Thunderstorms may develop in parts of the Inland Empire heading into the weekend as a fast-moving storm system ratchets up instability across the region, according to the National Weather Service.
The agency said Monday that a trough of low pressure currently gathering energy off the Northern California coast will spin toward Southern California in the latter half of the week, producing showers as early as Thursday night.
“The approach of this low will generate gusty southwest to west winds in the mountains and deserts, as well as a deeper marine layer with low clouds extending into the valleys each night,” the NWS stated. “Instability increases Saturday as the cold core moves overhead, bringing a chance of thunderstorms. Any thunderstorms that develop could produce locally heavy rain.”
No watches or warnings had been posted as of Monday afternoon.
Forecasters said most of the precipitation will likely be the lighter variety where no thunderstorms mature. However, the probability of at least a quarter-inch of rain was high along the coastal slopes, with lesser amounts farther inland, between 4 a.m. Friday and 4 a.m. Sunday, according to the NWS.
From Monday to Thursday, daytime temperatures in the Riverside metropolitan area will be 5 to 10 degrees above normal, hovering in the low 80s, with overnight lows in the mid 50s. Friday to Sunday, highs will peak in the upper 60s to low 70s, with lows in the low 50s.
In the Coachella Valley, temps will also be above seasonal averages, peaking in the mid 90s and falling into the mid 60s from Monday to Thursday. The mercury will settle lower from Friday to Sunday, peaking in the upper 70s and dropping into the upper 50s.
For the Temecula Valley, Monday to Thursday highs will reach the upper 70s, with lows in the upper 40s, while from Friday to Sunday, the mercury will max out in the upper 60s, dropping into the mid-40s during nighttime hours, according to meteorologists.