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Pacific Storm and Surf Forecast
Updated: August 18, 2012 5:07 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 = 3.0 - California & 1.0 - Hawaii
Using the 'Summer' Scale
(See Swell Category Table link at bottom of page)
Probability for presence of largest swells in near-shore waters of NCal, SCal or Hawaii.    
Issued for Week of Monday 8/13 thru Sun 8/19
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   

Chilean Swell Heading Down in CA
Quiet Pattern Takes Over

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 (8/18) North and Central CA had Gulf windswell producing waves in the knee high range and clean early. Down south in Santa Cruz surf was in the thigh to maybe waist high range on the sets and clean. Southern California up north had a thigh high windswell-southern hemi combo and clean. Down south waves were occasionally in the chest high range and clean and well lined up. Southern hemi swell finally looks like it's hitting here. Hawaii's North Shore was flat and clean with trades in effect. The South Shore was near flat with knee to thigh high sets and clean with light trades in effect. The East Shore report was not available.   

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

Meteorological Overview
Up north high pressure remained well west of the California coast resulting in no local windswell production. Trades were suppressed to over the Hawaiian Islands, only in the 10 kt range also offering no local windswell production. Beyond high pressure is to start moving east and rebuilding by late Sunday (8/19) with north winds starting to build to 15-20 kts along the North and Central CA coast focused near Pt Conception initially then lifting north and trades return at 15 kts over Hawaii holding well into the middle of next week. Finally by Thursday the regular pressure gradient is forecast to build along the North CA coast with rideable windswell resulting at exposed breaks in Central and maybe even Southern CA and holding well into the weekend. Trades to never exceed 15 kts over the Islands though with windswell staying pretty small.

Down south a solid storm developed well off Southern Chile on Thurs (8/9) and just barely in the California swell window with up to 38 ft seas pushing northeast then developed further with seas to 42 ft but pushing out of even the Southern CA swell window. Swell from it is currently hitting exposed breaks in California and is expected to provide something rideable but nothing more and then only at exposed breaks through the weekend, then fading out. Nothing else is expected to follow with no swell producing fetch forecast for the entire South Pacific through the week into the weekend (8/26). In short a swell drought is guaranteed starting Monday (8/20) with no end in sight. Make the most of whatever southern hemi and windswell you can get.


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

North Pacific

Surface  -  On Saturday (8/18) the North Pacific high pressure system was weak, diffuse and retrograded well to the west at 1020 mbs and positioned about 900 nmiles north-northwest of Hawaii. It was producing no fetch of interest anywhere in the North Pacific. As a result winds were light down the California coast as were trades over Hawaii. 

Over the next 72 hours the high is to get slightly better defined north of Hawaii on Sunday (8/19) resulting in trades barely reaching 15 kts over the Islands and a more dominant northerly flow materializing over California pushing down the North and Central coasts at 15+ kts. No real windswell to result in either location. More of the same is forecast through Tuesday (8/21) but with perhaps some small windswell starting to develop along Hawaii's East Shores and down the Central CA coast. But in both cases period is to be very short and form poor.  


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


No tropical systems were being monitored.

The models suggest some form of tropical system forming off the Northern Philippines on Sunday (8/19) tracking north and approaching Southern Japan mid-week and then turning west and moving inland over China on Thursday (8/23).  No swell for our forecast area suggested.

Yet another system is forecast developing  a bit further east of the Northern Philippines Thurs (8/23) and holding stationary into the weekend while building over a solid area. Something to monitor.  


California Nearshore Forecast
On Saturday (8/18) a weak wind pattern was in control of North and Central CA waters with high pressure di.cgiaced to the west and a weak upper low off the CA coast. A small patch of 15 kts north winds was isolated to Pt Conception, but otherwise, no wind of interest was occurring. High pressure is to get better footing Sunday with north winds 15 kts most locations and up to 20 kts over Pt Conception while an eddy flow remains for Southern. North winds to build to 20 kts impacting the entire North and Central coasts Monday and Tuesday and building in areal coverage. By late Wednesday a more typical pattern is to emerge with north winds pushing 20-25 kts up near Cape Mendocino and becoming better established into Friday. Winds less nearshore in Central CA and and eddy flow to remain in Southern CA. The Cape Mendo gradient to reach 30 kts on Saturday with an eddy flow starting to take hold over all of Central CA up to Bodega Bay. Windswell slowly building with improving conditions next weekend for Central CA.


South Pacific

Jet stream -  We're thinking of starting to switch jetstream monitoring to the North Pacific. But for now we'll continue Southern Pacific monitoring. 

On Saturday (8/18) a .cgiit jetstream pattern remained locked over much of the South Pacific with the southern branch di.cgiaced well to the south running slightly to the northeast starting down at 72S. Winds were below 100 kts over it's length. No support for gale development was indicated. Over the next 72 hours a solid ridge is to be building in the Central South Pacific pushing well into Antarctica offering no swell production capacity. Beyond 72 hours a push of east moving wind energy is to move into the southern branch on Tues (8/21) located down at 65S tracking flat west to east and continuing the across the width of the South Pacific over Antarctic Ice with reinforcements developing under New Zealand on Friday (8/24) continuing the flat eastward momentum with no end in sight.  

Surface  -  At the surface in the South Pacific on Saturday (8/18) no swell producing fetch of any kind was present over ice free waters. In fact, no winds greater than 30 kts were occurring. High pressure was locked in east of New Zealand at 1024 mbs reaching south to 60S and pushing any fetch in clear water to the south. A broad but weak low pressure center was off Southern Chile but generating winds of only 30 kts, good for only windswell pushing towards Chile. Over the next 72 hours that high is to drift east and build to 1032 mbs pushing south to 70S really putting a damper on swell development potential.    

Chilean Storm
 gale developed in the deep Southeast Pacific over Antarctic Ice Wednesday (8/8) with 45-50 kt southwest winds becoming exposed to ice free waters in the evening while lifting northeast with seas building to 35 ft at 59S 125W.  Thursday AM (8/9) a large fetch of 45-50 kts southwest winds were building seas to 39 ft at 56S 119W on the edge of the Southern CA swell window.  In fact the Jason-1 satellite passed directly over the core of the fetch at 14Z and confirmed a 15 reading average of 39.9 ft with a single peak reading to 41.3 ft, right in line with what the wave model projected. The fetch lifted northeast in the evening with winds fading from 45 kts and seas to 43 ft at 56S 110W and effectively out of even the Southern CA swell window but targeting Central America and South America well.  Fetch faded from 40-45 kts Friday AM (8/10) with seas dropping from 40 ft at 54S 103W targeting Chile and Peru well. A quick fade followed with seas fading from 36 ft at 52S 98W in the evening.

This system was just barely in the Southern CA swell window Thursday AM and was moving out by the evening. But that should be enough to push some small sideband swell northward and provide a much needed diversion for an otherwise lackluster summer surf season. Far better energy is to be tracking towards Chile and Peru assuming this system.cgiays out as forecast.

Southern CA: Expect swell to continue Friday (8/17) at 2.7 ft @ 18-19 secs (5 ft with sets to 6 ft) then fading Saturday from 2.6 ft @ 16 secs (4 ft). Swell Direction very southerly at 176-180 degrees.

Northern CA: Expect swell to be fading Sunday from 2.3 ft @ 16 secs (3.5 ft with sets to 4.5 ft). Swell Direction very southerly at 174-179 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 hours high pressure is to get a little better foothold by Wednesday (8/22) with north winds building to 20 kts over North and Central CA starting to produce more normal northerly short period windswell for Central CA. And by Friday winds speeds to near 25 kts and the core of the gradient is to appear over Cape Mendocino setting up larger windswell (4 ft) for exposed breaks. Winds possibly to 30 kts by Saturday (8/25) suggesting yet bigger windswell for the weekend.

Easterly trades over Hawaii to hold at 15 kts covering a larger area Tuesday-Wednesday (8/22) then retreating some and holding into Saturday (8/25), suggesting only small easterly short period windswell at best for that timeframe. 

A series of 2 weak low pressure systems to move through the Bering Sea over the weekend (8/18) and again next week (8/22) but with no real fetch protruding southward, offering no swell potential. No real signs of Fall yet. 

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 (8/18) the daily Southern Oscillation Index (SOI) started it's positive bound trend as expected up to 10.38 (after being negative or nearly so for 26 consecutive days). The 30 day average was up slightly at -10.81 with the 90 day average at -7.79. But with the Active Phase of the MJO gone, the SOI is expected to begin a 2-3 week trend back into neutral if not positive territory. The good news is this last Active Phase push sent the 30 day average down and equaling that of the Active Phase in early July, and that was the lowest it had been since the El Nino January of 2010.

Current equatorial wind analysis indicated a broad area of light east anomalies over the dateline and continuing into the Maritime Continent (WPac). Neutral anomalies extended east from the dateline to Central America. This suggests the Active Phase was gone and has moved into the Atlantic Basin and the Inactive Phase is getting a foothold. A week from now (8/25) light east anomalies are forecast over the entire Maritime Continent to the dateline theoretically held at bay by a large forecast tropical system developing east of the Philippines. Light east anomalies are forecast over most of the East Pacific too suggesting the Inactive Phase still trying to get it's footing. If all this.cgiays out as forecast, that would not be too bad of an outcome, suggesting a rather anemic Inactive Phase. But it's way too early to proclaim that at this early date. .

The longer range models (dynamic and statistical) run on 8/17 are in agreement suggesting that the Inactive Phase was in.cgiace over the Maritime Continent and starting to reach the dateline area pushing east. Both suggest the Inactive Phase is to peak in the next 5-7 days over the Maritime Continent extending to the dateline and east of there more, then fading and be gone 11-14 day out. And it is to be di.cgiaced north some with a small area of enhanced precipitation holding over the dateline during it's peak. For now we will continue to raise the concern that this Inactive Phase has the potential to halt or significantly degrade what is already a weak eastward moving warm water transport pattern, possibly interrupting the established warm water build-up in the East Pacific. But the current model runs help dampen some of those concerns now.

More warm water in the equatorial East Pacific means more storm production in the North Pacific during winter months (roughly speaking). In fact warmer than normal water accumulated off Ecuador through 7/2 (part of a continuous pattern that started in Jan 2012). And a pocket of blocking cold water that had been under the equator south of California the bulk of the past Winter (2011-2012) evaporated in April allowing warmer water to slowly but steadily pushing east into the vacuum (Kelvin Wave). This activity was the result of an Active Phase of the MJO (early April) and a continued weak MJO signal beyond, and appeared to be reinforcing itself. If one inspects the water temperature anomaly charts, through 7/2 an unmistakable El Nino-like pattern developed extending from south of Hawaii into Ecuador and extending north to Cabo San Lucas and south well into Chile. Updates through 8/6 indicated no effective change in the warmest anomalies occurring off Columbia, regardless of ongoing MJO phases. But the 8/9 and 8/16 updates did finally depict a slight reduction in warmest waters off Central America, the result of previous Inactive Phase activity. But they also depicted a modest increase in the coverage of the warm water pool, with it finally reaching up into Southern CA waters up to Pt Conception. But with no apparent reinforcements in the form of a Kelvin Wave forecast, and the Inactive Phase now in control, it seems possible continued erosion of the warm pool could occur. The preference is for a weak MJO pattern to continue (a sign of some flavor of El Nino, and preferably a weak multi-year event) and no Inactive Phases of any magnitude. In short, we'll be watching the actual data closely to see how close the projections track to it.   

Only limited atmospheric evidence of a possible El Nino pattern is in.cgiay right now (as of 8/12).  Remnants of La Nina are still affecting the atmosphere and will likely continue for several months if not into the middle of Fall. One such indicator is the continued presence of high pressure over the Eastern Pacific. It has been locked in.cgiace for 2 years now and is not going to be easily dislodged. Drought conditions over portions of North America are another indicator. The high continues to generate consistent/unrelenting north winds pushing down the California coast (the reason for non-stop windswell in Central CA) and stronger than normal trades over Hawaii. This is evidenced by a large pool of cooler than normal water radiating southeast off California and over Hawaii reaching the equator at the dateline, the result of enhanced upwelling.  Cooler than normal nearshore water remains an issue for much of the CA coast per the imagery, though periodic declines in nearshore north winds have occurred with some eddy flow working its way up into Central CA with water temps on the rise, but only to be beat back down as the high rebuilds and north winds regenerate. The presence of 3 hurricanes in mid-July in the East Pacific, and then subsequent weaker systems are all attributable to the warmer waters temps building near the equator and period Active MJO activity over that portion of the Pacific. But the larger picture still reflect La Nina. So in reality, we're in a hybrid atmospheric state. The longer the MJO remains biased towards a neutral or Active state, and the more warm water the builds off Central America, the more the atmosphere will respond (especially come Fall) turning more towards at least a neutral if not an El Nino-like configuration.  We remain on the bubble as of this date. Historical Note: It is unusual for El Nino (of any magnitude) to develop directly following 2 years of La Nina.            

As of right now its seems the Active Phases of the MJO are not doing much to usher in some flavor of El Nino, but the Inactive Phases are not quite strong enough to shut off the warm water buildup in the East either.  Regardless, where we are is better than where we've been for the past 2 years (under the influence of La Nina).    

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


South Pacific

Beyond 72 hours no swell producing weather systems are forecast. Another high pressure system at 1028 mbs to develop east of New Zealand on Fri (8/24) pushing down to 60S and continuing the lock on swell production through the weekend.

Details to follow...


External Reference Material: El Nino Southern Oscillation (ENSO), Madden Julian Oscillation (MJO), Pacific Decadal Oscillation (PDO), Southern Oscillation Index (SOI), Kelvin Wave

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Local Interest

Chasing 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:

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: 

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.   

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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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Surf Height-Swell Height Correlation Table


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