LOS ANGELES, CA – A storm system arriving late Friday could bring Los Angeles its first rainy Halloween in more than a decade, according to the National Weather Service.
In its forecast discussion issued at 4:38 p.m. Monday, Oct. 26, the weather service’s Los Angeles/Oxnard office said there is very high confidence that rain will fall over the weekend. Confidence in when the rain starts and when it peaks is low.
The forecast discussion estimates about an inch of rain for most areas south of Point Conception, with higher amounts in the foothills and on coastal slopes. It also gives a 20 to 30 percent chance that totals will be double that amount.
Before the storm arrives, historically high tides are forecast to keep pushing water onto the coast through Thursday morning. Coastal flood alerts are in effect for Los Angeles and Orange counties.
Forecasters call the timing a low-confidence forecast
The weather service wrote in the discussion that its forecasters have “all eyes on the next storm system, which unfortunately, remains a low confidence forecast.” The storm is forecast to arrive late Friday, Oct. 30, and the Halloween weekend falls on Oct. 31 and Nov. 1.
Rich Thompson, a National Weather Service meteorologist in Oxnard, said “it looks like it will be a wet Halloween holiday weekend.” He said it is the first Halloween in a while that could actually be wet.
Forecasters have not pinned down the exact timing or location of the heaviest precipitation. That uncertainty applies to Halloween night, when many neighborhoods hold trick-or-treating and other events.
About an inch of rain forecast for most areas
The weather service’s estimate of about an inch applies to most areas south of Point Conception, a stretch that includes the Los Angeles and Orange county coastlines. Foothill communities and coastal slopes are forecast to receive more.
The forecast discussion says there is a 20 to 30 percent chance that rainfall totals will reach double the baseline estimate. It also gives a 50 to 60 percent chance of above-normal precipitation into the following week.
Rain on Oct. 31 would be first since 2014 downtown
If rain falls on Oct. 31, it would be the first rainy Halloween in downtown Los Angeles since 2014, according to a weather service meteorologist. Weather in Southern California is otherwise forecast to be mostly benign until Friday, apart from the tides.
Historically high tides reach Southern California coast
The weather service’s forecast discussion says very high tides of 7.5 to 8 feet are expected in the morning hours through Thursday over all coastal areas. It lists the San Pedro record as 7.93 feet, set Jan. 10, 2005.
According to initial reports, the San Pedro tide gauge reached 8.02 feet on Monday, breaking that record. Those same reports say the highest tides in Southern California were projected for Monday, Tuesday and Wednesday mornings.
A coastal flood advisory covers Los Angeles County, and a coastal flood warning covers parts of Orange County. Both run through 1 p.m. Thursday, Oct. 29.
Newport Beach emergency and sandbag sites
Newport Beach city officials declared a local emergency on Oct. 20 and activated the city’s Emergency Operations Center. They said recent ocean water levels had been running about 18 to 22 inches above predicted astronomical tides.
Free prefilled sandbags are available at the City Corporation Yard, 592 Superior Ave., and at Marina Park, 1600 W. Balboa Blvd. On Monday, the Newport Beach Police Department advised residents to use sandbags or temporary flood barriers and to move vehicles to higher ground if needed.
Orange County Board of Supervisors Vice Chair Katrina Foley said Newport Beach built a giant berm and the county is distributing sandbags with the city. She said county public works and flood district teams are clearing gutters and flood channels.
According to initial reports, water in Newport Beach reached 8.3 feet on Monday and flooded low-lying streets, with 8.5 feet forecast for Tuesday.
Metrolink suspends Orange County Line service
Metrolink announced that it suspended Orange County Line service south of the Laguna Niguel/Mission Viejo Station from Monday, Oct. 26, through Friday, Oct. 30, because of the anticipated high tides. Trains operate only between Los Angeles Union Station and the Laguna Niguel/Mission Viejo Station.
The agency said alternate bus transportation will not be provided. It said weekend service is not expected to be affected.
Rain is forecast to begin late Friday
The weather service’s next forecast updates will refine when the rain starts and how much falls in each area. For now, the forecast discussion calls for rain beginning late Friday, Oct. 30, and continuing through the Halloween weekend.
The coastal flood advisory for Los Angeles County and the coastal flood warning for parts of Orange County remain in effect through 1 p.m. Thursday.
