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Pacific Storm and Surf Forecast
Updated: May 1, 2010 11:59 AM
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   

More Windswell for California
Small Dateline Swell For Hawaii


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 Saturday (5/1) North and Central California was getting more local northwest windswell with waves 1 ft overhead and pretty much blown out even early. Southern California was getting wrap around local windswell too with surf less than waist high up north and pretty chopped early. It was cleaner down south, but still no more than waist high and weak. Hawaii's North Shore was small with sets no more than waist high and clean with trades in effect. The East Shore was getting chest high.cgius east windswell and chopped. The South Shore was pretty much flat and clean. 

The forecast for North and Central CA is for northwest windswell fading from 5.5 ft and trashed. Windswell to be head high on Monday, shoulder high Tuesday then up some Wednesday to a little overhead. Southern California is to see very limited northwest windswell at exposed breaks to waist high Sunday fading to thigh high Monday, knee high Tuesday and maybe up to thigh high Wednesday with southern hemi swell arriving then to near chest high late. The North Shore of Oahu is to see a little pulse of dateline swell on Sunday at a little overhead fading to head high Monday then holding into Tuesday but junky then before dropping out on Wednesday. The East Shore to see east tradewind generated windswell at chest to head high Sunday dropping to chest high Monday, waist high Tuesday then gone.  The South Shore is to see southern hemi swell at waist high Sunday and a little less Monday. Limited southern hemi southeast swell possible by Tues/Wed peaking at chest high.

High pressure is in control of the Northeast Pacific with local junky windswell and poor conditions forecast for the foreseeable future. No swell producing weather systems of any kind are forecast for the North Pacific. Down south a small gale wrapped up well to the north on Wed (4/28) producing 30 ft seas for 18 hours which should result in limited swell pushing north into Hawaii later Tuesday and the US West Coast on Wednesday. But no other swell producing systems are forecast down there in the days ahead.


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

North Pacific

On Saturday (5/1) the North Pacific jet was  .cgiit in the east with most energy in the northern branch and ridging hard north through the Gulf of Alaska. In the west another ridge was occurring, with a steep almost pinched off trough in between the two just northwest of Hawaii and offering no hope to support gale development. Over the next 72 hrs the Gulf ridge is to fade as does the one in the west, with the trough in between dissipating as well. What is to be left is a weal almost flat flow pushing from the Southern Kuril ISlands west over the dateline and reaching to about 900 nmiles north of Hawaii. No signs of support for gale development indicated, but it is better than the high pressure /ridge configuration of late. Beyond 72 hours an almost flat flow is to take up residence on the 40N latitude, then starting to develop a trough near the dateline and another in the Gulf a week out (Sat 5/8). Maybe some hope then, but energy levels are to be pretty modest.

At the surface on Saturday (5/1) high pressure at 1032 mbs remained positioned midway between Hawaii and California ridging into Southern and Central CA producing a pressure gradient and solid north to northwest winds along the entire coast there at 25 kts producing windswell and poor conditions. A second high at 1036 mbs was on the dateline heading east and continuing to effectively provide a complete lockdown of the North Pacific eliminating any odds for productive low pressure development. A tiny gale that was west of the dateline generated 35 kt winds and 25 ft seas at 37N 160E Tuesday evening (4/27), setting up minimal 12 sec period swell for Hawaii late Saturday (5/1) with pure swell early Sunday reaching 4.5 ft @ 13 secs (6 ft faces) from 310 degrees. Over the next 72 hours a weak area of low pressure is forecast to develop 900 nmiles north of Hawaii on Sunday (5/2) producing 30 kt north winds and 18 ft seas late perhaps increasing the odds for 10 sec north windswell for the Islands late Mon/Tues (5/4).That low is to be lifting north on Tuesday and fading. Otherwise high pressure is to give up some of it's grip mid-week though still holding just west of California with the pressure gradient along the coast holding resulting in more north winds to 30 kts by Wed (5/5) and more windswell. This is actually pretty typical for the May timeframe.    


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


California Nearshore Forecast
On Saturday (5/1) high pressure at 1032 mbs continued ridging into the coast setting up a pressure gradient and moderate north winds at 25 kts along the entire California coast with near-chop in effect. The pressure gradient is to actually build on Sunday with 30 kt north winds forecast from Cape Mendocino down to Morro Bay, resulting in more windswell and chop. Finally on Monday (5/3) the gradient is to break a little with light winds from Pt Arena southward, but still blowing up north at 20+ kts.  But come Tuesday (5/4) the gradient is forecast to rebuild off San Francisco pushing near 35 kts north winds from Pt Conception northward to the Oregon border with full chop in effect, then maybe weakening some Wed/Thurs to the 20-25 kts range and holding through next weekend. In shore, windswell and chop is to be the norm for everywhere but maybe Southern CA.


South Pacific

On Saturday (5/1) no swell producing fetch of interest was occurring in the South Pacific. 

South Pacific Gale
On Wed (4/28) a small spurious gale developed in the upper latitudes of the South Pacific with 40 kts winds aimed well north resulting in about 18 hours of 31 ft seas at 36S 141W. This is pushing swell towards Hawaii (from the southeast) and California.

Hawaii: Expect swell arrival on later Tuesday (5/4) with swell to 2 ft @ 15-16 secs (3 ft faces), holding at 2 ft @ 14 secs on Wed (thigh to waist high) then dropping out. Swell Direction: 170 degrees

Southern CA: expect swell arrival on Wed (5/5) with swell to 2 ft @ 16 secs (3 ft faces) continuing on Thurs at 2.8 ft @ 15 secs (4.0-4.5 ft faces), then fading from 2.8 ft @ 14-15 secs on Thurs (4.5 ft faces). Swell Direction: 195 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 hold tight between California and Hawaii with trades in effect for the ISlands and limited East windswell there, and north windswell along the Central California coast. There's some suggestion of low pressure trying to develop over the dateline next weekend (5/7) but no clear swell producing fetch is indicated.

MJO/ENSO Update (reference): As of  Saturday (5/1) the Southern Oscillation Index (SOI) was hovering around neutral. The daily SOI was up to -8.83.  The 30 day average was down to 11.92 (It bottomed out for the winter on 2/16 at -24.82) with the 90 day average up to -5.25 (bottomed out at -14.2 on 3/14). El Nino maxed out on 2/15.  This looks like the peak of what was a massive upward trend that started in early March and now hold well into La Nina territory. 

Wind anomalies at the 850 mb level (approx 5000 ft up) as defined by models westerly anomalies over most of the Eastern Pacific, suggesting that the Active Phase of the Madden Julian Oscillation has been occurring and is not fading out. That seem unlikely given the.cgiacid weather pattern of late. In the Indian Ocean Easterly anomalies are in control pushing almost to the dateline, suggesting the Inactive Phase is brewing. It is scheduled to seep east into 5/10 and hold on the dateline covering pretty good ground. the dissipate while pushing over the Eastern equatorial Pacific through 5/20. This pretty much signals the end of El Nino and eliminates any support for gale development. At this point were monitoring the MJO more for signs of Active Phase dominance in the critical March-May time frame (versus monitoring for storm support) to see if this Midoki El Nino can hang on for another year, or whether we 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. 

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. 

At this point we're monitoring to determine whether this El Nino will degrade into La Nina (which typically happens after stronger El Nino's), or whether it will hold in some mild El Nino-like state for several years in a row. This would be the best outcome, but far from expected.  The months of Mar-June normally are when the transition takes.cgiace.  

See more details in the new  El Nino update.


South Pacific

Beyond 72 hours the models indicate the storm pattern is all to be aimed all due east, offering no fetch pushing well up into the great circle tracks for North Pacific locations.

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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