Californians may be asked to voluntarily conserve electricity this week as record-breaking heat blankets the West.The California Independent System Operator, which runs the state's power grid, said Tuesday that it could issue "Flex Alerts" Wednesday and Thursday because torrid conditions engulfing the West have tightened energy supplies.The potential Flex Alerts would be in effect during the hours from 4 p.m. to 9 p.m. Utility customers would be asked to set thermostats to 78 degrees or higher, avoid using major appliances and turn off unnecessary lights.The summerlike heat wave arrived with spring still on the calendar as a dome of high pressure over the Four Corners region spread west. Oppressive daytime highs have been followed by very warm nights. Palm Springs hit a record 120 degrees on Tuesday, four degrees above the old June 15 record set in 1961. Many other locations across Southern California also topped 100 degrees.A coastal eddy swirling low clouds and a marine layer off the ocean and over Southern California brought enough cooling Wednesday for forecasters to reduce some heat warnings to advisories around the Los Angeles region.Excessive-heat warnings were to go into effect widely in the Central Valley on Thursday.| RELATED | Here's where to find cooling centers this week in the Sacramento area, San Joaquin County