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Pacific Storm and Surf Forecast
Updated: August 16, 2011 7:35 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 = 2.5 - 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 8/15 thru Sun 8/21
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   

More From the South
Waiting for Something Bigger To Get Our Attention


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 Tuesday (8/16) North and Central California was seeing
 no real northwest windswell up north with northwest winds starting to add heavy texture on top. Down south background swell was producing thigh high rare southern hemi sets and clean early.  Southern California was getting waist high northwest windswell up north and textured. Down south southern hemi swell was producing waves in the head high range and well textured late AM. Hawaii's North Shore was effectively flat. The South Shore was still getting southern hemi background swell with waves at chest to head 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 all but gone on Tuesday but is to slowly start regrouping and ridging into the North and Central CA coast producing small northwest local windswell late in the workweek into the weekend (8/21). It was only generating easterly trades at 15 kts over Hawaii's Eastern Shores and is expected to hold through late in the workweek offering minimal support for windswell there. Weak low pressure is to track over the North Pacific High eventually reaching the Northern Gulf of Alaska by the weekend generating westerly winds at 25 kts well off the Pacific Northwest possibly enough to generate some windswell there. Down south a weak weather system formed under New Zealand Monday (8/8) tracking northeast with seas barely 30 ft and producing utility class swell that is currently hitting Hawaii.  Far less expected for the US mainland. Sideband swell from a storm that was off Chile Mon-Tues (8/9) is hitting CA on Tues (816), biggest at the south end of the state. A gale previous forecast for New Zealand last weekend hasn't done much, with only a short lasting area of 32 ft seas on Tues AM (8/16) pushing north-northwest, maybe even bypassing Hawaii to the west.  The models are teasing about a series of two stronger systems under New Zealand next weekend and again early next week, but that is far from believable at this early date. Basically we're in a holding pattern, waiting for Fall to start. But we might be waiting for a while. 


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

North Pacific

At the surface on Tuesday (8/16) no real fetch of interest was in.cgiay. Weak high pressure at 1024 mbs was 750 nmiles northeast of Hawaii generating 15 kt trades  pushing over the Islands resulting in minimal east windswell. Over the next 72 hours the high is to lift a bit northeast resulting in slightly less trades and windswell over the Hawaiian Islands but building north winds over Northern CA by Thursday (8/18) pushing 20-25 kt on Friday with lesser winds covering the entire North and Central CA coasts. Building northerly windswell (at best). At the same time low pressure is to be migrating over the Aleutian Islands and Bering Sea trying to get a toehold in the Gulf of Alaska but not quite reaching there yet. No swell being generated yet. 


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


On Tuesday (8/16) Tropical Storm Fernanda was 1350 nmiles east-southeast from the Big Island with winds 45 kts and pushing energy up the 109 degree path there. Steady slow intensification is forecast with this system tracking just north of due west and peaking on Thursday mid-day at 65 kts (minimal hurricane strength) positioned 1100 nmiles out with energy pushing up the 114 degree path to the Big Island. Possible small swell to result. Will monitor. 


California Nearshore Forecast
On Tuesday (8/16) no real high pressure was off the Northern CA coast and instead weak low pressure at 1018 mbs was 600 nmiles west of Cape Mendocino , minimizing the impacts of any high pressure in the area.  By Wednesday the low is to be falling south and fading fast allowing high pressure to again get a toehold  off Cape Mendocino at 1028 mbs with north winds building over Northern CA at near 25 kts late Thursday and building down the Central CA coast. Those winds to reach near 30 kts Friday evening with increased local north windswell expected and chopped conditions nearshore of all of Central CA. By Saturday (8/20) the high is to try and hold on producing more 25 kt north winds up north by coming under pressure as low pressure starts building east from the Gulf of Alaska and a front approaches Vancouver Island late. By Sunday all north winds are to be gone and windswell is to be one the decline fast with a weak front moving to within 600 nmiles of Cape Mendocino Monday night. This configuration to hold into mid-Tuesday. 


South Pacific

On Tuesday (8/16) a .cgiit jetstream pattern continued over Central and Southeast Pacific with the southern branch running just over the northern edge of Antarctic Ice across the width of the South Pacific. There was no upper support for the formation of gales. Over the next 72 hours the same basic pattern is to hold offering no support for gale development. But a general easing of the ridge is to develop over the Central Pacific by Friday (8/19). Beyond 72 hours the first of two troughs are forecast forming under New Zealand starting Sun (8/21) with winds to 140 kts pushing pretty well to the north and providing  some limited support for gale development in the Central Pacific.

At the surface a broad but poorly organized low continued circulating east of New Zealand. It was generating 40+ kt west-northwest winds all pushing towards Antarctica and though 32 ft seas were being produced, they were also heading southeast and away from our forecast area.  But at first light Tuesday (8/16) previous 40 kt south-southeast winds had generated 32 ft seas at 45S 175W pushing north-northwest.  Maybe some sideband swell to result for Hawaii. Over the next 72 hours this  gale is to continue heading off to the east-southeast at a good rate of speed with winds not exceeding 35 kts, offering little in terms of swell generation potential.

Chile Storm
A broad gale developed off Southern Chile starting Sun (8/7) producing 32 ft seas at 40S 115W  building to 42 ft in the evening at 40S 105W and holding into Monday evening. This offered great raw swell potential for Chile up into Peru, but was well east of any great circle route to the California coast.  Just the same the there is some suggestion that some degree of sideband swell from this system is to somehow push up the great circle paths to California.

Southern CA:
 Expect swell holding at 3 ft @ 15-16 secs (4.5 ft) Wed (8/17), then fading from  2.6 ft @ 13-14 secs (3.5 ft) early Thursday .  Swell Direction 176 degrees

North CA:  Expect swell arriving on sunset Tues (8/16) with pure swell to 1.6 ft @ 18 secs (2.5 ft) building to near 3 ft @ 16 secs (5 ft) late Wednesday (8/17) and holding at 3 ft @ 15 secs (4.5 ft) on Thurs (8/18).  Swell Direction 174 degrees

New Zealand Fetch

A new gale organized in an upper level trough positioned under New Zealand late Sunday (8/7). Southwest winds were modeled at 40 kts with seas on the increase, reaching 30 ft on Monday AM (8/8) at 51S 172E. But then winds were down to 35 kts and fading from there. Seas dropped to 28 ft in the evening at 50S 177E moving to 48S 170W Tues AM then dissipating from there.

Background energy for California by Wed noon (8/17) from 210 degrees but shadowed by Tahiti and buried in theoretical Chilean swell. Maybe swell of 1.6 ft @ 16 secs on Thursday (2.5 ft).  


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.


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 North Pacific jetstream is to be tracking along the Aleutians on the 50N latitude with winds at 130 kts then dipping a bit further south into the Gulf of Alaska on Saturday (8/20).  No real troughs forecast until Tuesday (8/23) when something that almost resembles a real trough is to develop. Modest low pressure is to follow the stream through the Bering Sea into the Northern Gulf of Alaska by Saturday (8/20) producing 20-25 kt west winds maybe aimed towards the Pacific Northwest. No real swell generation potential suggested with seas only to 12 ft projected.  And even when the trough builds in the Gulf on Tuesday, only 20-25 kt west wind and seas in the 12 ft range forecast.  Not enough to generate any swell. And with low pressure in the Gulf, it will dampen the development of high pressure off California and the production of northwest windswell down into Central CA and trades and easterly tradewind swell over the Hawaiian Islands.    

As of Tuesday (8/16) the Southern Oscillation Index (SOI) was fading. The daily SOI was down to 2.18. The 30 day average was down to 6.21 with the 90 day average down at 5.35. This continues to look like a neutral if not slightly La Nina biased long-term pattern.  

Current wind analysis indicates extremely light southeasterly anomalies in control over the Central equatorial Pacific pushing just a little west of the dateline, then turning to stronger easterly anomalies west of there.  This remains not substantially different than it has been for the past week and suggests a weak version of  the Active Phase was stationary over the extreme Western Pacific/Eastern Indian Ocean just northeast of New Guinea and maybe easing east a little from there. But it also indicates that this area was weakening. The models indicate that weak westerly anomalies if not dead neutral winds are to drift east, perhaps reaching east of the dateline by 8/22-8/24 but with easterly anomalies building strong over the far West Pacific at the same time.  This suggests the Active Phase, weak as it is, is to be moving towards the Central Pacific and fading with a moderate Inactive Phase building in the West Pacific. This would indicate the area conducive to formation of moderate tropical systems moving east to the Central Pacific in-sync with the MJO.  

Sea Surface Temp anomaly data (8/15) 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. 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. 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. But then 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 8/2 with waters -3 deg C below normal, down to -4 degs C below normal on 8/4 and down to -5 degs C below normal on 8/8 and holding strength and position on the equator and south of Hawaii through 8/16 and blocking the warm water flow eastward. It was down at 100 meters and was rising while gaining areal coverage.  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 real storm is to develop south of New Zealand on Sat (8/20) with southwest winds to 55 kts resulting in modest sized area of 40 ft seas at 52S 165W mid-Sunday. And a very similar system is forecast right behind it  on Tuesday (8/23) with a broader area of 45 kt southwest winds and  40 ft seas in the evening at 50S 170W. Both these are to be in the heart of the Tahitian swell shadow relative to California, but with decent energy pushing up towards Hawaii. At this early date this is just something to monitor. But don't expect it.   

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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