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Pacific Storm and Surf Forecast
Updated: May 19, 2009 9:32 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 North and Central CA
Still Quiet Down South


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 Tuesday (5/19) North and Central California had waist high weak sectiony and windblown northwest local short period windswell at exposed breaks. Southern California was effectively flat with knee high sets at standout breaks and northwest winds blowing. Hawaii's North Shore had north windswell producing shoulder high sets and a bit warbled. The East Shore was small with thigh high east windswell at best. The South Shore had some small southwest swell at waist to maybe chest high on the sets coming from the Tasman Sea.  Pretty textured  conditions by late morning. 

The forecast for North and Central CA indicates more and larger northwest local windswell is expected to start building in By Wednesday and slowly inch its way up through the weekend.  Nothing great but sure better than flat. Get on it cause next week it's to all fade out.  Southern CA is to see a tiny fraction of this same northwest windswell starting Thursday (5/21), but until then nothing of interest is forecast.Maybe even a weak hint of southern hemi swell too in by the weekend.  Oahu's North Shore to continue seeing some north windswell through Wednesday with faces to maybe head high and period at only 9 secs, then dropping out.  The East Shore is not expected to have any trade induced easterly windswell for the foreseeable future. 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.   

Longterm virtually no swell producing weather system are forecast in the North Pacific. In the South Pacific not much is expected either, with high pressure remaining the dominant weather feature for a while longer.  


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

North Pacific

At the surface strong high pressure at 1036 mbs was centered over the dateline ridging both east and west and effectively filling the North Pacific from just off Japan the whole way to Cape Mendocino California.  Only a small and weak cutoff low 300 nmiles north of Hawaii was protecting the Islands from what otherwise would be a solid dose of trades driven by the high.  North winds were light along the California coast with the leading edge of the the high just a few hundred nmiles out.  Over the next 72 hours this high pressure system is to seep east  generating the usual  pressure gradient off Cape Mendocino CA by late Tuesday (5/19) setting up north winds to 25 kts building to 30 kts late week and generating local short period windswell. Some flavor of the cut off low is to hold 300-600 nmiles north of Hawaii not doing anything swell wise, but serving only to mute trades reducing odds for local easterly windswell. No other swell producing systems are forecast with summer like conditions continuing. 


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


California Nearshore Forecast
On Tuesday (5/19) high pressure was starting to build off coastal California, with northwest winds to 20 kts off Pt Arena and starting to build.  By Wednesday (5/20) a solid gradient is to start forming over Cape Mendocino with 25-30 kt north winds starting to build there and windswell on the upswing, building to 30 kts late Wednesday, fading some Thursday (5/21) then returning on Friday and holding through the weekend. Windswell the expected result. Local north winds to be an issue for Central CA  on Wednesday at 15 kts, but then pulling away from the coast from Pt Arena southward and remaining that way into the weekend.  Perhaps an eddy flow (southwest) to build nearshore. Beyond the gradient is to start fading on Monday and windswell dying, with a fully calm pattern in.cgiace by Tues (5/26). 

No tropical activity of interest was occurring.


South Pacific

On Tuesday (5/19) the South Pacific jetstream remained completely .cgiit from the west to the east with a solid ridge pushing the southern branch down over the Ross Ice Shelf from under New Zealand to the Southeast Pacific totally shutting off any chance for surface level low pressure development. A bit of a trough remained in the far Southeastern Pacific but outside the US swell window and of interest only to Southern Chile. A semi persistent steep trough was pushing north into New Zealand, but was so steep to be of no use for surface low pressure development of consequence. Over the next 72 hrs the same basic .cgiit pattern is to continue reinforced by more southward moving energy in the southern branch of the jetstream. This is to continue suppressing storm development over the entire South Pacific.  Beyond 72 hrs no change is forecast with a .cgiit pattern in firm control and the southern branch ridging south over or near the northern edge of the Ross Ice Shelf. No support for gale development is suggested. A week out there's a hint of perhaps the start of a weak and broad trough forming under New Zealand.  But that is likely just a fantasy of the model. 

At the surface on Tuesday strong high pressure at 1036 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 no significant change is forecast with high pressure holding at 1032 mbs while inching north but still dominating the South Pacific.  As series of gale are forecast to start pushing east over the Ross Ice Shelf but all are to be over ice with no fetch in contact with ice free waters. 

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 continue pushing into California generating north windswell through weekend, then withering early next week with winds off Cape Mendocino falling below 25 kts by Tuesday AM (5/26) and windswell dropping out. But another strong high is forecast to start building over the intersection of the dateline and the Aleutians at 1032 mbs on Tues (5/26) while the cutoff low north of Hawaii evaporates. As this high tracks southeast odds are expected to increase for east winds and windswell to be pushing into the Islands, perhaps starting late next week. 


MJO/ENSO Update (reference): As of Tuesday (5/19) the Madden Julian Oscillation (MJO) was well past the peak of the Active Phase, but the ENSO (El Nino Southern Oscillation) index remained heading down. The Daily SOI index dropped to -23.96 with only 3 days last week in the positive range of an otherwise unbroken string of 24 consequetive negative readings. The 30 day average was down to -5.98 (the lowest since July of 2007) and the 90 day average was down to 1.67 (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 has re-energized with weak westerly wind anomalies over the entire equatorial Western Pacific reaching to the dateline and expected to hold till 5/23. It's to push east reaching central America by 5/28 and holding till 6/2 there.  There is no sign of a Inactive Phase forecast behind it either. 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 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 high pressure might start giving up some ground with a tiny spurious gale forecast developing off the northeastern tip of New Zealand on Fri/Sat  (5/23) with 35-40 kt south winds and up to 30 ft seas over a tiny area, but that seems real optimistic. A second pulse is forecast under New Zealand early next week with a broader area of 30 ft seas projected, but the weather models don't really support that optimistic output. In either case, Hawaii and Tahiti would probably benefit most if these systems were to form. 

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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