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Pacific Storm and Surf Forecast
Updated: May 9, 2010 4:26 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   

Windswell to Rebuild for CA
Southern Hemi Swell On the Way for Later


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 (5/9) North and Central California was getting no rideable surf but local wind was down some and out of the west, at 5 kts. Southern California was getting very local northerly windswell with surf thigh high high on the sets up north and warbled early. Down south the windswell was pushing waist high with onshore winds and pretty hacked. Hawaii's North Shore was flat. The East Shore was getting chest high .cgius east windswell and chopped. The South Shore had some thigh high sets and was clean. 

The forecast for North and Central CA is for no windswell Monday but maybe thigh high background southern hemi swell easing in, with windswell building on Tuesday to head high or a little more, hovering to head on Wednesday then fading to shoulder high Thursday and holding into Friday with a little more period. Southern California is to see minimal southern hemi swell at thigh high on Monday fading out later on Tuesday. Thigh high north windswell is expected for Wednesday and Thursday fading Friday while new southern hemi swell moves in. The North Shore of Oahu is to remain effectively flat till Wednesday when a little pulse of dateline windswell arrives to chest high holding into Thursday then drops out. The East Shore to see east tradewind generated windswell at chest to head high Monday then chest high Tuesday and holding there through the workweek. The South Shore is to remain in the flat zone for the week. 

Summer has settled into the North Pacific with nothing other than local north windswell for CA and tradewind generated east windswell for Hawaii for the future. A weak gale did develop over the dateline Sunday (5/9) setting up windswell for the North Shore midweek (chest high), but that's it. Down south a gale developed in the far Southeastern Pacific Fri (5/7) with up to 36 ft seas with some energy now expected to push north, through the focus remains South America. More is forecast behind that too with another smaller gale forecast pushing northeast off New Zealand on Tues/Wed (5/12) with 30 ft seas followed by a bigger one in the deep southeast Pacific on Fri-Sun (5/16), though most energy from this one is to be aimed east. Still, some swell might push north from it. At this point it looks like it's all southern hemi swell from here on out.


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

North Pacific

On Sunday (5/9) the North Pacific jet remained reasonably consolidated running generally flat east on the 43N latitude. A weak trough was on the dateline with another trying to push into Northern CA. Winds in both troughs were 130 kts and the trough themselves were only small. Limited support for gale development possible from the dateline trough. Over the next 72 hours a short lived ridge is forecast building and pushing through the Gulf of Alaska, while the rest of the just settles even further south, down around 38N. But wind speeds are to be very light and no troughs are forecast. Beyond 72 hours a fairly energetic trough is forecast forming just off Japan on Fri (5/14) with 150 kt winds developing east of there building into a ridge over the dateline and then falling into a decent sized trough off the US West Coast Sat/Sun (5/16) providing decent odds for gale development there if all goes as.cgianned (unlikely).

At the surface on Sunday (5/9) high pressure at 1028 mbs remained locked 1200 nmiles off Central CA with weak low pressure pushing over the North and Central CA coast. No swell producing fetch was indicated. But the high was generating trades at near 20 kts over the Hawaiian Islands, producing east short period windswell there. Low pressure that was off the Kuril Islands migrated to the dateline on Sunday starting to generate a fetch of 30-35 kt northwest winds at 40N 180W expected to hold till the evening at 37N 174W with 16-18 ft seas resulting.  Weak windswell to make it to Hawaii by Wed (5/12) afternoon with luck at 4 ft @ 11-12 secs (4.4 ft faces). Over the next 72 hours a weak low pressure system is to develop off Oregon on Mon (5/10) pushing into North CA on Tuesday with high pressure building in right behind it, setting up another north wind event there Wed/Thurs with winds 25 kts generating localized short period windswell. Trades to continue over Hawaii with limited east windswell resulting.


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


California Nearshore Forecast
On Sunday (5/9) high pressure at 1028 mbs was north-northeast of Hawaii but pulled away form the CA coast with weak low pressure trying to move into the Central CA area. Even a few drops of rain were falling in the San Francisco Bay area, enough to get the pavement wet. Another stronger low is forecast forming off the Oregon coast Monday and moving into the area late Mon/early Tues with better odds for rain then and even snow accumulations in Tahoe. But high pressure is to be ridging into Southern CA on Monday with northwest winds in control, though light winds early up into Central CA. High pressure is to be building in behind the low in Central and North CA later Tuesday evening (5/10) with north winds back to 25+ kts focused on Southern CA, then 25 kts Wednesday but focused more on Central CA barely holding into Thursday (5/13). Wind is to be dropping from 15 kts over Central CA on Friday and fading in Southern CA. A light wind regime is expected for the weekend with low pressure off the coast.


South Pacific

On Sunday (5/9) no swell producing fetch of interest was occurring in the South Pacific. Over the next 72 hours the models indicate another small gale might be pushing east 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 is to take a more northeasterly track with only 35 kt winds resulting in 30 ft seas at 50S 165W holding into the evening and pushing even more to the northeast with 30 ft seas at 46S 160W on the 205 degree track to California and in the middle of the Tahitian swell shadow relative to CA. The gale is to be fading and tracking even better to the north on Wed AM with a small area of 30 ft seas at 42S 155W pushing up the same heading relative to CA and shadowed. Given the weak wind speeds, the 30 ft sea estimate put forth by the models seems unlikely. 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). Will monitor.


Southeast Pacific Gale
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: Rough data suggests 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: 190-193 degrees

Northern CA: Rough data suggests 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: 190 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 to fade off California Friday (5/140 with another weak lo pressure system setting up in the Eastern Gulf and holding through Sunday (5/16). The low is to not have any fetch of interest associated with it, but it should reduce north winds to almost nothing in CA. Trades to back off over Hawaii next weekend too reducing the odds for east windswell there.

MJO/ENSO Update (reference): As of Sunday (5/9) the Southern Oscillation Index (SOI) was hovering near zero. The daily SOI was at 8.60.  The 30 day average down to 8.92 with the 90 day average up to 0.48. 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 here. It is scheduled to push hard east into 5/13 and be exiting over Central America 5/18. This signals the end of El Nino and eliminates any support for gale development. The Active Phase is forecast brewing behind it, stronger yet again than previous runs of the model reaching the dateline on 5/18, then slowly fading while pushing east towards Central America on 5/28. 

At this point we belie 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 (5/69) 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 solid gale forming in the deep Central Pacific on Friday with a solid area of 45 kt south winds at 58S 159W moving quickly east in the evening to 61S 138W with fetch taking more of a northeast tilt, then dissipating. Seas forecast in the 38 ft range. It's way too early to make any pronouncements yet about this system.

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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