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Pacific Storm and Surf Forecast
Updated: May 13, 2010 9:46 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 5/10 thru Sun 5/16
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   

Swell #5S Moving Into CA
More Behind It and a Tease from the North Pacific Models


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 Thursday (5/13) North and Central California was getting more small local windswell with waves maybe to chest high and pretty warbled. Southern California was getting local northerly wrap-around windswell with surf thigh high and heavily textured up north but clean down south. Hawaii's North Shore had some chest high sets coming from the dateline and clean. The East Shore was getting chest high east windswell and chopped. The South Shore had some thigh high tradewind generated wraparound sets and clean. 

The forecast for North and Central CA is for slowly fading northwest windswell at chest high Friday fading to less than chest high Saturday and waist high Sunday then dropping out. Southern hemi swell is also forecast at 1 ft overhead Saturday, head high Sunday and fading from chest high early Monday.  Southern California is to see knee high north wrap around windswell Friday and fading out while new southern hemi swell moves in Friday at 1 ft overhead holding on Saturday then fading from head high Sunday and chest high Monday. The North Shore of Oahu is to see no rideable swell through the weekend into at least the early part of next week. The East Shore to see east tradewind generated windswell holding at head high Friday, then settling down to chest high for the weekend into early Monday, and down from there. The South Shore to maybe see a pulse of southwest background swell to thigh high on Sunday then dropping off to nothing for several days. 

The models continue hinting a a local gale off Oregon by Sunday, with maybe 30 kt northwest winds and 15 ft seas aimed well at the Central CA coast, maybe good for some 11 sec period windswell early next week. And a bigger/stronger gale is forecast up in the Northern Gulf dropping southeast Mon-Wed (5/19) with 35 kt winds and up to 25 ft seas late Tues (5/18).  Will see what really happens. Some sideband swell might push into the Islands though CA see the best bet. Down south a gale developed in the far Southeastern Pacific Fri (5/7) with up to 38 ft seas with some southern hemi energy now expected to push north reaching CA for the weekend. More is forecast behind that too with another smaller gale having formed northeast off New Zealand on Tues/Wed (5/12) with 30 ft seas and possible swell for Hawaii and the US West Coast.  And the models continue to suggest a strong system in the deep southeast Pacific on Fri-Sun (5/16) with seas pushing 46 ft aimed pretty well to the north. Possible larger swell if one is to believe the models. 


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

North Pacific

On Thursday (5/13) the North Pacific jet was holding together pretty well tracking from off Japan down at 30N then east-northeast up into the Central Gulf of Alaska, before diving back south along the California coast then pushing inland over Northern Baja. No real wind velocity was occurring except off Japan where a ridge was building with winds to near 140 kts and offered no indication of supporting gale development at the oceans surface. Over the next 72 hours the same basic pattern is expected with the Japan ridge pushing over the dateline and into the Gulf of Alaska with winds up to 170 kts.  A bit of a trough is to start carving out in the Gulf of Alaska on Saturday (5/15) and continuing through the weekend offering increased odds for gale development there. Beyond 72 hours that trough is forecast holding  off the Pacific Northwest into Wed (5/19) providing decent odds for gale development there if all goes as.cgianned.  This trough to push into North CA on Fri (5/21).  Another weaker tough is forecast forming on the dateline at that time too.    

At the surface on Thursday (5/13) the same old high pressure system at 1028 mbs was positioned 700 nmiles west of Southern CA with weak low pressure inland producing a modest pressure gradient over coastal waters and generating 20 kt north winds resulting in limited north windswell there.  The high was also generating trades at 20 kts pushing up to but not over the Hawaiian Islands, producing east short period windswell there. A rather vigorous gale was just off Japan with 35 kt west winds and 26 ft seas, but a long way away from even Hawaii. Maybe some impulse class swell at 14 secs could result for the Islands with luck later next week. Otherwise another high pressure system was over the dateline pretty much locking things down locally. Over the next 72 hours high pressure off the CA coast is to fade some with north winds backing off. A weak low pressure system remains forecast setting up in the Eastern Gulf Saturday with up to 30 kt north winds aimed south of CA, then fading while moving closer to CA on Sunday (5/16). Seas forecast to 15 ft on Sunday AM (5/16) at 43N 135W aimed well at the Central CA coast and possibly setting up 11 sec period windswell for Tues or so.  That gale is to dissipate off the Oregon coast Monday and never reach shore.  Trades to continue near Hawaii but positioned more to the south than days past, limited eastward moving windswell.


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


California Nearshore Forecast
On Thursday (5/13) high pressure was slowly loosing it's grip over the Eastern Pacific but not completely with 20 kt north winds still in.cgiace over outer waters  generating nearshore bump and lurp. Wind is to be dropping from 15 kts over outer Central CA waters on Friday and down to 10-15 kts Saturday with an even lighter wind regime expected by Sunday courtesy of low pressure trying to build off the North CA coast. It is to dissipate with more light northwest winds at 5 kts forecast Monday into Tuesday (5/18).  A stronger gale is forecast building in the Gulf of Alaska, suppressing winds locally into maybe early Thursday (5/20).  But as soon as that low pressure system moves out of the area, high pressure is forecast moving back in with north winds on the increase, likely by Friday.  


South Pacific

On Thursday AM (5/13) the models indicate another broad and decent strength gale was forming in the deep Central Pacific with 45 kt southwest winds at 58S 162W pushing pretty quickly east.  By evening a large fetch of 40-45 kt south -southwest winds are to be positioned at 53S 150W generating 35 ft seas at 53S 150W.  On Friday AM a solid area of 40-45 kt south winds are forecast at 55S 150W aimed right up the 196 degree path to Southern CA with sideband swell up the 178 degree path to Hawaii.  36 ft seas are forecast at 50S 145W.  In the evening stronger 45-50 kt south-southwest winds are to build over a larger area again aimed well to the north at 59S 140W over the same area as before producing a large area of 36 ft seas at 53S 140W.  That fetch is to hold and lift a bit north Sat AM (5/15) with 45 kt south winds at 57S 135W pushing up the 188 degree path to CA with 44 ft seas at 55S 135W.  Fetch is hold solid in the evening at 52S 130W with 46 ft seas at 51S 131W. 40-45 kt southwest winds to fade on Sunday AM (5/16) with 44 ft seas fading at 46S 124W.  

If all this comes to pass some decent degree of south angled southern hemi swell would seem likely for California with sideband energy into Hawaii. Will monitor. 


Southeast Pacific Gale (Storm #5S)
Previously a gale organized, winding up in the far Southeast Pacific late Thurs (5/6) tracking east-northeast resulting in a fetch of 45 kts southwest winds on Thurs PM at 52S 137W aimed 35 degrees east of the 189 degree path to California with seas 35 ft at 52S 138W. The Jason-1 satellite passed directly over this area and confirmed a 15 reading average of 30.5 ft with one reading to 35.8 ft, lower than what the model suggested. On Friday AM fetch held with 40 ft with seas modeled peaking at 51S 128W. 36 ft seas were fading Fri PM at 47S 123W. 

The models looked pretty good on this one, but there was no confirmation that the 40 ft seas forecast actually materialized. And if anything, the limited confirmed data available suggested something less. Still, it appears that some degree of decent swell might radiate north into California, though most energy is to be focused on Central America down into South America. The forecasts below are using the modeled data,.but are likely on the high side (optimistic)

Southern CA: Expect swell arrival on Friday (5/14) with swell to 3.3 ft @ 18 secs late (6 ft faces with top spots to 7.5 ft). Swell to continue decent on Sat (5/15) with pure swell 3.3 ft @ 16 secs (5.0 ft faces with top spots to 7 ft). Swell to be dropping on Sunday from 3.0 ft @ 15 secs early (4.5 ft faces). Swell Direction: 186-189 degrees

Northern CA: Expect swell arrival Friday afternoon (5/14) with swell to 3.0 ft @ 19 secs late (5.5 ft faces with top spots to 7.0 ft). Swell to continue decent on Sat (5/15) with pure swell 3.3 ft @ 18 secs (6.0 ft faces with top spots to 7.5 ft). Swell to be dropping on Sunday from 3.0 ft @ 16 secs early (5 ft faces with top spots to 6 ft). Swell Direction: 183-186 degrees

New Zealand Gale
A gale formed under New Zealand on Mon (5/10) with a small area of 40 kt west-southwest winds producing 30 ft seas. By Tuesday AM the gale was taking a more northeasterly track but with only 35 kt winds at 50S 160W resulting in 30 ft seas at 49S 160W.  In the evening 35-40 kt south winds continued at 43S 157W and pushing even more to the northeast with up to 32 ft seas at 45S 156W on the 203 degree track to California and in the middle of the Tahitian swell shadow relative to CA. The gale was fading and tracking even better to the north on Wed AM (5/12) with a small area of 35 kt winds and barely 30 ft seas at 42S 151W pushing up the same heading relative to CA and shadowed. This system faded after that. 

Given the weak wind speeds, the 30 ft sea estimate put forth by the models seems like a best case scenario. Still some degree of limited support for small scale swell is possible in CA. But Hawaii looks to be better positioned, with energy pushing unshadowed up the 180-185 degree tracks. And Tahiti will do even better, especially considering the close proximity of this system (1400 nmiles out).  

Hawaii: Expect swell arrival in Hawaii on Tuesday (5/18) with pure swell 2 ft @ 17 secs (3.0-3.5 ft faces) and holding.  Swell to continue on Wednesday (5/19) at 2.0-2.3 ft @ 14 secs (3.0 ft faces) and fading as the day progresses.  Swell Direction:  185 degrees.  

Southern California:  Expect swell arrival on Wednesday afternoon (5/19) with pure swell 1.6 ft @ 18 secs (2.5-3.0 ft faces) peaking Thursday at 2.3 ft @ 16-17 secs (3.5-4.0 ft faces).  Swell Direction: 208 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 the gale currently off Japan is to race northeast and start re-developing in the Northwestern Gulf of Alaska on Sunday (5/16) with 35 kt northwest winds forecast at 52N 165W dropping southeast and still near 35 kts mid-Tuesday (5/18) at 45N 155W aimed well up the 295 degree path to Central CA.  Seas forecast up to 25 ft at that location then. This system to continue southeast into mid-Wednesday with winds still 30 kts and seas to 21 ft at 38N 147W  then fading out. Larger swell possible for CA with sideband swell seeping south into Hawaii, but odds are low at this early date. 

MJO/ENSO Update (reference): As of Thursday (5/13) the Southern Oscillation Index (SOI) was hanging around neutral territory. The daily SOI was at -6.72.  The 30 day average was down to 7.78 with the 90 day average up to 1.84.  A massive upward trend started in early March, peaked at the end of April, and is now loosing ground. This looks like the transition from El Nino to a neutral state.  

Wind anomalies at the 850 mb level (approx 5000 ft up) as defined by models suggest moderate easterly anomalies filling the entire equatorial Pacific basin, indicating the Inactive Phase is still in control. It is scheduled to push hard east into 5/15 and be exiting over Central America 5/22. This signals the end of El Nino and eliminates any support for gale development. The Active Phase is forecast brewing behind it, and is fairly strong in the Indian Ocean as of 5/12.  It is to reach the dateline on 5/20, then slowly fading while pushing east towards Central America, but still influencing a large area of the North Pacific on 6/1. Maybe some support for gale development from this Active Phase of the MJO when it happens. But it will be pretty late in the season to see much if any impact.    

At this point we believe that El Nino will not hang on for another year, and that rather we'll fall back into at least a neutral pattern if not a La Nina Pattern (where the Inactive Phase takes control). Of other interest will be whether the Iceland Volcano will spew enough high level fine particle dust and aerosols into the atmosphere to produce a reflective effect, dropping surface temperature and pushing us into a multi-year La Nina.  This is a very real concern.  

Sea Surface Temp anomaly data (5/9) indicated no dramatic change from previous weeks, with warmer than normal waters consolidated on the equator with a new pocket of warmer water off Ecuador and the Galapagos Islands, fading some south of Hawaii and then regrouping the in the West Pacific. A massive buildup of warmer than normal waters is occurring in the Atlantic, of concern to hurricane forecasters there. We'll see if upper level winds support development of hurricane activity though. Suspect residual upper level shear from El Nino will have an impact well into the summer there.

Below the surface on the equator no Kevin Wave activity was present and if anything colder than normal water was building over the dateline and pushing east. Not good.. 

Over the entire Equatorial Pacific trades were blowing all the way to almost the Philippines, but only in the normal range. This looks like the normal Springtime transition typical for this time of the year. 

El Nino is effectively gone and slowly loosing it's grip on the global atmospheric weather pattern. Still some lingering impact is to continue into the Summer of 2010 enhancing the storm track in the South Pacific some. A slow transition to a normal state is expected through Nov 2010. 

See more details in the new  El Nino update.


South Pacific

Beyond 72 hours the models indicate another broad and decent strength gale is to form in the deep Central Pacific on Thursday AM (4/13) with 45 kt southwest winds at 55S 158W pushing pretty quickly east and positioned at 57S 143W in the evening. 35 ft seas are forecast building at 55S 150W.  On Friday AM a solid area of 40-45 kt south winds are forecast at 60S 140W aimed right up the 190 degree path to Southern CA with sideband swell up the 178 degree path to Hawaii .  35 ft seas forecast at 50S 145W.  In the evening 45 kt winds to build over a larger area again aimed well to the north at 60S 140W over the same area as before producing a large area of 36 ft seas at 57S 140W.  That fetch is to hold a lift north Sat AM (5/15) with 45 kt south winds at 57S 135W pushing up the 188 degree path to CA with 42 ft seas at 55S 135W.  Fetch is hold solid in the evening at 52S 132W with 43 ft seas at 50S 133W. 40-45 kt southwest winds to fade on Sunday AM (5/16) with 42 ft seas at 46S 126W.  If all this comes to pass some decent degree of  south angled southern hemi swell would seem likely for California with sideband energy into Hawaii. 

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

A Luau for the Wave Riders is presented by the HMB Surf Club (an affiliate of the Boys and Girls Cub of the Coastside). All proceeds will benefit the HMB Middle and High School Surf Teams. Date: Saturday the 8th of May 2010 at 6pm Location: Sea Crest Gym at 901 Arnold Way, Half Moon Bay, CA. Cost: $40.00 per person [tickets purchased after May 1st $50], $25.00 per kid (12 and under) For more information or to purchase tickets,.cgiease contact Paula (email: or call: 650-269-3180)

  • 6:00pm - Appetizers
  • 7:30pm - Buffet Dinner
  • 8:30pm - Live Music by, Blame it on the Dog
  • Cash Bar- Beer & Wine
  • Raffle & Silent Auction

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:

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:

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

North California Surf Report Works Again: After an extended downtime we finally got the North California Surf Report working again. Thanks for your patience. See it here:

Shark Video: Our friend Curt Myers of Powerlines productions shot this footage of 2 great whites munching on a whale carcass off Devils Slide (south of San Francisco) on Thursday. Kind of interesting to watch. Check it here: (Fixed link)

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.

Stormsurf Wave Models Updated: On Friday (2/6) we installed the latest upgrade to our wavemodels. A year in the works, this upgrade essentially is a total re-write of every wave model product we produce. They now take advantage of the new Version 3 of the Wavewatch wavemodel. This version runs at a much higher resolution, specifically 0.0 X 0.5 degrees for the global grib with local products at 0.1667 X 0.1667 degrees, and it uses the hi-res GFS model for wind speeds. And of even more interest, the model now identifies primary swell and windwave variables. As such we now have new model images which displays this data. Also we've included out special 3D topographic land masks into all models. In all it makes for a radical step forward in wave model technology. We'll be upgrading minor components (FAQ, new menu pages etc) for a few weeks to come, but all the basics are available for your use now. Check it out here:

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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