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Pacific Storm and Surf Forecast
Updated: September 15, 2012 1:04 PM
Buoys: Northern CA - Southern CA - Hawaii - Gulf of Alaska - Pacific Northwest
Buoy Forecast:
Northern CA - Southern CA - Hawaii - Gulf of Alaska - Pacific Northwest
Pacific Links:  Atmospheric Models - Buoy Data - Current Weather - Wave Models
Forecast Archives: Enter Here
A chronology of recent Mavericks Underground forecasts. Once you enter, just click on the HTML file forecast you want to review (e.g. 073199.html equals July 31, 1999). To view the maps that correspond to that forecast date, select the html file labeled 073199 maps.html
Swell Potential Rating = 2.0 - California & 2.0 - Hawaii
Using the 'Summer' Scale
(See Swell Category Table link at bottom of page)
Probability for presence of largest swells in near-shore waters of NCal, SCal or Hawaii.    
Issued for Week of Monday 9/17 thru Sun 9/23
Swell Potential Rating Categories
5 = Good probability for 3 or more days of Significant swell
4 = Good probability for 1-2 days of Significant swell
3 = Good probability for 3 or more days of Intermediate/Advanced swell
2 = Good probability for  1-2 days of
Intermediate/Advanced swell
1 = Good probability for 3 or more days of Impulse or Windswell
0 = Low probability for 1-2 days of Impulse or Windswell   

The Pause Before Fall
Weak Active Phase of MJO In Control - Models Teasing Both North and South

Swell Classification Guidelines

Significant: Winter - Swell 8 ft @ 14 secs or greater (11+ ft faces) for 8+ hours (greater than double overhead).
- Head high or better.
Advanced: Winter - Swell and period combination capable of generating faces 1.5 times overhead to double overhead (7-10 ft)
Summer - Chest to head high.
Intermediate/Utility Class: Winter - Swell and period combination generating faces at head high to 1.5 times overhead (4-7 ft).
- Waist to chest high.
Impulse/Windswell: Winter - Swell and period combination generating faces up to head high (1-4 ft) or anything with a period less than 11 secs.
- up to waist high swell. Also called 'Background' swell.

Current Conditions
On Saturday
(9/15) North and Central CA had no local windswell and only limited very south angled southern hemi swell. Most spots were flat up north and clean or slightly textured. Down south in Santa Cruz surf was effectively flat with rare southern hemi sets at thigh high and clean. Southern California up north was knee to thigh high and warbled but clean. Down south southern hemi swell was hitting at chest high and clean with maybe a few bigger sets. Hawaii's North Shore was flat and clean with trades in effect. The South Shore had mini southern hemi swell producing a few knee high.cgius sets and clean with trades in effect. The East Shore had no real east windswell producing waves only knee to thigh high and chopped.    

See QuikCASTs for the 5 day surf overview or read below for the detailed view.

Meteorological Overview
Up north high pressure was ridging north into Northern Canada and was pulled a bit away from the California coast resulting in no local pressure gradient over Cape Mendocino CA and no north winds or local windswell for the remainder of the coast. High pressure was also fairly diffuse over Hawaii resulting in only 10 kt easterly trades and no real easterly windswell there. Low pressure was trying to organize in the Bering Sea, but of not real interest swell wise. The forecast calls for no real change into mid-week (9/19) with trades light over Hawaii and no windswell producing local fetch relative to California. But by Thursday that is to change as a gale supposedly forms over the dateline well south of the Aleutians pushing east then stalling in the Western Gulf while developing nicely. And another developing gale is to be right behind it. If one is to believe the models, Fall might actually start. Down south a small gale tracked east with seas to 34 ft last Thurs (9/6) pushing small swell northward that is currently moving into Southern CA this weekend (9/15). On Monday (9/17) a better gale is forecast tracking under New Zealand with seas to 41 ft aimed a little bit to the northeast offering the potential for small southern hemi swell long term. And another smaller system is modeled right behind it. So for now, if one is to believe the models, things are starting to look up.

Current marine weather and wave analysis.cgius forecast conditions for the next 72 hours

North Pacific

Jetstream - On Saturday (9/15) the jet remained di.cgiaced well to the north running west to east generally north of the Aleutians tracking through the Bering Sea at 55N with a small steep trough on the dateline dipping south of the Aleutians with winds 160 kts offering limited support for low pressure development there. Big ridges were on either side of the trough, resulting in the jets overall northward di.cgiacement and only supporting high pressure down in lower levels of the atmosphere. Over the next 72 hours a significant change is forecast with the ridge in the west dissipating and the jet falling south into a developing broad trough again centered near the dateline. 170 kts winds are to be falling into it by late Monday (9/17) offering improved odds for gale formation. Beyond 72 hours the trough is to hold nicely on the dateline easing east while moderating through late Wednesday, still not gone and tracking east some into Saturday (9/18) with winds still 130 kts. Good support for gale formation if one is to believe the models. And in the far west the jet is to be dropping south to 40N, a more favorable position for this time of year.

Surface  -  On Saturday (9/15) high pressure was over the Northeast Pacific ridging north into Northern Canada and positioned a bit west of the US West Coast offering none of the usual pressure gradient over Cape Mendocino nor local fetch.  The high was also centered too far north of Hawaii suppressing the usual easterly trades there, with winds only 10 kts and no real east windswell resulting along east facing shores of the Islands. Low pressure was trying to organize over the far Eastern Aleutians but no fetch of interest was occurring. 

Over the next 72 hours no windswell is expected from the Northeast Pacific High relative to either Hawaii or California. The little low in the Northern Gulf is to track northeast moving into Alaska with no direct result swell wise, but it might prime the pump a little and take a piece out of the Northeast Pacific High. By Monday (9/17) a modest low pressure system is to be tracking east centered just north of the intersection of the Aleutians and the dateline with winds 25 kts in it's south quadrant south of the dateline, but not quite strong enough to support swell generation. It is to ease east into Wednesday with no real change forecast but is to provide enough energy to prime the pump for something potentially better behind it (see the Longterm Forecast).


  North Pacific Animations: Jetstream - Surface Pressure/Wind - Sea Height - Surf Height


As of Saturday (9/15) Typhoon Sanba was 600 nmiles south of South Korea tracking north winds winds 110 kts and seas to 48 ft. This same heading is forecast through the weekend with Sanba moving into South Korea late Sunday night (9/16) with winds down to minimal typhoon strength at 70 kts, then tracking inland. Remnants to possibly east east by Friday (9/21) pushing off Japan and towards the dateline, if one is to believe the models. At this time no swell of interest is expected for our forecast area.

Also a weak tropical storm (Kristy) was west of Cabo San Lucas tracking northwest with winds 35 kts and forecast to fall to tropical depression status later this morning. No swell to result.

The models suggest another system is to develop midway between Hawaii and mainland Mexico on Sunday (9/16) tracking northwest, moving fairly quick over cooler waters and dissipating late Wednesday (9/19). No swell to result.


California Nearshore Forecast
On Saturday (9/15) high pressure was a bit off the coast and di.cgiaced north typical for this time of year. A hint of the usual pressure gradient and north winds over Cape Mendocino is forecast on Sunday (north winds 20 kts) while a weak eddy flow continues over the remainder of California. The weak gradient is to fail on MOnday with no real change forecast otherwise until Wednesday (9/19) when north winds to build to 20 kts over Pt Conception and trying to move northward but not making it till late Thursday with north winds 15 kts over all of North and Central CA. This pattern to hold through Friday then finally Saturday the core of the fetch (down to 15 kts) is to move to North CA with a weak eddy flow become established over Central CA. A weak eddy flow to continue non-stop for Southern CA. 


South Pacific

Surface  -  On Saturday (9/15) no swell producing fetch of interest was occurring. over the next 72 hours theoretically on Monday AM (9/17) a gale is to organize under New Zealand producing a solid area of 45 kt west-southwest winds and seas building from 34 ft at 56S 172E. This system is to track east and build in the evening with winds to near 50 kts and seas peaking at 41 ft at 57S 179W (193 degs HI and 209 degs CA right on the edge of the Tahiti swell shadow. A quick fade is forecast thereafter with winds dropping from 45 kts Tuesday AM (9/18) tracking flat east and seas fading from 35 ft at 55S 165W. If all this happens possible modest southern hemi swell could result for both Hawaii and California. Will monitor.


Small New Zealand Gale
At the surface on Monday (9/10) a broad but ill defined low organized over and just east of New Zealand. It previously had producing 32-24 ft seas in the Southern Tasman Sea on Sun (9/9) offering some energy aimed obliquely towards Fiji. On Monday AM it produced an infinitesimal fetch of 40-45 kt south winds just off southeast New Zealand holding into the evening while tracking east-southeast resulting in 27 ft seas in the evening at 47S 177E targeting Hawaii and holding into mid-Tuesday (9/11) at 28 ft at 48S 176W. It all faded by Tuesday evening.

Some degree of limited 16 sec swell is expected to hit Hawaii by Sunday AM (9/16) from when the gale was in the Tasman Sea (2 ft @ 16 secs - 3 ft faces - from 215 degrees) then reorganizing late Monday (9/17) at 1.5 ft @ 16 secs (2.5 ft) fading Tuesday from 1.5 ft @ 15 secs (92.0-2.5 ft) coming from 200 degrees. 


Small Southeast Pacific Gale
Another gale organized in the far Southeast Pacific producing a small area of 45 kt south winds Monday AM (9/10).  Fetch faded to 40 kts in the evening but still aimed northward with seas building to 28 ft at 55S 119W. Fetch regenerated Tuesday AM (9/11) to 40 kts over a broader area with seas to 30 ft over an infinitesimal area at 49S 118W,  then faded while moving out of even the Southern CA swell window. Limited odds for tiny southern hemi swell isolated mainly to Southern CA arriving on Tuesday (9/18) with pure swell 1.3 ft @ 18 secs (2.0-2.5 ft) coming from 180 degrees building to 2.0 ft @ 15-16 secs (3 ft) on Wednesday (9/19) then fading fast from there. .


South Pacific Animations: Jetstream - Surface Pressure/Wind - Sea Height - Surf Height




Marine weather and forecast conditions 3-10 days into the future

North Pacific

Beyond 72 hours another gale is forecast developing off Kamchatka falling southeast to the dateline by Thursday (9/20) with winds building to 35-40 kts over a small area and seas to 25 ft late at 43N 175W late aimed at Hawaii and the US West Coast. The gale is to ease east Friday (9/21) with fetch increasing in areal coverage and solid at 40 kts targeting the same location with seas holding at 25 ft at 45N 170W. A slow fade is forecast on Saturday with seas peaking early at 26 ft at 44N 168W. If one is to believe the model, possible swell could result. But this system is a long ways from even starting to form. Maybe Thursday a more realistic assessment can be made.

And yet another smaller system is forecast pushing off Japan tracking towards the dateline on Sat (9/22) possibly feeding the system forecast above.

Note: The Madden Julian Oscillation is a periodic weather cycle that tracks east along the equator circumnavigating the globe. It is characterized in it's Inactive Phase by enhanced trade winds and dry weather over the part of the equatorial Pacific it is in control of, and in it's Active Phase by slack if not an outright reversal of trade winds and enhanced precipitation. The oscillation occurs in roughly 20-30 day cycles (Inactive for 20-30 days, then Active for 20-30 days) over any single location on the.cgianet. During the Active Phase in the Pacific the MJO tends to support the formation of stronger and longer lasting gales resulting in enhanced potential for the formation of swell producing storms. During the Inactive Phase the jet stream tends to .cgiit resulting in high pressure and less potential for swell producing storm development. The paragraphs below analyze the state of the MJO in the Pacific and provide forecasts for MJO activity (which directly relate to the potential for swell production).

As of Saturday (9/15) the daily Southern Oscillation Index (SOI) was at 1.73 (4 days in a row between -8 and +2). The 30 day average was up more to 4.11 with the 90 day average at -4.25. This is neutral territory and not indicative of El Nino.

Current equatorial wind analysis indicated weak westerly anomalies over the Maritime Continent (WPac) falling to neutral before reaching the dateline and holding at neutral the rest of the way across the equatorial Pacific into Central America.  This suggests that a weak Westerly Wind burst that started Sept 1 in the West Pacific is continuing (a good thing for maintaining the warm water pump) and that the Active Phase of the MJO was taking hold over the far West Pacific. A week from now (9/22) neutral anomalies are forecast to be in control of the Maritime Continent and dateline all the way into the East Pacific suggesting a very weak Active Phase (at best). This is what we were hoping for to prevent further degradation of the warm pool. But the warm water pump remains very weak. 

The longer range models (dynamic and statistical) run on 9/14 remain in agreement suggesting a weak Active Phase is in.cgiay over the West Pacific with the Inactive Phase moving over Central America bound for the Caribbean and Atlantic Basin. The Active Phase is to hold for about a week to 10 days then is to dissipate while the Inactive Phase builds weakly in the Indian Ocean. This all favors some degree of weak maintenance.cgian for the warm water pool off Ecuador, but not adding much to it (at best). 

More warm water in the equatorial East Pacific means more storm production in the North Pacific during winter months (roughly speaking). Warmer than normal water accumulated off Ecuador through 7/2 (part of a continuous pattern that started in Jan 2012) fueled by a Kelvin Wave, weaker than normal trades and a MJO pattern dominated by the Active Phase in early April and a continued weak MJO signal beyond. The warm water pattern peaked on 7/2 in an unmistakable El Nino-like configuration. But since then a steady but weak degradation of the warm pool has ensued. The warm pool has also showed signs some signs of shrinking in areal coverage, but has also migrated some to the north (up along Baja) while shrinking in the south along Chile. And the latest update on 9/13 has again depicted a thin track of cooler than normal water snaking it's way west through the heart of the warm pool off Ecuador. We've also been tracking the cool pool that has dominated between California and Hawaii, generated by 2 years of La Nina and stronger than normal high pressure there. There's some signs it is weakening, but it is still quite obvious and a force to be reckoned with atmospherically. There is also a steady build up of very warm water migrating east from Japan towards the US West coast (presumably driven by the north quadrant of the North Pacific High). Something that looks very much like a weak Kelvin Wave appears to be propagating east both subsurface (2 deg C anomaly at 118W) and at the surface (1 deg C anomaly). If this is real, it would help to r.cgienish the warm water pool maybe 3-4 weeks out (early Oct), but nowhere near the levels it was in July (our best guess). The overriding concern is there is no indication that the warm water pool is building in temperature or areal coverage as one would expect if El Nino were developing, and.cgienty of evidence that it is in a slow but steady decline or at best just just barely hanging on in maintenance mode. Hopefully the Kelvin Wave (mentioned above) pushing east will add a little fuel. And if in fact a WWB is occurring now in the far West Pacific, another Kelvin Wave could result with yet more warming expected a few months out. But this is looking less like a legitimate El Nino and more like a pulse towards a neutral or slightly warm pattern. That said - the long range models continue to suggest that a weak warm water pattern is to hold if not build slightly into the late Fall, which is pretty typical for a developing weak El Nino. So the evidence is not promising, but the models are saying otherwise.      

A weak MJO pattern (both Active and Inactive Phases) is a sign of the weak version of El Nino. Strong Active Phases accompanied by Westerly Wind Bursts (WWB) is a sign of a strong El Nino. Given the data to date, the current event is looking more like a weak El Nino at best. As we move into the Fall months (starting late August), the tendency is for whatever pattern has been dominant to only become a.cgiified. In short, the true MJO character will become exposed in Fall, with summer just being a build-up. The expectation is that a near failure of the MJO could occur with trades fading and more slow-but-steady warm water propagation continuing eastward. If this happens the question then becomes: Will it be slow enough and weak enough to turn into a multi-year warm event, or will the atmosphere switch as usual in February 2013 and usher in a new La Nina.  As of right now, with the very weak MJO pattern in.cgiay, the weak evidence of any WWBs, the declining warm pool, our bets are for this warm event to not reach a real El Nino status. And this would actually be a good thing (see final paragraph).    

At this time there is only limited atmospheric evidence of a possible El Nino pattern in.cgiay (as of 9/6).  Remnants of La Nina are still affecting the atmosphere and will likely continue for several months into the middle of Fall (mid-Oct), but steadily degrading. One such indicator is the continued presence of high pressure over the Eastern Pacific. It has been locked in.cgiace for 2 years now and it's momentum is not going to be easily be halted. The high has caused unrelenting north winds pushing down the California coast and stronger than normal trades over Hawaii. The high is evidenced by a large pool of cooler than normal water radiating southeast off California and over Hawaii reaching the equator at the dateline, the result of enhanced upwelling.  Recent imagery suggest the high is shifting west and north some and winds along the California coast are becoming less of an issue.  But there has been no change in local water temperatures off Central and North CA. 

We're in a hybrid atmospheric state but the trend is starting to shift more towards the normal category. The longer the MJO remains biased towards a neutral or Active state, and the longer warm water holds if not builds off Central America, and the more the cool pool fades between CA and HI, the more the atmosphere will respond (especially come Fall) turning towards at least a neutral if not an El Nino-like configuration. The atmosphere is like a big ship, it takes a long time to turn. We remain on the bubble as of this date. Historical Note: It is unusual for El Nino (of any magnitude) to develop directly following 2 years of La Nina.            

As of right now its seems the Active Phases of the MJO are not strong enough to usher in some flavor of real El Nino, but the Inactive Phases are not strong enough to shut off the warm water pump to the East Pacific either.  Regardless, we are effectively past the La Nina hump and the tendency will be for a return to a normal if not slightly El Nino-like enhanced state. This is way better than where we've been for the past 2 years (under the influence of La Nina). The preference is that El Nino does not form this year, because that would only usher in another La Nina the year or two beyond.  Rather, a neutral pattern biased slightly warm would be good, followed by at least another year of slightly warmer temps ultimately converging in a stronger El Nino 2-3 years out. And historically, this is the 'normal' pattern (a few years of false starts before a legit El Nino forms). The models suggest otherwise. So it will be interesting to see whether the pattern we are currently in is a tease or the real thing. The preference is for a tease with a real El Nino a year or 2 beyond.    

See imagery in the ENSO Powertool and more details in the  El Nino update.  


South Pacific

Beyond 72 hours a small gale is forecast forming southeast of New Zealand on Thursday (9/20) with 32 ft seas tracking just north of due east. No big deal.

Details to follow...


External Reference Material: El Nino Southern Oscillation (ENSO), Madden Julian Oscillation (MJO), Pacific Decadal Oscillation (PDO), Southern Oscillation Index (SOI), Kelvin Wave

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Greg Long XCel Core Files - Here's a great profile of Greg Long and his contributions toward pushing the state of big wave surfing. Well Done -

Chasing Mavericks - The Jay Moriarty Movie: Two trailers for the new movie about Jay, Frosty and Mavericks has been posted. Movie opens on 10/26/12. Here's the link: &

Props from the Pros:  Stormsurf was mentioned over the past week in two different media sources.  One was in an interview Kelly Slater did with the New York Times and another was in a promotional piece Ramon Navarro did for the Big Wave World Tour. Many thanks to Curt Myers from Powerline Productions for alerting us and of course thanks to Kelly, Ramon and the Tour for using our service. Here's the links:

Steve Colleta Surfboards - Check out surfboards by local shaper Steve Coletta - A long time Santa Cruz local and master shaper. Progressive shapes for North and Central CA waves

Chasing the Swell has been nominated for a Webby Award. See details of this great piece of video journalism below. Some say this is the "Oscars" of online awards.One of the awards is voter based. If you have a moment,.cgiease cast your ballot by going to:, register, then click on the "Get Voting" tab and then to the "Online Film and Video" > "Sports" category and vote for "Chasing the Swell".

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Stormsurf Mobile App (1/9/11) We are proud to announce the official public release of our smartphone mobile app. It provides access to our most popular and commonly used products, optimized for use on the road, on the beach or anywhere you don't have a desktop or laptop.  With a smart phone and signal, you will have access to our data. And we're not talking just a few teaser products - We're talking full feature wave models, weather models, real-time buoy data, manually built forecasts and hundreds of spot wave and wind forecasts enabling you to construct a surf forecast for any location on the.cgianet, all from your cell phone and all for free.  No subscription required and no hidden fees. And better yet, there's a few new things sprinkled in that are not yet available even on our full-featured web site. From your smart phones browser just navigate to: 

Chasing The Swell: Sachi Cunningham from the LA Times spent the entirety of last winter chasing surfers and swells around the North Pacific with her high def video cam. Her timing couldn't have been any better with the project exactly coinciding with the strongest El Nino in 12 years resulting in the best big wave season in a decade. And being an acco.cgiished surfer herself helped her to bring a poignant and accurate account of the what it's like to ride big waves and the new (and some not so new) personalities that are revitalizing the sport. This is must-see material for any surfer or weather enthusiast. Check it out here:

New Weather Models With the activation of our new server we have now released a new block of weather models including North America jetstream, wind and precipitation, local coastal wind forecasts in 1 hr increments and snow and mountain wind forecasts in both 1 and 3 hours increments. The new animations can be found here (look for those items tagged with the New! icon):

New Weather Model Server Stormsurf has installed another weather model production server. This has enabled us to spread the load across more servers allowing us to post both wave and weather model updates much quicker.  Also we are testing new content (like North America jetstream, winds and precipitation, local wind forecasts in 1 hr increments and snow and mountain wind forecasts in both 1 and 3 hours increments). The model menus will be updated shortly with these new links.   

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New Wave Model Facts: Click HERE to read more about the new wave models. Important info.

Time Zone Converter By popular demand we've built and easy to use time convert that transposes GMT time to whatever time zone you are located. It's ion left hand column on every page on the site near the link to the swell calculator.

Stormsurf Google Gadget - Want Stormsurf content on your Google Homepage? It's si.cgie and free. If you have Google set as your default Internet E.cgiorer Homepage, just click the link below and a buoy forecast will be added to your Google homepage. Defaults to Half Moon Bay CA. If you want to select a different location, just click on the word 'edit', and a list of alternate available locations appears. Pick the one of your choice. Content updates 4 times daily. A great way to see what waves are coming your way! .xml

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Surf Height-Swell Height Correlation Table


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