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Pacific Storm and Surf Forecast
Updated: August 20, 2011 12:49 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 & 2.1 - 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 8/22 thru Sun 8/28
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   

Gulf of Alaska to Stir
Models Continue Suggesting Something Stronger Down 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 Thursday (8/18) North and Central California was seeing waist high warbled northwest windswell up north with south wind 12 kts early adding alot of bump to south facing breaks. Down south there were some rare thigh high waves and clean early. Southern California was getting minimal knee high  northwest windswell up north with occasional southern hemi sets to knee to thigh high intermixed and clean early. Down south southern hemi swell was producing waves in the waist high range with top spots to chest high and reasonably clean early. Hawaii's North Shore was effectively flat. The South Shore was getting minimal leftover southern hemi background swell with waves at thigh to maybe waist high and clean with light trades in effect. The East Shore had waist high easterly tradewind generated windswell with lightly chopped conditions. 

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

Meteorological Overview
The North Pacific high was fading on Saturday with local windswell on the decline both in Hawaii and along the Central CA coast. But weak low pressure was moving into the Gulf generating 20-25 kt west winds possibly resulting in some minimal windswell focused mainly on the Pacific Northwest with sideband energy radiating south into Central CA for early next week. And that pattern is forecast to a.cgiify later next week with 2 gales forecast, one over the dateline and another in the Gulf. Will believe it when it happens. The models have been having a hard time of late predicting even 4 days out. Down south a gale alongside of New Zealand produced only a small pulse of  32 ft seas on Tues AM (8/16) pushing north-northwest, with minimal swell likely for Hawaii on Tues-Wed (8/24) and CA late Thurs (8/25).  The models continue to suggest another gale building under New Zealand by Sun-Mon (8/22) with up to 32 ft seas (way down from previous forecasts) followed directly by a stronger one Tues-Thurs (8/25) with up to 46 ft seas. But again, it's all a tease with the models being all over the.cgiace the past few days and hardly stable. Expect next to nothing to result, then whatever does come is all a gift.


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

North Pacific

At the surface on Saturday (8/20) high pressure was all but gone in the Northeast Pacific with just residuals at 1020 mbs stretched east to west along the 35N latitude pushing up to the Cape Mendocino CA coast generating maybe 20 kt north winds there early resulting in minimal northwest windswell pushing into Central CA. With the high being di.cgiaced to the south it was also generating trades at 15 kts pushing over Hawaii resulting in minimal east windswell. But the bigger story was that low pressure had moved into the Gulf of Alaska. Not even a closed isobar low, but enough to set up a decent sized fetch of 20-25 kt west winds up at 48N aimed at the Pacific Northwest, then forecast to fade to 20 kts on Sunday. Some small windswell with period in the 10 secs range might result for the Pac NW with far smaller remnants reaching down to Central CA by Tues (8/23). Over the next 72 hours that low is to die off but high pressure is to remain well at bay, holed up in the West Pacific near the dateline. This means no more local windswell for either Hawaii or California. At the same time more low pressure is looking to be organizing for the North Pacific, but not quite there yet.


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


Hurricane Greg was 250 nmiles south-southwest of the southern tip of Baja on Thursday (8/18) with sustained winds 75 kts and tracking due west at 16 kts.  Minimal strengthening was occurring then. Regardless the system started to slowly fade out as it moved over cooler waters Friday, and was down to tropical storm status on Saturday with winds 35 kts and is expected to be a depression by Sunday (8/21).  Gregs rather rapid forward motion all to the west precluded the propagation of swell to the north pushing towards California. No swell expected to result.  


California Nearshore Forecast
On Saturday (8/20) high pressure was fading fast off the Northern CA coast at 1020 mbs barely ridging into Cape Mendocino and generating north winds at 20 kts there early and expected to fade fast through the day down to 15 kts or less by nightfall but coming under stress as low pressure starts building east from the Gulf of Alaska and a front approaches Vancouver Island late. By Sunday north winds are to be gone and windswell is to be on the decline fast with a weak front and southerly winds moving to within 600 nmiles of Cape Mendocino Sunday night and stalling there. This configuration with relatively slack winds off the Central and South CA coasts is to hold through mid-Wednesday before high pressure tries to get a toehold in by the evening with 15 kt north winds starting to blow over the entire CA coast. Those winds to hold Thursday building to 20 kts on Friday (even having some effect into Southern CA, especially in the afternoons) with the core of the fetch starting to lift north, finally setting up off Cape Mendo on Sat (9/27) at 25 kts with an eddy flow finally taking over most of Central CA down into Southern CA. At the same time low pressure is to be building in the Gulf of Alaska.  


South Pacific

On Saturday (8/20) a .cgiit jetstream pattern continued over the South Pacific with the southern branch running just over the northern edge of Antarctic Ice across the width of the South Pacific. No troughs capable of supporting gale development were indicated. Over the next 72 hours that is to change with a new northward push of energy forecast in the southern branch of the jetstream under New Zealand late Saturday (8/20) with winds to 150 kts but fading within 24 hrs. Some support for gale development forecast for this pulse. And yet another northeastward moving pulse is to push under New Zealand late Monday (8/22) with winds 150 kts fading to 130 kts late Tuesday opening up just a bit of something that looked like a trough, but pushing more to the east than north. This to provide some more support for gale development in this area. Beyond 72 hours the southern branch of the jet is to continue flowing basically flat west to east down on the 60S latitude, and offering nothing of interest in terms of support for gale development. And by Sat (8/27) a big ridge is forecast taking over the West Pacific.

At the surface on Saturday AM (8/20) a small but decently organized gale was pushing under New Zealand with 40-45 kt southwest winds building in coverage still at 40 kt in the evening, then fading from 35 kts Sunday AM.  Theoretically 28 ft seas to result at 52S 171W Sunday AM, but fading before exceeding that height. This would be good for maybe some 15 sec period swell for Hawaii, but this system is to mainly serve to rough up the oceans surface acting as a primer for more energy forecast directly behind.

On Sunday evening (8/21) a new small gale is to be organizing south of New Zealand with southwest winds to 45 kts over a small area.  That fetch is to push hard to the northeast over night with a moderately large area of 40-45 kt southwest winds forecast Monday AM (8/22) with 32 ft seas building at 55S 180W (210 degs NCal/212 SCal) and in the Tahitian swell shadow and pushing up the 193 degree path to Hawaii. But the fetch is fade fast in the evening with only 35 kt southwest winds remaining and seas fading from 31 ft at 50S 168W (207/209 degs NCal/SCal and still shadowed and up the 186 degree path to Hawaii. Will see what actually forms. The models have had a poor grasp on this system since day one.


Second New Zealand Gale
On Sunday PM (8/14) 40-45 kt south fetch is to start building just southeast of New Zealand with seas building to 28 ft pushing into New Zealand on Monday. But by Monday AM a new area of 45+ kt south fetch was building off New Zealand resulting in seas to 30 ft seas in the evening at 50S 172W targeting primarily Hawaii. The fetch fading by  Monday night with more 32 ft seas at 45S 175W on Tuesday AM. A quick fade occurred thereafter. Maybe some small swell to push north towards Hawaii arriving late on Mon (8/22) then peaking Tues at 2.3 ft @ 15 secs (3.5 ft).  But little fetch is to be aimed northeast towards the US mainland.  Maybe some fragments arriving in California by late Thursday (8/25).

Southeast Pacific Gale
On Thursday AM (8/18) a modest gale was circulating in a weak trough over the Southeast Pacific producing a moderate area of south winds at 40-45 kts.  Seas were on the increase.  By evening 40 kt south winds held and inched just a little more to the east. 28 ft seas were modeled building at 55S 142W.  On Friday AM the fetch was all but gone but seas from previous fetch reached to 32 ft at 52S 138W.  Seas dissipated quickly thereafter. Another small pulse of 17 sec period swell is radiating north up the 188/190 degree paths to North and South CA respectively. It was 5254 nmiles from SCal on the 192 degree path with swell arriving Sat 9 AM (8/26) with period 17 secs, and 5476 nmiles from NCal on the 189 degree path with 17 secs period swell arriving Sat (8/26) at 6 PM. Size again to be minimal.


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 more low pressure is to be tracking through the Bering Sea dropping southeast into the Western Gulf of Alaska on Wednesday (8/24) setting up a small fetch of 30 kt west winds pushing quickly to the east through the day, then lifting northeast through the Northeastern Gulf on Thursday with winds 25-30 kts and pushing into Central Canada on Friday. 15 ft seas forecast on Wed fading some Thursday then regrouping to 18 ft on Friday AM (8/26) up at 50N 140W and on the 319 degree path to North CA.

Directly behind it a second gale is forecast forming on the dateline Thursday (8/25) producing 35 kt northwest winds then moving into the Western Gulf on Friday with more 35 kt west winds before fading and lifting north late in the day. Theoretically 20-22 ft seas to result during the day Friday peaking near 46N 165W. If this occurs some small 13 sec period swell could result for both Hawaii and the US West Coast. But given the models track record as of late, it seems highly unlikely that either gale will even form. Something to monitor though. This all is likely a result of the Active Phase of the MJO, weak as it was traversing the Pacific the last few days.

As of Saturday (8/20) the Southern Oscillation Index (SOI) was still low. The daily SOI was down to -3.34. The 30 day average was down slightly to 4.73 with the 90 day average down to 5.08. These readings are lagging indicators of the Active Phase of the MJO that traversed the Central Pacific the week of 8/13-8/20 and continues to look like a neutral if not slightly La Nina biased long-term pattern.  

Current wind analysis indicates light easterly anomalies were in control over the Central and Western equatorial Pacific and building to stronger easterly anomalies north of Indonesia. Light west anomalies were over the far Eastern Pacific. This suggests that what was essentially a weak version of the Active Phase stationary over the extreme Western Pacific/Eastern Indian Ocean has now moved east to the East Pacific and is likely headed for the Atlantic. The models indicate that easterly anomalies are to build over the West Pacific through at least 8/28 and likely much longer.  This suggests the Inactive Phase is starting to take control and will likely help to dampen storm development (especially in the Northern Hemisphere) for the next 3 weeks or so. 

Sea Surface Temp anomaly data (8/18) remains essentially unchanged and continues to indicate that cooler waters (-1 C degs) had a grip on the equator covering from a point south of Hawaii to the dateline and holding steady if not increasing their coverage slightly. The larger issue was cooler than normal waters present in feeder bands originating off the US West Coast and Chile sweeping fully to the intersection of the dateline and the equator, serving to continue the existing La Nina pattern.  This is typically what is referred to as a horseshoe pattern.  And those cooler waters off the US West Coast were getting cooler still and expanding some. Warmer than normal waters appeared to not be building anymore over the Galapagos Islands extending west to a point south of Hawaii. 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. A cold tongue of water previously developing in the tropical Atlantic tracking west from Africa on the equator was fading. For now the big picture still looks like a La Nina.  

Below the surface on the equator things continue to look bad, but have taken a step in a slightly better direction. Colder than normal water that had been locked all winter (2010-2011) southeast of Hawaii under the equator evaporated in late February 2011, but then returned starting in early July. An impenetrable wall of colder than normal water (-3 degs C) developed in mid-July locked at 140W separating warm anomalies in the east and west, blocking any eastward progress of warmer subsurface water. On 7/21 it vaporized, with a clear subsurface path present allowing warmer subsurface water to flow eastward. But then as quickly as it redeveloped, it died with the cold pool re-emerging starting on 7/30 and built far stronger by 8/8 with waters -5 deg C below normal and holding strength and position on the equator and south of Hawaii through 8/18 and blocking the warm water flow eastward. It was down at 100 meters and was rising while gaining areal coverage.  On 8/20 it looked a bit weaker, down to -4 degs below normal, but effectively still blocking the normal warm flow to the east. This suggests the foretasted 2 year La Nina is growing roots.  

Ocean currents for the equatorial Pacific on 8/11 we flowing anomalously west in the far West Pacific with a small pocket of strong easterly flow at 120W. Previously we found anomalies developed flowing from west to east starting in February and were continuing through June 2011 (a little weaker towards mid-June than earlier in the month). Westerly anomalies continued in July to (thru 7/22)  Easterly anomalies were isolated to a small area on the equator at 120W. We oft look at such symptoms as an El Nino indicator, but that does not seem likely given all the other data.  But that co.cgied with a falling SOI at least it depicts a tendency towards normal conditions.  Will monitor. Historically it is very unlikely if not impossible to have an El Nino form directly behind a La Nina.  More typical is several years of a slow buildup before an actual El Nino event occurs.  This suggest the warm waters currently pooling up off Ecuador will likely dissipate as summer progresses but at the same time, the cooler than normal horseshoe pattern over the North and South Pacific will dissipate too. 

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


South Pacific

Beyond 72 hours the models suggest a far stronger storm is forecast tracking under New Zealand on Tuesday (8/23) with a solid area of 55 kt southwest winds. It actually is to originate under Southern Australia on Monday.  32 ft seas are forecast building south of the Tasman Sea. 55-60 kt westerly fetch to bloom in the evening resulting in 40 ft seas building at 54S 175E pushing flat east and just barely free on the west side of the Tahitian swell shadow (212/214 degs) for NCal/SCal and 197 degs for HI and unshadowed by NZ. 55 kt southwest winds to hold with a large area of 50 kt southwest winds backing it up Wed AM (8/24) and seas building to 47 ft at 52S 172W (209/211 degs NCal/SCal) and shadowed by Tahiti and 189 degs relative to HI but alot of fetch passing east of the great circle tracks heading there.  A quick fade is forecast in the evening with a broad area of 40 kt southwest winds forecast and seas fading from 50S 160W pushing up the 203/205 degrees path to NCal/SCal and passing out of the eastern edge of the Tahitian swell shadow. limited sideband energy pushing up the 182 degree path to Hawaii. This system to effectively be gone by Thursday AM (8/25). This system to be a long ways away but better set up than previous projections with more fetch aimed northeast and certainly capable of producing some swell for all Northern Hemi locations in our forecast area.  But for now this is just a forecast, with no wind blowing yet. At least it's something to monitor.

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

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".

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

Free Stormsurf Stickers - Get your free stickers! - More details Here

Read all the latest news and happenings on our News Page here

Surf Height-Swell Height Correlation Table


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