SoCal Forecast
Updated most Sundays, Tuesdays, and Thursdays

Sunday October 17, 2021 6:40 AM
By Nathan Cool


Surf Charts for SoCal

Rincon | Ventura, C-St. | County Line | Malibu | Hermosa | Huntington Beach
Trestles | Old Mans | Oceanside | Beacons | Sunset Cliffs

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At a glance:
Today (Sunday) is the smallest day in the forecast. A series of five North Pacific storms are lining up to send NW ground swell our way, with impressively sized surf by the coming weekend, and possibly bigger next week. Minor southern hemi comes into the mix early next week as well. More NW ground swell is possible around the end of the month. Condition-wise: onshore flow this week with the return of marine layer, cooler temps, and light precip chances; better precip amounts tease the longer range forecast; winds to trend onshore; the tide is swinging wide; and water temps remain cool in many spots.

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Current Conditions:
Early this morning, periods were primarily running 14 seconds from 295° and 14 seconds from 190°.

Most breaks were running waist high.

Buoys in the outer waters off SoCal were running 7'. Nearshore buoys were running 1.5-2.5'.

Tide levels are swinging wider as we approach a Full Moon Wednesday the 20th. Today we have a 5.3' high around 8:30 AM, a 1.2' low around 2:30 PM, and a 5.3' high around 8:30 PM.

Water temps yesterday were running 61-64° in much of SD. OC was running 57-61°. LA was running 59-62°. In VC, Channel Islands Harbor reported 57° late yesterday afternoon. SB Harbor reported 59° overnight.

Surf Forecast:
We're off to an early start to the NW swell season as the North Pacific has taken on a winter-esque pattern to send at least five ground swells our way. Things remain fairly well on track from last week's reports, but with some additions, a few minor changes, some slight inconsistency across the models, and some new weather features as well. All of this will be influenced by the jetstream as it sets up an ideal track for swell-making storms to ride into our swell window after spinning up in the Western Pacific (model by NOAA MAG):

Right now, the jet (green) is at a fairly high latitude blocked by high pressure (blue) sitting over the American West that brought our recent Santa Ana. But the jet is starting to dip southward near the west coast, and in a couple days it'll be draped just to the north of SoCal as high pressure exits to the southeast (model by NOAA MAG):

Low pressure systems (red Ls) light up across the North Pacific, with some swiping the west coast just north of SoCal. Low pressure in the Gulf of Alaska is where each of the approaching, swell-making storms will grow, and by this time next week, a contiguous storm track will ride well into the U.S., unabated as high pressure stays to the east (model by NOAA MAG):

It's at this point in the forecast that swell-making storms will have a better chance to grow significantly to send impressively sized surf to SoCal. But let me back up...

Monday the 18th into Tuesday the 19th sees the first, initial ground swell, which will start out small from storm #1 (model generated by XyGrib from NFCENS data):

With just 15-18' seas from 1,300 miles away, size should run waist to chest high Monday the 18th at west facing breaks and then chest high Tuesday the 19th. Swell should be angled from 300-320° and periods 12 seconds. At the same time, storm #2 is brewing in the Bering Sea and storm #3 is growing in The Sea of Okhotsk, waiting their turns to hop on the jetstream's west coast express.

Wednesday the 20th (late) into Thursday the 21st (peak) should see swell from storm #2 once it peaks in the Gulf of Alaska (model generated by XyGrib from NFCENS data):

When this peaks Thursday the 21st, west facing breaks are looking at head high sets with swell angled from 295° and periods 13-14 seconds. Storm #3 would have crossed Kamchatka by then, staying strong in the Bering Sea, preparing to cross the Aleutians into our swell window.

Saturday the 23rd should see swell from storm #3 after it grows into a fairly impressive fetch in the Gulf (model generated by XyGrib from NFCENS data):

Many models show this topping out with seas in the 25' range, which is enough to send head high swell to SoCal's west facing breaks; however, some models show that fetch getting much closer to SoCal, which would send surf running well overhead this coming weekend. In fact, the nearshore data from NCEP shows potential for 15' seas right off of the SoCal coast, which would push surf toward the DOH zone Saturday the 23rd. That, btw, is the data used to generate surf charts here on WaveCast and some other forecasting websites, which can make those charts look a bit overdone right now. I'll know more in a couple days; but for now, I'd call for surf running at least head high Saturday the 23rd, with size somewhat likely running 1-3' overhead. Swell should be angled from 300° with periods 14 seconds.

Monday the 25th (building day) into Tuesday the 26th (peak day) would see swell from storm #4, which, according to the 160-hour-plus models, would grow into this monster fetch (model generated by XyGrib from NFCENS data):

That purple blob in the center of the fetch equates to 40-45' seas, which could easily put SoCal's west facing breaks into surf running 2-4' overhead by Tuesday the 26th, with DOH sets at standouts. Swell would be angled from 300° with periods 18 seconds. But, being on that far of a long-range outlook, it's a bit early to call that right now. Confidence is high (so far) on at least 2-4' overhead surf by Tuesday the 26th.

At the same time, light southern hemisphere ground swell would come ashore from a storm traversing the low latitudes off Antarctica, south of Pitcairn (see earlier model here). Chest max at south facing breaks would be the call for Tuesday the 26th; however, NW wrap from NorthPac storm #4 could easily meet or exceed that size.

Saturday the 30th could then see NW ground swell from storm #5, which is way out on the 240-hour-plus models (model generated by XyGrib from NFCENS data):

Note the heavy seas off SoCal from storm #4, showing how it would still be bringing heavy surf Wednesday the 27th. After lesser surf lingers Thursday the 28th and Friday the 29th, Saturday the 30th could see head high+ surf from storm #5, with some models hinting at a few feet overhead at west facing spots. At this point though we're entering into tricky territory on long range outlooks, so I'll hold off for now and see how these storms progress over the next few days. I'll keep you posted.

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Here's how the day-to-day is breaking down so far:

Monday the 18th is expected to run waist to at times chest at west facing breaks and waist high at south facing spots.

Tuesday the 19th looks about chest max at west facing breaks and waist high at south facing spots.

Wednesday the 20th looks about waist high at most breaks, with NW swell building overnight.

Thursday the 21st is expected to run head high at west facing breaks.

Friday the 22nd looks about chest to head high at west facing breaks.

Saturday the 23rd, so far, is expected to run head high to 2' overhead at west facing spots; however, some models show potential for bigger surf. Due to proximity (fetch forecast to be nearer to the west coast) I'll firm this up in my next report.

Sunday the 24th, so far, looks about head high to slightly overhead at west facing spots.

Monday the 25th, so far, should see NW ground swell build during the day, starting out at chest to head high early AM and running a couple feet overhead by midday.

Tuesday the 26th, so far, is expected to run 2-4' overhead at most west facing breaks and DOH at standouts.

Wednesday the 27th, so far, is expected to run 1-3' overhead at west facing breaks with pluses at standouts.

Thursday the 28th, so far, looks about chest to at times head high at west facing breaks.

Friday the 29th, so far, looks about chest high at west facing spots.

Saturday the 30th, so far, holds potential for overhead surf at west facing breaks; however, this is out on the extended long range models right now.

 

Weather Outlook:
High pressure is breaking down and moving east as low pressure begins to dominate the Gulf of Alaska with the jetstream/storm-track setting up that pattern (noted above) to drive NW ground swells our way. Each swell-making storm will take a swipe at the west coast, staying north of SoCal, but tapping us with their tails as they pass by the region. This will keep an onshore flow in place with AM marine layer likely most days this week, and with some minor-amount precip chances as well.

Today (Sunday) should remain clear with beaches in the mid to upper 60s. Marine layer with drizzle is expected tonight into Monday morning, with a late burn-off Monday and max beach temps in the low 60s. Some areas may see some measurable precip, but more than likely below a tenth of an inch.

Tuesday may be a brief clearing day once low #1 passes to the east, but beaches should remain in the mid 60s.

Wednesday through Friday see the return of AM marine layer, late AM burn-offs and max beach temps in the low to mid 60s as the next low passes to the north.

Saturday (23rd) could see another shot of AM drizzle with minor-measurable precip amounts at the coast. AM marine layer will likely be late to burn off with max beach temps in the mid 60s. Sunday the 24th would likely see AM marine layer, drizzle less likely, and max beach temps in the mid to upper 60s.

Monday the 25th into Tuesday the 26th could see a minor rain event in SoCal, with some spots potentially seeing 0.1". That's on the bullish side, with drizzle-plus the more likely call. Either way, AM marine layer is likely with beach max temps in the mid 60s...by the looks of things so far.

 

Wind Outlook:
Winds at 7:00 AM were light and variable most everywhere. Afternoon onshores are expected to reach 7-11 mph. Monday should see AM light and variables with afternoon onshores 10-15 mph. Tuesday looks similar, but with lighter afternoon onshores in the 8-12 mph range. Wednesday will likely see onshores pick up by mid morning and reach 15 mph in the afternoon. Thursday and Friday look similar so far.

 

Until my next report (Tuesday), take care, be safe, and smile in the lineup!

—Nathan

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