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Pacific Storm and Surf Forecast
Updated: May 21, 2009 8:43 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 & 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 5/18 thru Sun 5/24
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 For CA for the Weekend
Small Southern Hemi Swell For SCal and HI Too


New Swell Classification Guidelines (Winter)

Significant: Swell 8 ft @ 14 secs or greater (11+ ft faces) for 8+ hours (greater than double overhead)
Advanced: Swell and period combination capable of generating faces 1.5 times overhead to double overhead (7-10 ft)
Intermediate: Swell and period combination generating faces at head high to 1.5 times overhead (4-7 ft)
Impulse/Windswell: Swell and period combination generating faces up to head high (1-4 ft) or anything with a period less than 11 secs.

On Thursday (5/21) North and Central California had chest to shoulder high weak and windblown northwest local short period windswell at exposed breaks. Still ,size was up some from a day or two before. Southern California was near flat with knee to maybe thigh high sets at standout breaks and northwest winds on it mid-day. Hawaii's North Shore had more north windswell producing waist to maybe high sets with some warble in it. The East Shore was small with knee to thigh high north windswell at best. The South Shore had some small southwest swell at waist to rarely chest high on the sets at top spots coming from the Tasman Sea.  Textured conditions. 

The forecast for North and Central CA has not changed with more and larger northwest local windswell expected to start building in on Friday peaking on Saturday and then holding into early Sunday.  Might make for some fun surf for the weekend even though it is to be pure windswell. Some form of rideable windswell is to hold through the end of next week too, though steadily shrinking.  Southern CA is to see some of this same northwest windswell later Friday, peaking over the weekend, and then fading.  And some weak south angled southern hemi swell is expected in by the weekend too.  Oahu's North Shore to descend into flatness by Friday with no real change forecast. Maybe a hint of thigh high northwest windswell on Sunday, but don;t count on it. The East Shore is not expected to have any of the usual easterly windswell for the foreseeable future, with trades suppressed. The South Shore is to see another tiny pulse of background southwest swell originating from the Tasman Sea starting Sunday holding into Monday evening (5/25), then dissipating.  Otherwise, very quiet.  

Longterm no swell producing weather system are forecast in the North Pacific with summer now fully in effect. In the South Pacific nothing is expected either with a .cgiit jet and high pressure sitting in between the streams locking things down tight.   


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

North Pacific

At the surface high pressure at 1028 mbs was centered just east of the dateline ridging to the east east and impacting the US Coast from Oregon up to Canada.  This was serving to generate the usual pressure gradient over Cape Mendocino resulting in 25-30 kt north winds there with northerly windswell starting to propagate south into Central CA. Trades remained suppressed over the Hawaiian Islands with a very weak cutoff low 400 nmiles north of there, protecting the chain from the buildup of pressure. Over the next 72 hours this high pressure system is to seep even further east taking up residence off the Pacific Northwest fueling the usual  pressure gradient off Cape Mendocino CA with north winds solidifying at 30 kts by Friday and generating larger local windswell down into Central CA and exposed breaks of Southern CA and holding into Monday (5/25). a steadily weakening version of the cutoff low is to hold 300-600 nmiles north of Hawaii during this time frame minimizing trades and reducing odds for local easterly windswell. No other swell producing systems are forecast with summertime conditions fully in-effect. 


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


California Nearshore Forecast
On Thursday (5/21) high pressure was building into the gulf of Alaska generating north winds to 25 kts over Cape Mendocino and lesser winds pushing south from there, but remaining well off the beaches from Pt Arena south. Windswell was the upswing.  North winds to build more on Friday as the high builds stronger in the Gulf , with winds at 30+ kts and holding through the weekend. Windswell the expected result. Local north winds to possibly be an issue early Friday and Saturday, though mostly north of Pt Reyes. Otherwise and eddy flow (southwest) should be expected at 5-10 kts.  Beyond the gradient is to start fading on Monday and windswell dying, but not out through Wednesday (5/27) with a light wind pattern nearshore. 

No tropical activity of interest was occurring.


South Pacific

On Thursday (5/21) the South Pacific jetstream remained completely .cgiit from west to east with a solid ridge pushing the southern branch down over the Ross Ice Shelf from under New Zealand into the Southeast Pacific and totally shutting off any chance for surface level low pressure development. A bit of a trough remained in the far Southeastern Pacific but was outside the US swell window and of interest only to Southern Chile. A trough that had been in the Tasman Sea and over New Zealand was gone. Over the next 72 hrs this same pattern is expected to continue offering no opportunity to support gale development at the oceans surface.  Beyond 72 hrs the models are now hinting at a trough forming under New Zealand and building eastward providing a pocket to support some form of low pressure development by Tuesday (5/26) in the Central South Pacific.  Winds to only be 110 kts, not really strong enough to do much, but it's a mile better than the configuration we were in a week ago.  Keep your fingers crossed.

At the surface on Thursday bulletproof high pressure at 1040 mbs remains locked down well south of Tahiti and east of New Zealand, sitting between the two branches of the .cgiit jetstream and totally blocking the normal summer time storm corridor and eliminating any swell production in the South Pacific. Over the next 72 hours the high is to try and hold on, but then late Saturday it is to start fading and moving east almost out of the picture, the first time in a few weeks. At the same time a series of gales are forecast to start pushing east over the Ross Ice Shelf and strengthening, but all are to remain over ice with no fetch getting in contact with ice free water. 

Previously a gale had formed in the far Southeast Pacific off Chile generating 30 kt south winds on and off since late Tues (5/12) with seas to 26 ft by Thurs AM at 56S 122W.  It lifted northeast to 52S 120W by Thurs evening with seas still 26 ft at 53S 120W then faded some before regenerating off Chile Sat/Sun with seas to 36 ft. The best this could do for the US is to produce background 14-15 secs very south angled swell for Southern CA 9 days later, or Sat (5/23).  Swell size to be 2.6 ft @ 14 secs (3.5 ft faces) but limited to Southern CA.  swell to hold at 2.6 ft @ 13 secs (3 ft faces)  on Sunday, then fading out.

Previously on Saturday (5/16) some more wind energy seeped into the Tasman Sea at 35 kts from the southwest winds expected to push to New Zealand on Sunday. 30 ft seas from previous fetch rounded under Tasmania Sat AM (5/16) at 43S 154E dropping to 26 ft in the evening at 41S 161E. 26 ft seas held to Sunday AM at 40S 155E and then faded out. More swell likely for Fiji with perhaps some very limited swell southwest for Hawaii starting Sunday (5/24) at 1.6 ft @ 16 secs (3 ft faces) from 215-220 degrees. Period dropping to 14 secs on Mon (5/25) and dissipating that evening. 


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 hours high pressure is to slowly dissipate off Northern CA through Wednesday (5/27), falling below 25 kts at that time with windswell dropping steadily, but not out. There's some indication it might try and resurge late next week, adding hopes for rebuilding windswell, but that is more a guess than anything that resembles a certainty. No sign of trades yet for the Islands.


MJO/ENSO Update (reference): As of Thursday (5/21) the Madden Julian Oscillation (MJO) was well past the peak of the Active Phase, but the ENSO (El Nino Southern Oscillation) index remained negative. The Daily SOI index was up to -5.34 making it 27 days of near consecutive negative readings. The 30 day average was down to -6.98 (the lowest since 7/2007) and the 90 day average was down to 1.28 (the lowest since Mar 2007, but still not negative). The SOI indicies remained completely neutral at the moment. Wind anomalies at the surface and the 850 mb level (approx 1000 ft up) indicated that the Active Phase had surprisingly re-energized itself with weak westerly wind anomalies over the entire equatorial Western Pacific reaching to the dateline and building eastward.  It was as if a whole new Active Phase of the MJO had built in.  It is expected to seep east through 5/25 reaching Central America,  then slowly dissipating through 6/4.  A new Inactive Phase is trying to form in the Indian Ocean but is expected to die while trying to push into the Pacific on 6/9, having no impact. A neutral if not slightly Active Pattern ENSO pattern appears to be in.cgiay.  The residual effects of 3 years of La Nina are effectively gone over the ocean, and fading fast in the Northern Hemisphere atmosphere (though the Southern Hemi will take 2 months longer to heal). Cooler than normal surface waters off of Central America are gone with slightly warmer than normal waters temps reported over the entire width of the equatorial Pacific. Below the surface on the equator a steady flow of slightly warmer than normal subsurface water was tracking from the West Pacific over the dateline and then breaking the surface near Central America with warmer water starting to pool up there. It appears that the last episode of the Active Phase has primed the warm water pump, pushing them eastward with more building up behind, and feeding a slightly warm regime in the equatorial Eastern Pacific.  Months of high pressure off California and stiff north winds there turning trades over Hawaii had resulted in a huge cool tongue of water extending from Central CA the whole way over Hawaii to the dateline which generated massive upwelling. That continues to moderate, through a large pocket of cooler than normal waters remains off California extending to almost Hawaii. We expect 1-2 more months of high pressure before a fully neutral pattern takes hold (warmer waters off California).


South Pacific

Beyond 72 hours the models suggest that by Tuesday (5/26) low pressure is to try and start congealing at the oceans surface in the exact same location as the high pressure system that had locked things down the week below. Winds to only reach 35 kts and be rather broad and diffuse, rather than concentrated and focused, with no decent seas forecast to result.  Either way, this is a step in the right direction.  But for now, no swell to result. 

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

Rebuild Jeff Clark: Jeff Clark the first pioneer of Mavericks, recently underwent hip resurfacing surgery due to severe pain from deterioration of his hip. Needless to say the procedure is very expensive and his insurance only covers tiny portion of the bill. If you're interested in learning about the procedure or would like to donate to help Jeff out,.cgiease take a look here:

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:

The Kelly Slater Project - A group of dedicated surfers from Cocoa Beach are working to construct a statue of the the home town legend and set it up for all to enjoy near the break where Kelly grew up surfing. Take a look at the statue and read all about it here:

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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