Storm systems that are forecast to start pounding the Inland Empire Thursday will produce intense winds, heavy rain and snowfall at higher elevations, prompting the National Weather Service to issue a series of advisories Tuesday.
The agency posted a winter storm watch from Wednesday night to Friday afternoon, a flood watch from 6 a.m. Thursday to 10 a.m. Friday, and a high wind watch from 4 a.m. to 4 p.m. Thursday.
The advisories cover most of the inland region.
“Widespread moderate to heavy rain is expected on Thursday,” the NWS said in a statement. “There is also a slight chance of thunderstorms for Thursday into Thursday evening … west of the mountains. Rainfall totals through Friday will range from 1.5 to 2 inches near the coast, 2 to 3 inches in the mountains, and .3 to .5 inches closer to the deserts.”
Low-lying areas, particularly around mountainous terrain, may be exposed to significant runoff, raising flood dangers, according to the agency.
The activity stems from back-to-back troughs of low pressure driven by an “atmospheric river” directed over Southern California by a southward bending jet stream, meteorologists said.
The NWS noted that as the initial trough and cold front push into the region Wednesday night, “strong southerly winds are expected.”
“Peak wind gusts along the coast will be 40 to 50 mph, with gusts 35 to 45 mph possible in the valleys,” the agency stated. “In the mountains and deserts, peak gusts of 40 to 50 mph are possible.”
Communities along Highway 243, including Idyllwild-Pine Cove, are in store for varying amounts of snow accumulations, according to forecasters.
“The snow level will start at 6,500 to 7,000 feet Thursday morning at the onset of the precipitation,” the NWS said. “Periods of heavy snowfall are expected in the San Bernardino and Riverside County mountains above 6,500 feet Thursday morning to early afternoon. Snow levels will fall to 4,500 feet by early Friday.”
The agency predicted one to three inches of snow at 4,500 feet, three to six inches at 6,000 feet, and up to two feet of snow above 8,000 feet from Thursday to Saturday.
There will be a lull Saturday and Saturday night before another, less intense storm front reaches the region Sunday into Monday.
Daytime temperature in the Riverside metropolitan area Wednesday will hover in the upper 70s, dropping to the lows 50s overnight, while Thursday to Saturday highs will peak in the upper 50s, with lows in the low 40s.
In the Coachella Valley, highs will top out in the mid-70s Wednesday, with lows in the mid-50s. Thursday to Saturday, the daytime mercury won’t edge much above 60, falling to the mid-40s at night.
In the Temecula Valley, daytime temps will stall in the upper 60s Wednesday, dropping to the upper 40s Wednesday night, while Thursday to Saturday, the highs won’t exceed 55 degrees, with lows in the low 40s, according to the NWS.