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Pacific Storm and Surf Forecast
Updated: August 22, 2009 4:07 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 = 3.2 - 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 8/24 thru Sun 8/30
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   

More S. Hemi Swell For California
Gulf of Alaska to Become Moderately More Productive


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 Saturday (8/22) North and Central California had locally generated northwest windswell in the chest high range with southern hemi swell at waist to chest high with some bigger sets at the top spots and reasonably clean early. Southern California was getting a good piece of southern hemi swell with waves waist high up north but chest to near head high at top spots down south but pretty heavily textured early. Hawaii's North Shore was flat. The East Shore had shoulder high east windswell hitting exposed breaks with onshore winds and chopped. The South Shore had more waist high southern hemi sideband swell and clean.    

The forecast for North and Central CA is for more locally generated north windswell in the chest high range on Sunday at 5 ft @ 9 secs with a little north swell intermixed at 4-5 ft @ 11-12 secs.  Also more small southern hemi swell from a storm that was off the Ross Ice Shelf last week is expected pushing 2.5 ft @ 16 secs (4 ft faces) on Sunday (8/23). And more southern hemi swell to shoulder high is expected Mon-Wed at least with local windswell and yet another Gulf swell intermixed Wed-Thurs (8/27). Southern California is to continue with the southern hemi swell on Sunday (2.5 ft @ 15 secs - 3.5-4.0 ft faces). And yet more southern hemi swell is expected in for Mon -Wed.  The North Shore of Hawaii is to remain flat for the next 7 days. The East Shore is to seeing a little more easterly local tradewind windswell Sunday but slowly fading through the early part of the week and almost gone by Wednesday (8/26). The South Shore is to have one more day of southern hemi sideband swell on Sunday at 1.6 ft @ 16 secs (up to 3.0 ft faces) originating from a storm that was off the Ross Ice Shelf,  but then gone by Monday.   

Over the long term down south the gale that was off the Ross Ice Shelf reformed in the far Southeast Pacific Sun/Mon (8/17) producing 32 ft seas, with energy pushing a bit more to the north. Decent utility class swell is expected into  US Mainland Mon-Wed (8/26), then fading out with absolutely nothing on the charts expected to follow. Up north the models continue indicating that a series of weak gales will develop in the Eastern Gulf of Alaska, with the first already developed and it's swell on the way to exposed breaks in Central CA for Sunday and points northward. Yet another, this one a bit stronger, is on the charts late for Mon/Tues (8/25) with up to 25 ft seas focused mainly on the Pacific Northwest. And a much broader one is on tap for Thurs-Sun (8/30) with 15-20 ft seas targeting the entire US West Coast and maybe even Hawaii. So there's better things to look forward too, but nothing even moderately strong yet.


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

North Pacific

At the surface today high pressure at 1024-1028 mbs was poorly organized over a broad area from the dateline east ridging into Oregon generating the usual pressure gradient off Cape Mendocino producing 25 kt north winds and moderate north short period windswell pushing into exposed breaks in Central CA. It was also producing easterly trades over the Hawaiian Islands at 15-20 kts resulting in moderate short period easterly windswell there too. Previously on Thursday (8/20) a small gale formed in the far Northeastern Gulf of Alaska at 1000 mbs creating a pressure gradient with high pressure to it's west generating confirmed northwest winds at 35 kt at 52N 145W aimed at Washington but likely setting energy up down into Central CA down the 319 degree path. This gale faded a little with 30 kt winds on Thursday evening (8/20) at 52N 142W and seas up to 19 ft at 52N 143W and 19 ft again Friday AM at 51N 140W while pushing into British Columbia with 25 kts winds later Friday. Small 12-13 secs period swell is confirmed pushing down the Pacific Northwest coast on Saturday at 7 ft @ 12 secs and is expected to limp into Central CA on Sunday at 5 ft @ 11-12 secs (5.5 ft faces with luck).

Over the next 72 hours another gale is to form in the Northeastern Gulf of Alaska 1100 nmiles west of Washington with 35 kt fetch aimed well at California Sunday evening (8/23) and drifting east with 40-45 kt west-northwest winds Monday AM at 50N 142W aimed down the 319 degree path to Central CA, but targeting the Pacific Northwest better. 23 ft seas forecast at 50N 144W Monday AM (8/24). Still 35-40 kts winds are forecast Monday evening at 50N 140W pushing a bit down the 319 degree path to Central CA but favoring Oregon and Washington with 25 ft seas at 49N 139W again on the 319 degree path to Central CA then fading while moving towards British Columbia proper. If all this occurs a good chunk of 14 secs period swell looks likely for Oregon and Washington late Tues into Wed (8/26) and 13 sec energy for Central CA on Wed AM. Nothing for Hawaii yet. Looks like Fall is starting.


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


California Nearshore Forecast
On Saturday (8/22) high pressure at 1028 mbs was in control centered 1200 nmiles west of North CA ridging east and forming the usual pressure gradient over Cape Mendocino resulting in 25 kt north winds there, but not pushing any further south than Pt Arena. A weak northwest flow was south of there down into South CA. This pattern is to hold Sunday then starting to fade Monday as low pressure builds in the Gulf of Alaska, but not totally out of the picture till Wednesday (8/26). But there's suggestions of northwest winds at 15 kts moving very close to the Central CA coast Mon-Wed, before the high pressure system totally dissipates. Regardless. but late Wednesday low pressure is to fill the Gulf with neutral pressure off CA Central and a front pushing towards the US, reaching as far south as Cape Mendo on Friday before dissipating. There's suggestions of more weak high pressure off CA next weekend with possibly northwest winds, but that's a reach. The battle of the change of season is looking to start setting up locally.


The Active Phase of the MJO is fading over the East Pacific, which likely will reduce the odds of tropical storm formation over the coming days for the next 3 weeks: 

On Saturday (8/22) Typhoon Vamco was positioned 800 nmiles northwest of Wake Island continuing to track due north with sustained winds down to 90 kts and slowly fading as it tracks over cooler waters. But Vamco is still to be at minimal typhoon force on Monday (8/24) while making a turn to the northeast and accelerating off the Kuril Islands.  This is good news.  It is expected to eventually get picked up by the jetstream and head northeast towards the Gulf of Alaska, reaching there late Thursday (8/27) and possibly redeveloping. No immediate swell production is forecast, but this is worth monitoring and is one of the classic symptoms of El Nino.

Tropical Storm Hilda had 35 kt winds and was positioned  850 nmiles east-southeast of Hawaii.  Hilda is forecast to track slowly west while intensifying, with up to 55 kt winds (still tropical storm force) as it approaches a point about 300 nmiles south of the Big Island on Friday (8/27). Possible southeast swell for east shore of the Big Island if this comes to pass.     


South Pacific

On Saturday (8/22) the fully .cgiit jetstream pattern continued over the South Pacific was in effect, with the northern branch flowing flat east on the 30S latitude while the southern branch pushed weakly east on the 62S latitude and mostly encased in ice over the Ross Ice Shelf offering no odds for gale development.  Over the next 72 hrs a reinforcing ridge is to build pushing hard to the east over the Southwest Pacific Sun/Mon (8/24) continuing the lockdown in the upper atmosphere and eliminating any odds for gale formation there.  Beyond 72 hours not much of a change is forecast. If the North Pacific continues to show promise, we might shut down the jetstream analysis for the South Pacific and start focusing on the North Pacific.

At the surface on Saturday (8/22) high pressure at 1028 mbs was locking in east of New Zealand ridging to the northern edge of the Ross Ice Shelf and completely blocking the south Pacific storm corridor in the western South Pacific. No low pressure of interest was occurring. Over the next 72 hours reinforcing high pressure at 1032 mbs is build east of New Zealand and drifting east more or less continuing the lock down and eliminating any odds for gale development. 


New Zealand Storm
A vigorous storm started building fast on Wednesday AM (8/12) over the Ross Ice Shelf with 50 kt west-southwest winds confirmed at 60S 175W aimed 20 degrees east of the 205 degree great circle path to CA and in the heart of the Tahitian swell shadow 45 degrees east of the 188 degree path to Hawaii. 30 ft seas were modeled building at 60S 180W just barely ice free. In the evening 50-55 kts winds were confirmed moving rapidly northeast to 55S 158W aimed 30-35 degrees east of the 203 degree path to CA and 65 degree east of the 180 degree path to Hawaii. 38 ft seas were modeled at 58S 165W and building, moving a little more clear of the Ross Ice Shelf. The Jason-1 satellite passed over the southeast quadrant and reported seas 36.4 ft with a peak reading on 41 ft were the model suggest seas should have been 32-33 ft. This was much better than what was expected. Winds were fading fast Thursday AM (8/13) from 40 kts, not adding any energy to the seas generated the day before. 38 ft seas from previous fetch were modeled at 56S 156W and fading fast. Thursday PM no fetch of interest was forecast with seas fading from 33 ft at 55S 146W. The Jason01 satellite passed over this area and confirmed seas at 32.4 ft with a peak reading to 37.1 ft where the model suggested 30 ft seas. Again, the models appeared to be on the low side.

Some minimal background sideband energy is expected to travel north towards the Islands with larger but slightly shadowed energy pushing up towards the US mainland.  But the main issue here is that although the Jason-1 satellite reported seas higher than what was modeled, almost all the fetch was aimed well east of any great circle path to either Hawaii or the US mainland, instead focused more on Central and South America.

Expect swell to continue arriving in California at 2.5 ft @ 16 secs (4 ft faces) on Sunday (8/23).  Swell Direction: 205 degrees SCal/202 degrees NCal.     

Second Pulse - From the Southeast Pacific

On Saturday (8/15) the remnants of the New Zealand Storm (see details above) were positioned mostly over the Ross Ice Shelf, though a fragment of it's winds in the 30-35 kt range were still blowing over Ice free waters at 52S 145W resulting in a small area of 30 ft seas off the edge of the Ross Ice Shelf at 58S 150W.All of this was aimed due east towards Chile rather than north towards US interests. This system reorganized better in the Southeast Pacific lifting a bit north on Sunday AM (8/16) with central pressure 948 mbs (over Antarctic Ice) with a fetch of 40-45 kt southwest winds building at 50S 140W generating 30 ft seas at 54S 147W aimed 40 degrees east of the 192 degree route into California.  That fetch continued into Sunday evening aligned about the same way with 35-40 kt southwest winds at 49S 130W aimed 45 degree east of the 190 degree path to NCal (193 SCal) generating 32 ft sea at 48S 138W.  Some form of 16-17 sec swell is expected to push north towards CA, though Central and South America to get the best of it.

A secondary decent push of 40 kt south winds occurred Monday AM (8/17) at 53S 140W aimed almost straight to the north generating more 32 ft seas at 54S 130W holding into the evening with more 32 ft seas at 52S 132W, then fading after that. A better pulse of small swell is to result tracking up into the California and Central America swell windows.    

Southern CA:  Expect swell arrival on Mon (8/24) at 2.3 ft @ 17-18 secs (4 ft faces with top spot to 5 ft) holding at 2.3 ft @ 16 secs (4 ft faces) on Tues. Additional swell to move in on Tuesday from the second pulse at 3 ft @ 17 secs (5 ft faces with top spots to 6 ft). Swell to continue Wednesday at 3 ft @ 15 secs (4.5-5.0 ft faces) then fading into late Thursday (8/27)     Swell Direction: 193 degrees.

Northern CA:  Expect swell arrival on Mon (8/24) at 2.3 ft @ 17-18 secs (4 ft faces with top spot to 5 ft) holding at 2.6 ft @ 16 secs (4 ft faces) on Tues. Additional energy from the second pulse to arrive late Tuesday pushing up to 3 ft @ 16 secs on Wednesday (5 ft faces with top spots to 6 ft), then settling down into Thursday and early Fri (8/28). Swell Direction: 190 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 hours yet another gale, this time a co.cgiex gale with two pulses is forecast to move into the Northwestern Gulf on Tuesday (8/25) producing 30 kt northwest fetch over a larger area and offering a hint of energy even for Hawaii with a good dose for Central CA and maybe even Southern CA. This one to hold in the Central Gulf into Wednesday producing 15 ft seas while the remnants of Typhoon Vamco get sucked northeast by the jetstream. Theoretically is to rebuild in the Central Gulf Thurs/Fri (8/28) resulting in a decent sized fetch and 18-20 ft seas. But this is quite a reach for the models. Still, it's something to monitor.

MJO/ENSO Update (reference): As of Saturday (8/22) the Madden Julian Oscillation (MJO) was in the Inactive Phase. The ENSO (El Nino Southern Oscillation) index has continued to defy expectations through (in a good way) remaining negative. The Daily SOI index was at -8.86 (4 days in a row) making it effectively a 33 day negative run (since 7/21), typical of the Active Phase. This is being caused by a slow moving low pressure system tracking east under Tahiti and is expected to hold into Friday (8/28). The 30 day average was down to -5.29 and the 90 day average was up to -0.79.  The SOI index continues to regain some of the ground it lost when the MJO went Inactive in early July.

Wind anomalies modeled at the 850 mb level (approx 5000 ft up) indicated that a strong area of easterly anomalies that was previously modeled over the Philippines has now all but evaporated. Only a small patch remains extending from the Philippines west into the Indian Ocean while westerly anomalies hold down the East PAcific from the dateline into Central America. This is good news. The models project the easterly anomalies to slowly fade  through 8/31, never making it east of the Philippines. This is the best news we've seen in a long while. But, the Active Phase is not expected to develop anytime through 9/10. That said, the models obviously don't have much of a handle on the situation. There is no way that a previously forecast strong Active Phase disappears in 1-2 days. Suspect the Active Phase will appear weakly in early Sept, but it will just take a while for the models to figure it out when it does happen.

Sea Surface Temp anomaly data (8/20) indicates that a solid area of warmer than normal water extends over the equator from the dateline east and building into Central/South America with temps to 2.0 deg C above normal. This is suggestive of a moderate El Nino.  These warmer waters are pushing north up the coast of Baja Mexico and are now pushing up over the California coast too. Much cooler than normal waters (-2.5 deg C) are mirrored streaming off Africa and pushing east, now reaching South America. This is probably the height of this Atlantic event. Looking back in the records, exactly the same flow developed during the big El Nino of 1997 and is likely to suppress Atlantic hurricane actively due solely to the frigid water temps. 

Below the surface on the equator a steady flow of slightly warmer than normal subsurface water has been tracking from the West Pacific (150 m below the surface) under the dateline and breaking the surface near Central America for months now. Another Kelvin Wave is migrating east from 165W, the result of a Westerly Wind Burst (WWB) in the West Pacific that occurred on 7/25-8/2. It is 2 deg C above normal and building while feeding the warm water pump, providing reinforcements on the way to Ecuador. This is critical to the formation of a legitimate El Nino, but will take 2 months from the time it is generated to reach it's target (9/27 or so).  Of note - a small pocket of cooler water 100 meters down on the equator south of South CA that was previous mentioned a week or more ago is still present, and has risen to 75 meters in depth. If this trend continues it could block the eastward progress of the Kelvin Wave. Will monitor.

Fully blowing westerly winds in the far West Pacific and westerly anomalies reached to the dateline starting 8/12. They had pretty much settled down by 8/19, and were reduced to weak anomalies as of 8/20, and those weak westerly anomalies but do not appear to be going anywhere as of 8/22.  Looking at the models dead slack winds are forecast on the equator in association with low pressure tracking east and centered south of Tahiti through the coming workweek (8/28). This is good news and might continue to prime the warm water pump pushing east. If this pattern holds for a few more days, perhaps another Kelvin wave could result (not likely), or at least reinforcement for the existing Kelvin Wave already in-transit. Will continue monitoring this situation.   

The belief at this time is this developing El Nino is past the critical juncture, and will survive in some fashion with effects continuing in the atmosphere until at least the Spring of next year. It is certainly doing much better for much longer than last year. But the picture is far from black and white. That is not to say this will be a strong El Nino, more likely a weak to moderate one. NOAA is now also forecasting the same outcome. Of note, some data suggests that during the development of moderate to stronger El Nino's and La Nina's, it is normal for the MJO signal to become exceedingly weak. That was the case in late July into early August, and is still the case today. That co.cgied with the solid accumulation of warm water in the equatorial East Pacific is evidence in-favor of continued development. As long as there continues to be WWB's, then warm water will be migrating east, and the warm water pattern will hold if not build, and the atmosphere above it will respond in kind to the change (towards El Nino). Therefore the delineation of whether development will continue versus stall is dependent upon more WWBs. And the scales continue to tip in favor or more development rather than less.

The next milestone were looking for is development of the next Active Phase of the MJO, expected sometime near the 3rd week of Sept. Also water temps need to hold if not build (i.e.or whether another WWB will occur - as is maybe happening even now on 8/15),. A final confirmation should be possible in Sept. In the mean time, 21 days of the Inactive Phase are in progress, but much weaker than previously forecast. Strong El Ninos bring lot's of bad weather to the US West Coast, along with the potential for storm and swell enhancement. A moderate El Nino provides storm and swell enhancement, without necessarily all the weather. So as of right now things remain miles better than anything the Pacific has seen in the past 12 years regarding anomalous sea surface temperatures, besting anything since the big El Nino of 1997. That is very good news.  But the lack of a clear response in the atmosphere as evidenced by a unremarkable SOI remains pe.cgiexing (even though all other indicators suggest an El Nino is well underway), causing us to remain cautious.  

See more details in the new  El Nino update.


South Pacific

Beyond 72 hours no swell producing fetch is forecast with high pressure holding moderately strong in the mid-South Pacific at 1024 mbs pushing the storm track mostly over Antarctic Ice.  

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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