rocky Fire has scorched nearly 70,000 acres. Cal Fire estimated that it would be fully contained by Thursday.

Lowenthal said fire crews wouldn’t necessarily view it as a bad thing if the Jerusalem Fire were to merge with the Rocky Fire. “It would run out of fuels, because then it would burn into something that’s already been burned before,” he explained.

But as of the latest reports, that hadn’t happened — and as firefighters’ experience with the Rocky Fire showed, erratic daytime winds can defy firefighters’ expectations for typical wind flow patterns, adding to the challenge.

According to a Cal Fire update posted Sunday morning, small flare ups could still occur within the interior of the Rocky Fire even as crews make progress on containment. And residents should remain vigilant, the bulletin noted, since “fire activity and direction can change at any time.”