California braces for a fall heatwave with temperatures of up to 90 degrees that could spark MORE wildfires after the 8,400 blazes that have already burned more than 4 million acres this year

California residents are bracing for a fall heat wave with temperatures of up to 90F this week that could spark more blazes to add to the 8,400 wildfires that have already burned more than 4 million acres across the state this year.  

Fire weather watches will go into effect in much of Northern California early Wednesday due to high pressure producing hot and dry conditions with gusty offshore winds, the National Weather Service said. 

Peak gusts are likely to start late Wednesday, according to the NWS. Forecasts show temperatures up to 90F on Thursday. Temperatures on Wednesday and Friday are predicted to hit the high 80s.

'#RegFlagWarning in effect for portions of Northern California for Wednesday through Friday for gusty winds and low humidity. This is #CriticalFireWeather so use caution outdoors,' Cal Fire tweeted on Tuesday.

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'#RegFlagWarning in effect for portions of Northern California for Wednesday through Friday for gusty winds and low humidity. This is #CriticalFireWeather so use caution outdoors,' Cal Fire tweeted on Tuesday

Firefighters are already battling several blazes across the state as forecasters warn that the critical weather could spark even more fires  

More than 8,400 wildfires (pictured in Calistoga) have burned well over 4 million acres in California since the start of the year, but mostly since mid-August

Pacific Gas & Electric (PG&E) said it is likely that some circuits will be turned off to try to prevent fires from being started by damaged power lines.

Southern California, which started the week with triple-digit high temperatures, is predicted to see particularly gusty northeast winds Friday.

More than 8,400 wildfires have burned well over 4 million acres in California since the start of the year, but mostly since mid-August.

Thirty-one people have died and more than 9,200 structures have been destroyed.

Most of the huge fires have been fully or substantially contained over the past eight weeks but thousands of firefighters remain on the lines 

Thirty-one people have died and more than 9,200 structures have been destroyed

Most of the huge fires have been fully or substantially contained over the past eight weeks but thousands of firefighters remain on the lines.

Earlier this week, Cal Fire investigators announced that they are looking at a possibility utility issue stemming from PG&E in the Zogg Fire, which killed four people and destroyed over 200 homes since sparking on September 27.

PG&E equipment failures caused a number of significant fires in 2017 and 2018, which killed over 100 people and destroyed at least 27,000 properties.

The utility company was forced to file for bankruptcy in the aftermath of those fires, which PG&E only recently emerged from.

Investigators also said that the Bobcat Fire remains under investigation, with  damaged power equipment now being viewed as a potential cause of the wildfire.

The Bobcat Fire has been raging in California since September 6, when an undisclosed incident sparked yet another wildfire in the state.

Temperatures on Wednesday and Friday in California are predicted to hit the high 80s

Forecasts show temperatures up to 90F on Thursday  

Southern California, which started the week with triple-digit high temperatures, is predicted to see particularly gusty northeast winds Friday

On Monday, Southern California Edison sent a letter to the California Public Utilities Commission, detailing progress in the investigation into the Bobcat Fire.

In the letter, SCE stated that US Forest Service investigators took possession of a 23-foot line of conductor owned by SCE, according to Fox News.

While the fire could've been caused by damage to the electrical equipment, lingering smoke at the time of the spark is also creating questions about vegetation being a root cause of the Bobcat Fire.

SCE reportedly experienced a 'relay operation' at 12.21pm on September 6, but smoke was reported approximately 11 minutes earlier.

As of Monday, the Bobcat Fire was 92 per cent contained. It has burned over 115,000 acres, destroying 171 structures (87 residences) and damaging 47 more

Numerous studies have linked bigger wildfires in America to climate change from the burning of coal, oil and gas. 

Scientists say climate change has made California much drier, meaning trees and other plants are more flammable.