A significant warm-up is coming to much of Southern California with triple-digit heat expected to scorch parts of the valleys and Inland Empire. Temperatures will remain normal through Tuesday with a gradual increase on Wednesday. Forecasters predict conditions will peak on Thursday.

Triple-digit temperatures will arrive in parts of Southern California on Wednesday as a heat wave descends, exacerbating the woes of firefighters who already are batting a number of wildfires across the region.