Scary Weather Report: Thursday, Oct. 29 Through Monday, Nov. 2
South Pasadena hasn’t needed an umbrella for trick-or-treating in 12 years. That streak is likely about to end.
The National Weather Service office in Oxnard says a storm spinning off the coast will bring rain to Los Angeles County from as early as Friday through Sunday, with the heaviest stretch expected Saturday evening into Sunday morning. That is prime trick-or-treat time. Forecasters put it bluntly earlier this week: “Halloween activities are likely to be impacted.”
Los Angeles last saw Halloween rain in 2014, when about a quarter inch fell downtown. Before that it was 2003, at roughly half an inch, and 1987, when 1.39 inches came down.
The Day-by-Day Forecast for South Pasadena
Thursday, Oct. 29: Partly to mostly cloudy, with high clouds and some morning marine layer gray. Highs in the low to mid 70s, a couple of degrees cooler than Wednesday. Lows in the mid 50s. A stray spot of drizzle is possible, but nothing that will register.
Friday, Oct. 30: Cooler and cloudier, with highs in the upper 60s to around 70. Rain chances begin Friday night, with lows in the mid 50s. Friday evening is the drier of the two big event nights.
Saturday, Oct. 31 (Halloween): Mostly cloudy with highs in the mid to upper 60s. Shower chances build after about 11 a.m. and keep climbing into the evening. Through Saturday evening, forecasters expect a tenth to a third of an inch across the area, and Los Angeles County is where the best rain chances line up. Temperatures during trick-or-treating will sit in the upper 50s to low 60s.
Saturday Night: The main event. Steady rain is most likely overnight into Sunday morning. Lows in the mid 50s.
Sunday, Nov. 1: Rain tapers off by the afternoon. Highs in the upper 60s. Partly cloudy Sunday night, with lows in the low to mid 50s.
Monday, Nov. 2: High pressure builds back in. Dry, sunny and warmer, with highs in the low to mid 70s and a light offshore breeze. Tuesday stays dry and warm.
How Much Rain?
Most of the region is expected to pick up half an inch to an inch and a half by the time the storm clears Sunday. South-facing mountain slopes, including the front face of the San Gabriels, could see up to 2.5 inches. Rainfall rates should run a tenth to a third of an inch per hour.
The weather service is openly hedging. Forecasters give a 20 percent chance that totals and rates come in at double those numbers, and a 20 percent chance they come in at half. Thunderstorm odds are 10 percent or less, with the most unstable air expected to stay south of Los Angeles County.
Why the Timing Is Still A Best-Guess The two main forecast models disagree on how fast the storm’s center tracks east toward northern Baja. The European model is faster, which would push rain into the area earlier on Saturday and squarely into trick-or-treat hours. The American GFS model is slower, which would shift more of the rain later into Saturday night. Forecasters are splitting the difference for now.
The Thursday and Friday forecast discussions from the Oxnard office are the ones to watch. Once the low pinches off from the parent trough Friday night, the timing should come into sharper focus.
Foothill and Burn Area Residents: Keep an Eye on This One
Expected rainfall rates are modest, and as of Wednesday night the weather service had issued no flood watch for Los Angeles County. But the higher-end scenario, double the expected rates with up to 2.5 inches on south-facing slopes, is the one residents near the Eaton Fire burn area in Altadena and Sierra Madre should track. Check weather.gov/losangeles before heading out Saturday night.
Clocks Fall Back Sunday
Daylight saving time ends at 2 a.m. Sunday, Nov. 1. Set clocks back one hour. Sunset Saturday is right around 6 p.m. By Sunday it drops to just before 5 p.m.
Where to Go This Weekend
Friday, Oct. 30: Pasadena’s Día de los Muertos celebration runs 5 to 8 p.m. at Villa Parke Community Center, 363 E. Villa St., with dance performances, crafts, food and ofrendas.
Friday, Oct. 30: The San Gabriel Mission District’s Fall Fun Festival runs 5 to 9 p.m.
Friday and Saturday, Oct. 30 and 31: The Huntington’s Strange Science Halloween bash runs 6 to 10 p.m. both nights in San Marino.
Saturday, Oct. 31: Spooktoberfest takes over the historic South Pasadena Masonic Lodge, 1126 Fair Oaks Ave., from 5:30 to 9:30 p.m. Admission is free. The haunted maze is inside the lodge. The block party with DJs, carnival games and fortune tellers is outdoors, so plan accordingly.
Saturday, Oct. 31: Old Pasadena’s Halloween Spooktacular brings store-to-store trick-or-treating around One Colorado from 4 to 8 p.m., with plenty of storefront cover if the showers arrive early.
Saturday, Oct. 31: Kidspace Children’s Museum wraps its Halloween season, open 10 a.m. to 5 p.m. at 480 N. Arroyo Blvd.
Trick-or-Treat Survival Notes
Go early. The best window for a dry walk is late afternoon and early evening Saturday, before the heavier rain is expected to settle in.
Pick costumes that work with a rain shell over them, and add a flashlight or reflective tape. Wet leaves and slick porch steps are the real hazard on a dark, rainy night.
Drivers: The first real rain after a long dry stretch leaves roads extra slippery. Slow down in neighborhoods, especially after dark.
Homeowners: move the candy bowl under cover and turn the porch light on early.
Beach Note
A Coastal Flood Advisory remains in effect for Los Angeles County beaches until 2 p.m. Friday as unusually high tides continue along the coast.
