Los Angeles-area valleys and mountains will see a fourth day of dangerously high heat Thursday but the National Weather Service says scorching temperatures will plunge by the weekend.
Other areas of California that sweltered since Monday have cooled, leaving excessive heat warnings Thursday only in some mountains and the San Fernando, San Gabriel and Santa Clarita valleys.
Highs there will top 100 but they're expected to drop as much as 30 degrees by Saturday.
A low-pressure area from the Pacific Ocean is bringing cooler weather. On Wednesday, a subtropical flow from the south fueled wild thunderstorms that sparked small brushfires and flash flooding inland.
However, the weather service says there's only a slight chance of storms Thursday in the mountains and deserts.
Copyright 2010 The Associated Press.