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Pacific Storm and Surf Forecast
Updated: August 17, 2013 1:00 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 = 1.0 - California & 0.5 - 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 8/12 thru Sun 8/18
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   

Small Windswell Into Mid-Week for CA
Southern Hemi to Stir Slightly

Swell Classification Guidelines

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

Current Conditions
On Saturday
(8/17) North and Central CA had surf that was 1 ft with sets to 2 ft (knee to almost thigh high) and pretty ragged early as northwest wind was on the upswing. Overcast in control too. Down in Santa Cruz surf was flat with light winds and clean. Southern California up north was flat and clean and fogged in. Down south waves were knee to thigh high and clean with high fog early. Hawaii's North Shore was flat and clean. The South Shore was getting thigh to waist high tradewinds generated wrap-around windswell and clean with trades in effect. The East Shore was getting tradewind produced east windswell at waist high and occasionally bigger and chopped from trades.

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

Meteorological Overview
In the North Pacific on Saturday (8/17) l
ow pressure was moving through the Northern Gulf of Alaska generating 20-25 kt west winds with seas forecast building to 14 ft on Sunday there possibly setting up some northerly windswell for the US West Coast next week. It's a reach but it's the only thing going.

Of more immediate interest to California was the local pressure gradient over the north end of the state, forecast to build with north winds to 25 kts on Sunday and expected to hold through at least mid-week (8/21), possibly providing small local north windswell for North and Central CA.    

Relative to the Hawaii easterly tradewinds were blowing at 15+ kts due to a combination of building high pressure north of the Islands and semi tropical low pressure tracking west just about exiting west from under the Islands. Trades to drop later Saturday to the 15 kt range then fading more Sunday and all but gone by Monday as high pressure gets eroded some by low pressure in the Gulf.  Rideable windswell to continue along exposed east facing shores for Saturday, then dropping out and flat by next week and holding in that range.   

Over the past 7 days no swell producing weather system of interest have occurred in the South Pacific. And looking forward no storms of solid interest are forecast. That said a gale is now modeled in the deep Central Pacific starting Sunday producing a steady fetch of 35-40 kt south winds aimed up at Tahiti, Hawaii and the US West Coast slowly easing east into Wed (8/21) while winds slowly fade to 35 kts producing 25-27 ft seas again aimed well to the north. This is nothing remarkable by normal standards, but given the flatness of late, should be good for a pulse of 14-15 sec period swell for our forecast area if all pans out as forecast. At least it's a start at chipping away the southern hemi swell drought that has.cgiagued us lately.

Details below...

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

North Pacific

Surface Analysis  -  On Saturday (8/17) the North Pacific high pressure system was a bit better organized at 1024 mbs centered 90 nmiles north of Hawaii and starting to touch the California coast with north winds starting to pick up at 15 kts there, more than has been seen in a while. The high was also producing 15 kt easterly trades over Hawaii and perhaps a bit more enhanced by tropical low pressure that was exiting west from under Hawaii. This setup has produced easterly short period windswell for exposed east facing shores of the Hawaiian Islands for several days now. But that is coming to a close. Also weak low pressure at 1000 mbs migrated from the Bering Sea southeast and was now tracking through the Northern Gulf of Alaska producing a decent sized fetch of 20-25 kt west winds there targeting primarily Vancouver Island and the Pacific Northwest with seas building to 12 ft.

Over the next 72 hours the high is to slide east more while the low in Northern Gulf pushes east too, continuing to generate 20-25 kt west winds into Sunday AM (8/17) with seas building to 14 ft at 48N 150W again targeting primarily Vancouver Island down into the Pacific Northwest.  Windswell likely for those targets early in the workweek, but nothing remarkable.  By Monday the low is to be inland over Canada with fetch dissipating.

Relative to California high pressure is to be getting a better toe in the door over the north end of the state Sunday AM (8/18) producing a small pressure gradient and north winds just off North California at 20-25 kts resulting in small northerly short period windswell for most of North and Central CA. This gradient is to hold if not covering slightly more area into Tues (8/20) with windswell slightly better defined down the Central coast at that time. The gradient is to start fading on Wednesday AM then collapse in the evening with windswell falling with it.  

Relative to Hawaii weak high pressure north of the Islands is to erode on Sunday (8/18) with east winds from it fading steadily through the day from 15 kts, and down below the critical 15 kt threshold by Monday (8/19) with no rideable windswell being produced. No change is forecast through Wed (8/21).

Otherwise no other swell producing fetch of interest is forecast.


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


On Saturday (8/17) the following tropical systems were being monitored:

Tropical Depression 12: It was 250 nmiles a bit west of Taiwan drifting east with winds 30 kts. It is expected to eventually recurve back on a northwest track and build with winds to 60 kts on Wed (8/21) positioned just east of Northern Taiwan, building to hurricane strength 24 hours later and missing taiwan bound for mainland China.

Tropical Depression 13: It was 600 nmiles northeast of Taiwan tracking roughly west with winds 25 kts and forecast to build while falling south towards Taiwan on Wednesday with winds 65 kts.  

Tropical Storm Pewa was just east of the dateline tracking west-northwest winds winds 50 kts, forecast holding this track while building with winds to 70 kts (typhoon strength) Monday and holding together well. The GFS model has Pewa taking a more westerly course by Fri (8/23) and intensifying. Of course none of this is believable at this early date, but it is something to monitor.

California Nearshore Forecast
On Saturday (8/17) high pressure was starting to build into the coast with a steady local northerly wind flow in control of the North and Central coasts at 10-15 kts expected to build to 15-20 kts later in the day. 20-25 kt north winds are forecast for Cape Mendocino on Sunday (8/18) with north winds 15 kts pushing down the outer Central Coast reaching into Point Conception early and north windswell on the upswing. An eddy flow to build in as the day progress. By Monday a gradient is to be developed over Cape Mendocino with north winds 25 kts there (30 kts late) and a full eddy flow in control of the Central and South coasts, holding into Tues (8/20). On Wednesday the gradient is to start fading though still 25 kt north winds early, then dropping to 20 kts over North CA with a weaker eddy flow nearshore for Central CA. Thursday the gradient is to start falling south with 20 kt north winds off Pt Arena and 15 kt north winds pushing off the coast of Central CA and the eddy fading late. Friday the north winds at 15 kts forecast nearshore for all of North and Central CA starting to dissipate on Saturday. Southern CA to remain under a light wind flow for the duration.    


South Pacific

Jetstream  -  On Saturday (8/17) the jet was well .cgiit over the Southwest Pacific then merged over the far Southeast Pacific east of even the Southern CA swell window. Winds were up to 120 kts south of New Zealand in the influential southern branch, but were landlocked over the Ross Ice Shelf. No support for gale development was indicated. Over the next 72 hours the same basic pattern is forecast but with a weak trough developing in the Central Pacific on Monday (8/19) lifting the jet north of the Ross Ice Shelf but with winds only 80 kts, not really supportive of gale development in lower levels of the atmosphere. Beyond 72 hours the trough is to have good staying power, still circulating and getting larger and better defined into Wed (8/21) with 90 kt winds pushing up into it while slowly easing east. A slow fade is forecast later Thursday with the trough dying out over the Southeast Pacific. Limited support for gale development forecast. Beyond a .cgiit flow is to take over with the southern branch landlocked over Antarctic Ice.

Surface  - On Saturday (8/17) no swell producing fetch of interest was occurring. But on Sunday (8/18) a weak gale is forecast developing in the Central Pacific but abutted against solid high pressure at 1028 mbs under New Zealand setting up a nice pressure gradient producing 40 kt south winds just north of the Ross Ice Shelf with the whole fetch lifting slowly due north. Seas building to 26 ft at 56S 160W in the evening. On Monday AM (8/19) winds to fade to 30 kts over the same area of the ocean with seas 26 ft at 54S 158W, with more of the same in the evening with seas and seas fading to 25 ft at 52S 152W. Tuesday AM (8/20) winds to rebuild to 40 kts from the south with seas up to 26 ft at 52S 145W. Fetch fading to 35 kts in the evening but covering more area with seas still 26 ft at 48S 144W. The gale to hold Wed AM (8/21) with 35 kt south fetch over a solid area and seas 23 ft at 48S 140W. The gale to fade out in the evening. If all goes as forecast some degree of rideable 15 sec period swell to result for Tahiti, Hawaii, and the US West Coast.


A gale developed in the far Southeast Pacific on Tues AM (8/13) producing 40 kt south to southwest west winds aimed barely at Southern CA and better at Chile with 28 ft seas over a tiny area at 58S 120W then quickly raced east by evening with seas to 29 ft at 54S 113W totally east of even the Southern CA swell window. Maybe a dribble of swell to radiate north towards CA. By Wednesday (8/14) this system developed more with seas exceeding 30 ft but all energy targeted Chile and well east of the California swell window. 

Southern CA: Minimal swell arriving late Tues (8/21) building to 1.3 ft @ 18 secs (2.0-2.5 ft) building to 1.6 ft @ 16 secs (2.5 ft) on Wed (8/22). Swell Direction: 175-180 degrees

Weak low pressure circulating in the far Southeast Pacific on Thursday (8/15) starting to generate 30 kt south winds on the eastern edge of the Southern CA swell window and held through Friday building to near 30 kts. Seas built to 26 ft over a tiny area Friday at 18Z (8/16) at 53S 124W aimed north.  

Maybe swell of 1 ft @ 15-16 secs to reach Southern CA on Sat (8/24) with luck.


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




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

North Pacific

Beyond 72 hours another weak low pressure system is to track through the Northern Gulf late Friday (8/23) producing 20 kt northwest winds targeting Oregon and North CA into Saturday AM producing 9 ft seas. Nothing of interest to result.

Relative to California high pressure is forecast surging slightly Thursday PM (8/22) reinvigorating the local pressure gradient near Cape Mendocino with north winds building to 20 kts into Friday AM, good for more tiny north windswell down into Central CA, then dissipating through the day with windswell dropping out.

Relative to Hawaii trades to remain below 15 kts until Thurs (8/22) when a supposed tropical low tracks south of the Islands enhancing trades to almost 15 kts, but with no enough areal coverage to produce meaningful windswell. Trades to hold into Saturday.

In all, no clear signs of Fall yet. In 'good' years, those influenced by mild El Nino conditions or better, about 8/15 is when one could expect to see arrival of some early North Pacific swell along the Hawaiian and Us West Coasts originating from tropical cyclones approaching Japan then recurving northeast and becoming extratropical. unfortunately, there is no indication of such a pattern setting up.

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

As of Saturday (8/17) the daily Southern Oscillation Index (SOI) was down to -10.99. The 30 day average was down to 5.19 with the 90 day average down some at 7.56. The nearterm trend based on the SOI is towards a weak Active Phase of the MJO while overall the pattern was in weak La Nina territory and not indicative of El Nino and illustrative of a dominance of the Inactive Phase of the MJO.  

Current equatorial surface wind analysis indicated weak east wind anomalies over the Eastern Maritime Continent turning westerly over the dateline and continuing south of Hawaii. Neutral anomalies extended from there into the coast of Central America. Of note - there has been a distinct lack of westerly anomalies for months. A week from now (8/25) weak easterly anomalies are forecast holding over the Maritime Continent then turning westerly over the dateline region and a bit beyond a point south of Hawaii. Neutral anomalies are forecast from there into Central America. In all this suggests a neutral phase of the MJO if not almost slightly Active.    

The longer range models (dynamic and statistical) run on 8/16 are in general agreement. Both models suggests no MJO activity was occurring with a neutral pattern over the West Pacific. No change is forecast for the next 15 days per the statistical model while the dynamic model holds tight hinting at some degree of weak Inactive Phase building while tracking east off the Philippines 5-15 days out. This tendency has started appears 2 days ago and remains steady. The ultra long range upper level model favors formation of some flavor of weak Inactive Phase of the MJO from 8/22 through 9/11, then falling back towards a neutral pattern if not Active pattern for the remainder of September. But overall no coherent MJO signal is expected. 

The more warm water in the equatorial East Pacific means more storm production in the North Pacific during winter months (roughly speaking). Cold water in that area has a dampening effect. Regardless of what the atmospheric models and surface winds suggest, actual water temperatures are a ground-truth indicator of what is occurring in the ocean. As of now (8/15) a very weak La Nina-like pattern continues in the East Pacific on the equator. If anything the small pocket of cooler water we've been monitoring off the immediate coast of Peru is starting to pulse again, with the outflow from it tracking to the Galapagos if not west of there, then breaking up with pockets of cooler water radiating west almost to a point south of Hawaii. Imagery from 8/5 to present  suggest the cool pool has been re-generating, and the 8/15 image is the coolest yet. Historically this is no different from what has been occurring all summer with the cool pool fluctuating and sporadically spitting occasional larger pockets of cool water westward along the equator and keeping a lid on any legitimate warm water from developing. The sympathetic anomalous cool pool off West Africa appears to be gaining some ground too with a faint cool flow building and becoming more distinct reaching again almost to South America. It had previously built almost to the coast of South America then retrograded in late June. The African cool pool is a direct reflection of what has been occurred in the Pacific, an unexpected burst of cool water gurgling up off both the South America and West Africa coasts simultaneously - suggestive of a global teleconnection. Further north a.cgiume of slightly cooler than normal water that has been radiating southeast off California for 2 years closed off mid-May, returned in June when the cold pool emerged off Peru and Africa, then fully closed off in July.  As of 8/12 into 8/15 is appears to be rebuilding off the California coast with a well defined track radiating off California almost reaching a  point south of Hawaii. But a considerable pocket of warmer than normal water is also building west of California tracking east, so it's anyone guess whether the local pool will get mowed over by the eastward moving warm pool. For now cooler waters over the equatorial East Pacific are under control, but still present, with no sign of a warm pattern developing. In short, we're still under some weak influence of La Nina or at least a neutral pattern biased cold.  

Subsurface waters temps on the equator indicate a neutral temperature pattern. Warm water from the West Pacific previously migrated east over top of a cold pool - eliminating it's impact and continues holding.

Projections from the CFSv2 model run 8/17 indicate water temps have been hovering near neutral since January within only a +-0.25 deviation. Recent runs of the model have consistently been suggesting a slow warming trend (up to +0.25 degs C) by Nov 2013 and near +0.6 C by April 2014. But for the immediate future a neutral pattern is expected. So overall the immediate outlook remains nothing stellar, but trending towards something that would be considered right on the threshold of warm, by Spring 2014, assuming one were to believe the model. This is good news. If anything the ocean is in recharge mode, with cold water dispersing and temperatures gradually on the rise again in fit's-and-starts. Historically, if a warm water buildup indicative of any kinda of El Nino pattern were to occur in 2013, it would have started building in Feb-Mar. That is clearly not the case for this year. Expect a neutral pattern for Winter of 2013-2014 with perhaps a slightly warmer pattern for 2014. 

We are in a neutral ENSO pattern with neither a solid El Nino or La Nina imminent. But a weak prevalence of the Inactive Phase of MJO seems to be biasing the weather global pattern. This is a better.cgiace than previous years (2010-2011, 2011-2012 and 2012-2013) under the direct influence of La Nina, but we're still not in a pure neutral pattern either. We're still recovering from the 2009-2010 El Nino. Longer term the expectation is there will be at least one to two years of neutral temperatures ultimately converging in a stronger warmer pattern and possible El Nino 2-3 years out (2015 or 2016). And historically, this is the 'normal' pattern (a few years of false starts post La Nina before a legit El Nino forms).

See imagery in the ENSO Powertool and more details in the  El Nino Update Last Updated 10/6/12 


South Pacific

Beyond 72 hours no swell producing fetch is 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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Local Interest

Visit! Boardshorts - Looking for a sick pair of boardshorts? Check out the selection at with brands from O'Neill, Quiksilver and Rusty and free shipping on every order. They won't disappoint.

Wall of Skulls - Here's a great video featuring Tahiti's famous wave. There's also a nice little.cgiug for Stormsurf in it too.

Super Natural - Powerlines Productions has released their new big wave surf video chronicling the epic El Nino winter of 2009-2010.cgius many other big wave event through the 2012-2013 winter season. It's a must see event for any big wave rider. It's for sale here:

Nantucket Marine Mammals has documented a short video concerning whale conservation and awareness off the Northeast US Coast. See it here:

Jason-1 Satellite Decommisioned - On June 21 an error occurred on board the Jason-1 satellite and it automatically shut down all critical functions. The satellite has since officially been decommissioned. It's last working transmitter failed on 6/21. All efforts have been made to get a response to no avail. The satellite has been.cgiaced in a parking orbit with it's solar panels turned away from the the sun. It's batteries are to discharge in the next 90 days. No additional data is expected from this satellite. We are working to start capturing data from the Jason-2 satellite, but that will take some time. More information to follow.

'CBS This Morning' with the Mavericks Invitational Surf Contest - See a nice morning TV show piece on the Mavericks Contest held Sun 1/20/13. The show aired Wed 1/23. Interviews with Colin Dwyer, Jeff Clark, Mark Sponsler and Grant Washburn:

Jaws Redbull Contest Forecast E.cgiained By Stormsurf

Cortes Bank Mission (12/21-12/22/2012)

The Making of 'Chasing Mavericks' - See some background footage on how the movie was made: Part1, Part2

The Psychology of Big Wave Surfing with Greg Long - A must see for any aspiring big wave rider:

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

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

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

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

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

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

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