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Pacific Storm and Surf Forecast
Updated: May 14, 2011 5:40 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 = 4.8 - 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 5/16 thru Sun 5/22
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 Towards Chile
Another Small Gale Forecast for Dateline Early Week


New Swell Classification Guidelines (Winter)

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 (5/14) North and Central California was seeing small semi-swell generated in the Gulf of Alaska 2 days earlier with waves 1 ft overhead and pretty torn up by local onshore winds.
Southern California was near flat up north with waves knee to maybe thigh high and mushy with no wind but warbled conditions. Down south windswell was thigh high and heavily warbled. Hawaii's North Shore was effectively flat and clean. The East Shore was effectively flat with easterly tradewind generated windswell at knee high and semi clean early. The South Shore was getting background southern hemi swell with waves thigh to maybe waist high and clean with light trades in effect. 

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

Meteorological Overview
The North Pacific has another weak gale modeled developing on the northern dateline on Sunday (5/15) tracking through the Western Gulf into Monday with 22 ft seas, offering the hint of more windswell for the US West coast later next week. Another smaller gale is forecast on a eastward track positioned further south in the Western Gulf Thurs-Fri (5/20) with 25 ft seas. Something to watch. Down south Storm #1S organized on the very eastern edge of the California swell window Wed-Thurs (5/12) with seas pushing to 42 ft late on Wed (5/11) with most of that energy aimed northeast towards South and Central America. Still a solid shot of swell 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 by Thurs (5/19) with up to 40 ft seas. But that has come and gone from the models mult.cgie times already, so no particular outcome is certain.


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

North Pacific

On Saturday (5/14) the jetstream was pushing off Japan tracking northeast to the intersection of the dateline and the Aleutians with winds 150 kts then turning and heading southeast with much less wind velocity falling into a steep trough just 300 nmiles off Central CA before heading hard north and pushing up the coast of the Pacific Northwest and moving inland over northern British Columbia. Limited support for low pressure development just off Northern CA in the trough there. Over the next 72 hours the trough off Central CA is to push inland over Cape mendocino on Sunday while the energy off Japan moves through the entirety of the Pacific jetstream, ridging slightly over the dateline through Monday but with winds speeds starting to pick up and a trough building in the Western Gulf Tuesday. Some support for gale development possible there. Beyond 72 hours the trough in the Western Gulf is to track east with 130 kts winds dropping into it and supporting more gale potential into late Wednesday, then fading. Energy levels to drop over the length of the jet but it still is to be flowing more or less flat from Northern Japan up to the Oregon coast, but not moving onshore there just yet. Not much support for gale or even low pressure development indicated.

At the surface on Saturday (5/14) weak low pressure was 600 nmiles off the California coast generating 25-30 kt north winds early but aimed well south of state and of no real interest other than possibly bring colder air and precipitation in to the state on Sunday. Otherwise a rather large gale was organizing just west of the northern dateline region with west winds at 35+ kts and starting to generate some seas there. Over the next 72 hours the only area of interest is to be the gale over the dateline still producing 35 kt west winds at 47N 178W early with seas to 22 ft and holding into the evening at 48N 171W then fading on Monday while pushing east with winds at 30 kts and seas 20 ft at 28N 157W, then dissipating. Possible small 13-14 sec period swell could result for the US West Coast later in the workweek but likely bypassing Hawaii.


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


No tropical systems of interest were being tracked.

California Nearshore Forecast
On Saturday AM (5/14) weak low pressure at 1012 mbs was located 400 nmiles off the coast of Pt Arena and was starting to push east. Nearshore winds for all of CA were weak with even a light southerly flow starting to set up over San Francisco. By Sunday the low is to move inland with a modest 10-15 kt westerly flow pushing into the Central CA coast with rain possible as far south as San Diego County with maybe 8-12 inches of snow in the Central Sierra and snow levels down to 2500 ft (early). Southern CA to remain protected from any southerly winds and if anything, north winds to 15 kts might set up on Sunday over the Channel Islands. Theoretically another low is forecast building behind it suppressing winds early Monday then hitting the Central Coast in the evening with south winds at 25 kts and rain fairly solid for the time of year with 4 inches of snow in higher elevations of the Central Sierra. By Tuesday northwest winds are to try and build into the Central coast with southwest winds at 15-20 kts in control of Southern CA. Lingering occasional light rain showers. Wednesday high pressure and north winds are to return at 15-20 kts over the entire coast including Southern CA and continuing on Thursday but lifting out of the Southern CA area. More of the same on Friday and then even worse on Saturday with stronger high pressure building in and north winds to 35 kts just off San Francisco. Southern CA to remain barely protected on Saturday by not likely by Sunday (5/22).  


South Pacific

On Saturday (5/14) another gale was organizing from the remnants of Storm #1S in the deep Southeast Pacific with pressure 944 mbs and 45-50 kt south-southwest winds at 65S 140W with seas building from 28 ft near there. In the evening fetch is to drop from to 40-45 kts over a solid area at 60S 130W with 30 ft seas building at 57S 132W. Fetch is to be retracting Sunday AM (5/15) but still 40 kts at 57S 122W with seas building to 34 ft at the same locale (180-182 degrees relative to CA and pushing 25 degrees east of there). A quick fade of the gale is forecast there after with residual 32 ft seas at 55S 118W and effectively out of the CA swell window. There's some potential for decent southerly angled swell pushing up into CA a week or so out with better odds for Chile up into Central America. Otherwise over the next 72 hours a new storm co.cgiex is forecast trying to organize south of Tasmania on Sat-Sun (5/15) pushing east impacting the southern tip of New Zealand on Sunday (5/15) with seas to 36 ft.  Some sideband energy might travel up through the Tasman Sea towards Fiji, but not as much as previously speculated. This system is to be destroyed once it impact New Zealand.


Storm #1S (updated)
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 8 AM with period 20 sec and size on the increase. Swell up to 3.4 ft @ 19 secs late (6-7 ft with bigger sets). 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 4.3-4.7 ft @ 17-18 secs  (7.3-8.5 ft faces with occasional sets to 9.1-10.6 ft).  Swell to hold solid into early Friday (5/20) near 4.5 ft @ 16 secs (7 ft faces with sets to 9 ft) then dropping off as the day progresses with period down to 15 secs by sunset. Residual swell on Saturday at 4 ft @ 15 secs early (6 ft with sets to 7.5 ft) with period dropping to the 14 secs range late. Swell Direction: 182-190 degrees

Northern CA: Expect swell arrival starting on Wed (5/18) near noon with period 20 secs and size building and rideable (2 ft @ 20 secs - 4 ft faces) with period dropping at 9 PM to 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 4.3-4.7 ft @ 17-18 secs  (7.3-8.5 ft faces with occasional sets to 9.1-10.6 ft)  Swell to hold solid through Friday near 4.5 ft @ 16+ secs (7 ft faces with sets to 9 ft) then be tapering off late. Residuals on Saturday with swell 4 ft @ 15 secs early (6 ft with sets to 7.5 ft) and heading down. 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 another gale is to start winding up just west of the dateline and a bit further to the south on Wednesday (5/18) with up to 40 kt northwest winds at 43N 177E in the evening with seas on the increase. 40-45 kt westerly fetch is to hold into later Thursday at 44N 175W with up to 26 ft seas at the same location. A turn to the northeast is forecast thereafter with seas backing off and taking aim mostly on Alaska and Northern Canada into early Saturday (5/21). The issue is the jetstream models indicate that little support for such development is expected in the upper levels of the atmosphere, so at this time we suspect this gale is just a fantasy. Will monitor.

As of Saturday (5/14) the Southern Oscillation Index (SOI) lifted back to positive territory, not so good. The daily SOI was up to 14.73 (the previous 8 consecutive days were negative). The 30 day average was down to 5.54 with the 90 day average down some at 17.71. This was the lowest the monthly SOI has been since July 1, 2010, the start of La Nina and was still heading down. But to put things in perspective, the whole of 2009 was pretty below where the 30 day average is now (but that was an El Nino year). So at least were are starting to make inroads towards neutral territory.  

Wind anomalies as of Friday (5/13) at the 850 mb level (approx 5000 ft up) as defined by models indicated the Active Phase of the MJO was maxing out and in control of the entire Pacific. It remained moderate and was filling the area from India eastwards over the PAcific into Central America. It is expected to start fading while holding control of the Pacific through 5/18, then dissipating near 5/23. At the same time the Inactive Phase is already building in the Indian Ocean and is to continue organizing to moderate levels before starting to seep east into the far West Pacific on 5/23 reaching the dateline on 5/28 then fading there into 6/2. These recent oscillations are still forecast to be moderately strong and fast moving. 

Sea Surface Temp anomaly data (5/12) 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 in fits and spurts. 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 and holding through 5/14, presumably driven by the previous Inactive Phase of the MJO. We expect that to disappear shortly as more warm water get pushed east by the current 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 Monday (5/16) traveling fast to the northeast with seas at 38-40 ft and again impacting the Southern tip of New Zealand late Monday into early Tuesday.  There continues to be some suggestion it might try to regroup just east of New Zealand on Wednesday (5/18) with a small area of 45 kt southwest winds holding into Thursday AM with seas in the 36-38 ft range near 45S 170W pushing up the 211 degree path to California and just barely unshadowed by Tahiti (188 degs HI), then pushing east from there into Friday and moving into the Tahitian swell shadow and fading out. But this is all just idle speculation at this early date. Again, some degree of sideband swell might reach up into Fiji early in this storm life with decent odds for swell into Hawaii and the US West Coast if all comes to pass as forecast.  

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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TheJay@Mavericks MAVFILM MAVSURFER SURFPULSE Inside Mavericks Randy Cone Surfboards

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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