This week, afternoon temperatures are expected to reach 100 degrees in the Valley for the first time this summer, forecasters said.
An upper-level ridge of high pressure over Southern California is expected to gradually build through Friday, bringing sunny skies and warmer temperatures with each passing day, said Kevin Stenson, a meteorologist with WeatherData Inc., which provides forecast information to The Times.
"The Valley should reach 100 degrees by Thursday, possibly as early as Wednesday," Stenson said.
The warmest area in the Valley today and Tuesday should be Woodland Hills, which is expected to see an afternoon high of 96.
Afternoon highs in Chatsworth, Van Nuys and Burbank are expected to be slightly lower.
Morning lows through Friday are expected to range from the low to upper 60s, Stenson said.
Today's ultraviolet index at noon, when the sun's rays are most direct, is expected to be nine, Stenson said.
People with fair skin will begin to burn after seven minutes of exposure, he said.
"I'd definitely recommend sunscreen, especially around the forearms and the back of the neck, for people who will be outside in and around noon," Stenson said.