Another bout of fire-fueling weather is expected to overpower Southern California this week, prompting San Diego agencies to prepare for the worst. 

The National Weather Service elevated a fire weather watch to a Red Flag Warning for Thursday and Friday, when whipping Santa Ana winds have the greatest potential to fan any wildfire that sparks amid dry and hot conditions. 

San Diego Gas & Electric warned nearly 24,000 customers that the severe winds could lead to forced power shut offs. The move is meant to prevent fires that could spark from a downed power line, according to the agency. 

Customers alerted to planned outages were not given any scheduled time. Instead, SDG&E said they would continue to monitor weather conditions and alert customers if a shut off was necessary.

A Red Flag Warning means the combination of gusty winds, hot temperatures and low humidity that make the perfect conditions for wildfires to spark and spread rapidly. 

The warning was in effect for all areas of San Diego County except the coast from 5 a.m. Thursday to 5 p.m. Friday. During this time, winds were expected to average 40 to 50 miles per hour with some isolated gusts reaching 60 mph.

Humidity was expected to be less than 10 percent and temperatures were expected to be in the mid-90s to low-100s. 

On Tuesday, a record daily high of 84 degrees was recorded at the Oceanside Harbor, topping its previous high of 78 degrees in 2016.

While no warning was in effect, a fire sparked Tuesday on base at Camp Pendleton and grew to around 80 acres in about five hours. A large plume of smoke was visible from various parts of the county but officials said the fire posed no threat to the public.

Another fire sparked in the river area near homes on Hazard Center Drive. A nearby resident was alerted to the fire by her companion dog and immediately grabbed a hose and started protecting her residence.

Another fire sparked in the riverbed less than a mile away. Both started near known homeless encampments. Fire investigators have not confirmed either fire was started by people living near the riverbed.

This week's extreme heat could cause heat exhaustion or heat stroke. The National Weather Service urges residents to drink plenty of water, stay in air-conditioned rooms and stay out of the sun as much as possible.

NBC 7 Weathercaster Ashley Matthews pinpointed some coastal areas that are predicted to have the lowest high temperatures as possible "cool off spots." Those beaches include Encinitas, with a forecasted high of 77 degrees, and La Jolla, with a forecasted high of 78 degrees. For the South Bay, Imperial Beach is expected to see a high temperature of 83 degrees.  

For a list of cool zones in San Diego County, click here. 

Editor's Note: A previous version of this story said classes in Julian were canceled Wednesday due to the potential power shut-offs announced by SDG&E. The district later clarified to say the school closure was due to unplanned power outages in the area.