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Pacific Storm and Surf Forecast
Updated: May 12, 2011 9:48 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 = 1.5 - California & 1.0 - 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 5/9 thru Sun 5/15
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   

Southern Hemi Swell #1S Pushing North
Small Windswell for Central CA For the Weekend


New Swell Classification Guidelines (Winter)

Significant: Winter - Swell 8 ft @ 14 secs or greater (11+ ft faces) for 8+ hours (greater than double overhead). Summer - 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: Winter - Swell and period combination generating faces at head high to 1.5 times overhead (4-7 ft). Summer - 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. Summer - up to waist high swell. Also called 'Background' swell.


Current Conditions
On Thursday (5/12) North and Central California was seeing minimal
locally generated northwest windswell producing waves to thigh high, mushy with chopped.  Southern California was near flat up north and blown out in the afternoon.  Down south windswell was maybe thigh to waist high and pretty chopped. Hawaii's North Shore was flat and clean. The East Shore was getting minimal easterly tradewind generated windswell at thigh high or so and chopped. The South Shore was getting background southern hemi swell with waves chest high and and sets to maybe shoulder high at top spots but trades kinda sideshore creating cross bump. 

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

Meteorological Overview
The North Pacific has no real swell producing weather systems forecast for the next 7 days. That said, low pressure is falling down the Pacific Northwest coast and expected to reach down to a point off Central CA on Sunday with 16 ft seas offering the potential for small windswell for the US West Coast. And another weak gale to follow tracking through the Western Gulf  Sun-Tues (5/17) with 20 ft seas, offering more windswell for the US West coast. Down south a solid gale  organized on the very eastern edge of the California swell window Wed-Thurs (5/12)  with seas pushing to 42 ft into late Wed with most of that energy aimed northeast towards South and Central America. Still a  solid shot of well is expected pushing up into California for late next week into the weekend .  There's also some suggestion of another gale tracking over the southern tip of New Zealand possibly organizing in the far West Pacific a week out.


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

North Pacific

On Thursday (5/12) the jetstream was pushing off Japan forming a trough off the Kuril Islands, then riding hard north over the dateline pushing up into the Bering Sea only to drop south off the Canadian coast with winds near 130 kts before weakening and pushing inland over Oregon. Some support for low pressure development was likely in the trough in the Eastern Gulf.  Over the next 72 hours the trough off Canada is to sink south providing more limited support for low pressure development there. But in the west energy levels are to ramp up with a good blast of 140 kts winds pushing off Japan and driving the jet further south, south of the Aleutians and pushing over the dateline and reaching into the Western Gulf by Sunday (5/15). No troughs forecast and hence no low pressure development likely, but it is a start. Beyond 72 hours the jet is to continue falling south and flattening, running from Japan east into Central CA by Tues (5/17) with winds near 150 kts over it's length. Again no troughs are forecast, meaning no low pressure systems of interest developing.  But clearly the effects of a building Active MJO are to start becoming manifest.  And maybe by Friday a bit of a trough is forecast in the Western Gulf.  Something to monitor.

At the surface on Thursday (5/12) high pressure at 1032 mbs was positioned mid-way between Hawaii and the Aleutians trying to ridge into the California coast but not quite making it. It was only generating trade at 15 kts over Hawaii and with a bit of a southerly tilt to them at that.  A weak area of low pressure at 1006 mbs was off the Northeastern Canadian coast generating 25 kt northwest winds and 16-18 ft seas, with a little windswell being generated. Another low was pushing east off the Kuril Islands tracking towards the dateline through the Southern Bering Sea. Over the next 72 hours the weak area of low pressure off Canada is forecast dropping south along the US West Coast with winds to 25 kts over a tiny area generating a small area of seas to 16 ft, moving to 600 nmiles off the California coast by the weekend with seas up to 16 ft still. Possible small windswell to result for the Pacific Northwest coast down to maybe Central CA. Period expected at maybe 10 secs. Also by Sunday (5/15) low pressure from the Kuril Islands is to be pushing over the dateline producing 35 kt west winds and seas to 20 ft aimed due east offering windswell potential for the US West Coast.  


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


No tropical systems of interest were being tracked.

California Nearshore Forecast
On Thursday AM (5/12) high pressure at 1032 mbs was trying to ridge into the Central and South CA coasts from it's core well north of Hawaii, but was been cut off by low pressure dropping south from the eastern Gulf of Alaska off British Columbia. Northwest winds along the Central Coast were in the 15 kt range and expected to build to near 20 kts in the evening and holding into Friday. But by Saturday the BC low pressure system is to move south into outer CA waters and calm if not light south winds are to start getting a foothold continuing through the weekend as the low dissolves off the coast through Sunday. Rain possible as far south as  Ventura County by Sunday with maybe 4-5 inches of snow in the Central Sierra and snow levels down to 2500 ft. Seems a bit far fetched. Southern CA to remain protected from any southerly winds and if anything, north winds to 15 kts over the Channel Islands might be more of an issue. Theoretically another front is forecast building behind it suppressing winds Monday then hitting the Central Coast Tuesday (5/17) with south winds rain with rain also up into the Central Sierra. By Wednesday high pressure and north winds are to return focused strongest on Pt Conception (to 25 kts there) and holding into Thursday (5/19). 


South Pacific

On Thursday (5/12) high pressure at 1028 mbs was still locked east of New Zealand but not having as much of an influence as days before.  Of most interest was a gale in the Southeast Pacific (see Storm #1S below). Over the next 72 hours the remnants of Storm #1s are to fade and push out of the California swell window. A new storm co.cgiex is forecast trying to organize south of Tasmania pushing east impacting the southern tip of New Zealand on Sunday (5/15) with seas to 34 ft.  Some sideband energy might travel up through the Tasman Sea towards Fiji, but not as much as previously speculated.       

Storm #1S
Low pressure starting to get a foothold Tuesday AM at 63S 137W at 948 mbs. A broad fetch of 40+ kt west-southwest winds developed at 59S 150W and seas were building. By Tuesday evening up to 45-50 kt south-southwest winds took hold at 60S 133W aimed 20 degrees east of the 187 degree great circle path up to California. This was all be well east of any path to Hawaii. Seas built to 32 ft at 58S 142W. On Wednesday AM (5/11) the fetch was moderating some but still patches of 45 kt southwest winds were modeled in the general area of 52S 123-140W with seas building to 36 ft at 53S 130W pushing 30 degrees east of the 183 degree path to California. In the evening a secondary fetch of 40 kt southwest fetch took hold at 48S 130W with 42 ft seas from previous fetch modeled at 50S 135W aimed pretty well up the 188 degree path to California. The Jason-1 satellite made 2 passes over this area and confirmed seas exactly like what the models were suggesting. By Thursday AM (5/12) 35-40 kts winds were fading while pushing northeast at 48S 128W with 38 ft seas at 44S 125W pushing 30 degree east of the 182 degree path to California.  By evening most fetch is to be pushing out of the California swell window and fading with residual seas of 34 ft hanging near 45S 120W. In all, some degree of decent sized (small significant class) swell from a very southerly angle swell seems possible for California. But better potential is likely for Peru and Chile extending up into Panama. 

Southern CA: Expect swell arrival on Wed (5/18) near 10 AM PM with period 19-20 sec and size on the increase. Swell to be building solid through the evening and into Thursday AM (5/19) peaking from 10 AM to 10 PM.  Pure swell expected at 3.5 ft @ 17-18 secs (6 ft faces with sets to 7.5 ft)  Swell to hold solid into early Friday then dropping off as the day progresses with period down to 15 secs by sunset. Residual swell on Saturday with period 14-15 secs. Swell Direction: 182-190 degrees

Northern CA: Expect swell arrival on Wed (5/18) near 9 PM with period 19 sec and size on the increase. Swell to be building solid through the day Thursday (5/19) peaking from sunset into 4 AM Friday.  Pure swell expected at 3.5 ft @ 17-18 secs  (6 ft faces with sets to 7.5 ft)  Swell to hold solid into early Friday then be tapering off through the day with period down to 15-16 secs by sunset. Residuals on Saturday with period 15 secs. Swell Direction: 180-188 degrees


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 hrs the models suggest that low pressure moving over the dateline just south of the Aleutians on Sunday (5/15) is to be tracking east, with winds holding at 30 kts over a good sized area Monday still producing seas to 20 ft, then fading Tuesday in the central Gulf of Alaska. Maybe some modest swell for the Pacific Northwest down into Central CA if all goes as forecast. 

As of Thursday (5/12) the Southern Oscillation Index (SOI) continued it's tear diving into negative territory - a good thing. The daily SOI was down to -20.13 (8 consecutive days in the negative). The 30 day average was down to 6.65 with the 90 day average down some at 17.96. This was the lowest the monthly SOI has been since July 2010, the start of La Nina and was still heading down.  

Wind anomalies as of Wednesday (5/11) at the 850 mb level (approx 5000 ft up) as defined by models indicated the building Active Phase of the MJO was in control of the entire Pacific. It remained strong and filling the the Eastern Indian Ocean pushing east into the West Pacific reaching the dateline and extending a bit east of there. It is expected to move more solidly over the dateline by 5/16 and fading some, filling the Pacific into 5/21, then dissipating near 5/26. At the same time the Inactive Phase is to be again building in the Indian Ocean starting 5/16 and starting to seep east into the far West Pacific on 5/21 reaching the dateline on 5/26 then fading there into 5/31. These recent oscillations are still forecast to be strong and fast moving - interesting. 

Sea Surface Temp anomaly data (5/9) is unchanged and continues to indicate that cooler waters (-1 C degs) had a grip on the equator covering from a a good bit west of South America westward to the dateline. Cooler than normal waters also were present in feeder bands originating off the US West Coast (not as strong as earlier in the Winter) and somewhat colder ones off South America sweeping fully to the intersection of the dateline and the equator, serving to continue the existing La Nina pattern. These colder waters are a reflection of stronger than normal high pressure built in over both hemispheres causing upwelling in the Gulf of Alaska and off South America, though it looks like the upwelling effect was stronger in the southern hemi than in the north. But the cooler waters in the North Pacific continue to slowly relent in spurts as are the cool temps over the equator. Warmer than normal waters remain over the Galapagos Islands and over a very narrow band west of there and continue slowly building in coverage. And tongues of warmer water are positioned in the both the Northwest and Southwest Hemispheres trying to make inroads to the east but not very effectively. Regardless, the big picture still looks like a La Nina setup (though fading in intensity). 

Below the surface on the equator there had previously been indications of Kevin Wave activity.  Colder than normal water that had been locked all winter southeast of Hawaii under the equator evaporated in late February and moved to dead neutral presumably from the effects of two consecutive bouts of the Active Phase of the MJO which in turn might have driven a Kelvin Wave. In parallel warmer than normal water had edged east from the West Pacific, previously up +2 degrees above normal and positioned due south of Hawaii (150W) under the equator through 3/22. But there had also been an impenetrable wall at 140W separating the warm anomalies, and cool anomalies east of there that was blocking any eastward progress of warmer subsurface water. But on 4/4, it appeared that that wall was fading if not gone entirely (by 4/7).  And by 4/19 a small but steady finger of normal to slightly warmer (0 to +1 deg C) water was flowing east making it to the equatorial East Pacific up at 100-150 meters and building some.  Almost +1 degrees anomalies are tracking from the West Pacific to the East Pacific short of one small break at 160W as of 5/1. But on 5/7 a small pool of negative temperature water was starting to make a faint showing at 140W again, presumably driving by the Inactive Phase of the MJO. We expect that to disappear shortly as more warm water get pushed east by the building Active Phase of the MJO. It would be best to see warm anomalies down to 200 meters, but the current state is the best it's been in 9 months and suggestive of a near normal subsurface thermocline.  The thought is this normalization of the subsurface flow will eventually affect water temps at the surface and then the atmosphere above it (6 months later).  So all this is a step in the right direction though painstakingly slow.  

Over the entire Equatorial Pacific trades were blowing all the way to the Philippines and beyond. From a historical perspective these easterly winds were 'normal' with only light easterly anomalies persisting in the far Western Pacific.  

Remnants of what was a moderate.cgius strength La Nina Pattern (where the Inactive Phase takes control) are still evident and momentum from this La Nina event are expected to hold well into the Fall of 2011 (and likely to early 2012) in the upper atmosphere regardless of how quickly La Nina's demise occurs in the ocean. In short, it's going to be tough for surfers on west facing shores in the Eastern Pacific and Eastern Atlantic, though east facing shores of the West Pacific and Atlantic might do well from the Inactive Phase's dominance, especially in summer months.  That is not to say there will be no storms, in fact, there could be short periods of intense activity when the Active Phase gets an opportunity to come to fruition, but that will be the exception rather than the rule, with the Inactive Phase trying to keep a cap on storm activity. Best bet's at this time are for an enhanced tropical season in the Atlantic (2011).  

See more details in the   El Nino update.


South Pacific

Beyond 72 hours another gale is forecast pushing under Tasmania again impacting the Southern tip of New Zealand Monday (5/16) with seas to 40 ft.  There is some suggestion it might try to regroup just east of New Zealand on Tuesday, but that is all just idle speculation at this early date. Again, some degree of sideband swell might reach up into Fiji. 

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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Local Interest

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".

Timmy Reyes - Curt Myers from Powerlines Productions found this little gem with Timmy Reyes providing a brief statement about which sites he uses for swell chasing. Thought we'd pass it on. Enjoy:

Buell Wetsuits - When surfing in Santa Cruz, we've been seeing a new wetsuit in the line-up worn by many top flight surfers. They're getting good traction and are well respected. Take a look:

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: 

Mavericks Surf Shop Grand OpeningSunday, December 19 2:00 - 6:00 p.m. rain or shine!  Check out the new home of Jeff Clark's Mavericks Surf Shop, now located at 25 Johnson Pier in Pillar Point Harbor.  The shop features much of Clark's surfing memorabilia, classic boards and photos, as well as an entirely new line of Jeff Clark original Mavericks clothing, accessories and surfboards. The shop has been open in the new location since December 8, and the Grand Opening party is set for this coming Sunday, just in time for Christmas.  The party starts at 2 p.m., with live music, food and drinks. Jeff Clark and many Mavericks surfers will be there to meet the public. Local restaurants Ketch Joanne's and Princeton Seafood will serve up delicious food, while San Francisco Wine Trading Company is providing the beverages.  The shop will be open all weekend, from 9 a.m. to 8 p.m. on Saturday and Sunday.

Stormsurf Maintenance Upgrades: Buoy 46059 and 46012 were r.cgiaced a month or so ago. Totally new buoys were installed. Here on Stormsurf we had to reset the algorithms used to calculate 'pure swell' for them. That was acco.cgiished on 11/13. Pure swell numbers are now correct. Links: 46012, 46059

Also since we moved to the new weather model server last month we discovered that our Longrange Precipitation Models ceased to display frozen precipitation (as they once did). Some of our scripts did not get installed on the new server. That has been fixed (11/13) and now snow is again viewable worldwide. Here the new North America sa.cgie.

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.   

Click here to learn more about Casa Noble Tequila! Casa Noble Tequila If you are looking for an exquisite experience in fine tequila tasting, one we highly recommend, try Case Noble. Consistently rated the best tequila when compared to any other. Available at BevMo (in California). Read more here:

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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