Winter storms appear to be piling up at the end of the season for the inland region, as another round of wet weather, including thunderstorms, is forecast for the latter half of the week.
The National Weather Service said that an “atmospheric river” will drop down from the Pacific Northwest and flow across Southern California beginning Wednesday night, lingering into Friday morning.
“There are some differences in the depth and timing of the main trough (of low pressure) Wednesday into Thursday,” the agency said in a statement. “In general, there is a 60-75% chance of at least .5 inches of rain for the coasts and valleys. For the high deserts, there is a 20-45% chance of at least .25 inches. Snow levels will be upwards of 7,000 feet at the onset of precipitation Wednesday evening, quickly falling to around 4,500 feet by Thursday morning and as low as 3,500 feet on Friday morning.”
Forecasters said Interstate 15 through the Cajon Pass might be impacted by the wintry weather Thursday night into Friday.
“There is also some indication that an isolated thunderstorm or two could develop as cold air aloft moves into the area and vorticity moves through the main flow … both Wednesday evening and Thursday,” the NWS stated.
Thunderstorm cells developed in the Riverside metropolitan area Sunday night as the past weekend’s storm activity subsided.
After the upcoming storm system exits Friday, a dome of high pressure will deliver clear and warmer conditions for the weekend, but the Weather Service said more precipitation may arrive at the start of next week.
For Monday and Tuesday in Riverside metro, daytime highs will reach the upper 60s, with overnight lows in the mid 40s. Wednesday to Friday, the mercury will peak in the upper 50s, and temps will drop into the low 40s nightly.
In the Coachella Valley, the highs will peak in the mid 70s Monday and Tuesday, dropping into the mid 50s at night, while Wednesday to Friday, temps will top out in the mid 60s, with lows in the mid to upper 40s.
For the Temecula Valley, the mercury will settle in the mid 60s Monday and Tuesday, falling to around 40 at night, and Wednesday to Friday, the highs will edge into the upper 50s, slipping into the upper 30s overnight, according to meteorologists.