Excessive heat warnings were in effect for Riverside and San Bernardino counties as above-normal temperatures continued to roast Southern California.
The warnings were set to expire Friday at 8 p.m.
"High pressure still in control and that's what's drawing in the warmth, along with the humidity, so we will see a slight risk for some afternoon thunderstorms, mainly across the mountain areas of Riverside and San Bernardino counties," NBC4 meteorologist Elita Loresca said.
Triple-digit highs were expected Wednesday in the low desert and Inland areas, with new records possible. Temperatures were expected to reach 110 in the Antelope Valley, as the heat wave continued through the weekend.
"Broke another record yesterday in Ontario," Loresca said. "I think we can do it again on Day 3 of this heat wave."
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Excessive heat warnings for Los Angeles and Ventura counties have been canceled, and the National Weather Service reported that humidity will be lower than had been forecast.
The NWS forecast highs Wednesday of 80 in Avalon; 81 in Newport Beach and at LAX; 89 in Long Beach; 91 in downtown L.A.; 94 on Mount Wilson; 97 in Anaheim; 98 in San Gabriel; 100 in Burbank; 101 in Pasadena; 107 in Woodland Hills and Saugus; 108 in Palmdale; and 109 in Lancaster.
Temperature highs will climb down by a couple of degrees on Sunday, but no cooling trend will get underway in earnest until Monday, when highs are expected to be around five degrees lower than today, according to an NWS forecast.
"This is still a dangerous heat wave, which will last through the weekend," according to the NWS.
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A swarm of earthquakes near Yorba Linda was not related to the current SoCal heat, said Dr. Kate Hutton, staff seismologist at Caltech.
"These quakes were 5 miles below the surface, so weather is not an issue here," Hutton said.