Light rain fell in the Southland Wednesday morning and showers are likely Wednesday afternoon, when there also will be a chance of thunderstorms, according to the National Weather Service.
Showers are also likely Wednesday evening, and there will be a slight chance of thunderstorms, forecasters said.
The chance of measurable precipitation Wednesday has been set at 70 percent in both L.A. and Orange counties.
The day’s first rains were reported after 6 a.m., with the NWS reporting light rain in Santa Ana and Fullerton.
The remnants of Hurricane Rosa — now a tropical depression — will not be much of a factor in the Southland’s rain episode, having largely migrated to Arizona and New Mexico, NWS forecasters said. Instead, the rain will be largely a product of an upper-level low-pressure system that originated in the central Pacific .
Although not a monster, Wednesday’s weather system will be unusually strong for this time of the year, said NWS meteorologist Dave Bruno, adding that the lion’s share of the precipitation will appear between noon and midnight.
The approaching system is raising some fears of mud slides and debris flows over areas previously denuded by wildfire — including near the site of the Holy Fire in Orange County and, in L.A. County, the La Tuna Fire near Burbank and the Creek Fire north of Sylmar — but those concerns are not particularly acute because mostly light rain is expected, according to Bruno. However, the risk of slides will increase considerably if thunderstorms appear since they can generate heavy downpours.
The NWS forecast thunderstorms in most of L.A. County Wednesday and showers in the Antelope Valley, along with highs of 61 on Mount Wilson; 69 in Avalon; 71 at LAX; 73 in Downtown L.A., Burbank, Saugus and Lancaster;; 74 in Long Beach; 73 in Burbank, 74 in Long Beach and Pasadena; and 75 in San Gabriel and Woodland Hills. Temperatures in the county will remain in the low-to-mid 70s through at least Tuesday.
Showers were forecast in Orange County, along with highs of 70 in San Clemente; 72 in Laguna Beach; 74 in Newport Beach; 76 in Anaheim; 77 in Fullerton, Irvine and Mission Viejo; and 78 in Yorba Linda. Highs will be in the mid-to-high 70s and low 80s through at least Tuesday.