A statewide flex alert has been issued as extreme heat strains California’s energy grid; Customers are asked to conserve power during peak hours of 5-10 PM today. The grid operator is predicting an increase in electricity demand, primarily from air conditioning use due to the heat wave. The hottest days will be today and tomorrow, with temperatures in Lake and Mendocino Counties expected to reach 100 to 110-degrees both days. Hot temperatures will linger into the weekend.