Surf Forecasts and Marine Weather - No Hype - Just the Facts!
Kelvin Wave Situation Gets Interesting! - Video Forecast HERE (12/3)
Buoys | Buoy Forecast | Bulletins | Models: Wave - Weather - Surf - Altimetry - Snow | Pacific Forecast | QuikCAST | El Nino | Tutorials | Great Circles | Video


Stormsurf Mobile App

Create Your Own Surf Forecast
Swell Calculator
Swell Decay Tables
Sea Height Tables
Swell Category Table
Convert from GMT:
 to timezone:

Pacific Storm and Surf Forecast
Updated: April 29, 2010 6:18 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 = 3.5 - 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 4/26 thru Sun 5/2
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   

Local Windswell for California
Small Dateline Swell Coming 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 Thursday (4/29) North and Central California was getting northwest windswell generated by a local gale off Oregon days before with waves 2-3 ft overhead and building but trashed by strong northwest wind. A total of nearly 2 ft of snow has fallen over the past 2 days at the few Tahoe ski resorts still open. Squaw is reporting a 200+ inch base on the upper mountain. Southern California was trashed with surf less than waist high and blown to bits by northwest winds. Hawaii's North Shore was up to waist high and clean with trades in effect. The East Shore was getting waist high.cgius east windswell and chopped. The South Shore was still seeing limited residual energy from the southern hemi with waves maybe waist high and clean. 

The forecast for North and Central CA is for northwest windswell 2 ft overhead Friday and 1 ft overhead Saturday and head high Sunday and Monday and holding on for a while longer. Northwest wind to be on it all days with poor conditions. Southern California is to see northwest windswell at exposed breaks to chest high  Friday then dropping to waist high Saturday and Sunday fading more Monday. Southern hemi swell to be fading to waist to chest high on Friday and waist high Saturday and thigh high Sunday. The North Shore of Oahu is to see a little pulse of dateline swell on Sunday at head high or so fading to head high Monday holding into Tuesday but junky then. The East Shore to see east tradewind generated windswell at chest high Friday and holding there for Saturday, down a little Sunday  to waist to chest high and holding Monday. The South Shore is to see southern hemi swell fading from waist high Friday and thigh high Saturday. More waist high background energy expected Sunday and a little less Monday.

High pressure is in control of the Northeast Pacific with local junky windswell and poor conditions forecast for the foreseeable future. But no swell producing weather systems of any interest are forecast for the entire North Pacific. Down south residual swell from a decent storm was fading in Hawaii and hitting the mainland but buried in local windswell and chop. The models continue to suggest minimal swell coming up from the south with the storm track aligned very much flat west to east, not pushing much energy north. 


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

North Pacific

On Thursday (4/29) the North Pacific jet was still .cgiit but with most energy in the northern branch tracking south of the Aleutians. A trough was on the dateline with no real wind energy associated with it pushing up into a large ridge pushing through the Gulf of Alaska then falling into t a trough over Nevada. In all only very limited support for surface level low pressure was occurring in the dateline trough. Over the next 72 hrs the dateline trough is to pinch off and become non-supportive of gale  potential positioned just northwest of Hawaii while the big ridge over the Gulf easts east, starting to push into the Pacific Northwest and California. No support for gale development expected. Beyond 72 hours the large ridge in the Gulf is to east into the US West Coast and degrade, while a very weak and unorganized flow persists over the greater Pacific. No clear support for gale development indicated. 

At the surface on Thursday (4/29) high pressure at 1032 mbs was positioned midway between Hawaii and California ridging into Southern and Central CA producing a pressure gradient and strong north to northwest winds along the entire coast there almost up to Oregon. Local windswell was on the increase with poor conditions in control.  A second high at 1036 mbs was just west of the dateline heading east and providing a complete lockdown over the North Pacific eliminating any odds for substantial low pressure development. Low pressure in the Eastern Gulf on Tuesday (4/27) had generated 24 ft seas off Oregon resulting in swell which was starting to push into Central CA on Thursday.  Over the next 72 hoursa 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. Otherwise high pressure is to pretty much rule supreme resulting in a pressure gradient and north winds and windswell along the Central and North CA coast. Also a weak area of low pressure is forecast to develop 900 nmiles north of Hawaii on Sunday (5/2) producing 30-35 kt north winds and 20 ft seas late perhaps increasing the odds for 10 sec north windswell for the Islands late Mon/Tues (5/4).    


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


California Nearshore Forecast
On Thursday (4/28) high pressure at 1032 mbs was ridging into the coast with lower pressure inland over Nevada, setting up a pressure gradient and strong north winds along the Central and South CA coast with full chop in effect. The pressure gradient is to hold Friday (4/30) with north winds at 25-30 kts making a mess of things in Southern CA and building northward to Cape Mendo.  On Saturday the gradient is to move north some giving Southern CA a break while 30 kt north winds continue just off the coast of San Francisco later and continuing into Sunday . Finally on Monday (5/3) the gradient is to break with light winds over the CA coast from Pt Arena southward, but still blowing up north at 25 kts.  The gradient is now forecast to rebuild over Central CA on Tuesday with 35 kt north winds off Pt Arena, maybe weakening Wed/Thurs providing a bit of a break from San Francisco southward to Pt Conception in the mornings. Southern CA to be spared all of next week.   


South Pacific

On Thursday (4/29) no swell producing fetch of interest was occurring in the South Pacific. 

Storm #3S (Hawaii)
far more interesting storm started developing on Saturday evening (4/17) with pressure at 968 mbs in the deep southwest Pacific just off Antarctica getting traction on the early season ice free waters down there. 50 kts southwest winds were modeled at 61S 155E aimed up the 214 degree path to California and unshadowed by Tahiti and almost shadowed by New Zealand on the 201 degree path to Hawaii. On Sunday AM  (4/18) a broad fetch of 45 kt southwest winds were modeled at 60S 167E aimed right up the 214 degree path to CA and barely unshadowed by Tahiti and a shade east of the 200 degree path to Hawaii. 28 ft seas were building at 60S 165E.  In the evening 45 kt winds continued at 58S 171E with seas building to 34 ft at 56S 172E.  Monday AM (4/19) 45 kts southwest winds  continued though over a smaller area at 52S 177E aimed right up the 212 degree path to CA and just barely clear of the Tahitian swell shadow and well up the 193 degree path to Hawaii. 38 ft seas were modeled at 55S 180E. In the evening the fetch was fading from 40 kts in the same general area with 36 ft seas at 50S 172W pushing up the 210 degree path to CA and a bit shadowed on the very western edge of the Tahitian Island swell shadow and also up the 187 degree path to Hawaii. Tuesday AM (4/20) a large fetch of 40+ kt southwest winds were holding at 45S 165W with more 35 ft seas at 50S 170W pushing up the 208 degree path to CA and a bit unshadowed and the 191 degree path to Hawaii. The fetch is to fade some in the evening and loose some coverage and not moving any further north, still at 40 kts at 50S 165W with 36 ft seas at 48S 162W or up the 205 route to CA and totally shadowed.  This system to fade after that. Assuming all goes as forecast a rather solid sized 17-18 sec period swell could result for Tahiti, Hawaii and the US West coast.  

Southern CA:   Swell dropping from 2 ft @ 15-16 secs on Friday (3.0-3.5 ft faces) and down from 2 ft @ 15 secs on Sat (3 ft faces).  Residuals on Sunday. Swell Direction 209-212 degrees   

Northern CA:  Swell dropping from 2 ft @ 15-16 secs on Friday (3.0-3.5 ft faces) and down from 1.6 ft @ 15 secs on Saturday (2.5-3.0 ft faces).  Residuals on Sunday. Swell Direction 206-209 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 North Pacific is to go effectively dormant with no swell producing weather systems forecast. High pressure is to gradually weaken but no organized low pressure of interest is forecast.  With the SOI still positioned hard in the positive range, El Nino's big run of North Pacific storms is effectively over. 

MJO/ENSO Update (reference): As of  Thursday (4/29) the Southern Oscillation Index (SOI) was dropping down a bit. The daily SOI was down to -8.65.  The 30 day average was down to 12.48 (It bottomed out for the winter on 2/16 at -24.82) with the 90 day average up to -5.99 (bottomed out at -14.2 on 3/14). El Nino maxed out on 2/15.  In short, a massive upward trend started in early March and it currently sit well in La Nina territory. 

Wind anomalies at the 850 mb level (approx 5000 ft up) as defined by models indicated dead neutral conditions suggestive of neither the Active or Inactive Phase of the Madden Julian Oscillation. No change is forecast through May 18. 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 (4/26) 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, building slightly (likely the result of a recent impact by a Kelvin Wave). Erosion of warmer waters over the Galapagos is expected, symptomatic of the fading of El Nino but not occurring yet. 

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

Add a STORMSURF Buoy Forecast to your Google Homepage. Click Here: Add to Google
Then open your Google homepage, hit 'edit' button (top right near graph), and select your location


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


Contact | About | Disclaimer | Privacy
Advertise/Content | Links
Visit Mark Sponsler on Facebook Visit Stormsurf on Instagram Visit Stormsurf on YouTube
Copyright © 2023 STORMSURF - All Rights Reserved
This page cannot be duplicated, reused or framed in another window without express written permission.
But links are always welcome.
Buoys | Buoy Forecast | Bulletins | Models: Wave - Weather - Surf - Altimetry - Snow | Pacific Forecast | QuikCAST | El Nino | Tutorials | Great Circles | Calculator