The mercury will reach triple digits across parts of the Inland Empire Sunday and Monday as weather patterns shift, creating unseasonably hot conditions, forecasters said Friday.
According to the National Weather Service, a ridge of high pressure bearing down from the north will thrust aside a low pressure trough that had been keeping a lid on daytime temperatures, leading to a brief but sharp warming trend.
“Warming takes place on Sunday and Monday across all regions, as the ridge peaks in strength,” the NWS said in a statement Friday. “This will bring the inland region 15 to 20 degrees above normal. Moderate heat risk is expected for the Inland Empire and high desert, as high temperatures rise into the mid- to upper 90s, with some spots (exceeding) 100 degrees.”
An Extreme Heat Warning is in effect from 10 a.m. Sunday to 8 p.m. Monday, encompassing all of the Coachella Valley, as well as the Banning Pass and San Jacinto Valley.
Daytime highs may surge toward 110 degrees in a few inland locations Monday, meteorologists said.
The high pressure will give way and roll eastward by Tuesday, after which a coastal trough will overtake it, lowering temps to seasonable levels for the remainder of next week, according to the Weather Service.
For the Coachella Valley, the highs Friday and Saturday will peak in the low 100s, with overnight temps in the mid 70s. On Sunday and Monday, the mercury will top out around 108, with lows hovering in the upper 70s.
In the Riverside metropolitan area, temps will max out in the low 90s Friday and Saturday, with lows in the upper 50s. They’ll jump to near 100 Sunday and Monday, dropping at night into the low 60s.
In the Temecula Valley, coastal influences will contain temps, which will peak in the mid-80s Friday and Saturday, falling to around 50 overnight. On Sunday and Monday, the mercury will crest in the upper 80s, dropping to the mid-50s at night.