LOS ANGELES — A powerful storm system is moving through Southern California Thursday, bringing with it concerns about potential flooding and gusty winds expected to stretch into Friday.
But there were some indications the storm may weaken significantly by the time the center of the system reaches Los Angeles County.
“A strong storm will bring many hours of steady moderate-to-heavy rain today through Thursday,” according to the National Weather Service. “… This is a fairly slow moving front and significant flooding is possible as it works its way east through the forecast area.”
A flood watch will be in effect across Los Angeles County until late Thursday night. In Orange County, a flood watch will be in effect Thursday evening through Friday evening.
A tornado warning was issued for central Ventura County around 2 a.m. It expired shortly thereafter because of reports the storm was weakening.
Rain fell on much of the area Tuesday and into Wednesday morning, although the showers were scattered and generally light. As of early Wednesday morning, most of Los Angeles County had only received about a tenth of an inch of rain, according to the NWS. Light to moderate rainfall continued into the afternoon Wednesday.
As of 5 a.m., there was 1.06 inches of rain reported in Huntington Beach and 1.02 inches reported in Coto De Caza. There was 1.62 inches of rain reported in Upper Harding Canyon and 1.34 inches reported at Santiago Peak.
NWS forecasters said rainfall rates were expected to decrease as the center of the storm moves into Ventura County and ultimately Los Angeles County, although there will still be chances of small cells dropping large amounts of rain in a short period of time.
“L.A. County, particularly the south and eastern portion, may be more on the outside looking in with this system, as the models are showing rapid weakening of the front in that area,” according to the NWS. “Still, as mentioned, isolated stronger cells could still drop very heavy rain just about anywhere in L.A. County with the best chances Thursday night into early Friday. Overall though, rain totals from this system should be much less in L.A. County than areas to the west.”
Forecasters said earlier there will be a 20% to 30% chance of thunderstorms through Thursday night.
Los Angeles County Lifeguards warned people to exercise caution if they visit the beach.
“Ocean conditions will also have a bit more activity with waves in the head to overhead range,” lifeguards warned on social media. “Plenty of varying factors these next few days, so make sure to stay tuned, and if you decide to come to the beach make it a point to check in with a lifeguard tower prior to entering the water.”
County health officials issued their standard warning for people to avoid entering the ocean water in the days following rain, noting that runoff can carry bacteria and debris into the ocean, raising the risk of illness.
Snow levels are expected to remain above 7,500 feet, with several inches possible at elevations over 8,000 feet.
Los Angeles County officials said various agencies were coordinating to ensure public safety while also hoping to capture as much stormwater as possible for future use.
“L.A. County owns a world class system of water conservation and flood protection. This system is prepared to capture and conserve valuable stormwater while protecting communities,” county Public Works Director Mark Pestrella said in a statement. “Our system is primed to capture as much stormwater as possible in our efforts to increase the region’s overall local water supply by 600,000-acre feet by 2045.”
County officials urged residents to heed instructions from emergency responders and alert notifications; drive cautiously and slow down in wet conditions; and avoid trying to cross flooded roadways.
Daytime temperatures will remain in the 60s in the region for much of the week. Overnight lows will generally be in the upper 40s and lower 50s throughout Southern California but will dip into the 30s in some parts of the mountains and high desert.
Thursday is the first day of winter. Conditions are expected to dry out on Friday, although gusting northwest winds are expected to linger into Saturday.