A torrent of rain covered Long Beach on January of 2017. Photo by Brian Addison.
A file photo of rain in Long Beach. Photo by Brian Addison.

Rain and thunderstorms are forecast for later this morning and through the day in the Long Beach area.

Light rain was already falling in some parts of the Southland Wednesday morning, according to the National Weather Service.

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, today’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 today with a high of 73 in Long Beach. Temperatures in the county will remain in the low- to-mid 70s through at least Tuesday.