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Pacific Storm and Surf Forecast
Updated: September 9, 2010 9:07 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 = 1.9 - California & 0.5 - 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 9/6 thru Sun 9/12
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   

Southern Hemi Gale Turning North
North Pacific Models Teasing


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 (9/9) North and Central California was getting small locally generated short period north windswell at waist to rarely chest high and reasonably clean though still a bit warbley. Southern California was clear and clean with northerly windswell waves maybe knee high up north and small southern hemi swell barely waist high down south with slight texture on it. Hawaii's North Shore was flat and clean with summer sand clogging the reefs. The East Shore was getting thigh high tradewind generated east windswell with lightly chopped conditions. The South Shore was knee high on the sets and clean all coming by way of wrap around minimal eastern windswell.    

The forecast for North and Central CA is for more small north windswell continuing on Friday at 3 ft on the faces dropping to 2.5 ft on Saturday and fading to 2 ft on Sunday (9/12) with minimal south angled southern hemi swell sneaking in at 2.5 ft from 175 degrees at select breaks.  Monday and Tuesday windswell to hold at about 2 ft.  Southern California is to see northerly windswell at knee high or less through the rest of the workweek into the weekend. Still some suggestion of small southern hemi swell forecast by Saturday at waist high pushing near chest high on Sunday with luck from a very south direction, then dissipating by Monday. The North Shore of Oahu is to see no ridable surf for the next 7 days.  The East Shore to see no real short period east windswell with waves being knee high or less through Friday (9/10) maybe coming up a notch on Saturday and reaching thigh to waist high on Sunday (9/12), then dropping from thigh high Monday and gone by Tuesday. The South Shore is to maybe see some thigh high background southern hemi swell late Friday holding into Saturday AM (9/11) before dropping from knee high Sunday. Nothing Monday but then swell from New Zealand is to start arriving Tuesday (9/14) hitting waist to chest high and ending the surf drought.      

Up north no swell producing fetch is forecast over the next 7 days though the models continue to hint at a more activity pattern in the West Pacific with a tropical system moving into the Central Gulf on Thursday (9/16) but having next to no swell production potential associated with it while a stronger system sets up on the dateline with 26 ft seas.  This all seems highly unrealistic, but it's something to monitor. Weak locally generated north windswell is the more likely scenario. Down south we continue tracking a pretty good gale that pushed east from under New Zealand with 36 ft seas Mon-Tues (9/7) and is now reorganizing while making a turn to the north,  with 32-36 ft seas forecast and aimed well to the north and unshadowed by Tahiti. Some small longer period swell is likely already in the water heading north with more size expected behind (from the northward turn). This seems far more.cgiausible than anything coming out of the North Pacific yet.  


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

North Pacific

On Thursday (9/9) the North Pacific jetstream continued weakly flowing off the Kuril Islands at 80-90 kts pushing into a small trough there, then lifting northeast over the dateline and ridging through the Western Gulf of Alaska before falling into a trough that was pushing down the Pacific Northwest and into Central CA. In all no clear cut signs of support for surface level low pressure development was indicated. Over the next 72 hours that trough over the West Pacific  is to build some and receive reinforcing energy, with winds building to 120 kts by Sunday (9/12) providing better support for low pressure development there. But a big ridge is to be pushing hard to the north over the Gulf of Alaska, even north of Alaska, eliminating any good from happening there. Beyond 72 hours things are to start looking alot more interesting with energy from the trough in the west miraculously pushing hard east and forming a decent sized trough in the Gulf of Alaska late Tuesday (9/14) with a reinforcing trough building just west of the dateline and 120 kts winds in both.  Decent support for maybe even gale development indicated. And that trough in the East is to only deepen into Thursday (9/16) with more energy streaming east off Siberia.  It almost looks like Fall is trying to take a stand with support for low pressure development possible mainly in the Gulf.  

At the surface on Thursday (9/9) high pressure at 1028 mbs continued locked in the Western Gulf of Alaska centered 1500 nmiles north of Hawaii and positioned a good bit west of the California coast, offering no support for the usual Cape Mendocino pressure gradient resulting in only minimal north winds pushing down the CA coast at 10-15 kts. No windswell of interest was being generated. Likewise, this rather northern position of the high was dampening the production of trade winds over Hawaii with a easterly flow only 10-15 kts and easterly windswell at a minimum. No fetch in excess of 20 kts was occurring anywhere over the North Pacific. Over the next 72 hours high pressure in the east is to fragment and appear to start dissolving while a weak tropical low pressure system tracks northeast off Central Japan, reaching the intersection of the dateline and the Aleutians on Sunday (9/12) producing 35 kt south winds, but no fetch aimed at Hawaii or the US Mainland. But, it is to help nudge remaining high pressure more to the east, possibly starting to clear a pathway for something to follow. Weak 20 kt north winds are to redevelop off Cape Mendocino on Sat (9/11) perhaps building minimal short period windswell for Central CA. At the same time trades to remain at about 15 kts for the Hawaiian Islands and of no real use towards windswell production, but there's some suggestion of a weak tropical system tracking south of there.    


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


No tropical activity of interest is forecast.

California Nearshore Forecast
On Thursday (9/9) high pressure at 1028 mbs was 1500 nmiles north of Hawaii in the Western Gulf of Alaska and not pushing at all into North CA resulting in only weak 10 kt north winds pushing down the coast and no real windswell production capability.  This was creating some warble at exposed breaks, but not much more. More of the same is forecast on Friday.  Then by the weekend remnants of the high are to form a very weak version of the usual pressure gradient over Cape Mendocino with 20 kt north winds there and a light flow nearshore from Central CA southward though not clearly an eddy flow. By Monday (9/13) the gradient is to dissolve with only weak 15 kt north winds over Cape Mendocino and a 5-10 kt northwest flow pushing into Central CA and getting weaker by the day as theoretically low pressure building the Gulf of Alaska. Calm winds forecast nearshore for the entire state Tuesday (9/14) onwards. 


South Pacific

On Thursday (9/9) the jetstream had a big trough pushing into the Southeast Pacific reaching up to about 50S at 140W with 120 kt south winds feeding up into it.  this was providing good support for gale development down at the oceans surface there. Back to the west the same old very .cgiit jetstream pattern was in control with the southern branch pushing hard south into mainland Antarctica and pretty much eliminating odds for gale formation back there. The was was also happening over the far east into mainland South America. Over the next 72 hours
that trough in the mid-Atlantic is to continue undulating while slowly weakening and pushing east, out of even the Southern CA swell window. Most energy of interest is to be gone by late Friday (9/10). Otherwise the ridging pattern previouly discussed is to pushing east from New Zealand and shutting down the potential for gale development.  Beyond 72 hours the big ridge in the west is to take over the greater South Pacific minimizing the odds fro gale development. But a new trough is forecast building under New Zealand by Thursday 99/16) with winds energy to 120 kts feeding into it.  It's too early to know with any certainty, but there is a smidgon of support for gale development at the oceans surface if this were to occur. 

At the oceans surface high pressure at 1028 mbs was positioned just east of New Zealand while a gale low continue tracking northeast ahead of it (see South Pacific Gale below). Over the next 72 hrs that gale is to remain the only weather system of interest.  To it's west high pressure at 1036 mbs is to be building and shutting down the potential for low pressure development.    

South Pacific Gale
A strong gale started to wrap up under New Zealand on Monday AM with 45-50 kt west to almost southwest winds building, pushing to 50 kts solid in the evening at 60S 175E and aimed more to the northeast or 20 degrees east of the 209 degree path into North CA and barely shadowed by the western edge of the Tahitian Islands chain. Seas reached 35 ft at 58S 174E (210 degs CA and 194 degs for Hawaii). 

A solid area of 45 kt southwest winds continued Tuesday AM at 57S 172W producing 36 ft seas at 57S 175W now heading right up the 209-210 degree route to CA and 35 degrees east of the 188 degree path towards Hawaii. Having the fetch track right up the same great circle paths to CA might help improve set consistency. In the evening the fetch backed off some though still covering a reasonably large area with 40 kt southwest winds at 50S 156W tracking up the 202 degree path to California, on the eastern edge of the Tahitian swell shadow and aimed well east of the 178 degree path to Hawaii. 34 ft seas persisted at 56S 164W (202 degs CA). 

By Wednesday AM (9/8) the fetch fragmented and decayed with a smaller areas of 40-45 kts southwest winds trying to hang on at 50S 154W and seas from the original fetch at 30 ft at 51S 156W. In the evening a new broad fetch of 40-45 kt south-southwest winds developed at 56S 170W getting traction on an already agitated ocean surface, producing more 31 ft seas back at 55S 170W with seas from the original fetch at 30 ft at 50S 149W (196 degs CA - 187 degs HI). 

This fetch held at 40-45 kts and aimed pure north from 49S 154W on Thursday AM with seas to 32 ft at 50S 159W. The models suggest a tiny area of up to 45 kt south wind is to peak out Thursday PM at 50S 143W pushing right up the 195 degree path to California and unshadowed by Tahiti with sideband energy to Hawaii up the 175 degree path.  32 ft seas are forecast at 44S 151W.

Still on Friday AM (9/10) 40-45 kt south winds are to persist pushing well to the north at 42S 142W aimed right up the 196 degree great circle path to California and even with sideband energy aimed up the 169 degree path to Hawaii. A small area of 32 ft seas are forecast at 44S 144W pushing almost due north. A quick fade is forecast in the evening with winds dropping from 40 kts at 40S 140W but still aimed due north. momentum from previous fetch is to hold seas at 30 ft at 40S 140W.  This extreme north position would greatly decrease swell decay if it were to occur.  A quick fade is forecast thereafter. 

In all this remains a pretty interesting scenario, especially the later half of this gales life and considering the complete lack of swell and fetch in the Southern Hemi at present. But the models have back off considerably from previous estimates, likely meaning less swell size than what was hinted at earlier. Still it's better than nothing. Will monitor and update once confirmed data becomes available. 


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 remnants of the dateline tropical system are to race east, carried by a building jetstream flow aloft and form into a closed isobar low in the Gulf of Alaska on Tues/Wed (9/15) holding essentially stationary and producing a nice fetch of 30 kt northwest winds aimed well at Oregon down into Central CA. Possible swell resulting if this comes to pass, but that seems highly optimistic at this time. And yet another tropical system is to be streaming northeast off Japan reaching the dateline-Aleutian intersection on Wed (9/15) generating a decent sized fetch of 35 kt west winds resulting in 26 ft seas late.  Will believe it when it happens.  

MJO/ENSO Update (reference):   As of Thursday (9/9) the Southern Oscillation Index (SOI) continued solid in the positive range. The daily SOI was at 19.97 and has been that way in excess of 52 days now. The 30 day average was holding at 22.12 with the 90 day average up to 16.06.  The Inactive Phase of the MJO appears to still be in control.  

Wind anomalies as of Wednesday (9/8) (latest data from BOM) at the 850 mb level (approx 5000 ft up) as defined by models indicated the Inactive Phase was still in control with modest to light east anomalies covering the entire width of the tropical Pacific and just poised to push into Central America. A weak incarnation of the  Active Phase of the MJO was trying to build in the far west Indian Ocean. This pattern was to continue with easterly anomalies and the Inactive Phase holding over the greater Pacific pushing into Central America through 9/18 then slowly dissipating into 9/23 while a minimal version of the Active Phase and it's much needed westerly anomalies are forecast to try and push into the West Pacific on 9/18, but stall and so weak as to not even be there. By 9/28 a near neutral pattern is forecast. This does not do much for building a Fall pattern over the North Pacific.

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 (9/8) indicates that downright cold waters continue to expanded 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 almost 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 the existing 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 -5 degs below normal (getting colder). Not good. 

Over the entire Equatorial Pacific trades were blowing all the way to the Philippines and beyond. But from a historical perspective these easterly winds were not anomalous, only in the normal range. And this has been the case all summer.  But the Pacific current that runs along the equator turned abruptly from flowing to towards South America to flowing towards the west in mid-March (2010), right as the SOI started it's impressive drive into positive territory and the storm machine abruptly shut down. And it has not wavered since.  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 slow transition to a normal if not 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 high pressure at 1036 mbs is to be building east of New Zealand and ridging south to nearly Antarctica or at least influencing the weather pattern there well into next week.  The result is to be nearly continuous south winds over the mid-South Pacific area pushing towards Antarctica, offering no support for swell development pushing up into the North Pacific.  But, a very solid storm is forecast tracking under Australia pushing up towards and over New Zealand Tues-Thurs (9/16) with 50 kt southwest winds and 40 ft seas pushing up into the Tasman Sea. This looks like a good Fiji swell set up, with perhaps some very filtered energy reaching to Hawaii with luck.  Still, that's a long ways off.     


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

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New Wave Model Facts: Click HERE to read more about the new wave models. Important info.

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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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