It’s bad enough that triple-digit temperatures have scorched the San Fernando Valley for 12 days with no letup expected through the weekend. But as a muggy storm system sent humidity soaring Monday, residents begged for relief from the heat wave that drew record power use throughout the state. “It’s crazy weather, crazy,” said 84-year-old Mavis Jones of Sherman Oaks, watering the plants on her front porch. “It’s hot. “I hope the weather changes soon.” AD Quality Auto 360p 720p 1080p Top articles1/5READ MORE11 theater productions to see in Southern California this week, Dec. 27-Jan. 2Sudden showers punctuated morning commutes across the Southland, starting a workweek of expected thunderstorms and stifling heat caused by a giant high-pressure umbrella, weather forecasters said. Temperatures hit 103 in Woodland Hills and Simi Valley, a record 102 in Chatsworth and 93 in downtown Los Angeles, with humidity reaching 60 percent. “It’s like being in a sauna in Houston,” said Bill Patzert, research oceanographer at the Jet Propulsion Laboratory. “This is never ending. “We’re getting this monsoon from the Gulf of California and the Northern Mexican desert. It’s illegal humidity, undocumented moisture, coming across the border,” he joked. The soaring temperatures put new strains on the state’s overworked power grid, setting a record Monday for demand and sparking new fears of power shortages. The state’s power grid experienced peak demand of 46,561 megawatts Monday afternoon, breaking the previous record from one year ago of 45,431 megawatts. Gov. Arnold Schwarzenegger called on Californians to conserve energy by keeping their thermostats at 78 degrees, closing windows during the day and using more energy-efficient appliances. “If any of my kids leave a light on, the light bulbs will be unscrewed,” Schwarzenegger said. “And eventually, after two or three times doing that, they’re in a dark room.” Meteorologists attributed the heat wave to a massive high pressure zone lurking above the Southwest, spinning heat and moisture into Southern California. The National Weather Service has forecast a 20 percent chance of showers or thunderstorms through Saturday, when high temperatures in valleys are expected to “come back with a vengeance,” said Jamie Meier of the National Weather Service in Oxnard. As storm clouds grew in the east, residents flocked to swimming pools and ducked into the chill of air-conditioned homes and offices. “Oh, my God, it’s horrible,” said Miriam Lozano, 21, walking to her job at Western Bagel in Encino. “I’m more of a winter person – throw on a sweater, you’re fine. “But if it’s hot, nothing helps.” firstname.lastname@example.org (818) 713-3730160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set!