Rainy weather is forecast for the Inland Empire later this week, with heavy downpours possible in some locations, raising the risk of flash flooding, according to the National Weather Service.
Forecasters said two systems dropping out of the Gulf of Alaska will make landfall in Southern California in quick succession, the first arriving Thursday.
The upper level trough will usher in colder temperatures and atmospheric instability, with precipitation amounts varying from a tenth of an inch in the deserts to an inch closer to the coast.
“Heavier showers and thunderstorms could create locally higher amounts,” according to the NWS. “Isolated flash flooding is possible over slow-moving heavy showers and thunderstorms.”
The Riverside County Emergency Management Department was monitoring forecasts, but officials were not yet prepared to issue advisories or precautionary voluntary evacuation warnings for communities along the eastern boundary of the Cleveland National Forest.
Multiple neighborhoods fell under mandatory evacuation orders at intervals between Jan. 14-17, when a storm series triggered locally intense downpours, resulting in a number of street closures. Mud and debris flows, however, did not cause any serious damage to residential properties.
A wide area skirting the eastern side of the national forest, bordering Lake Elsinore and the Temescal Valley, was left exposed to potential flood damage because of the 23,000-acre Holy Fire last August. The blaze, allegedly the work of an arsonist, denuded steep terrain below Santiago Peak, permitting water to flow unchecked onto lower slopes where subdivisions are situated.
According to the Weather Service, the disturbance that will envelop the region Thursday into Friday will be succeeded by a “deeper, broader” low pressure system Saturday. Forecasters indicated the inclement weather will canvass most of the state, though it was too early to tell where the precipitation may be heaviest.
Snow levels will linger above 7,000 feet Thursday and Friday, with accumulations between 3 and 5 inches, and they’re expected to drop to 5,000 feet by Saturday night, according to the NWS.
High temperatures in the Riverside metropolitan area will hover in the low 60s Thursday to Sunday, while Coachella Valley communities will be closer to 70 degrees during the same period, meteorologists said.