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Pacific Storm and Surf Forecast
Updated: May 6, 2010 9:43 PM
Buoys: Northern CA - Southern CA - Hawaii - Gulf of Alaska - Pacific Northwest
Buoy Forecast:
Northern CA - Southern CA - Hawaii - Gulf of Alaska - Pacific Northwest
Pacific Links:  Atmospheric Models - Buoy Data - Current Weather - Wave Models
Forecast Archives: Enter Here
A chronology of recent Mavericks Underground forecasts. Once you enter, just click on the HTML file forecast you want to review (e.g. 073199.html equals July 31, 1999). To view the maps that correspond to that forecast date, select the html file labeled 073199 maps.html
Swell Potential Rating = 1.0 - California & 2.0 - Hawaii
Using the 'Winter' 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 5/3 thru Sun 5/9
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   

Possible Gale Forecast Down South
Windswell to Drop Off In CA for a While


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 (5/6) North and Central California was getting local northwest windswell with waves chest high and almost clean but still quite warbled and junky. Southern hemi swell was chest high at select breaks. Southern California was getting wrap around local windswell with surf maybe thigh to waist high high on the sets up north and reasonably clean early. Down south southern hemi swell was pushing shoulder high and up to head high at top spots and reasonably clean. Hawaii's North Shore was effectively flat and clean. The East Shore was getting waist high east windswell and chopped. The South Shore had some thigh high combo tradewind sets and background southern hemi swell and clean. 

The forecast for North and Central CA is for windswell to drop out to knee high Friday with southern hemi swell fading from shoulder high. Thigh high windswell expected on Saturday with southern hemi swell dissipating. No real rideable surf forecast Sunday, then more windswell moves in for Monday at chest high and waist high Tuesday hovering there or maybe a little bigger beyond. Southern California is to see southern hemi swell fading to chest high on Friday and waist high Saturday. Nothing on Sunday then maybe new thigh high southern hemi swell on Monday fading out on Tuesday. The North Shore of Oahu is to remain effectively flat through Tuesday. The East Shore to see east tradewind generated windswell at chest to head high Friday, then near chest high Saturday and a little less Sunday drifting down from there to waist high Tuesday.  The South Shore is to fall into the flat zone southern hemi wise on Friday and stay there. 

High pressure remains in control of the Northeast Pacific with local junky north windswell and poor conditions forecast for Central CA for the foreseeable future. A weak gale is forecast over the dateline Sunday (5/9) possibly setting up really small swell for the North Shore midweek (waist high or so). Otherwise no swell producing weather systems are forecast for the North Pacific. Down south a new gale is forecast in the far Eastern South Pacific developing on Fri with up to 36 ft seas, but the focus is to be South America with only a little energy tracking to the north. In all, a really quiet pattern is taking hold, and quite a letdown from the pumping surf of just a few months ago. 

Closing day for Squaw Valley is Sunday (5/9) with a 168 inch base still in.cgiace up top (that's 14 ft)!   539 cumulative inches of snow fell up top for the season, surpassed only by the 628 inch accumulation in 2005/2006 (looking back since the big El Nino winter of 97/98'). That much snow really opens up a lot of terrain that otherwise would be a rock field.  Will likely be years till we see another season like this one.  All hail El Nino for both snow and surf! 


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

North Pacific

On Thursday (5/6) the North Pacific jet was consolidated running generally flat east on the 40N latitude with a cutoff low up in the Bering Sea. Wind speed were mostly less than 100 kts over it's width. A hint of a trough was starting to appear on the dateline with 120 kt winds flowing down into it, providing the only hope that a gale could form there. Over the next 72 hours that area is to develop into a semi-real trough with 150 kt winds flowing down into it briefly Friday then moderating into Saturday while it pushes east of the dateline.  Decent support for gale development there.
Also a small trough is  to build just off the California coast pushing inland on Sun (5/9) maybe supporting some rain there.  Beyond 72 hours remnants of the dateline trough are to fade and lift northeast into the Gulf of Alaska and into Canada on Wed/Thurs (5/13). The general trend after that is fore the jet to follow that lead, starting down around 40N off Japan and pushing northeast up into Northern Canada with low energy levels and no obvious troughs capable of supporting largescale gale development. 

At the surface on Thursday (5/6) generic high pressure at 1028 mbs was nestled along the coasts of British Columbia down to Central California and west to a point 600 nmiles north of Hawaii and out to the dateline. This was generating the requisite pressure gradient along the Central CA coast with 20 kt north winds there then pushing west resulting in trade winds over Hawaii in the near 20 kts range.  Windswell of limited magnitude was being generated by these winds along the California  and Hawaiian Shores. Ill defined low pressure was off the Kuril Islands drifting east with no swell producing fetch of interest occurring. Over the next 72 hours generalized high pressure is to hold over the Eastern Pacific (though weaker than in days past) continuing a lighter gradient along California resulting in limited 15 kt north winds and small windswell at best.  Trades to continue over Hawaii resulting in modest east windswell). Low pressure that was off the Kuril Islands is to migrate to the dateline on Sat/Sun (5/9) generating perhaps up to 35 kt northwest winds at 38N 180W for 24 hrs with 16-18 ft seas possibly resulting.  Weak windswell might make it to Hawaii with luck.


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


California Nearshore Forecast
On Thursday (5/6) high pressure at 1024 mbs was ridging into the Central CA coast setting up a weak pressure gradient and modest north winds at 15 kts along the entire California coast, pushing 20-25 kts near Point Conception, down some from days and weeks past.  The gradient is to fade some more north of Pt Conception Friday with northwest winds down to 15 kts or less on Saturday and even weakening more on Sunday as weak low pressure moves near Northern CA.  But if anything, northwest winds to pick up in Southern CA Fri-Sunday with a full on wind fest expected there later Monday. High pressure is to be building in behind the low in Central and North CA later Monday evening (5/10) with north winds back to 25+ Tuesday pushing near 30 kts in the evening, then 25 kts Wednesday but focused more up near Cape Mendocino and holding into Thursday (5/13). Southern CA to get a break from Wednesday onward. But overall, no real end to north winds, chop, upwelling and short period windswell.


South Pacific

On Thursday (5/6) no swell producing fetch of interest was occurring in the South Pacific. Over the next 72 hours a gale is to be come better 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 38 ft seas peaking by Fri AM at 50S 130W. 36 ft seas to be fading Fri PM at 47S 125W.  If this occurs some sideband swell could result pushing up into California about a week out, though most energy is to be focused on Central America down into South America. Will monitor.  

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 remnants of the dateline gale are to remain poorly organized and track northeast up in to the Gulf of Alaska and into Canada late Tues (5/11) with no swell producing fetch resulting. A secondary low is to develop well north of Hawaii on Wednesday and follow the same northeastward track with no swell production suggested either. High pressure to remain dominant along the California coast forcing a pressure gradient and stronger north winds by Monday (5/10) and continued steady trades over the Islands. Windswell is to be the result. 

MJO/ENSO Update (reference): As of  Thursday (5/6) the Southern Oscillation Index (SOI) was bobbling down. The daily SOI was down to 8.14.  The 30 day average down to 10.48 with the 90 day average up to -1.02. A massive upward trend started in early March, peaked at the end of April, and is now loosing some ground, symptomatic of the Inactive Phase of the MJO and possibly La Nina. Though in all things look neutral now, and mix of both El Nino nd mild La Nina. 

Wind anomalies at the 850 mb level (approx 5000 ft up) as defined by models suggest moderate easterly anomalies from the mid-Indian Ocean to  the dateline and beyond to the east are in control, suggesting the Inactive Phase is here. It is scheduled to push hard east into 5/10 and be exiting over Central America 5/15-20. This signals the end of El Nino and eliminates any support for gale development. The Active Phase is forecast brewing behind it, stronger than previous runs of the model reaching the dateline on 5/20, but only weakly and holding there while dissipating. 

At this point were believing that El Nino will not hang on for another year, and that rather we'll fall back into 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 (4/29) indicated no dramatic change from previous weeks, with warmer than normal waters consolidated on the equator more towards the dateline and less in the vicinity of the Galapagos Islands, but not gone from South America and if anything, holding their ground. Erosion of warmer waters over the Galapagos is expected, symptomatic of the fading of El Nino, but is not occurring yet. 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 small gale might develop well south of Tahiti on Mon/Tues (5/11) with a small area of 45 kt west-southwest winds producing 32 ft seas Tuesday AM at 48S 157W holding into the evening at 46S 150W on the 200 degree track to California and slightly shadowed by the east end of the Tahitian Island chain. Limited support for small scale swell possible. Better odds for swell pushing into Central and South America. Will monitor. 

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

Free Stormsurf Stickers - Get your free stickers! - More details Here

Read all the latest news and happenings on our News Page here

Surf Height-Swell Height Correlation Table


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