A high-pressure system will bear down again on LA County today, with potentially dangerous heat and humidity that could generate more thunderstorms in the mountains and deserts. An excessive heat warning has been extended through tomorrow night for the San Fernando and Santa Clarita valleys, as well as the San Gabriel and Santa Monica mountain ranges.
The potential for afternoon thunderstorms could mean more hail and rain, as well as lightning-strike fire starts and flash flooding, which could be a concern in previously burned areas on the north side of the San Gabriels, but whether storms develop or not, its definitely going to be hot, and LA County is going to be hotter than Orange County again.
In downtown LA, Hollywood and Malibu, the high is expected around 94. Pasadena can expect a high of 102 or hotter, with a 10 percent chance of thunderstorms. The forecast high in Santa Clarita today is 105, with a 10 percent chance of thunderstorms.