LA Halloween forecast: Rain storm to bring wet weekend across Southern California
Weather Forecast for Friday, Oct. 30
The latest forecast and air quality conditions for the greater Los Angeles area, including beaches, valleys and desert regions.
LOS ANGELES - A rainy Halloween weekend is expected in Southern California, with heavier downpours forecast to hit right during peak trick-or-treating hours.
What we know:
The shifting weather pattern will bring cooler temperatures to the Southland, dropping daytime highs into the 60s and low 70s while driving up moisture levels across the region.
"This upper-level low is going to pick up all the moisture related to this system down to our southwest, and all that moisture is clashing with the colder air to the north," FOX 11 meteorologist Maria Quiban said.
That collision creates a 10 to 20 percent chance of isolated thunderstorms starting Saturday night and lasting into early Sunday morning.
"If you are headed out to trick-or-treat, make sure you have your umbrella and, of course, rain boots," Quiban added.
In addition, a coastal flood advisory remains in effect for beaches in Los Angeles, Orange, and Ventura counties through Friday at 2 p.m., with surf sets reaching 4 to 5 feet and minor coastal flooding possible.
Timeline:
Friday
- High temperatures stay cool in the upper 60s and low 70s with pockets of light, scattered shower activity.
- Minor coastal flooding and high surf linger along area beaches.
Saturday morning to afternoon
- Mostly cloudy and cool conditions continue, with daytime highs near 68 to 70 degrees.
- The morning and early afternoon remain mostly dry, with light scattered rain producing less than a tenth of an inch in most inland and coastal valleys.
Saturday night: Peak trick-or-treat hours into overnight
- The main storm system sweeps into Southern California, bringing widespread rainfall right as evening neighborhood festivities begin.
- Cold northern air mixing with southern moisture brings a 10-20% chance of isolated thunderstorms.
- Rainfall turns moderate to heavy after dark, picking up significantly overnight into Sunday morning.
Sunday morning into Sunday night
- Widespread showers and lingering isolated thunderstorms continue through early Sunday before tapering off later in the day.
How much rain will Southern California get?
While daytime Saturday will only bring minor sprinkles, the storm will drop significant moisture Saturday night and Sunday.
"Perhaps an inch in San Bernardino, maybe four-tenths of an inch in Woodland Hills and Burbank, a little more in Santa Clarita," Quiban said. "Palm Springs could also get hit pretty hard with almost an inch of rain as we get into tomorrow night."
Overall, storm rainfall totals across Southern California are projected between a half-inch and 1.5 inches by the time the system moves out Sunday night.
Past rainy Halloweens in Los Angeles Measurable precipitation on Halloween is relatively rare in Southern California, making this weekend's storm an unusual occurrence.
"We've had some wet Halloweens before. In fact, 2014 was the most recent one," Quiban noted, pointing out that downtown Los Angeles recorded roughly a quarter-inch of rain that year.
Before 2014, the region saw measurable rain on Halloween in 2003, when more than a half-inch fell downtown. The wettest Halloween on record for downtown Los Angeles came in 1987, when a heavy storm dumped 1.39 inches of rain.
What's next:
The storm will begin to taper off by late Sunday and drier conditions are expected by Monday.
Daylight saving time
Dig deeper:
Along with packing raincoats and umbrellas, Southern California residents have one more task before heading to bed Saturday night. Daylight saving time officially ends at 2 a.m. Sunday, meaning clocks should be turned back one hour.
SUGGESTED: Here’s how daylight saving time impacts your body and what you can do
The Source: This story was written with information from the National Weather Service and FOX 11's Weather Team.