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Pacific Storm and Surf Forecast
Updated: August 22, 2010 4:40 PM
Buoys: Northern CA - Southern CA - Hawaii - Gulf of Alaska - Pacific Northwest
Buoy Forecast:
Northern CA - Southern CA - Hawaii - Gulf of Alaska - Pacific Northwest
Pacific Links:  Atmospheric Models - Buoy Data - Current Weather - Wave Models
Forecast Archives: Enter Here
A chronology of recent Mavericks Underground forecasts. Once you enter, just click on the HTML file forecast you want to review (e.g. 073199.html equals July 31, 1999). To view the maps that correspond to that forecast date, select the html file labeled 073199 maps.html
Swell Potential Rating = 4.8 - California & 1.5 - 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 8/23 thru Sun 8/29
Swell Potential Rating Categories
5 = Good probability for 3 or more days of Significant swell
4 = Good probability for 1-2 days of Significant swell
3 = Good probability for 3 or more days of Intermediate/Advanced swell
2 = Good probability for  1-2 days of
Intermediate/Advanced swell
1 = Good probability for 3 or more days of Impulse or Windswell
0 = Low probability for 1-2 days of Impulse or Windswell   

Southern Hemi Swell #6 On the Way to CA
Quiet Storm Pattern to Follow


New Swell Classification Guidelines (Winter)

Significant: Winter - Swell 8 ft @ 14 secs or greater (11+ ft faces) for 8+ hours (greater than double overhead). Summer - 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: Winter - Swell and period combination generating faces at head high to 1.5 times overhead (4-7 ft). Summer - 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. Summer - up to waist high swell. Also called 'Background' swell.

On Sunday (8/22) North and Central California was getting southern hemi swell in the chest high range with local windswell at exposed west doing at waist high with northwest winds on it early. Southern California was getting southern hemi swell up north at exposed breaks in the chest high range and reasonably clean and chest to near head high down south and clean but a little warbled and uneven. Hawaii's North Shore was flat and clean with piles of sand built up at all breaks. The East Shore was getting thigh to waist high tradewind generated east windswell with moderately chopped conditions. The South Shore was still getting limited and fading southern hemi swell with waves occasionally waist high though generally less and clean early with light trades in effect.  

The forecast for North and Central CA on Monday (8/23) is for reinforcing southern hemi swell moving in at 4.5 ft on the face with windswell still in water at 3.5 ft.  Then Tuesday real southern hemi swell starts arriving reaching 7.0 ft on the faces with larger sets to 9 ft late pushing 8-10 ft on Wednesday then dropping slightly to 7.5-9.0 ft Thursday fading more on Friday from 6 ft (faces).  Swell angle to be very southerly at 186 degrees with northwest windswell in the 3 ft range over the duration of the swell. Southern California is to see the same pattern less the windswell with southern hemi swell in the shoulder high range on Monday before the real swell hits on Tuesday reaching 7.5 ft range with 9.5 ft sets late then peaking out on Wednesday at 8-10 ft early, fading Thursday from 7-8 ft early and 6 ft on Friday morning. The North Shore of Oahu is to see no rideable surf for the next 7 days.  The East Shore to see short period east windswell at knee to thigh high Monday and Tuesday dropping to knee high Wednesday and Thursday then back to thigh high Friday on into the weekend. The South Shore is to see southeast angled southern hemi swell on Monday at at thigh to waist high early fading to thigh high Tuesday with perhaps some reinforcements from the southwest on Wednesday at thigh high then dropping to knee high Thursday before going flat.  

Up north no swell producing fetch is forecast over the next 7 days other than minimal local generated short period windswell for Central CA through the workweek, but building for the weekend as a strong pressure gradient sets up over Northern CA.  Down south the first of three southern hemi swell has hit. The second is expected produced by a larger system in the far Southeast Pacific Sun/Mon (8/16) producing 46-47 ft seas targeting South America excellently with decent energy pushing up into the US West Coast by Sunday (8/22) but from a very southerly angle. And yet a third system developed in the Southeast Pacific Mon/Tues (8/17) with up to 40 ft seas pushing due north.  Significant class Swell #6 from this system is expected into the US West Coast on Tues-Thurs (8/26) with lesser sideband energy into Hawaii as early as Mon (8/23). But beyond virtually no other swell producing weather system are expected to develop. 


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

North Pacific

On Sunday (8/22) the North Pacific jetstream was generally weak though cohesive tracking  just off the Northern Kuril Islands in the west, lifting north above the Aleutians Islands, the drifting south a bit tracking over the extreme northern Gulf of Alaska pushing into Oregon. Wind speeds did not exceed 110 kts and were far less over the dateline offering no support for development of gale strength weather systems at the oceans surface.  Over the next 72 hours the same basic pattern is to persist with weak troughs in the extreme west and east with a big ridge driving the jet up into the Bering Sea over the dateline and offering no real support for surface level gale development. Beyond 72 hours more of the same is expected but with a bit of a push of almost real energy occurring in the west (with winds to 120 kts there on Wed 8/25) but again being driven well to the north just east of the dateline then falling south down the US West Coast on Sun (8/29). This somewhat suggest that high pressure that has been lodged over the Central North Pacific might start pushing east and opening up the West Pacific some for business, but that is mostly just wishful thinking because no trough with winds of interest are forecast.

At the surface on Sunday (8/22) the same old broad area of high pressure at 1024 mbs remained locked over the Eastern Pacific centered 1000 nmiles north of Hawaii and ridging east almost to California and west well beyond the dateline. This was generating 15+ kt north winds down the Central CA coast making for messy conditions there and minimal northerly short period windswell, while also generating trades at 15 kts over the Hawaiian Islands also producing limited short period east windswell there along east facing shores. In short, unremarkable. Over the next 72 hours more of the same is forecast with the high ridging stronger into Cape Mendocino with winds there to 25 kts on Monday fading to 20 kts on Tuesday (8/24) setting up slightly larger windswell with the gradient itself pulling away from the coast making for better local conditions in Central CA. Trades to remain unchanged over Hawaii holding at 15 kts making for bare minimal east windswell pushing in east facing shores there.


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


California Nearshore Forecast
On Sunday (8/22) a generalized fetch of 15-20 kt north winds was blowing over Central and North CA outer and nearshore waters making a good bit of warble and only minimal short period windswell. On Monday (8/23) the gradient is to lift north and focus on Cape Mendocino with 20-25 kt north winds there, while pulling away from the Central CA coast. Windswell production to be on the upswing with conditions starting to improve south of there. The gradient is to hold over Cape Mendo into Wed (8/25) producing 20 kt north winds and minimal windswell but pulled away from the coast, allowing an eddy flow to take over Central CA waters.  Southern CA is to remain protected from any wind issues. A new ridge of high pressure is to build in starting Friday (8/27) with north winds building to 30 kts over Cape mendocino with 20 kt north winds pushing down to Pt Conception, just a bit off the coast. Windswell production likely but also chop and warble expected near shore over these locations.  The gradient is to hold into Saturday then quickly dissipate on Sunday as low pressure drops down the coast from the Pacific Northwest. Conditions expected to clean up some then, but windswell will be gone then too. Southern CA to remain unaffected by any of this.      


South Pacific

On Sunday (8/22) a very .cgiit jetstream pattern continued over the South Pacific with the largest divergence in the streams centered just southeast of New Zealand. This was driving a strong ridge southward in the southern branch pushing it effectively in land over Antarctica and sending the storm track over land as well, eliminating odds for gale development there. The jet gently lifting northeast into the extreme Southeast Pacific of the southern tip of South America, with something that almost resembled a trough in.cgiace there. Bu t it was well east of even the Southern CA swell window offering no odds for swell producing gale development. Over the next 72 hours the same pattern is to hold with a strong ridge in control of the west pushing the storm track over land (antarctica) and a bit of a trough just southwest of the southern tip of South America offering nothing in term of gale production for US interests. Chile is the most likely target for anything produced here. Beyond 72 hours reinforcements are forecast building in under New Zealand with the .cgiit flow and southwards tracking jetstream continuing if not stronger than current by Sun (8/29) offering absolutely nothing to support gale development at the oceans surface.

At the oceans surface high pressure, or at least the effects of high pressure in the upper reaches of the atmosphere were.cgiainly apparent with no gale forecast winds present from 130W all the way to New Zealand and beyond. In the extreme Southeast Pacific a gale was present with up to 40 kts southwest winds at 60S 120W all aimed at Chile. Nothing was pushing towards event Central America. Over the next 72 hrs no change is forecast with virtually no gale forecast winds forecast in the Central and West Pacific as a major ridge continue to dominate the weather pattern there. Likewise weak low pressure is to persist in the upper trough just west off the southern tip of South America, well east of the CA swell window, but offering some moderate potential for swell production heading towards Chile.

In short, no swell producing fetch is forecast for our forecast area. 


Second Gale
On  Sat/Sun (8/15) yet another gale formed in the far southeast Pacific generating 40-45 kt southwest winds.  Seas were modeled to 42 ft Sunday Am at 45S 115W building to 47 ft in the evening at 44S 105W and then fading from 46 ft at 43S 100W Monday AM.  All this was outside the California swell window, though some fragments of energy from early in this systems life invariably pushing up the great circle paths to the north. This is really a reach of a forecast given the limited data available. Also ASCAT wind data was not conclusive. In reality, whatever swell was generated will appear as a second pulse of the First Gale swell (above).  No energy from this system was in the Hawaii swell window.     

 South CA:  Expect swell arrival at sunset on Saturday (8/21) with pure swell reaching 2.3 ft @ 18 secs (3 ft faces).  Swell to peak on Sunday (8/22) at 2.6 ft @ 16-17 secs (4.0-4.5 ft faces), dropping from 2.6 ft @ 15 secs (4 ft faces) on Monday (8/23).  Swell Direction: 188 degrees

North CA:  Expect swell arrival at sunset on Saturday (8/21) with pure swell reaching 1.6 ft @ 18 secs (2.5 ft faces).  Swell to peak on Sunday (8/22) at 2.3 ft @ 17 secs (4.0 ft faces), dropping from 2.6 ft @ 16 secs (4 ft faces) on early Monday (8/23).  Swell Direction: 185 degrees  


Storm #6S
On Monday AM (8/16) a gale produced 40-45 kt south winds at 50S 142W fading to 35-40 kts at 44S 132W on Tuesday AM (8/17) resulting in peak seas of 40 ft at 18Z on Tuesday at 43S 132W fading to 38 ft in the evening at 40S 130W.  The good thing about this system is all fetch was aimed due north, directly up the 187 degree path to NCal and the 191 degree path to SCal.  There even some potential for sideband swell to directionally spread west into the Hawaiian swell window up the 165-170 degree track. Significant class well is heading north towards the US west coast with this likely being the biggest swell of the summer.

Hawaii: Even some small swell is to reach into Hawaii for Monday (8/23) with pure swell 1.6 ft @ 18 secs (3 ft faces) from 170 degrees lingering into Tuesday. 

Southern CA: expect swell arrival on Mon (8/23) with period 20 secs and size tiny but building maybe reaching 2 ft @ 20 secs late (4 ft faces). Swell to peak at sunset on Tues (8/24) pushing up to 4.6 ft @ 17 sec (7.8 ft faces with sets to 10 ft).  Swell to be holding on Wednesday at 5.2 ft @ 16 secs (8.5 ft faces with sets to 10.5 ft and bigger at top spots).  Swell to be settling down on Thursday with swell 4.8 ft @  14-15 secs (7 ft faces) and fading through the day. Swell Direction:  190 degrees.

Northern CA: Expect swell arrival on Mon (8/23) with period 21 secs and size tiny but building maybe reaching 1.6 ft @ 21 secs late (3.5 ft faces), building through the day Tues (8/24) pushing up to 4.2 ft @ 18 secs late (7.6 ft faces with sets to 10 ft).  Swell to be maxing on Wednesday at 5.0 ft @ 16-17 secs (8.5 ft faces with sets to 10.5 ft and bigger at top spots).  Swell to be settling down on Thursday with swell 4.8 ft @ 14-15 secs (7 ft faces) and fading through the day. Swell Direction: 187 degrees.


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




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

North Pacific

Beyond 72 hrs high pressure is to regenerate in the Gulf of Alaska to 1032 mbs and surging a bit to the east ridging into North CA by Friday (8/27) with 30 kt north winds building over Cape Mendocino and holding through Saturday with lesser winds pushing into the coast down to Pt Conception.  Larger local windswell is expected to build into Central CA at that time, then decaying Sunday (8/29) as the gradient dissipates though north winds are to continue along the coast. Trades to remain pretty weak over Hawaii through the week and weekend (8/29) holding at 15 kts producing minimal local short period windswell there. 

MJO/ENSO Update (
reference):   As of Sunday (8/22) the Southern Oscillation Index (SOI) continued solidly in the positive range. The daily SOI was holding at 24.16 and has been that way in excess of 34 days. The 30 day average was up to 19.36 with the 90 day average up to 12.40.  The Inactive Phase of the MJO was in full control.  

Wind anomalies as of Sunday (8/22) at the 850 mb level (approx 5000 ft up) as defined by models indicated the Inactive Phase was in full effect with anomalous east winds blowing hard over the Philippines and extending east midway between South America and the dateline and west to a little beyond India. This pattern is to start moderating with easterly anomalies extending over the dateline barely reaching mid-way to Central America on 8/24 and decaying steadily after that. East anomalies are to totally fade out by Sept 3, but with absolutely no signs of a much needed Active Phase developing. 

We believe the remnants of El Nino are just about gone from the upper atmosphere. The expectation is that we'll fall back into some form of a moderate La Nina Pattern (where the Inactive Phase takes control) for later 2010 into 2011. NOAA seems to support that.cgian too per the latest ENSO update. 

Sea Surface Temp anomaly data (8/19) indicates that cooler than normal waters continue to expanded their grip on the equator covering solidly from South America west to the dateline and beyond are in fact getting cooler and covering a larger area over time, extending the whole way to almost New Guinea.  It remained  downright cold just off Ecuador and then from a point south of Hawaii to just west of the dateline, a clear signal of strong easterly winds there and solid upwelling. Feeder bands of much colder than normal water continued building off the US West Coast and South America reaching to the dateline, only serving to reinforce the existing pattern, suggesting stronger than normal high pressure has built in both hemispheres and upwelling is in full effect. Good for sea life and the food chain, bad for storm production. Looks like a classic La Nina setup. This is a turn for the worse and only seems to be getting stronger. At the same time a massive buildup of warmer than normal waters continues in the Atlantic almost bleeding into the far Eastern Pacific, of concern to hurricane forecasters there. We'll see if upper level winds support development of hurricane activity or whether residual upper level shear from El Nino will chop the tops of developing systems. Suspect shear will be gone by the heart of hurricane season in the Atlantic.

Below the surface on the equator no Kevin Wave activity was present and if anything colder than normal water was building strong over the dateline and pushing east (sort of like a cold Kelvin Wave). This pocket was -5 degs below normal (getting colder). Not good. 

Over the entire Equatorial Pacific trades were blowing all the way to the Philippines and beyond, with easterly anomalies now in control of the entire Western Pacific, though normal conditions in the East. But the Pacific current that runs along the equator turned abruptly from flowing to towards South America to flowing towards the west in mid-March (2010), right as the SOI started it's impressive drive into positive territory and the storm machine abruptly shut down. And it has not wavered since.  This suggests trade wind anomalies might be a byproduct of the Pacific equatorial current change and not the other way around.  And if anything, the change in the current might actually foretell a coming change in the trades, and then with the advent of the trade wind change, it only serves to reinforce the current in a self a.cgiifying loop, until such time as the cycle runs it's course and the self feeding system collapses over a multiyear period. At that time the current then switches direction, and a whole new self-enforcing cycle stars anew. Something to consider (regarding the formation and El Nino/La Nina).     

El Nino is effectively gone and slowly losing it's grip on the global upper atmospheric weather pattern. Still some lingering impact might continue through the Summer of 2010, but likely not enhancing the  storm track in the South Pacific any longer. A slow transition to a normal if not cooler than normal conditions (La Nina) is expected through Nov 2010, and the signs continue to point to a La Nina pattern for the long term future. 

See more details in the   El Nino update.


South Pacific

Beyond 72 hours there is no indication of any swell producing weather systems forecast for the Southern Hemisphere for the next 7 days. 

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

Interview with Stormsurf: Coastviews Magazine has written up a very nice article on Stormsurf in their latest edition. You can read it here:

Stormsurf Hi-Res Coastal Precipitation Models Upgraded Though a bit late in the season, on 3/20 we i.cgiemented the same basic technology used in our new snow/ski models into the coastal hi-res precipitation models. So now you can not only determined whether rain is forecast for your area, but also snow. And not just light, medium or heavy snow like most sites, but the exact snowfall amount (in inches) for each 3 hr frame of the animation. Here's a sa.cgie, but now this approach is used in all our precipitation models.

Stormsurf Precip Models Upgraded! On 2/20 we upgraded some of the broader precipitation models driven by the hi-def GFS model to include snow fall. The algorithm used is similar to the recently released snow models for the Southwest US in that the areas where snow is expected are identified and the exact amount of snow forecast over a 3 hr window is e.cgiicitly color coded. For East and West Coast US interests the following links provide good exa.cgies:
West Coast:
East Coast:

Stormsurf Weather Models have all been upgraded! Over the New Years break we installed all new and upgraded weather models. Also new are experimental snow models for the Southwest US. Take a look here:

Read about Eric Nelson and Curt Myers, the makers of Ride-On and other Big Wave Surf Movies here:

Ride On! Powerlines new big wave epic is now available on DVD. Get the entire big wave story of the 2008-2009 season here:

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Interview With Stormsurf:  The crew at worked with Stormsurf on a feature about why surfers should be able to read wave charts themselves. They are firm believers that a little learning can go a long way to help your surfing.  This is a great article to help convince your friends that they can benefit from being able to read the data themsleves rather than just relying on the forecasts of others.  See the full thing here:  Create Your Own Surf Forecast with Stormsurf

Wave Model Upgrade Status Report: At this point we believe the installation of the new wave models is complete, with no problems being reported, the server stabilizing and the much requested return of the old style hemispheric Surf Height models now operational (again) and running side-by-side along the new ones. We thank you for your patience and input as we went though this process.  Your feedback helps guide our efforts and ultimately results in a better product for everyone.  Now we're off to start providing better menus to some wave model products most of you probably haven't uncovered yet (site specific graph and text forecasts), updateing the wave model FAQs and then upgrading the Weather Models.  

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

Story About Stormsurf: The folks at SurfPulse (and specifically author Mike Wallace) have written up a really nice article about Stormsurf, complete with some good pics. Learn about how we came to be and a little of where we are going. Check it out here:

Stormsurf Video: Just for fun - here's a clip about Stormsurf that ran on Bay Area TV a while back. Thought you might enjoy it:

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.

Need Chiropractic Help? Visit our friends at Darrow Chiropractic. Not only will Dr. Darrow fix you up, he might give you some big wave surfing tips too! See more here:

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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