Unseasonably warm weather will continue Thursday in Riverside County, then temperatures will drop sharply on Friday, followed by rain and snow showers this weekend, according to the National Weather Service.
A ridge of high pressure anchored over the Great Basin is driving the mercury well into the 90s and keeping skies clear over the region currently, but will give way to cold, wet conditions on Saturday and Sunday — with a warning from Caltrans that some higher elevation roads may be impacted.
Humidity levels will fall to around 10% Thursday amid the warm conditions, causing an elevated risk of wildfires throughout Riverside County, forecasters said.
High temperatures Thursday are forecast to reach 97 in the Coachella Valley and the San Gorgonio Pass near Banning, 93 in Hemet, 95 in Riverside, 91 in Lake Elsinore, 94 in Temecula and 76 in Idyllwild.
On Friday, a cold trough of low pressure with drop into Central California and bring a sharp drop in temperatures, along with rain in most Inland Empire communities and snow in Idyllwild, according to the NWS.
The Riverside metropolitan area could get up to a quarter-inch of rain over the weekend, while the San Gorgonio Pass near Banning could get up to a half-inch, according to the NWS. If any rain falls in the Coachella Valley, it will be less than one-tenth of an inch, meteorologists said.
Snow levels will drop to around 5,000 feet by Saturday night, meaning Idyllwild could get a few inches of snow through Sunday, forecasters said.
According to Caltrans, motorists should be prepared if they’re traveling on mountain roads this weekend, bringing snow chains and checking ahead for closures and travel delays.
“Caltrans crews will be on 12 hours shifts, 24/7 throughout the storm event,” according to the agency. “Chain installers will be available on mountain routes for safety and convenience.”
Strong, westerly winds are also associated with the autumn storm, with gusts potentially reaching 55 mph near desert slopes on Saturday, forecasters said.
The forecast high for Riverside is 58 on Saturday and Sunday, while in Palm Springs, the mercury is expected to top out in the mid-60s both days, and in the Temecula Valley, the highs will be in the mid-50s.