(KTVU and wire reports) -- Early Saturday morning, the National Weather Service Bay Area expanded the hours of a red flag warning, due to temperatures forecast to reach into the upper 90s and 100s
The Red Flag Warning originally went from 9 p.m. Saturday to 8 a.m. Monday, but was changed to 11 a.m. Monday for the North Bay, the Peninsula and East Bay, amid concern of new wildfires.
Wind gusts could reach 50 mph this weekend. Low humidity is also expected to pair with the high temperatures to increase the danger of fires sparking along the Interstate 680 corridor, Highway 4 corridor and Interstate 580 east of the Altamont Pass.
While temperatures should soar Sunday and Monday, we are not expecting a repeat of the Labor Day weekend heat wave. Comparing the two events, temperatures should fall short by about 10 to 12 degrees this weekend.
The developing offshore flow—think of a big hair dryer that is blowing hot, dry air from land to sea—will be the biggest concern that will boost fire danger. The winds will accelerate late Saturday night into Sunday morning.
The winds have prompted another round of potential Pacific Gas and Electric Public Safety Power Shutoffs. There are some small clusters showing up in northern Napa County that could affect as many as 200 customers with a power shutoff this weekend.
Based on forecast guidance, the strongest winds should move in Sunday.
The wind will usher in very dry air. Humidity could drop to 10% Sunday. Any fire that starts could spread rapidly in the hot and dry environment. The hillsides are dry and ready to burn. Please be extra cautious and vigilant when heading outdoors this weekend.
Meanwhile, firefighters are continuing to battle 25 major wildfires across the state.
Many of the fires, including the LNU and SCU Lightning Complex, were sparked during the last West Coast heat wave in mid-August.
The LNU Complex has burned 567.5 square miles of Napa, Sonoma, Solano, Lake, Colusa and Yolo Counties.
Cal Fire listed LNU as 98-percent contained.
The SCU Complex Fires have burned nearly 620 square miles in Contra
Costa, Alameda, Santa Clara, San Joaquin, Merced and Stanislaus Counties.
Cal Fire listed SCU Complex as 98-percent contained.
Neither cluster of fires is expected to grow during the heat wave, but firefighters are continuing efforts to fully contain both complexes.
More than 8,000 wildfires across the state have burned 5,625 square miles.