Downpours, some of them heavy, are expected across the Inland Empire later this week as the winter season officially arrives, according to the National Weather Service.
Forecasters said two troughs of low pressure will slide through California over the next few days, generating rain showers and isolated thunderstorms, as well as some mountain snow.
“As the (second) upper low arrives at our latitude and turns inland over Baja, forcing is maximized over Southern California from Wednesday night through Thursday night,” the NWS said in a statement. “This is when showers will be most widespread and numerous, and the chance for heavy rainfall rates and areas of flooding will be highest.”
No flood advisories have been issued yet.
“Snow levels are forecast to remain near or above 7,500 feet through this event,” the NWS stated. “This should limit any impactful accumulations to the highest mountain tops. Snow levels could be briefly lower in heavy convective showers.”
The first trough will brush the region Tuesday, followed soon after Wednesday by the second one, originating from the northwest Pacific and producing the more intense downpours, meteorologists said.
The official start of winter is Thursday.
Temperatures will remain average throughout the storm series, with no influence from the Polar jet stream, according to the Weather Service.
In the Riverside metropolitan area, highs Tuesday to Friday will hold in the mid 60s, with overnight lows in the low 50s.
In the Coachella Valley, the daytime mercury will hover around 70 and fall into the mid 50s overnight this week, while in the Temecula Valley, the temperature range will be virtually identical to Riverside metro Tuesday to Friday.