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Pacific Storm and Surf Forecast
Updated: September 30, 2010 10:31 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 = 4.0 - 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   

Extratropical Swell from Dateline Arriving
Calmer Pattern Forecast Long Term


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 (9/30) North and Central California was reasonable leftover swell from Storm #1 at 2 ft overhead and clean but totally fogged in. Southern California was getting waist high or so sets still wrapping in from the Gulf of Alaska up north and clean early. Down south waves were chest to shoulder high from the Gulf too a bit crumbly with northwest winds starting to build. Hawaii's North Shore was getting leftover swell from th Gulf and new longer period swell from the dateline with waves  1-2 ft overhead with bigger sets and a bit mixed up. The East Shore was getting wrap around energy from the North Shore at waist to chest high with lightly chopped conditions. The South Shore was getting shoulder to head high New Zealand swell with good form and clean conditions.    

The forecast for North and Central CA is for new swell from the northern dateline arriving on Friday building to maybe 10 ft from a more northerly direction then fading to 8 ft faces on Sat AM and holding again on Sunday, then dropping from 7 ft on Monday with only local windswell to follow.  Southern California is to see fading Gulf swell at waist high Friday. New swell from the northern dateline region possible late also at exposed breaks to near chest high late and holding for Saturday on into Sunday and even early Monday, then heading down from waist high on Tuesday. The North Shore of Oahu is to see new north dateline swell to 1 ft overhead on Friday and maybe 2 ft overhead on Saturday then fading from head high to 1 ft overhead Sunday. Waist high leftovers on Monday and dropping out. The East Shore is to start seeing east local windswell on Monday (10/4) at chest high holding well into the workweek. The South Shore is to see more New Zealand swell fading from waist high Friday. New Zealand swell to push in for Saturday at near waist high and fading from waist high early Sunday and thigh high early Monday.   

Extratropical storm Malakas pushed north off Japan with seas at 48 ft late Saturday (9/25) then turned east just shy of the Aleutians Sunday with 45 ft seas then tracked over the northern dateline Monday with seas down to 38 ft before slowly fading in the Northwestern Gulf Tuesday with seas at 30-32 ft, gone on Wed AM.  This is the last pulse of Fall swell expected for HI and the US West Coast (hitting Fri though the weekend) with no other swell producing weather systems forecast for the next week.   

Down south reinforcing energy from one last storm that tracked under New Zealand last weekend is already in the water with sideband energy forecast to hit Hawaii over the weekend, but will likely be masked by north swell in Central California.  Southern CA to see it though starting Monday on into the work week.   


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

North Pacific

On Thursday (9/30) the North Pacific jetstream was flowing generally over the 45N latitude with a slight ridge just off the Kurils with winds at 140 kts falling into a steep almost pinched off trough in the Gulf of Alaska with winds falling to 90 kts, then ridging hard north into Northern Canada.  There was only limited support for gale development in the Gulf trough.  Over the next 72 hours the Gulf trough is set to capture those 140 kts winds flowing over the dateline, but the trough itself is to be moderating and pushing east into the Pacific Northwest late Sunday.  There's some limited support for gale development, but not much. Beyond 72 hours a new trough is to set up on  the dateline late Monday (10/4) with 130 kts winds flowing into it and holding for almost 48 hours providing some hope for gale development,  then moderating much by late Thursday.  After that a very weak and somewhat diffuse flow is forecast offering nothing of interest.  

At the surface on Thursday (9/30) the remnants of what was extratropical Typhoon Malakas were centered in the Northern Gulf of Alaska and lifting northeast fast.   They were generating a fetch of 30 kt northwest winds near 45N 150W and producing 19 ft seas just west of that region and expected to hold till Friday AM at 45N 150W. This will likely result in more 12-13 sec period swell energy radiating mostly towards the Pacific Northwest down into Central CA for Sunday on into Monday (10/4). Stronger high pressure at 1024 mbs was centered over the southern dateline region on back towards Japan with a light pressure pattern off the US West Coast and over Hawaii. No winds of interest was being generated in either of those locations.  Swell from the previous incarnation of ET Malakas was pushing slightly towards Hawaii and more towards the US West Coast (see details below).  Over the next 72 hours the remnants of Malakas are to continue circulating over the extreme northern Gulf of Alaska with winds regenerating to near 45 kts late Friday, but all aimed at land north of British Columbia with no swell potential south of there. And by Sunday (10/3) this system is to move fully into Alaska and dissipate. By Saturday weak high pressure is to start building north of Hawaii on into the US West Coast with northwest winds to 15 kts along Central CA and Hawaii building south into Sunday over the Channel Islands and increasing fetch area expanding over the Hawaiian Islands. Local windswell in both locations becoming more of a reality.      

Extratropical Storm Malakas
The extratropical remnants of Typhoon Malakas tracked 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.  This system tracked over the dateline and just barely clear of the Aleutians (partially obscured) on Monday AM (9/27) with west winds fading from 40-45 kts at 50N 173E (on the 307 degree path to NCal) and seas 45 ft early at 50N 174E, then pushed over the dateline in the evening with 40 kts west wind at 50N 170W with a tiny area of 38 ft seas free and clear of obstruction at 50N 178W.  The gale was tracking into the Northwestern Gulf of Alaska Tuesday AM (9/28) with winds fading from 35 kts at 50N 165W (307 NCal) and seas 32 ft at 50N 170W. 30 ft seas held into Tuesday evening at 48N 165W, then the gale really decayed with maybe 26 ft seas left Wednesday AM (9/29) at 50N 160W.  

Small  long period well organized swell is expected to push the entire way across the North Pacific to California, arriving Friday AM from a rather north angle (302-307). 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.

Hawaii: Minimal swell is forecast arriving on Thursday (9/30) building to 3.6 ft @ 15 secs (5-6 ft faces).  Swell to be fading from 4 ft @ 13 secs on Friday (5 ft faces) and maybe 6 ft @ 11 secs (6.5 ft faces) on Saturday. Swell Direction: 310 degrees initially moving to 350 degrees   

North CA:  Expect early arrivers hitting on Thursday afternoon (9/30) at 2-3 ft @ 20+ secs building over night.  Swell to peak near 5.0 ft @ 18 secs on Friday (8.5 ft faces)  continuing into Saturday at near 6 ft @ 15 secs (9 ft faces) . On Sunday swell is to be fading from 5.5 ft @ 13 sec (7 ft faces) with more 11-12 sec energy pushing in for Monday.  Swell Direction: 302-307 degrees   


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


No tropical systems of interest were being tracked.

California Nearshore Forecast
On Thursday (9/30) a weak pressure pattern was in effect locally with light winds in control. The models suggest a new weak gradient to start developing over Cape Mendocino later Friday (10/1) with only at 15 kt north winds likely late almost pulled away from Central CA and points south of there and then to near 20 kts on Saturday but again pulled away from the immediate coast early.  But by Sunday it is to start building nearshore early at 15 kts (from Pt Arena south to Pt Conception) and by Monday high pressure is to be in firm control with 20 kt north winds covering the state other than protected breaks in Southern CA. Tuesday winds to be 25+ kts over outer waters and 20 kts nearshore again (other than Southern CA which is to be in an eddy flow). Finally Wednesday (10/6) the gradient is to start fading and be pulled away from the Central and South CA coasts and dissipating to calm everywhere by Thursday with good conditions fully returning.  


South Pacific

On Thursday (9/30) no troughs of interest were occurring and none forecast for 
the next 72 hours.  If anything a ridging pattern was building over the Central Pacific  pushing south and expected to continue if not build and offering no support for gale development at the oceans surface.  Beyond 72 hours a generally flat weak flow is expected with perhaps a broad weak trough setting up in the Southeast Pacific by Sunday (10/3) and holding into Tuesday perhaps supporting low pressure development at the oceans surface, but nothing more. Beyond a generally flat and southward di.cgiaced flow is to settle over the entire South Pacific offering nothing to support gale development.

At the oceans surface no swell producing fetch was occurring and none is forecast for the next 72 hours. 

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.

Swell to push into select Southern CA breaks on Fri (10/1) at 1.5 ft @ 16 secs (2.5 ft faces) and continue through the weekend (10/3) at 2 ft @ 16 secs (3.5 ft faces) falling to 2 ft @ 15 secs (3 ft faces). Swell Direction: 220 degrees

One More New Zealand Gale
A gale low 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. It 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. The issue was that though seas were large, all energy was aimed due east and not pushing up into the Hawaiian or CA swell windows.

Possible background swell for Hawaii 6 days out (Friday 10/1) with swell building to 1.6 ft @ 18 secs (3 ft faces) then holding at 2 ft @ 15-16 secs (3 ft) on Saturday (10/2). Swell fading from 2 ft @ 14 secs (2.5-3.0 ft faces) on Sunday (10/3). Swell Direction 200 degrees.

Limited swell for Southern CA at select south facing breaks not masked with stronger northerly swell is possible starting Monday (10/4) at 1.6 ft @ 17 secs (3 ft faces) continuing at 2 ft @ 15-16 secs (3.0-3.5 ft faces) on Tuesday (10/5) and 2 ft @ 15 secs on Wednesday. Swell Direction: 214 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 weak low pressure is to continue circulating over the extreme northern Gulf of Alaska while high pressure builds from Hawaii into the Pacific Northwest at 1032 mbs Mon-Tues (10/5) setting up the usual pressure gradient and northwest winds at near 25 kts over North and Central CA pushing 30 kts over Cape Mendocino on Tuesday resulting in increasing local north short period windswell and poor local conditions there. Trades to return to the Hawaiian Islands too at near 20 kts. More reinforcing high pressure is forecast over the dateline too at 1024 mbs. By Wednesday the gradient off NCal is to be fading and pulling away from the coast with trades backing off to 15 kts over Hawaii with a new low pressure center forecast building over the dateline by Thurs (10/7) with 25 kt northwest winds.  This may become a source for swell, but it is way too early to know if it will even form much less be productive at this early date.

We're updated the official El Nino forecast and it is now posted. See link below. 

As of Thursday (9/30) the Southern Oscillation Index (SOI) continued solid in the positive range. The daily SOI was at 30.49 and has been that way in excess of 73 days now. The 30 day average was up to 25.79 with the 90 day average up to 20.65 and still riding.  The Inactive Phase of the MJO is in firm control.  

Wind anomalies as of Wednesday (9/29) at the 850 mb level (approx 5000 ft up) as defined by models indicated a totally neutral (normal) wind pattern in control. A completely dead neutral pattern is expected to hold through 10/19.

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. 

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 -7 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 slightly 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 a weak gale is forecast building just off the northern edge of Antarctic Ice in the Central Pacific Sun/Mon (10/4) with 40 kt west-southwest winds and seas to maybe 32 ft aimed more east then northeast. Low odds for swell to result for Southern California.  Will monitor.  


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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