SoCal Forecast
Updated most Sundays, Tuesdays, and Thursdays

Thursday May 13, 2021 5:50 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 (Thursday) we have mostly moderate southern hemisphere ground swell in SoCal with little to no wind swell. Much of the same is on tap over the next couple days, with Sunday though seeing a boost when the next southern hemi comes ashore. Wind swell does pick up a bit over the weekend. The next southern hemi swell builds by the middle of next week. NW wind swell may make a more notable return for the second half of next week. A good-sized southern hemisphere swell is due late next week into the weekend of the 22nd, which could last for a few days. Models hint at more NW wind swell on the long range. Condition-wise: robust May Gray with drizzle for a while; winds trend onshore; a tidal swing is underway; water temps are varying; and La Niña has come to an end for a change in waves and weather for the extended outlook.

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Current Conditions:
Early this morning, periods were primarily running 15 seconds from 185-190° and 8 seconds from 305°.

Most south facing breaks were running chest high. West facing spots were mostly knee to waist, better though at SW exposed spots.

Buoys in the outer waters off SoCal were running 4-5'. Nearshore buoys were averaging 2.5'.

Tide levels remain moderate for daytime sessions even though a swing is underway from a New Moon that crested Tuesday. Today we have a -0.4' low around 5:30 AM, a 3.3' high around noon, a 2.2' low around 4:30 PM, and a 5.5' high around 10:30 PM.

Water temps were running 62-65° in most of SD yesterday. OC was more varied with Huntington and Newport 60° but San Clemente 69°. LA was mostly 61-63°. VC was also running 61-63°. SB Harbor has been running 61°.

Surf Forecast:
Today we're seeing the on-time arrival of the first notable southern hemisphere ground swell you may recall from earlier reports (model by FNMOC):

Swell from storm #1 (near Pitcairn) is what we're seeing today, and swell from storm #2 should arrive Friday the 14th into Saturday the 15th to keep south facing breaks in waist to chest high waves. Swell should be angled then from 200° from its peak south of French Polynesia. Periods should run 16 seconds.

Sunday the 16th should see a boost in size at south facing breaks as the southern hemi jetstream bent farther north to guide this next storm into higher latitudes (model by FNMOC):

That one peaked almost a week ago with seas topping out at 25-30'. Although not an impressive fetch, its northerly course into higher latitudes will result in less loss of swell energy. This should run chest+ at most south facing breaks Sunday the 16th, angled from 200° with periods 16 seconds.

The weekend will likely see a slight injection of NW wind swell as May Gray digs in deeper. Typical for this time of year, cool air above cold Pacific waters is smashing up against much warmer air over the deserts, creating one heck of an onshore flow. Even though water temps are up near the SoCal coastline, a very cold tongue of water is sitting just off our coast, keeping air temps quite cool once you go west of the islands (image by NOAA OSPO):

This is making for about a 20° difference in temps from ocean-to-land, which is a fairly strong temperature gradient. Warm air rising far inland over SoCal is being backfilled by moist, cool Pacific air, thus making for gray skies with hardly any burn-off at the coast. This weekend, despite high pressure being over the American West, a cut-off low should swing through SoCal to make matters worse (model by NOAA MAG):

This will kick up some wind swell Saturday the 15th while increasing afternoon onshore winds (with earlier onshores as well over the weekend). West facing breaks are looking at waist high wind swell waves this weekend. South facing breaks though will have the better size from southern hemi ground swell: waist to chest Saturday; chest+ Sunday.

Another round of NW wind swell is becoming likely around Wednesday the 19th into Thursday the 20th, this time from a more traditional trough of low pressure that models are starting to agree on (model by NOAA MAG):

Very few models showed this a couple days ago, but more are coming online with this idea today, dipping a hefty trough of low pressure south, staying just to the north of SoCal. This could bring at least chest high wind swell to SoCal's west facing breaks by Thursday the 20th, along with a robust onshore flow. But the dominant swell around that time continues to be southern hemisphere ground swell, which will build again by the middle of the coming week.

As you may recall from earlier reports this week, swells will be headed to SoCal next week thanks to this surf-worthy bulge in the jetstream near the Pitcairn longitudes (model by FNMOC):

That bulge in the jet (circled in red) should guide a couple storms slightly north off Antarctica (course shown with arrows), and today models are in fair enough agreement to start calling size and ETAs.

The first swell is that pattern is a slam-dunk call from this storm that peaked with 35' seas (model created from NFCENS data):

Swell should arrive in SoCal during the day Tuesday the 18th, peaking Wednesday the 19th with chest+ sets at south facing breaks, angled from 190° and periods 18 seconds.

Friday the 21st (building day) into Saturday the 22nd should see an increase at south facing breaks from this more impressive looking fetch (model created from NFCENS data):

Models continue to show that housing 40' seas, so its slight northward nudge comes out to head high sets at south facing breaks Saturday the 22nd, with swell angled from 185° and periods 18-20 seconds. BUT... since this system won't move too far north and remains in low latitudes, sets will likely be sporadic with long lulls between sets and fewer waves per set. Either way, swell may linger for a few days, at least Monday the 24th as many models show this system getting a reform boost as it treks toward Chile. At that point though it would steepen the swell angle to around 175°, making it tougher for some south facing breaks in SoCal. That portion of the forecast ventures into long-range-land, so I'll hold off on that until my next report.

Monday the 24th has a chance of seeing another shot of NW wind swell accompanied by a hefty onshore flow as models show another strong trough of low pressure pushing south toward SoCal (model by NOAA MAG):

If that 276-hour forecast has it right, then we'd be looking at possibly chest to head high NW wind swell by Monday the 24th, with one heck of a thick May Gray. It's too early to call that today.

Looking out further on the long range horizon, NOAA issued their latest ENSO diagnostic discussion, which officially ends our current La Niña. It's now inevitable that a neutral-Ni˜o will get underway shortly, peaking this winter. As you may recall from Surf, Flood, Fire and Mud, these neutral-Ni˜os can provide decent winter swells for the west coast, and they can bring heavier rain than a full-blown El Niño can. Before then, as we enter a neutral ENSO state, it's good news for summertime swells as the jetstream around Antarctica tends to be only moderate in strength, allowing surf-worthy storms to drift north to send swell to SoCal. And without a full-blown La Niña this summer, tropical waters should be warm enough to generate hurricane swell.

And last but not least, I'd like to give a BIG THANK YOU to everyone who donated the past couple months, which has kept things out of the red. But, donation goals are still on the razor's edge and starting to dip toward negative territory ( see report here). So if you haven't donated yet and you find this report useful, then I'd encourage you to please consider donating to support my forecasting efforts. Thank you again everyone, this report would not be possible without you.

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

Friday the 14th looks about waist to at times chest high at south facing spots and knee to waist at west facing spots.

Saturday the 15th looks about waist to chest high at south facing spots and waist high at west facing spots.

Sunday the 16th should run chest+ at south facing breaks and knee to waist at direct west facing breaks.

Monday the 17th looks about chest high at south facing breaks and knee to waist at direct west facing spots.

Tuesday the 18th should run chest high at south facing breaks and knee to waist at direct west facing spots.

Wednesday the 19th is expected to run chest+ at south facing spots. West facing breaks will likely see NW wind swell increase during the day.

Thursday the 20th should run chest high at south facing breaks. West facing breaks are likely to see NW wind swell running chest high.

Friday the 21st is expected to see long-period southern hemi ground swell build into SoCal, likely chest to head high at south facing breaks. West facing breaks will likely see chest high NW wind swell.

Saturday the 22nd is expected to run head high at south facing breaks. West facing breaks, so far, are likely to see chest high NW wind swell.

Sunday the 23rd, so far, is expected to run chest to at times head high at south facing breaks. West facing breaks are too early to call right now, but wind swell is somewhat likely in the chest high range.

Monday the 24th, so far, will likely run chest to head high at south facing breaks that can work at 175° angle, and chest max at other south facing spots. For west facing breaks, NW wind swell is becoming possible, but too early to call.

Tuesday the 25th, so far, looks similar.

Wednesday the 26th, so far, looks at least chest high at south facing breaks. West facing breaks are too early to call right now.

Thursday the 27th, so far, looks about waist to chest at south facing breaks. West facing breaks would likely see NW wind swell back off...by the looks of things today.

 

Weather Outlook:
May Gray has dug in for the long haul and will get thicker/cooler this weekend as a cut-off low swings through SoCal. Burn-offs will be late to near impossible at the coast now through the weekend and possibly early next week. AM drizzle is likely each day. As for max beach temps: mid 60s today and Friday; low 60s over the weekend; and mid 60s early next week. A small, temporary ridge of high pressure may nudge up temps a tick or two Tuesday or Wednesday, but no major clearing is on the horizon...yet.

Wind Outlook:
Winds at 6:00 AM were light and variable most everywhere with a slight onshore element. Onshores are expected this afternoon to 15 mph. No major change is expected through Friday. Saturday will likely see onshores pick up by mid to late morning and reach 15-20 mph by mid afternoon. Sunday looks similar.

 

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

—Nathan

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