Surf Forecasts and Marine Weather - No Hype - Just the Facts!
More Southern Hemi Queued Up! - Video Forecast HERE (4/21/24)
Buoys | Buoy Forecast | Bulletins | Models: Wave - Weather - Surf - Altimetry - Snow | Pacific Forecast | QuikCAST | El Nino | Tutorials | Great Circles | Video


Stormsurf Mobile App

Create Your Own Surf Forecast
Swell Calculator
Swell Decay Tables
Sea Height Tables
Swell Category Table
Convert from GMT:
 to timezone:

Pacific Storm and Surf Forecast
Updated: August 13, 2009 9:35 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 & 2.5 - 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 8/10 thru Sun 8/16
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   

Small S. Hemi Swell Pushes North and East
Another Possibly to Follow from the Southeast Pacific


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 (8/13) North and Central California had more locally generated northwest short period windswell in the waist to maybe chest high range with northwest winds on it and hacking it up. Southern California had knee high northwest locally generated windswell up north and up to about the same sized background southern hemi swell (a few thigh high sets) down south and clean even in the early afternoon.  Hawaii's North Shore was flat. The East Shore had knee high northeast windswell from the remnants of Felicia with southeast winds and chop at more exposed breaks. The South Shore had some weak thigh high windswell with onshore wind and chopped, backdraft from the remnants of Felicia.  

The forecast for North and Central CA is for more locally generated north windswell Friday pushing chest high and then coming up a little more over the weekend to near shoulder high on Sunday (8/160 wit improving conditions. A slow fade is expected next week but still rideable at waist high even into Thursday (8/20), so at least it will still be rideable at the more exposed spots. Southern California is to see only very limited north locally generated windswell and only at exposed north facing breaks, coming up a little Friday into the weekend reaching maybe thigh high, then settling down through early next week. Desperation surf. No southern hemi swell of interest is forecast. The North Shore of Hawaii is to remain flat for the next 7 days. The East Shore is to see no  east windswell for a while, possibly until next Wednesday when the next bout of tropically enhanced east windswell starts to arrive from a system forecast pushing northeast of the Islands (again).  Interesting pattern indeed. The South Shore is not expected to have any decent southern hemi swell until late next week, when the first signs of energy from a storm that was off the Ross Ice Shelf arrives (more below).  

Looking out over the long term a storm formed just off the northern edge of the Ross Ice Shelf on Wed/Thurs tracking east with 50-55 kt winds confirmed and up to 38 ft seas just barely ice free, but pushing more towards Central America than north towards the US or Hawaii. Still some sideband swell is expected for Hawaii by Thurs (8/20) and the mainland by Sat (8/22).  Beyond this system is forecast to try and reform Sun-Tues (8/18) in the Southeast Pacific producing maybe 30-32 ft seas but this time with more fetch aimed better to the north. This should result in better odds for the US Mainland, assuming one is to believe the models (not recommended). No activity is forecast for the North Pacific, though the tropics are to remain productive, especially the East Pacific Hawaiian corridor. Certainly a turnaround from recent years. 


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

North Pacific

At the surface today modest high pressure at 1028 mbs was positioned 1200 nmiles north-northwest of Hawaii ridging northeast towards British Columbia but not reaching there and then sagging south a bit towards Central CA, barely grazing the coast there. It was starting to generate north winds over Central CA in the 15-20 kt range, but not producing much windswell wise. The tail end of the remnants of Felicia were driving an unusual southeast flow over the Hawaiian Islands with chop occurring on southern shores. trades were not in.cgiay. more weak tropical low pressure was trying to organize between Mexico and Hawaii. And limited weak low pressure was tracking from off Japan to the dateline, with no fetch of interest occurring.  Over the next 72 hours that high pressure center is to push east and hold off the Pacific Northwest, producing the familiar pressure gradient over Central CA Friday (8/14) becoming more pronounced over the weekend with northwest winds centered off Cape Mendocino at 25 kts resulting in larger short period northwest windswell pushing south into Central CA. Trades to remain suppressed over the Hawaiian Islands through the weekend, but returning to a more normal east-northeasterly direction.  Weak low pressure originating off Japan is to migrate tot he dateline and build slightly with up to 30 kt west winds over a small area early Sunday, but it is to quickly get shunted northeast by the high pressure center off the US West Coast with all fetch turning to the northeast aimed at Alaska. No swell to result. 


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


California Nearshore Forecast
On Thursday (8/13) weak high pressure at 1024 mbs was holding off Central CA producing the usual pressure gradient and north winds at 15-20 kt building along the coast. The local gradient is forecast to build more into Friday with northwest winds forecast at 20-25 kts from the Channel Islands northward to Cape Mendocino and windswell and chop on the rise.  The gradient to start getting pronounced by Saturday AM with winds to 30 kts forecast off Cape Mendo while the fetch pulls away from the coast, improving local conditions from Pt Arena southward. This pattern is to hold into Sunday with decent windswell forecast and improving conditions. The gradient is to collapse on Monday (8/17)  with windswell on the way down, but not out.  Local winds to remain from the north at 10-15  kts in the afternoon from Cape Mendo southward through Thursday (8/20). Southern CA to be protected from all of this. 


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

Tropical Storm Guillermo was positioned 1100 nmiles south of Pt Conception CA and building in intensity, with sustained winds 60 kts and heading effectively west. Additional slow strengthening is forecast for the next 24 hrs making this system a minimal hurricane on Friday (8/14) with winds 70 kts, then slowly fading for the following 4 days with winds down to 35 kts on Tuesday as is moves up to the Big Islands of Hawaii following a path identical to Felicia.  No swell generation potential forecast immediately, though interests on Eastern shores of the Big Islands should monitor advisories on the progress of this storm.     

Tropical Depression Maka was positioned well west-southwest of Kauai with sustained winds 30 kts and fading while tracking to the west-northwest.  No swell generation potential is forecast from this system for US interests.


South Pacific

On Thursday (8/13) the northern branch of the Southern Hemisphere jetstream remained dominant pushing flat over the 30S degree latitude line into Central Chile. A strong ridge that had dominated the southern branch continued moderating, flowing effectively east under New Zealand on the 60S latitude and barely above the ice-line north of the Ross Ice Shelf. A semi-trough was tracking east well south of Tahiti and just above the Ross Ice Shelf with 110 kt winds and providing minimal support for gale development. It previously had supported development of a storm (see New Zealand Storm below). Over the next 72 hrs that trough is to try and redevelop in the far Southeast Pacific buoyed by 140 kt winds pushing up it's westerly flank forming a upper level low. Possible gale development to result down at the surface. Beyond 72 hours that trough is to push harder to the north by Mon (8/17) carving out a solid trough aligned south to north on the 120W longitude with up t o 140 kt south winds pushing up it's western flank aimed well at the the US mainland. Good  more support for gale development here if this occurs. But at the same time a new strong ridge is to be pushing hard to the south behind the trough, shutting down any potential for gale development over the Southwest Pacific.  

At the surface on Thursday (8/13) high pressure at 1038 mbs remained locked just east of New Zealand but not pushing as hard to the south as before and allowing limited low pressure to seep east into the South Pacific from the Indian Ocean.  A broad gale, the remnants of the New Zealand Storm (see details below)  was circulating mostly over the Ross Ice Shelf with 35-40 kt west winds still blowing over Ice free waters just north of there. Over the next 72 hours the remnants of the New Zealand storm are forecast to reorganize in the Southeast Pacific first on Sunday (8/160 with central pressure 952 mbs over Antarctic Ice with a fetch of 35-40 kt southwest building at 50S 140W generating 32 ft seas at 54S 144W.  That fetch is to continue in the evening aligned better to the north with 35-40 kt south-southwest winds at 49S 130W aimed 15 degree east of the 190 degree path to NCal (193 SCal) generating more 32 ft sea at 50S 133W.  That fetch to fade but not before pushing some form of 16 sec swell to the north if all goes as forecast.  Central and South America to get a good pulse too. 

A secondary small push of 35-40 kt winds are forecast Monday evening (8/17) at 53S 138W aimed straight to the north generating more 30 ft seas at 50S 138W perhaps holding into Tuesday AM with more 30 ft seas forecast at 49S 133W.  But that's quite a reach for the models and do not expect this to occur.           

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. 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.

Some bare 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 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 arrive in Hawaii on Thurs early AM (8/20) with swell pushing to 2 ft @ 16-17 secs  (3.5-4.0 ft faces) in the afternoon.  Swell fading from 2 ft @ 15 secs (3.0-3.5 ft faces) on Fri (8/21).  Swell Direction: 182-186 degrees

Expect swell arrival in California on late Friday afternoon in SCal with swell 1.5 ft @ 18 secs   (2.5-3.0 ft faces) and building overnight. Swell to peak early Sat (8/22) in SCal and late in NCal at 2.5 ft @ 17 secs  (4.0-4.5 ft faces with top spots to 5.0-5.5 ft). Period dropping to 16 secs on Sunday.  Swell Direction: 205 degrees SCal/202 degrees NCal.   


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 break down off the Pacific Northwest late Tues (8/18) and retrograde to the west again, with windswell fading off the California coast.  Trades are to redevelop on Wednesday for Hawaii too, fueled by the high pressure system and another batch of tropical energy pushing east towards the Big Island, moving closer still by Thursday (8/20).  This might be something to monitor. Another tropical system is modeled right behind it too. Another low pressure cell that migrated east off Japan is scheduled to be in the Western Gulf of Alaska on Thurs (8/20) with 30 kt northwest winds aimed at the Islands.  But that is more wishful thinking by the models than reality.  

MJO/ENSO Update (reference): As of Thursday (8/13) the Madden Julian Oscillation (MJO) was moving into a weak Inactive Phase. The ENSO (El Nino Southern Oscillation) index remained just bit south of neutral. The Daily SOI index was at -2.49 and has been negative (or nearly so) for the past 23 days (since 7/21). This is about all one could expect from a typical Active Phase. The 30 day average was down to -4.24 and the 90 day average was down a little at  -1.63.  The SOI index has regaining some of the ground it lost when the MJO went Inactive in early July, but not that much.  Wind anomalies at the surface and the 850 mb level (approx 1000 ft up) indicated that weak westerly wind anomalies, the signal of a weak Active Phase, had dissipated and a building  area of easterly anomalies had developed over the Philippines 1/2 way to the dateline and back into the Indian Ocean.  This was much larger than previous forecasts. The Inactive Phase is taking charge. The models expect the easterly anomalies to hold solid through 8/17 reaching a little east of the dateline, then dissipating slowly by  8/27 with neutral conditions taking hold by 9/1. As expected, this is a bit stronger than originally forecast (the models typically undercall it). so it will be quite interesting to see how much steam this Inactive Phase takes out of the developing El Nino, and whether it undercuts the developing warm pool in the east equatorial Pacific. Sea Surface Temp anomaly data (8/10) 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 was tracking from the West Pacific (150 m below the surface) under the dateline and breaking the surface near Central America with a previous Kelvin Wave almost completely dispersed there. And another Kelvin Wave is migrating east from 170W resulting from a  Westerly Wind Burst (WWB) in the West Pacific on 7/25-8/2. It is 2-3 deg C above normal and building and still feeding  the warm water pump, providing reinforcements on the way to Ecuador. This is critical to the formation of a legitimate El Nino.  Of some concern is a pool off cooler than normal water that's starting to appear 120M down at 140W.  The hope is this will not rise any higher and block the path of the new Kelvin Wave heading east from the dateline.  Of more interest is the appearance of more fully blowing westerly winds in the far West Pacific and developing westerly anomalies reaching almost to the dateline (starting 8/12).  If this materializes/holds even while the Inactive Phase is building in the West, it would be a significant event. But we suspect those winds will subside in a day or so as the Inactive Phase takes root. The belief at this time is this developing El Nino will not loose it's legs and falter like last year, but 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 still muddled. 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 is certainly the case right now. 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, in our minds the delineation of whether development will continue versus stall is dependent upon more WWBs. It will be most interesting to monitor the next active phase of the MJO, expected sometime near the 3rd week of Sept, and validate whether water temps hold if not build (i.e.or whether another WWB will occur - as is maybe happening even now on 8/13),. A final confirmation should be possible in Sept. In the mean time, 21 days of the Inactive Phase, or neutral conditions (if we're lucky) are setting up. 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. A update to the Stormsurf El Nino forecast page is in-work and should be posted in a few days.     


South Pacific

Beyond 72 hours the same gale in the Southeast Pacific is to perhaps generate yet more 35 kts fetch on Wed/Thurs (8/20) and 28 ft seas aimed well to the north.  More shorter period swell (14-15 secs) is possible for Central America up into the US Mainland if this occurs. 

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

Add a STORMSURF Buoy Forecast to your Google Homepage. Click Here: Add to Google
Then open your Google homepage, hit 'edit' button (top right near graph), and select your location


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

Free Stormsurf Stickers - Get your free stickers! - More details Here

Read all the latest news and happenings on our News Page here

Surf Height-Swell Height Correlation Table


Contact | About | Disclaimer | Privacy
Advertise/Content | Links
Visit Mark Sponsler on Facebook Visit Stormsurf on Instagram Visit Stormsurf on YouTube
Copyright © 2023 STORMSURF - All Rights Reserved
This page cannot be duplicated, reused or framed in another window without express written permission.
But links are always welcome.
Buoys | Buoy Forecast | Bulletins | Models: Wave - Weather - Surf - Altimetry - Snow | Pacific Forecast | QuikCAST | El Nino | Tutorials | Great Circles | Calculator