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Pacific Storm and Surf Forecast
Updated: July 21, 2009 9:54 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 = 5.0 - California & 4.0 - 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 7/20 thru Sun 7/26
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   

Swell #4S Poised to Hit Hawaii
A Little Windswell/Southern Hemi Combination Swell for CA for Now


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 Tuesday (7/21) North and Central California had junked out chest high local northwest windswell at exposed breaks with northwest wind on it early. Southern California has some thigh high short period northwest windswell at top spots up north with northwest winds on it. Down south it was cleaner with some background southern hemi swell producing thigh high sets and northwest windswell intermixed to thigh high too. Hawaii's North Shore was flat. The East Shore had knee high easterly windswell with onshore winds. The South Shore still had some of that southern hemi swell from a gale that tracked east under Tahiti, with waves in the waist high range on the sets.  

The forecast for North and Central CA is for short period north windswell holding at waist high.cgius on Wednesday then up some on Thursday to near head high before dropping a little Friday and Saturday.  Minor southern hemi background swell is forecast to waist high on Wednesday (2 ft @ 15 secs at best) then heading down on Thursday. Southern CA is expected to see fragments of the local north windswell Thursday into early Friday with the same small southern hemi background swell from under Tahiti holding into Wednesday AM at 2 ft @ 15 secs (3 ft faces) then fading Thursday. The East Shore to see a bit of easterly tradewind generated east windswell at thigh high on Wednesday pushing waist high Thursday, dissipating Friday. The South Shore is to start seeing Swell #4S on Wednesday (more below).

A moderate sized storm developed in the Southeast Pacific Thurs-Sun (7/19) with up 42 ft seas mostly unshadowed on the east end of the Tahitian shadow and aimed pretty well to the northeast. Significant class Swell #4S is expected into Hawaii on Wednesday into early Thursday (mostly sideband energy) and then on to the US West Coast by late in the workweek holding through the weekend. See details below. Beyond things to settle down for a bit in the South Pacific, though by Friday seas are to start building southeast of New Zealand pushing 35 ft by Saturday.  We'll have to see what happens in reality.   



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

North Pacific

At the surface today high pressure at 1028 mbs was centered 1500 nmiles northwest of Hawaii near the dateline and trying to ridge east, barely making it into North California.  North winds were near 20 kts off the Pacific Northwest down into North and Central CA generating minimal short period north windswell. This high was also generating modest northeast trades at 15 kts pushing into the Eastern Shores of the Hawaiian Islands, with minimal easterly windswell the result. But of far more interest was a gale low centered over the Eastern Aleutians generating 35 kt northwest winds pushing towards the Pacific Northwest. Over the next 72 hours this gale low is to build into Tuesday evening with winds up to 40 kts forecast at 52N 160W  then fading from 30-35 kts Wednesday AM at 53N 155W. Tuesday PM 24 ft seas are forecast at 52N 160W building to 26 ft Wednesday AM at 53N 154W.  This should theoretically produce swell of 4.8 ft @ 14 secs (6-7 ft faces) arriving in the SF Bay Area at 9 AM on Saturday AM from 310 degrees. Seems a bit of a reach, but for July, who can co.cgiain. Otherwise the dateline high pressure system is to totally fizzle out in relation to Hawaii with remnants taking up residence just of Oregon generating a steady flow of pesky north winds at 20 kts over nearshore Oregon and North/Central California waters, fading to 15 kts on Saturday. 

Trades over the Hawaiian Islands to dissipate as yet another low pressure system builds 1500 nmiles north of the Islands Friday AM (7/24) generating 30-35 kt north winds, but all on the east side aimed due north towards Alaska.  No swell to result.


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


California Nearshore Forecast
On Tuesday (7/21) weak high pressure was trying to ridge into North California coast with a shallow area of north winds at 15-20 kts over both North and Central CA, but ill defined. North winds  were also building into the Pacific Northwest. This is good for small short period windswell and chop but nothing better. High pressure is to get a little better situated off of Oregon and Washington on Wednesday with more north winds at 15-20 kts blanketing the entire US West Coast down to Pt Conception and holding through the workweek, the weekend and into early next week.  The result is to be chop and weak windswell everywhere in CA, with Southern CA likely protected.     


On Tuesday (7/21) no tropical systems of interest were being tracked, typical of the Inactive Phase of the MJO's control of the East Pacific for the moment. 


South Pacific

On Tuesday (7/21) a ridge in the south  branch of the jetstream remained pushing pretty firmly to the south from Tahiti eastward, totally shutting down swell production in that region.  A weak trough was set up under New Zealand but with no real winds feeding into it, offering no support for gale development. Over the next 72 hrs this same configuration is to hold if not become reinforced with a stronger ridge building over the Southeast Pacific pushing into Antarctica totally shutting down gale production there, and only a weak trough trying to hang on in the deep Southwest Pacific. Beyond 72 hours a fully .cgiit jetstream is forecast with the southern branch pushing over Antarctica and remaining very weak with the northern branch flowing flat west to east near 30S. A bit of a cut off trough is forecast under New Zealand Sunday (7/260 into early next week, but gale development seems unlikely there (regardless what the models say). 

At the surface on Tuesday (7/21) a weak and tiny gale was positioned 1300 nmiles south of Tahiti generating 40-45 kt southwest winds and a tiny area of 28 ft seas at 40S 140W. It is to track east for 24 hours with seas to 30 ft at 40S 130W on Wednesday AM (7/22).  But little is to result for the US West Coast given it's due east heading and very tiny size.  Over the next 72 hours no other swell producing weather systems are forecast.

New Zealand Gale
On Sunday a new gale started to build just north of New Zealand producing 40 kt south winds aimed towards Fiji, producing a tiny area of 28 ft seas. By Sunday evening winds built  in this gale to 45 kts over a tiny area at 34S 177W aimed 30 degrees northeast of the 224 degree path to California and 40 degrees east of the 201 degree path to Hawaii. Seas built to 28 ft at 33S 174W. Monday AM more 45 kt winds were modeled over a tiny area at 34S 172W aimed 30 degrees east of the 220 degree path to CA and 45 degrees east of the 195 degree path to Hawaii. 32 ft seas modeled at 34S 170W. In the evening the system continued east with 40 kt winds at 34S 165W and aimed 35 degrees east of the 216 degree path to CA (unshadowed) and 65 degrees east of the 183 degree path to Hawaii. 36 ft seas were modeled at 34S 166W. Tuesday AM (7/14) renewed 45 kt southwest winds were confirmed at 34S 163W resulting  in a larger area of 37 ft seas at 34S 161W aimed 25 degrees east of the 214 degree path to North CA and just barely unshadowed and 70 degree east of the 181 degree path to Hawaii. Tuesday evening 40-45 kts winds were confirmed at 34S 155W with a tiny area of 37 ft seas modeled at 33S 155W or in the heart of the Tahiti swell shadow relative to CA (208 degrees) and pushing almost totally east of the 180 degree path to Hawaii. By Wednesday AM (7/15) 40 kt winds held with 36 ft seas at 33S 148W pushing 35 degrees east of the 204 degree path to CA and emerging from the core of the Tahitian swell shadow. This system is to continue beyond but sinking southeast fast with far less energy drifting north towards the US mainland. 32 ft seas were modeled Wed PM at 33S 142W and dissipating. The only Jason-1 satellite pass over this fetch occurred at 06Z Thurs (7/160 with seas reported at 29.5 ft were the modeled suggested 30 ft seas.  So the model was right on track.   

Swell has already hit California late Tues (7/21) at near 2 ft @ 16 secs (3.0 ft faces) and is to hold at 2 ft @ 15 secs on Wed (3 ft faces).

Swell #4S - Southeast Pacific Storm
A new storm organized on Thursday (7/16) with pressure 960 mbs and a small fetch of 50 kt southwest winds at 50S 150W aimed 20 degrees east of the 198 degree path to California and partially shadowed by the east end of French Polynesia. 35 ft seas were building at 50S 151W, already mostly outside the Hawaiian swell window (179 degrees).  That fetch started withering in size in the evening with 45 kts winds at 48S 149W aimed more to the east producing barely 40 ft seas at 48S 145W as a new fetch built to the northwest at 40S 160W with barely 45 kt winds trying to develop.

Friday AM (7/17) the two fetches were joining forces forming a broad area of 40 kts winds at 33S 144W with seas quickly building to 32 ft at 35S 150W aimed almost directly up the 203 degree path to California and on the eastern edge of the core of the Tahitian swell shadow, only partially obstructed. The Jason-1 satellite passed over the western edge of the fetch and reported seas of 28 ft, exactly as the model projected. In the evening 45 kt south winds are to hold at 35S 140W aimed directly up the 194 degree path to California and completely unobstructed. A broad area of seas if forecast building to 35 ft at 35S 140W, outside of the Tahitian swell shadow for CA.

A small area of 45-50 kts south winds built over the same area early Saturday AM (7/18) at 31S 133W aimed right up the 191 degree path northward towards CA with 42 ft seas modeled at 31S 135W.  The Jason-1 satellite passed over the eastern edge of the fetch reporting seas of 37.6 ft with one peak reading to 41.3 ft where the modeled suggested seas should be 38-39 ft. The model was right on track with reality, a good thing. In the evening a quick fade of fetch occurred with winds dropping from 40 kts but still aimed due north at 33S 130W with seas 37 ft at 29S 130W.  This system dissipated after that fast with residual 32 ft seas at 30S 127W and aimed 40 degrees east of the 181 degree path to NCal (183 SCal).

This system was on the charts for a week before it formed and ultimately developed a fair bit weaker and smaller than originally modeled, but still not too bad, Confirmed data indicates is was the best fetch so far this summer relative to California, mainly attributable to it's very north position (reducing travel distance and therefore swell decay), the complete lack of any obstruction from Tahiti/French Polynesia thereby allowing the full effects of the swell to radiate north with no degradation, and the fetch angle, aimed directly up the great circle paths to the US West Coast at it's peak strength.  On top of that respectable wind speeds  (45-50 kts) were reported. 55-60 kts would be better, but you have to take what you can get. The fetch area was not large from any historical perspective, just what one would classify as normal. So this all looks good for the US West Coast down into Mexico and Central America (those locations not shadowed by the Galapagos Islands).  Hawaii should also receive some decent sideband energy, though the bulk of the fetch is to pass well east of the Islands.  Tahiti to get a good amount of size, but it's all to be sideband energy with the bulk of the size pushing east of there as well. In all, some degree of significant class surf is expected at all locations.

Hawaii: The forecast is a little tricky here given that the bulk of the storm was practically outside the Hawaiian swell window. Still, expect swell arriving late Tuesday after sunset with period at 20 secs and rideable size in by Wed AM (7/22) with swell 2 ft @ 18 secs building to 3.3 ft @ 17 secs by sunset (5.5 ft faces with better breaks 2 ft overhead and sets to 3.5 ft overhead). Solid size expected into Thurs AM (7/230 with swell 3.3 ft @ 15 secs holding all day (5 ft faces with best breaks to 1-2 ft overhead). By Friday (7/24) swell to be fading from 3.3 ft @ 13-14 secs early (4.0-.4.5 ft faces). Swell Direction 170-178 degrees    

South California: Expect swell arrival starting Thursday late morning with period 21 secs and size on the increase, pushing 2.6 ft @ 20 secs at sunset (head high with top spots 2 ft overhead or better on the rare sets). By Friday AM (7/24) the swell to be getting quite solid with swell 4.3 ft @ 17-18 secs (7.5 ft faces with sets 4-5 ft overhead and better at top spots).Saturday AM (7/25) expect swell to hold at 4.3 ft @ 15-16 secs (7 ft faces with top spots 3-4 ft overhead or better at top spots). Still solid swell of 3.6 ft @ 14-15 secs is expected on Monday (5 ft faces or slightly better). Swell Direction: 200 degrees

North California: Expect swell arrival starting Thursday evening with swell pushing 2.0 ft @ 21 secs at sunset (shoulder to head high with top spots 1 ft overhead on the rare sets). By Friday AM (7/24) the swell to be getting quite solid with swell 4.0 ft @ 19 secs (7.5 ft faces with sets 4-5 ft overhead and better at top spots) pushing 4.6 ft @ 18 secs at sunset (8 ft faces with double overhead sets or more). Saturday AM (7/25) expect swell to hold at 4.3-4.6 ft @ 16 secs (7 ft faces with top spots 3-4 ft overhead or better at top spots) and holding through the day. Still solid swell of 4.0 ft @ 14-15 secs is expected on Monday (6 ft faces or slightly better). Swell Direction: 192 degrees

Follow-On New Zealand Gale
On Sat PM/Sun (7/19) a massive 936 low pressure system was well southeast of New Zealand over the Ross Ice Shelf and ice locked with a broad area of 30-35 kt southwest winds off New Zealand pushing up to the northeast producing a broad area of 22-28 ft seas at 43S 180W and holding into Monday AM (7/20) producing more 26-27 ft seas at 50S 170W all aimed well to the north and northeast. It was up to 4270 nmiles from the Islands. Generic 14-15 sec period swell is likely already pushing up towards Hawaii and Tahiti.

Expect small utility class swell to arrive in the Islands on Sunday AM (7/26) with swell pushing 2.3 ft @ 15 secs (3.5 ft faces with sets at top breaks to 4.5 ft) from 190-200 degrees slowly fading into Monday and Tuesday (7/28) at 2.3 ft @ 13 secs (3 ft faces).


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 no swell producing weather systems are forecast. High pressure that was off the Pacific northwest is to retrograde west some bringing trades back to Hawaii by Monday (7/27) and weak easterly short period windswell with only 10-15 kt north winds over nearshore waters of North CA, and no windswell to speak of. .  


MJO/ENSO Update (reference): As of Tuesday (7/21) the Madden Julian Oscillation (MJO) was trying to move into a weak Active Phase, the first since the 6/23 when the last of consecutive Active pulses took control on April 20th. The ENSO (El Nino Southern Oscillation) index remained neutral. The Daily SOI index was down to -5.91. The 30 day average was up again to 10.38 and the 90 day average was down to -1.80.  The SOI index remained effectively neutral but had lost all of the ground it has gained since mid-April, the highest it's been since then.  Wind anomalies at the surface and the 850 mb level (approx 1000 ft up) indicated a fading weak easterly flow still trying to push up to and over Central America, consistent with the end of the Inactive Phase.  A weak area of westerly anomalies, the signal of a newly building Active Phase were developing over the Indian Ocean, modeled a bit stronger today than previous estimates. This is good news. The models suggest the final bits of the Inactive Phase are to push into Central America by 7/25 with the Active Phase starting to reach into the far West Pacific by 7/23, holding about mid-way to the dateline into 8/4 then dissipating, never even making it to the dateline. This is a bit disappointing with what appears to be neutral conditions taking root. As of right now the big push of west winds that had been associated with consecutive instances of the Active Phase of the MJO in the Spring and early Summer of 2009 have dissipated, and with it the mechanism that has been pushing warm water from the West to the East Pacific. Latest Sea Surface Temp anomaly data (7/20) indicates that a solid area of warmer than normal water extends over the equator from at least the dateline east getting solid under Hawaii and building into Central/South America with temps to 2.5 deg C above normal. This is highly suggestive of a moderate El Nino. These warmer waters are pushing north up the coast to Baja Mexico and Southern CA too. Interestingly, cooler than normal waters are in the same location streaming off Africa, likely completely suppressing Atlantic hurricane actively.  Below the surface on the equator a steady flow of slightly warmer than normal subsurface water was tracking from the West Pacific (150 m below the surface to be exact) under the dateline and breaking the surface near Central America with warmer water just below the surface there at 2 deg C.  Previous episodes of the Active Phase had primed the warm water pump and were feeding the warm regime in the equatorial Eastern Pacific.  Previous Westerly Wind Bursts (WWB) associated with the Active Phase of the MJO had generated Kelvin Waves resulting in the movement of warm subsurface water to the east, and just now stating to break the surface near Central America. Another Westerly Wind Burst appeared to be developing on 7/6, but faded by 7/12. No Kelvin Wave activity looks to have resulted. So all looks good at a glance, but the lack of any clear symptoms of the Active Phase of the MJO has become a problem. The next 2 weeks remains critical for the formation of a legitimate El Nino.  If a real El Nino were to occur one would expect to see the SOI tending back towards the negative and perhaps a Westerly Wind Burst and a new Kelvin Wave developing. There is some suggestions of stronger Westerly Wind anomalies building in the far West Pacific, but we've been teased by this recently, only to have nothing mature. The hope is that this developing El Nino will not completely loose it's legs and falter as it did last year at this time. At this point we're in 'wait and see' mode, and getting more conservative by the day. Regardless, where we are right now is miles better than anything the Pacific has seen in the last 3 years. 


South Pacific

Beyond 72 hours a broad and decent gale is forecast just southeast of New Zealand late Thurs (7/23) generating 45-50 kt southwest winds at 52S 175W with seas building.  Friday AM 45-50 kt southwest winds are forecast at 54S 172W with 30 ft seas building at 54S 175W.  In the evening residual 45 kt west winds are forecast at 58S 175W generating 35 ft seas at 54S 172W.  Some degree of swell is forecast pushing northeast towards Tahiti and Hawaii, with a little possibly into the US West Coast. Will see what really develops.  

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

The Kelly Slater Project - A fundraiser is scheduled for Aug 29th at the Cocoa Beach Country Club to help raise funds for both the Kelly Slater Project and the Central Florida Animal Reserve. A Casino night is.cgianned including a silent auction and raffle. Sponsors are also needed. Learn more about these projects at :

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:

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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