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Pacific Storm and Surf Forecast
Updated: April 22, 2010 9:52 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 = 3.9 - California & 3.0 - 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 4/19 thru Sun 4/25
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   

N. Pacific Pulse for the Weekend in CA
Decent Southern Hemi Swell for Hawaii Next Week


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 (4/22) North and Central California was getting primarily local north windswell with waves head high or a little more with warbled well intermixed. Southern California was getting waist to chest high local windswell pretty junky looking up north with modest northwest winds in control, but cleaner down south. Hawaii's North Shore was getting another pulse of northwest swell from the dateline with long lines and waves 3-4 ft overhead and clean with modest trades in control. The East Shore was also getting waist high east windswell and chopped. The South Shore was getting some limited southern hemi swell with waves chest high and a little more at top spots and clean. 

The forecast for North and Central CA on  Friday is for local north windswell dying, still in the head high range but fading.  New swell from the dateline is forecast at  4 ft overhead on Saturday with additional swell from the Gulf moving in on Sunday at about the same size, then dropping from 1 ft overhead on Monday. Southern California is to see north windswell fading from chest high at top exposed breaks on Friday and waist high on Saturday with new dateline swell intermixed at the same height. Sunday additional swell from the Gulf might add in providing chest high swell at exposed breaks, then fading from waist high on Monday.  The North Shore of Oahu is to see dateline swell fading from 3 ft overhead on Friday and chest high Saturday, dropping from waist high Sunday. New dateline swell to reach 3 ft overhead late Monday.  The East Shore to see east tradewind generated windswell to maybe head high Friday then fading some Saturday, down to waist high Sunday before dissipating. The South Shore is to see waist high or better southern hemi swell continuing Friday. This first of a series of southern hemi swell starts on Saturday to chest high pushing shoulder high or more Sunday with real swell at 1 ft overhead or more for Monday. 

A gale tracked up to the dateline on Monday evening (4/19) with barely 36 ft seas over a small area, possibly setting up some swell for early weekend pushing into Central CA. Remnants of this same gale were reorganizing late Thursday in the Central Gulf with a small area of 26 ft seas on the 298 degree path to CCal providing possible swell for later in the weekend. A weak gale is scheduled for the Northeastern Gulf on Mon (4/26) pushing up to the Oregon coast on Tuesday with up to 22 ft seas, likely setting up raw swell for CA next week. Down south a primer gale tracked northeast alongside of New Zealand Sat/Sun (4/18) with 30 ft seas.  That swell is starting to hit Hawaii and is to push into CA later Sunday (4/25). A stronger storm was right behind it and on the same track Sun-Tues (4/20) with 36-38 ft seas. Swell from this one to hit Hawaii on Monday and the mainland late Wed (4/28) but with not much size.  


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

North Pacific

On Thursday (4/22) the North Pacific jet remained .cgiit over it's width, with most energy in the northern branch tracking south of the Aleutians on the 45 N latitude. A weak trough was in the Gulf of Alaska with maybe 120 kts winds flowing under it, with a second stronger trough over the dateline with 140 kts winds feeding into it. Decent support for gale development was indicated in each. Over the next 72 hrs the Gulf trough is to weaken and push east into British Columbia late Friday while the dateline trough holds if not strengthens some pushing into the Western Gulf Saturday and Central Gulf 24 hours later, but starting to pinch off. Gale support to continue till then.  Beyond 72 hours the Gulf trough is to drive southeast and into North CA by late Tuesday (4/27) likely setting up more rain for that region, but not much in terms of swell production due to the extremely pinched configuration of the trough. Another small and steep trough is to be working it's way from well off Japan to the dateline into Tuesday and then just north of Hawaii on Thursday (4/29). 180 kts finds to be diving into the trough then, but doubt much will result in terms of gale development given it's very small size and steep almost pinched geometry. A convoluted jet is to be following behind not suggestive of gale development. 

At the surface on Thursday (4/22) high pressure at 1028 mbs was north of Hawaii ridging into the US West coast with north winds in control of outer waters at 25 kts over most of the state. Over the next 72 hours a new small gale was starting to wind up in the Northeastern Gulf on Thurs AM (4/22) generating 35 kt west winds over a small area at 45N 157W then building to 40-45 kts in the evening at 45N 148W. 26 ft seas are forecast Thurs PM at 45N 151W (299 Deg NCal) lifting northeast and regenerating a bit Friday AM with a decent sized area of 26 ft seas at 46N 143W (308 deg NCal) and pushing out of the swell window for all but the Pacific Northwest (but tracking directly at Washington. Possible swell to result for Central CA by Sunday at 7 ft @ 14 secs (9-10 ft faces from 300 degrees).

Another gale was starting to build on dateline too on Thursday AM (4/22) with 40 kt west winds through the day at 43N 165E-175E generating 25 ft seas at 43N 174E late pushing 26 ft Friday AM at 43N 177E. Possible sideband swell for Hawaii later Monday (4/26) at 5.5 ft @ 13 secs (7 ft faces) from 320 degrees. 

Second Dateline Gale
On Sunday (4/18) a gale developed west of the dateline and further south, with up to 50 kt northwest winds over a small area at 43N 160W and tracking northeast. Seas building.  In the evening winds continued at 45 kts at 42N 170E aimed a fair bit east of the 315 degree path to Hawaii with seas reaching 26 ft over a small area. Monday AM (4/19) 45 kt west winds occurred at 44N 178E resulting in 30 ft seas at 43N 172E.  Winds were heading down in the evening to 40 kts at 45N 175W pushing right up the 297 degree path to NCal with seas to 36 ft at 44N 180W. A quick fade occurred on Tuesday AM with seas fading from 34 ft at 46N 172W with most energy pushing towards Canada.

Limited sideband swell was expected into Hawaii on Thurs (4/22) at 6 ft @ 15 secs ( 9 ft faces) from 320 degrees. That arrived as predicted. 

Also swell from it is expected into Central CA on Friday (4/23) near 7 PM with pure swell to 6.6 ft @ 17 secs (11 ft faces) from 298 degrees, then fading from 6 ft @ 15 secs Sat AM (9 ft faces). 


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


California Nearshore Forecast
On Thursday (4/22) the pressure gradient in.cgiace over the California coast (low pressure inland - high pressure north of Hawaii ridging east) was still holding on, generating brisk north winds at 25 kts over outer waters and up to 35 kts off Cape Mendocino and generating much local north windswell and upwelling. The gradient and associated fetch is to holding over North CA Friday with northwest winds 25 kts though Central and Southern CA nearshore waters are to be almost free from the worst effects of the winds. The gradient and northwest winds are to push back into all of Central CA on Saturday then finally starting to fade on Sunday (3/25) through 15 kt northwest wind are still forecast over outer waters. Light winds expected Monday (4/26) ahead of another front with south winds pushing into the state from Pt Conception northward Tuesday and rain building from the north to the Mexican boarder late. High pressure and another broad pressure gradient with brisk northwest winds are forecast right behind pushing into even Southern CA by Wednesday (4/28) and continuing Thursday. Light rain is forecast over the entire state Wednesday with snow in upper elevations mid Tues AM into Wednesday evening.  The snow (skiing/boarding) is still good. 


South Pacific

On Thursday (4/22) no swell producing fetch of interest was occurring in the South Pacific. 

Primer Gale
On Friday evening (4/16) an ill defined fetch of 35 kt southwest winds built south of New Zealand lifting northeast, barely hitting 40 kts Saturday AM at 50S 180W with seas building to 28 ft at 52S 175E.  Near 40 kt winds held into the evening at 44S 170W with 28 ft seas continuing at 45S 172W. The gale faded Sunday AM (4/18) with seas fading from 29 ft at 42S 165W.

Some degree of rideable 15-16 sec period swell is expected to arrive in Hawaii starting Sat (3/24) near 10 AM at 2.6 ft @ 16 secs (4.0-4.5 ft faces) from 191-196 degrees. Swell to be fading from 2.6 ft @ 14 secs (3.5 ft faces) on Sunday (3/25).

California might swell swell of 1.6 ft @ 16-17 secs (2.5-3.0 ft faces) starting Sunday (5/26) pushing 2 ft @ 15 secs (3 ft faces) on Monday. Swell Direction: 215 degrees

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.  

Hawaii: Expect swell arrival on Sun (4/25) with pure swell 2.6 ft @ 18 secs late (4.5-5.0 ft faces with set to 7 ft). Swell to peak on Monday (4/26) with swell 3.3-3.6 ft @ 17 secs  (5.6 ft faces with sets to 7 ft).  Swell to remain solid  on Tuesday (4/27) with swell 4 ft @ 16 secs (6.3 ft faces with sets to 8 ft) then fading from 3.6 ft @ 15 secs (5.5 ft faces)  Wednesday (4/28). Residuals on Thursday at 3 ft @ 13-14 secs (4.5 ft faces).  Swell Direction: 191-198 degrees 

Southern CA:  Rough data suggest swell arrival late Wednesday (4/28) with pure swell 2 ft @ 18 secs (3.5-4.0 ft faces) pushing to 2.3 ft @ 16-17 secs (4 ft faces) early Thurs (4/29). Swell Direction 209-212 degrees   

Northern CA:  Rough data suggest swell arrival late Wednesday (4/28) with pure swell 2 ft @ 18 secs (3.5-4.0 ft faces) pushing to 2.3 ft @ 16-17 secs (4 ft faces) early Thurs (4/29). 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 maybe limited fetch from the gale that is to be over the dateline Thurs/Fri (4/23) is to fade, the regenerate slightly Tuesday (4/27) off Oregon, mainly from the interaction of it and high pressure building north of Hawaii, setting up a broad fetch of local northwest wind at 25-30 kts targeting North and Central CA. Sea building to 20 ft Wednesday AM (4/28) making for local windswell for the coast from Oregon southward. Very raw. 

MJO/ENSO Update (reference): As of  Thursday (4/22) the Southern Oscillation Index (SOI) was heading up again and weakly symptomatic of the Inactive Phase of the Madden Julian Oscillation. The daily SOI was down slightly to 15.79.  The 30 day average was up to 12.33 (It bottomed out for the winter on 2/16 at -24.82) with the 90 day average up to -6.96 (bottomed out at -14.2 on 3/14). El Nino maxed out on 2/15. 

Wind anomalies at the 850 mb level (approx 5000 ft up) as defined by models indicated weak east anomalies from east of the dateline into Central America and fading, suggesting the last incarnations of the Inactive Phase (weakly hindering storm generation potential).  But a solid area of westerly anomolies were now depicted from the mid-Indian Ocean pushing to Papa New Guinea and expected to nearly reach the dateline on 4/26, and to the dateline by 5/1, then fading there. Neutral conditions again forecast by 5/11. This suggest that the Active Phase we've been waiting for for 2 weeks now might finally materialize, and with it some increase 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). There some suggestions on models for a mild La Nina. 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 (4/15) 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. 

Below the surface on the equator a Kevin Wave attributable to the previous Active Phase of the MJO was fading. On 4/20 a fading tongue of warmer than normal water was in.cgiace extending east from 120W into Central America averaging 3 deg C above normal. This is expected to extend El Nino symptoms into summer, but is likely the last Kelvin Wave we are going to see. 

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 slowly loosing it's grip and it's affects on the global atmospheric weather pattern. Still some impact is to continue into the Summer of 2010. This suggests that the spring storm pattern be enhanced in the North Pacific, but also the early summer storm track in the South Pacific too.  This has not been a strong El Nino, more of a solid moderate one. A respectable accumulation of warm surface water in the equatorial East Pacific and a solid pool of warm subsurface water remains in.cgiace, but seems to be eroding some suggesting El Nino has maxed out. But the atmosphere is already being strongly influenced by the warm water buildup over the past 6 months, and it will not return to a normal state for quite some time. 

At this point were mainly 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 either southeast or east, offering no fetch pushing well up into the great circle tracks for North Pacific locations. High pressure is to be building hard over New Zealand by Tues-Wed (4/28) with some fetch pushing north up it's eastern edge, possibly generating something well south of Tahiti. 32-35 ft seas forecast near 40S 138W (closer to CA than usual but too far east of Hawaii to have an impact). It's way too early to know with any certainty.     

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

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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