The second winter storm to roll across the region in a week brought periods of heavy rain Thursday morning and prompted the National Weather Service to issue a flood advisory for western Riverside County, but no evacuations have been ordered as officials continue to monitor the potential of mud and debris flows in fire-scorched areas, forecasters said.
About 9:30 a.m., the NWS issued a flood advisory for the metropolitan Riverside area that lasts until 12:30 p.m. Thursday and a flash flood watch through this evening for parts of the Temescal Valley and Lake Elsinore which were scorched by the Holy Fire.
As of 10 a.m. no evacuations have been ordered for the Holy Fire burn area, but the Riverside County Emergency Management Department advised residents to arrange transportation, put fuel in cars, gather items to take and make plans for animals in preparation for potential evacuations.
“NWS radar indicated showers moving into Orange County and this activity will increase through noon. Showers will be heavy at times with rainfall rates of .15 to .25 per hour,” NWS forecasters said in a statement.
“Showers will also move into the western Inland Empire. The rainfall will cause urban flooding in low lying areas, poor drainages and swift water through channels,” forecasters said.
In a 24-hour period ending around 9 a.m., the metropolitan Riverside area received .20 of an inch of rainfall, the San Gorgonio Pass near Banning got .39 of an inch of rain, Corona received .29 of an inch of rain, .71 of an inch of rain fell near Silverado and Palm Springs received .19 of an inch of rain, according to the NWS.
NWS meteorologists say the storm will drop up to a half-inch of rain in the Riverside metropolitan area Thursday, up to four-tenths of an inch in the San Gorgonio Pass near Banning and around a quarter-inch in the Coachella Valley.
Lake Elsinore could see up to three-quarters of an inch of rain, and the county mountains are expected to get up to an inch of rain, according to the NWS.
Light snow could drop above 6,500 feet in the San Bernardino Mountains, meteorologists said.
No thunderstorms are forecast for Riverside County and the storm system is expected to move northeast out of the region by late Thursday evening, NWS meteorologist Miguel Miller said.
High temperatures Thursday are expected to reach 58 degrees in Riverside, 49 in the county mountains, 57 in the San Gorgonio Pass near Banning and 62 in the Coachella Valley.
Last week’s winter weather, producing periodic heavy downpours, resulted in mandatory evacuations on Nov. 28 and 29 for residents in Glen Ivy Hot Springs, Horsethief Canyon, north Lake Elsinore and parts of the Temescal Valley south of Corona.
All the evacuated locations abut the Cleveland National Forest, where the 23,000-acre Holy Fire in August denuded hillsides, raising the potential for damaging flash floods, mud and debris flows.
Public safety officials told the Riverside County Board of Supervisors Tuesday that evacuations will be a re-occurring possibility for the duration of rainy season.