SoCal Forecast
Updated most Sundays, Tuesdays, and Thursdays

Sunday October 18, 2020 7:30 AM
By Nathan Cool


Surf Charts for SoCal

Rincon | Ventura, C-St. | County Line | Malibu | Hermosa | Huntington Beach
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Today (Sunday) minor to moderate southern hemisphere ground swell is filling into SoCal and will peak in a few days. This should be southern hemi's last hurrah with activity now going seasonally silent south of the equator. All eyes now turn to the North Pacific as activity is starting to brew. NW wind swell is due by Thursday. More wind swell is likely Sunday the 25th into Monday the 26th. And NW ground swell is possible Tuesday the 27th. There may also be a favorable shift for NW swell development during the first week of November. Condition-wise: onshore flow this week cools temps and returns AM marine layer; there's a slight precip chance in the forecast over the coming weekend; the tide is swinging wide; and water temps are fair.

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Early this morning, periods were primarily running 15 seconds from 200° and 9 seconds from 315°.

Most south facing breaks were running waist high with occasional chest high pluses at standouts. Direct west facing breaks were mostly knee to waist high.

Swell Forecast and Schedule
Synopsis
Buoys in the outer waters off SoCal were running 4-5'. Nearshore buoys were running 1.6-2.1'.

Tide levels continue to swing wide from Friday's New Moon. Today we have a 1' low around 4:30 AM, a near 7' high around 10:30 AM, a -0.7' low around 5:30 PM, and a 4.5' high around midnight.

Water temps were running 68-71° in most of SD and OC yesterday, although San Clemente reported warmer at 73°. In LA, Cabrillo reported 67° yesterday, Santa Monica buoy has been running 65-70°, and many nearshore buoys were averaging 68°. In VC, Channel Islands Harbor reported 66° overnight. SB Harbor reported 68° overnight.

Swell-wise: NW swells have backed off and light southern hemisphere ground swell is filling in from a minor storm that swirled up south of French Polynesia about ten days ago. This will linger Monday and Tuesday, with then south facing breaks should see a boost in size Wednesday the 21st from this storm you may recall from last week's reports, south of Pitcairn:

Staying in such low latitudes with no northward trek means chest max surf at SoCal's south facing breaks with spotty sets and long lulls between sets. Swell should be angled from 180-185° with periods 18-20 seconds, with swell initially arriving Wednesday the 21st, peaking Thursday the 22nd, lingering to a lesser degree Friday the 23rd, and then dropping off Saturday the 24th.

Wednesday the 21st (building day) into Thursday the 22nd (peak day) we should also see an injection of NW wind swell, shown on this FNMOC model below:

As a trough of low pressure digs south over the American West over the next few days, it'll butt-up against high pressure that was once over our area but is now drifting northwest into the Gulf of Alaska. This will create pressure gradients off NorCal, centering its winds/wind-swell there. Only a fraction of NW wind swell should make it to SoCal, with Thursday the 22nd likely topping out at waist to chest high at west facing breaks. Swell would be angled from the wind-swell-usual 300°+ with periods around 10 seconds. Notice though that big ole honkin' fetch up in the Bering Sea across the Aleutian Chain...that's something on the charts for the 27th...more on that in a sec. Before then...

Sunday the 25th (building day?) into Monday the 26th (peak day?) could see more NW wind swell, preceded by a change in weather as many models show a trough low pressure digging so far south that it'd swipe SoCal, bringing with it a chance of precip (model from UQAM):

All models show some kind of trough (circled in red above) hitting our area, but the strength and position is where things differ — slightly so far. Basing this on a forecast so far out (168h on that model above) makes it too early to call, but notice also the patches of blue over the SoCal coast. This shows measurable precip, but more than likely that'd just be AM drizzle: trace (0.5mm) max, and hugging the coast like that smacks of drizzle from a thick marine layer deck. It's definitely something to watch for weather and waves, so it earned a yellow pin on the charts this morning, and I'll see how this plays out over the next few days.

Tuesday the 27th holds a decent chance of seeing minor to moderate NW ground swell as blocking high pressure in the Gulf would stop this dude from traveling any farther east than the Aleutians (model from FNMOC):

La Niña-esque high pressure in the Gulf (circled in blue) would put the brakes on this storm (circled in red) that, after originating off Kamchatka would reach its final destination here, at the tip of the Aleutian Chain. So far this only holds waist high hope for west facing breaks in SoCal, but it is a few days away on the models, so I'll keep my fingers crossed and keep you posted.

November may start out with a slightly more surf-worthy pattern for NW swells in SoCal, at least for a while. Using the GFS NOAA model we can peer into long-range land, with this 16-day (384h) projection to see potential for SoCal surf:

High pressure (blue circle on the right) would have been over SoCal over the weekend of the 31st-1st, but by the time of this forecast (11/2-11/3) it would be moving east with no high pressure backfilling it in the Gulf of Alaska. This would allow the storm track to run uninhibited toward SoCal, bringing two systems into our swell window. The first would be wind swell from a low near the coast, and the second would be from a larger system across the Aleutians. One should never place bets on such a long range projection, but this does seem feasible as high pressure below the storm track would keep these potential swell-makers in the moderate range, in fairly high latitudes. Either way, I'm on it...and I'll keep you posted.

And just real quick, before getting to the rest of the forecast, I want to personally thank everyone who's donated this year. Thank you for keeping this report alive! If you find this report useful but haven't donated yet this year, I would like to ask that you consider a small donation to keep this report going. Thank you everyone for your continued support!

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

Monday the 19th should run waist to at times chest high at south facing breaks and knee to waist at west facing spots.

Tuesday the 20th looks similar.

Wednesday the 21st should run chest high at south facing breaks. West facing breaks should run waist high.

Thursday the 22nd should run chest high at south facing breaks and waist to chest at west facing spots.

Friday the 23rd is expected to run waist high everywhere.

Saturday the 24th is expected to run knee to waist high everywhere. This is when southern hemisphere ground swell drops from the forecast.

Sunday the 25th, so far, looks similar.

Monday the 26th, so far, has a chance of seeing NW wind swell build into SoCal, waist high at west facing breaks by the looks of things right now.

Tuesday the 27th, so far, is expected to run waist high from ground swell and wind swell at west facing breaks, with chest high pluses possible.

Wednesday the 28th, so far, holds a chance of seeing more wind swell in SoCal, topping out at chest max at west facing beaks.

Thursday the 29th, so far, looks about waist high at west facing spots.

Friday the 30th, so far, looks smaller.

Saturday the 31st, so far, looks about knee to waist at west facing breaks.

Sunday the 1st, same deal so far.

Monday the 2nd...no major change yet.

Tuesday the 3rd...no major change yet.

Wednesday the 4th could see NW wind swell increase at west facing breaks...based on extended long range models today.

Weather Outlook
An onshore flow is underway as high pressure moved west, back over the Pacific, and a low pressure trough is starting to bear down on our region. AM marine layer returns this week with mid to late AM burn-offs, thicker with later burn-offs by the end of the week. Beach max temps should reach the low 70s today, 70° or so Monday and Tuesday, and then cooler Wednesday through the coming weekend in the upper 60s.

As mentioned in the surf section above, there is a slight chance of seeing some kind of precip at the coast this coming weekend. More than likely it would be merely AM drizzle at most, but it does need more monitoring over the next few days. Either way, a very robust onshore flow is highly likely this coming weekend.

Wind Outlook
Winds at 7:00 AM were light and variable most everywhere. Afternoon onshores are expected to reach 15 mph. Monday should see AM light and variables with afternoon onshores 9-14 mph. Same goes for Tuesday and Wednesday.

 

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

—Nathan

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