Boiling heat will bear down on the Inland Empire most of this week, beginning Tuesday, pushing temperatures over 100 degrees across the region, according to the National Weather Service.
The agency on Monday posted an Extreme Heat Warning for the entire Riverside metropolitan area, stretching east to Idyllwild-Pine Cove, starting at 10 a.m. Wednesday and concluding at 8 p.m. Thursday, though the times may be subject to change.
Forecasters said the heat wave will gradually take hold on Tuesday as, similar to last week, a ridge of high pressure builds over the Four Corners region. The high will start to give way to low pressure troughs on both sides of it Thursday night.
The Weather Service’s prognostication charts indicated that the pattern won’t change dramatically, but enough to allow moisture drawn into Southern California from Arizona and Mexico to generate monsoonal activity in the mountains and deserts on Friday and through the weekend.
In the meantime, the mercury will soar.
“Widespread moderate heat risk is expected below 6,000 feet Tuesday through Thursday, with major heat risk expected through much of the coastal basin and locally into the lower deserts on Wednesday,” according to the NWS. “There is still some uncertainty in exactly how hot temperatures will get, but current forecast highs on Wednesday show … 100s expected for the Inland Empire, High Desert and eastern San Diego valleys, and 90s for the western valleys and lower elevations of the mountains.”
The agency recommended taking all necessary precautions, including finding shade when the heat is most intense, staying close to air conditioners and remaining hydrated.
In Riverside metro, the daytime mercury on Monday will crest in the mid 90s, followed by upper 90s on Tuesday, while on Wednesday and Thursday, highs will top out in the low 100s, according to meteorologists. They said a moderation will begin Friday, with peak heat in the low to mid 90s for Riverside and surrounding locations. Weekend daytime temps are forecast to hover in the low 90s. Lows are expected to settle in the low to mid 70s all week.
In the Coachella Valley on Monday and Tuesday, highs will settle around 105, but on Wednesday and Thursday, they may peak closer to 115, with slight cooling going into the weekend. Lows will generally hover in the mid to upper 80s all week long.
The Temecula Valley will see temps cresting in the low to mid 90s Monday and Tuesday, approaching 100 on Wednesday and Thursday, and trending back to just below 90 on Friday and through the weekend, according to the Weather Service. Lows are forecast to be in the mid 60s to the end of the week.