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Pacific Storm and Surf Forecast
Updated: September 25, 2010 10:01 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 = 3.9 - California & 3.5 - 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 9/27 thru Sun 10/3
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   

Gulf Swell Moving Towards HI and CA
And Another Builds in Western Gulf


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 (9/25) North and Central California was getting combo dateline/Eastern Gulf swell with waves head high or a little more and clean early with clear skies. Southern California was getting knee high northwest swell up north and clean with some maybe thigh high sets down south and clean too.  Hawaii's North Shore was getting leftover dateline swell with waves waist to chest high and clean early. The East Shore was getting wrap around energy from the North Shore at waist high with lightly chopped conditions. The South Shore had more near waist high clean Tasman Sea swell hitting.    

The forecast for North and Central CA is for north swell is to continue fading from 5 ft on the face early Sunday and dropping from there. New swell from a gale in the western Gulf is to arrive late night Sunday and be pretty sizeable on Monday, double overhead or more (11 ft). That swell to be fading Tuesday AM from 9 ft with a new swell from a supposed gale building in the Gulf building overnight , and up to near 12 ft on Wednesday AM. Southern California is to see maybe some north angled Gulf swell at select breaks at thigh high Sunday AM and fading from there.  Limited southern hemi swell from the Tasman Sea to also arrive Sunday at thigh high or so, pushing waist to maybe chest high at top break on Monday but very inconsistent. Better odds on Monday of seeing a new swell from the Gulf of Alaska at head high and holding through the day. Tuesday that swell drops from chest high or so then new swell from the Gulf arrives overnight pushing shoulder high or so Wed AM. The North Shore of Oahu is to see new Gulf swell arriving overnight Saturday and pushing 13 ft (faces) on Sunday AM then dropping from 8-9 ft faces on Monday. Yet another new Gulf swell arrives for Tuesday AM at 12-13 ft (faces) fading from 8 ft Wed AM. The East Shore is off the radar now that Fall is here.  The South Shore is to see swell from the Tasman Sea filtered by Fiji fading from waist high Sunday AM then thigh high Monday. Another reinforcing pulse of Tasman Sea swell is expected in on Tuesday at near chest high building to chest to head high on Wednesday (with luck).   

Remnants of a dateline gale reorganized off Vancouver Island on Wed/Thurs (9/23) with seas to 26 ft, setting up north angled swell for CA for Saturday into early Sunday, with yet a larger system developing in in the Central Gulf of Alaska Thurs-Sat (9/25) with seas in the 32 ft range. And yet another gale is expected behind that in the Central Gulf on Sunday 32 ft seas while another extratropical system pushing north off Japan with seas at near 50 ft then turning east just shy of the Aleutians tracking into the Northern Gulf mid-week with seas at 37 ft. We are officially in a Fall pattern now, and not a moment too soon.   

Down south a gale tracked into the Tasman Sea Thurs AM (9/16) with seas to 38 ft and slowly fading into Saturday AM with seas dropping below 30 ft, all focused very well on Fiji and Northern New Zealand, with limited energy having filtered through Fiji and already hitting Hawaii with less for California by Sun/Mon (9/27).  Reinforcing energy from another smaller gale in the Tasman Sea to follow directly too. But with the North Pacific active now, this is of much less interest.


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

North Pacific

On Saturday (9/25) the North Pacific jetstream was ridging slightly over Kamchatka then dipping well tot he Southeast over the dateline on into the Gulf of Alaska with up to 190 kt winds on the dateline and less into the Gulf. Regardless this was the best we've seen so far this Fall and was providing a.cgie support for gale development in the Gulf. Over the next 72 hours that trough is to deepen but weaken slowly but steadily while starting to pinch off later Sunday into Monday (9/27) and gone by Tuesday. Still, it is to provide some support for gale development into Monday. Beyond 72 hours another surge is forecast on Wednesday with 160+ kt winds falling southeast into the Gulf again forming a nice trough and providing more support for gale development there and not pinching off, just slowly moderating into Friday while tracking east, almost reaching the Central CA coast Saturday evening and continuing to provide gale development support. Even at that the jet is to still be tracking fairly flat over the 45 N latitude, which is a good latitude for this time of year.

At the surface on Saturday (9/25) the remnants of what was a large gale in the Central Gulf was fading off Northern Canada (see Gulf Gale below). Also Typhoon Malakas was just 240 nmiles west of Central Japan tracking north-northeast with winds 75 kts. This is something to watch for the future. Over the next 72 hours another gale was developing in the far Western Gulf of Alaska Saturday AM (9/25) with winds to 45 kts at 46N 174W aimed well down the 335 degree path to Hawaii initially and 40 degrees south of the 297 degree path to NCal. By Saturday evening (9/25) 55 kt northwest winds are forecast at 42N 160W aimed a bit east of Hawaii down the 352 degree track and the 293 degree track to NCal. 29 ft seas expected at 44N 163W. It is to track rapidly east on Sunday AM  with up to 45 kt west winds forecast at 42N 151W taking aim exclusively on the US West Coast with seas to 34 ft at 42N 154W,  then lifting  northeast in the evening with 35 kt west winds fading at 44N 145W and 32 ft seas at 43N 147W focusing entirely on the California and Baja. It's to rapidly lift northeast and dissipate on Monday.   If this occurs another nice pulse of 15-16 sec period north swell could push into Hawaii late Monday afternoon pushing near 7 ft @ 15 secs likely after sunset (11 ft Hawaiian) with northwest angled swell into Central California perhaps after sunset on Tuesday.  

Gulf Gale
A new broad gale developed over the Western Gulf on Thursday AM (9/23) with pressure 968 mbs and west winds to 40 kts building at 48N 180W with seas building from 23 ft. By evening up to 45 kt northwest winds were modeled at 46N 162W on the 298 degree path to NCal and aimed 40 degrees east of the 353 degree path to Hawaii with 29 ft seas at 47.5N 163W.  Friday AM (9/24) 40 kt west-northwest winds dropped to 45N 153W on the 297 degree path to NCal and pretty much east of the Hawaiian swell window with 32 ft seas at 45N 155W. Friday PM winds faded to 35 kts but making more southeastward progress at 44N 150W generating 32 ft seas at 44N 151W (295 degs NCal).  A quick fade occurred thereafter.

this is the first real legitimate utility class swell of the Fall season and is expected to push into Hawaii on Sunday reaching to 7 ft @ 15 secs midday (11 ft Hawaiian) from 345-350 degrees. Swell to be fading rapidly on Monday.

Northern CA is to see the start of this swell arriving just past sunset Sunday peaking over night at 8 ft @ 16 secs (13 ft) then fading from 8 ft @ 14 secs Monday AM )11 ft). Swell Direction 296-298 degrees.    


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


On Saturday (9/25) Typhoon Malakas was 240 nmiles east of Central Japan and tracking effectively north-northeast with sustained winds 75 kts and on the increase. Fetch was building in it's south and southeast quadrants aimed up the great circle path towards the US West Coast and sideband energy towards Hawaii. the A steady track to the north is forecast with more strengthening, eventually turning extratropical while turning northeast and east surviving almost in tact while tracking over the extreme  northern dateline region into the Western Gulf of Alaska late Monday (9/27). See the long term forecast for details. Still, it's still early to believe too much of this, but it remains something to monitor. 

California Nearshore Forecast
On Saturday (9/25) high pressure was trying to make a slight return with a weak bit of it touching Central CA generating some north winds there at 15 kts over out waters, but calm nearshore. Low pressure was building into the Gulf of Alaska with a front pushing into Washington. High pressure is to try and build over outer waters on Sunday afternoon to 20 kts.  Still nearshore looks to be pretty light 10 kts or less early. More of the same forecast Monday with the gradient finally getting establish over Cape Mendo on Tuesday (9/28) at 20 kts and holding there into Thursday, then slowly fading.  Nearshore the picture is to be fine over the Tues-Thursday window.  And Southern CA is to be protected . The models show another little mini gradient developing over Cape Mendocino next weekend, but Central CA and points south of there to remain mostly wind free.    


South Pacific

On Saturday (9/25) a broad weak gentle trough was under New Zealand with no wind energy associated with it feeding into a weak ridge over the Southeast Pacific. No support for gale development was evidenced. 
Over the next 72 hours the trough in the west is dissipate as a big ridge builds there pushing southeast eliminating support for gale development at the oceans surface.  Beyond 72 hours a flat weak flow is expected generally over the 55S latitude offering nothing to support gale development.

At the oceans surface on Saturday AM (9/25) a gale low was fading. It had previously developed under New Zealand with up to 55 kt west winds over a small area on Friday AM (9/24) at 55S 175E aimed mostly east of any great circle track to Hawaii or the US West coast and continued east in the evening at 55S 177E then was fading into Saturday AM. 35 ft seas were indicated Fri AM At 55S 170E pushing 42 ft in the evening at 55S 180W and again at 42 ft Saturday AM at 55S 172W. Possible background swell for Hawaii and CA at select south facing breaks not inundated with stronger northerly swell if all develops as forecast.   Over the next 72 hours no other swell producing fetch is forecast. 


Tasman Sea Gale
At the oceans surface on Thursday (9/16) a broad gale built in the Tasman Sea.
This system started forming south-southwest of Tasmania on Wed (9/15) with 45 kt south to southwest winds pushing mostly into Tasmania, with maybe a little reaching clear of it's south end and tracking up into the extreme southern Tasman Sea. On Thursday 40 kt southwest fetch was finally pushing free and clear of Tasmania reaching to 39S 152E early and up to 36S 165E late resulting in 37 ft seas at 39S 159E (Thurs PM).  Then on Friday additional 40 kt southwest fetch built into the Central Tasman Sea near 40S 160W resulting in 33 ft seas at 40S 170E in the evening. This system faded fast on Saturday AM. Northern New Zealand is to receive the brunt of this swell though an almost equal amount of swell energy is to push up into Fiji starting on Sunday AM (9/19 GMT).

Filtered swell is expected to continue hit Hawaii at 3 ft @ 16 secs (head high) early Friday (9/24) then slowly settle down. But still swell of 2 ft @ 14 secs (waist high sets) is expected on Sunday (9/26). Swell Direction: 215 degrees.

Dribbles are forecast pushing into Southern CA on Sunday (9/26) at 1.6 ft @ 18 secs (2.5 ft faces) reaching 2 ft @ 16 secs (3 ft faces) on Monday.  Swell Direction: 231-235 degrees.

Another New Zealand Gale
A new storm wrapped up south of the Tasman Sea Sunday evening with 45-50 kt south winds at 56S 155E aimed directly at New Zealand. This fetch lifted northeast and starting to impact the southern tip of New Zealand Monday AM (9/20) with the core still at near 50 kts at 53S 160E (southwest of New Zealand). By evening the fetch was still at 45 kts located at 54S 168E moving into the 220 deg swell window for California. 32 ft seas were modeled at 50S 170E, perhaps pushing energy towards CA. Tuesday AM (9/21) a tiny fetch of 45 kt south winds persisted at 52S 170E resulting in near 32 ft seas at 50S 172E over a moderate area and pushing up the 216 degree path to California and unshadowed by Tahiti and the 200 degree path towards Hawaii. The fetch is to be gone by evening with sea to 34 ft from previous fetch at 50S 179E. It seems reasonably to assume that a decent little pulse of southern hemi swell will radiate towards Hawaii and California, with the Islands getting the better shot of the energy just due to being closer minimizing swell decay. But with swell from the North Pacific becoming more of a reality, this swell becomes less interesting.

Expect swell arrival in Hawaii starting Tues (9/28) with swell 2 ft @ 17 secs (3.5 ft faces).  Swell Direction 198 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 hrs the extratropical remnants of Typhoon Malakas were tracking north northeast off the coast of Japan on Saturday with winds at 75 kts at 40N 150E aimed well pushing up the 302 degree path to NCal and seas to 46 ft, then up to Kamchatka on Sunday (9/26) with winds 55 kts just south of the Aleutians Islands at 47N 160E (305 deg NCal) and seas fading from 48 ft,  then tracking over the dateline on Monday (9/27) with west winds fading from 45 kts at 50N 173E (on the 307 degree path to NCal) and seas 42 ft, then pushing into the Northwestern Gulf of Alaska Tuesday (9/28) with winds fading from 40 kts at 50N 165W (307 NCal) and seas 36 ft. Possible small but long period swell pushing the entire way across the North Pacific to California from a rather north angle if this comes to pass. Most of this fetch is to be aimed well north of the great circle paths into Hawaii, but some swell could result just the same there too.   

MJO/ENSO Update (reference):   As of Saturday (9/25) the Southern Oscillation Index (SOI) continued solid in the positive range. The daily SOI was at 30.66 and has been that way in excess of 68 days now. The 30 day average was up to 24.39 with the 90 day average up to 20.17.  The Inactive Phase of the MJO appears to still be in control.  

Wind anomalies as of Friday (9/24) at the 850 mb level (approx 5000 ft up) as defined by models indicated an almost neutral (normal) wind pattern in control with only weak west anomalies pushing into Central America. A completely dead neutral pattern is expected to hold through 10/14.

We believe the remnants of El Nino are just about gone from the upper atmosphere. The expectation is that we'll see a building moderate to moderate.cgius strength La Nina Pattern (where the Inactive Phase takes control) for the remained of 2010 extending well into 2011 and likely to early 2012. In short, the next year and half is going to be tough for surfers on west facing shores in the Eastern Pacific and Eastern Atlantic, though east facing shores of the West Pacific and Atlantic might do well from the Inactive Phase's dominance.     

Sea Surface Temp anomaly data (9/13) indicates that downright colder than normal waters continue to expand their grip on the equator covering solidly from South America west to the dateline and beyond and are in fact getting cooler and covering a larger area over time, extending the whole way to New Guinea.  The coldest waters extended from a point south of Hawaii to just west of the dateline, a clear signal of strong easterly winds there and solid upwelling. Feeder bands of cooler than normal water continued building off the US West Coast and South America sweeping fully to the dateline, only serving to reinforce what is already an impressive La Nina pattern, suggesting stronger than normal high pressure has built in both hemispheres and upwelling is in full effect in the Gulf of Alaska and off South America. This is good for sea life and the food chain (since they tend to like colder waters), but bad for storm production. Looks like a classic La Nina setup. This continues the turn for the worse and only seems to be getting stronger. At the same time a massive buildup of warmer than normal waters has stalled in the Atlantic almost bleeding into the far Eastern Pacific. This was of concern to hurricane forecasters there. But it appears residual upper level shear from El Nino has done a good job of if not chopping the tops off developing systems, at least directing then to the north. But that shear appears to be fading some as we move into the heart of hurricane season in the Atlantic. Regardless of this year, next year might be a very strong hurricane producer, with the El Nino shear gone and a mature La Nina in control.

Below the surface on the equator no Kevin Wave activity was present and if anything colder than normal water was building strong over the dateline and pushing east (sort of like a cold Kelvin Wave). This pocket was -6 degs below normal (getting colder). Not good. 

Over the entire Equatorial Pacific trades were blowing all the way to the Philippines and beyond. And now from a historical perspective these easterly winds were anomalous, blowing harder than normal from the east to the west, as would be expected looking at all the other data. But this is a rather recent development, with only normal winds indicated prior to 9/11. The interesting twist to all this is that the Pacific current that runs along the equator turned abruptly from flowing towards South America to flowing towards the Philippines in mid-March (2010), right as the SOI started it's impressive drive into positive territory and the North Pacific winter storm machine abruptly shut down. And it has not wavered since. But trades never waiver from the normal range.  This suggests trade wind anomalies might be a byproduct of the Pacific equatorial current change and not the other way around i.e. the trades do not drive the temperature change initially, but the current change does. And then the atmosphere responds in kind to the change, building high pressure and reinforcing the flow and water temps. Said a different way, the change in the current might actually foretell a coming change in the trades, and then with the advent of the trade wind change, it only serves to reinforce the current in a self a.cgiifying loop, until such time as the cycle runs it's course and the self feeding system collapses over a multiyear period. At that time the current then switches direction, and a whole new self-enforcing cycle stars anew. Something to consider (regarding the formation and El Nino/La Nina).     

El Nino is effectively gone and slowly losing it's grip on the global upper atmospheric weather pattern. Still some lingering impact might continue through early Fall 2010, but likely not enhancing the storm track in the South Pacific any longer. A transition to cooler than normal conditions (La Nina) is expected through Nov 2010, and the signs continue to point to a La Nina pattern for the long term future.   

See more details in the   El Nino update.


South Pacific

Beyond 72 hours nothing of interest is indicated. It's time to be looking to the north and west. 

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

Interview with Stormsurf: Coastviews Magazine has written up a very nice article on Stormsurf in their latest edition. You can read it here:

Stormsurf Hi-Res Coastal Precipitation Models Upgraded Though a bit late in the season, on 3/20 we i.cgiemented the same basic technology used in our new snow/ski models into the coastal hi-res precipitation models. So now you can not only determined whether rain is forecast for your area, but also snow. And not just light, medium or heavy snow like most sites, but the exact snowfall amount (in inches) for each 3 hr frame of the animation. Here's a sa.cgie, but now this approach is used in all our precipitation models.

Stormsurf Precip Models Upgraded! On 2/20 we upgraded some of the broader precipitation models driven by the hi-def GFS model to include snow fall. The algorithm used is similar to the recently released snow models for the Southwest US in that the areas where snow is expected are identified and the exact amount of snow forecast over a 3 hr window is e.cgiicitly color coded. For East and West Coast US interests the following links provide good exa.cgies:
West Coast:
East Coast:

Stormsurf Weather Models have all been upgraded! Over the New Years break we installed all new and upgraded weather models. Also new are experimental snow models for the Southwest US. Take a look here:

Read about Eric Nelson and Curt Myers, the makers of Ride-On and other Big Wave Surf Movies here:

Ride On! Powerlines new big wave epic is now available on DVD. Get the entire big wave story of the 2008-2009 season here:

Click here to learn more about Casa Noble Tequila! Casa Noble Tequila If you are looking for an exquisite experience in fine tequila tasting, one we highly recommend, try Case Noble. Consistently rated the best tequila when compared to any other. Available at BevMo (in California). Read more here:

Interview With Stormsurf:  The crew at worked with Stormsurf on a feature about why surfers should be able to read wave charts themselves. They are firm believers that a little learning can go a long way to help your surfing.  This is a great article to help convince your friends that they can benefit from being able to read the data themsleves rather than just relying on the forecasts of others.  See the full thing here:  Create Your Own Surf Forecast with Stormsurf

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.

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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