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Pacific Storm and Surf Forecast
Updated: August 25, 2009 8:53 PM
Buoys: Northern CA - Southern CA - Hawaii - Gulf of Alaska - Pacific Northwest
Buoy Forecast:
Northern CA - Southern CA - Hawaii - Gulf of Alaska - Pacific Northwest
Pacific Links:  Atmospheric Models - Buoy Data - Current Weather - Wave Models
Forecast Archives: Enter Here
A chronology of recent Mavericks Underground forecasts. Once you enter, just click on the HTML file forecast you want to review (e.g. 073199.html equals July 31, 1999). To view the maps that correspond to that forecast date, select the html file labeled 073199 maps.html
Swell Potential Rating = 3.2 - California & 1.0 - Hawaii
Using the 'Summer' Scale
(See Swell Category Table link at bottom of page)
Probability for presence of largest swells in near-shore waters of NCal, SCal or Hawaii.    
Issued for Week of Monday 8/24 thru Sun 8/30
Swell Potential Rating Categories
5 = Good probability for 3 or more days of Significant swell
4 = Good probability for 1-2 days of Significant swell
3 = Good probability for 3 or more days of Intermediate/Advanced swell
2 = Good probability for  1-2 days of
Intermediate/Advanced swell
1 = Good probability for 3 or more days of Impulse or Windswell
0 = Low probability for 1-2 days of Impulse or Windswell   

Weak North Swell for California
More and Stronger Gale Activity to Come on-Line


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 Tuesday (8/25) North and Central California had the usual locally generated northwest windswell in the waist to chest high range with southern hemi swell at chest high with some bigger sets at the top spots. Pretty warbled in the afternoon.  Southern California was still getting southern hemi swell from a more southerly direction with waves tiny up north but waist to chest high with head high sets at better breaks down south and heavily textured in the afternoon. Hawaii's North Shore was flat. The East Shore had chest high tradewind generated east windswell hitting exposed breaks with onshore winds and chopped. The South Shore had some thigh to maybe waist high sets and clean but overall very weak. Just residual impulse swell from the southern hemi.    

The forecast for North and Central CA is for more south angled southern hemi swell in the shoulder to head high range Wednesday from that gale that was in the southeast Pacific last week with 32 ft seas. Also on Wednesday mid-day another Gulf swell is to arrive pushing 1 ft overhead at top exposed breaks. Southern hemi swell to start fading on Thursday in the chest high range with Gulf swell dropping from head high, and heading down more on Friday. Southern California is to continue with south angled southern hemi swell on Wednesday maybe to head high or so, slowly fading Thursday and down to waist to chest high early Friday.  Possible small swell from the Gulf of Alaska to show at waist high at exposed breaks starting late Wednesday continuing Thursday. The North Shore of Hawaii is to remain flat for the next few days, but better things are forecast. The East Shore is to see perhaps waist high east windswell on Wednesday dropping to thigh high Thursday with something better beyond.  The South Shore is to be near flat for the foreseeable future.  Maybe some thigh high sets on Thursday, but fading Friday and beyond. 

Over the long term the southern hemi is to remain inactive with no swell in the water (other than what is already hitting) and northing forecast, with the focus all turning to the north.  Up north swell is already pushing south towards the Pacific Northwest and maybe down into Central CA  from a gale that was in the far Eastern Gulf of Alaska on Mon/Tues (8/25) with up to 24 ft seas, but primarily focused mainly on the Pacific Northwest. Swell hitting Central CA on Wednesday (8/26).  A much broader one is scheduled for Wed-Thurs (8/27) with 25 ft seas targeting the entire California Coast with sideband energy possibly into Hawaii. And yet a stronger one still is to follow on Friday with up to 32 ft seas targeting both Hawaii and the entire US West coast.  It's starting to look indeed like Fall, and not a moment too soon. 


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

North Pacific

At the surface on Tuesday (8/25) high pressure at 1028 mbs was centered over the dateline and well south of the Aleutians ridging east into North CA, but just barely. It's main influence was by generating limited 10 kt north winds along the Central CA coast and 15 kt trades and limited easterly windswell pushing over the Hawaiian Islands. Low pressure at 992 mbs was starting to build in the Western Gulf of Alaska.  This is something to watch. Over the next 72 hours this low is to build, to gale status by Tuesday evening (8/25) with 30-35 kt north-northwest winds taking root at 47N 155W and seas building. By Wednesday AM 40 kt north- northwest winds are forecast at 47N 152W aimed 40 degrees south of the 303 degree path into Central CA and 45 degrees east of the 10 degree path into Hawaii. 20 ft seas are to start building there. in the evening 40 kt northwest winds are to continue at 43S 150W aimed 40 degrees east of the 296 degree path to Central CA and 40 degree east of the 12 degree path to HI. 25 ft seas forecast at 45N 150W traveling about mid-way between Hawaii and CA.  Thursday AM (8/27) winds are to be rapidly fading from 30 kts with 23 ft seas fading at 40N 146W heading southeast.  If all this occurs as forecast a nice little dose of  northwest swell might move into Central and even Southern CA by Saturday (8/29) and north facing shores of the Hawaiian Islands on late Friday into Saturday.      

At the same time the extratropical remnants of Typhoon Vamco are to get sucked northeast out of the West Pacific by the jetstream, tracking up into the Bering Sea Wednesday (8/260 and then fall southeast towards the Northwestern Gulf of Alaska on Thurs AM (8/27) resulting in a building fetch of 45-50 kt north winds at 52N 172W partially obscured by the Aleutians Islands. In the evening 40-45 kt northwest winds are forecast at 47N 163W aimed 30 degrees south of the 204 degree path into Central Ca and right down the 350 degree path to Hawaii. 29 ft seas are forecast at 48N 164W.  Very nice. Friday AM (8/28) 40 kt northwest winds to hold at 45N 158W pushing more to the west or 30 degrees south of the 296 degree path to Central CA and 40 degrees east of the 360 degree path to the Islands. 32 ft seas forecast at 45N 160W. Residual 30 kts winds are forecast at 45N 150W in the evening with 26 ft seas at 45N 152W all pushing west-southwest towards the mainland (Central CA). Assuming this all comes to pass some form of decent longer period swell might push into Central CA early next week and Hawaii as early as late weekend, but that is really just a guess at this early date. 

Tiny Gulf Gale
Sunday evening (8/23) another small gale formed 1100 nmiles west of Washington with 35 kt fetch aimed well at California and drifting east with 40 kt west-northwest winds Monday AM at 50N 142W aimed down the 319 degree path to Central CA, but targeting the Pacific Northwest better. 20 ft seas were modeled at 50N 144W Monday AM (8/24). Still 35-40 kts winds were blowing Monday evening at 50N 140W pushing a bit down the 319 degree path to Central CA but favoring Oregon and Washington with 24 ft seas at 50N 138W barely on  the 319 degree path to Central CA, then fading while moving towards British Columbia proper. 10 ft @ 13 secs period swell is already hitting the OR/WA border late Tuesday (8/25) and is to continue into Wed (8/26) with lesser size and much more limited 13 sec energy for Central CA on Wed AM.  Swell of 5.0-5.5 ft @ 12-13 secs is likely ( 6 ft faces or a little better) for exposed breaks in Central CA.  Swell Direction 319 degrees. 

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


California Nearshore Forecast
On Tuesday (8/25) weak high pressure at 1022 mbs was trying to hang on off Central CA, but was taking a beating from developing low pressure west of it in the Western Gulf of Alaska.  by Wednesday that low pressure system is to totally fill the Gulf with a sliver of neutral pressure barely holding off Central CA and a front pushing towards the US.  Currently it doesn;t look like it will make landfall anywhere over the US (maybe some rain into Oregon and Washington on Friday) with a weak wind pattern forecast through the end of the workweek. Weak high pressure is to follow, building over Central CA on Saturday with north winds nearshore at 20 kts lifting north towards Cape Mendo on Sunday (8/30) building to 25 kts with decreasing winds from Pt Arena southward, and an light eddy flow (southwest) taking hold from Central CA to Pt Conception through Tuesday of next week (9/1). The change of seasons is starting.


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

On Tuesday (8/25) the extratropical remnants of Typhoon Vamco were a bit east of the Kuril Islands with sustained winds still 65 kts and racing northeast, expected to pass into the Bering Sea (highly unusual) early Wednesday. It is expected to race east with the jetstream and head southeast into the Gulf of Alaska, reaching there Thursday (8/27) and redeveloping. See forecasts above. 

Tropical Storm Hilda had 45 kt winds and was positioned  650 nmiles southeast of Hawaii.  Hilda is forecast to track slowly west under Hawaii (500-600 nmiles south) while intensifying, with up to 60 kt winds (still tropical storm force) as it pushing south of Kauai continuing on towards the dateline. Southeast swell for east shores of the Big Island should already be hitting and is expected to continue  into Thursday then diminishing. No other swell production forecast.  

Tropical Storm Ignacio was positioned 900 nmiles south of Pt Conception and tracking northwest with sustained winds 45 kts.   Slow strengthening to perhaps 50 kts is forecast over the next 24 hours, then Ignacio is to fade while pushing over cooler waters.  No swell production forecast.


South Pacific

On Tuesday (8/25) a fully .cgiit jetstream pattern continued over the South Pacific, with the northern branch flowing flat east on the 30S latitude while the southern branch pushed solidly  east on the 70S latitude and mostly encased in ice over the Ross Ice Shelf in the West offering no odds for gale development.  Over the next 72 hrs no real change is forecast other than perhaps a slight trough trying to get a foothold under Australia, but of now immediate use to the Pacific storm breeding grounds. Beyond 72 hours that trough is to try and push east into the Southwest Pacific, but it's to get totally squashed by a new ridge pushing hard south over New Zealand, continuing the lockdown on gale development in the South Pacific. No support for gale development suggested. 

At the surface on Tuesday (8/25) high pressure at 1032 mbs was locked-in east of New Zealand ridging to the northern edge of the Ross Ice Shelf and completely blocking the south Pacific storm corridor in the western South Pacific. No low pressure of interest was occurring. Over the next 72 hours that high pressure is to drift east, but not moving any further north, continuing the lockdown. No swell producing fetch of interest is forecast. 

Second Pulse - From the Southeast Pacific

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

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

Southern CA:  Swell to continue Wednesday at 3 ft @ 15 secs (4.5-5.0 ft faces) then fading into late Thursday (8/27)     Swell Direction: 193 degrees.

Northern CA:  Additional energy from the second pulse to arrive late Tuesday pushing up to 3 ft @ 16 secs on Wednesday (5 ft faces with top spots to 6 ft), then settling down into Thursday and early Fri (8/28). Swell Direction: 190 degrees.


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




Marine weather and forecast conditions 3-10 days into the future

North Pacific

Beyond 72 hours high pressure that has been holding over the dateline is to surge east filling the Gulf of Alaska by Monday (8/31) and ridging into Oregon producing the usual pressure gradient over Cape Mendocino generating north winds at 25 kts there resulting in short period north windswell. This is to shut down any gale activity in the Gulf of Alaska for a while, as one would expect with the turning of the MJO from the Active Phase to the Inactive Phase over the East Pacific. The tropics off Northern Mexico are to get quite active, but that is a pure guess by the models.      

MJO/ENSO Update (reference): As of Tuesday (8/25) the Madden Julian Oscillation (MJO) was in the Inactive Phase but you wouldn't know if from looking at the SOI. The ENSO (El Nino Southern Oscillation) index has continued to defy expectations by remaining negative. The Daily SOI index was at -1.27 (negative 7 days in a row) making it effectively a 37 day negative run (since 7/21), more typical of the Active Phase. This is being caused by a slow moving low pressure system tracking east under Tahiti and is expected to hold into Friday (8/28). And another is expected mid-next week. The 30 day average was down to -5.53 and the 90 day average was down to -0.82.  The SOI index continues to try and regain some of the ground it lost when the MJO went Inactive in early July.

Wind anomalies at the 850 mb level (approx 5000 ft up) as defined by models indicated that a strong area of easterly anomalies that was previously forecast over the Philippines has now all but evaporated. Only a small patch remains over the Eastern Indian Ocean with weak westerly anomalies holding down a small area just west of the dateline getting stronger on the dateline and east into Central America. Most unusual, but good news. Westerly anomalies is what you want to see to feed El Nino. The models previous projections of strong easterly anomalies slowly fading through 8/31 weren't even close. The easterly anomalies associated with the Active Phase are to slowly fade in the East Pacific  Through 9/2, with nothing other than purely normal conditions holding over the Pacific after that through 9/12. We still suspect the Active Phase will appear weakly in early Sept, but it will just take a while for the models to figure it out when it does happen.  If this happens, this means the Inactive Phase will be skipped all together.  Will monitor.   

Sea Surface Temp anomaly data (8/24) indicates no real change since the last update on 8/20, with a solid area of warmer than normal water extending 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 but have retreated from the California coast , the result of northerly winds over the past week. Much cooler than normal waters (-2.5 deg C) are mirrored streaming off Africa and pushing east reaching South America, but diminishing some from previous weeks. Looking back in the records, exactly the same flow developed during the big El Nino of 1997 and is likely to suppress Atlantic hurricane actively due solely to the frigid water temps. 

Below the surface on the equator a steady flow of slightly warmer than normal subsurface water has been tracking from the West Pacific (150 m below the surface) under the dateline and breaking the surface near Central America for months now. 203 deg warmer than normal waters have mysteriously appeared off Central America again.  And the Kelvin Wave we have been tracking of late is migrating east from 165W, the result of a Westerly Wind Burst (WWB) in the West Pacific that occurred on 7/25-8/2. It is 2 deg C above normal and building while feeding the warm water pump, providing reinforcements on the way to Ecuador. This is critical to the formation of a legitimate El Nino, but will take 2 months from the time it is generated to reach it's target (9/27 or so).  The small pocket of cooler water 100 meters down on the equator south of South CA that was previous mentioned a week or more ago appears to be fading. More good news. 

Fully blowing westerly winds in the far West Pacific and westerly anomalies reached to the dateline starting 8/12. They had pretty much settled down by 8/19, and were reduced to weak anomalies as of 8/20, and those weak westerly anomalies continue even today (8/25).  Looking at the models slack winds are forecast on the equator in association with low pressure tracking east and centered south of Tahiti through the coming workweek (8/28), maybe with just a touch of easterly flow at 5 kts, then dying totally into next week. This is good news and might continue to prime the warm water pump pushing east. We've been looking for perhaps another Kelvin wave to result from this slack wind flow/weak Westerly Wind Burst of late. And low and behold, the first faint signs of a second pocket of warming water is perhaps starting to appear under the dateline.  Very preliminary evidence indeed, but at a bare minimum it ought to provide reinforcements for the existing Kelvin Wave already in-transit. Will continue monitoring this situation.   

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

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

See more details in the new  El Nino update.


South Pacific

Beyond 72 hours the models are hinting at a storm trying to get footing east of New Zealand late on Sunday (8/30) with 55 kt west winds, but the fetch area is to be steadily sinking southeast. 32 ft seas are forecast Monday AM (8/31), but suspect that is more a fantasy than anything, especially considering the upper level flow.  Assume no swell producing fetch will result, but if something does materialize, it will be a.cgieasant surprise.  

Details to follow...


External Reference Material: El Nino Southern Oscillation (ENSO), Madden Julian Oscillation (MJO), Pacific Decadal Oscillation (PDO), Southern Oscillation Index (SOI), Kelvin Wave

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Local Interest

The Kelly Slater Project - A fundraiser is scheduled for Aug 29th at the Cocoa Beach Country Club to help raise funds for both the Kelly Slater Project and the Central Florida Animal Reserve. A Casino night is.cgianned including a silent auction and raffle. Sponsors are also needed. Learn more about these projects at :

Rebuild Jeff Clark: Jeff Clark the first pioneer of Mavericks, recently underwent hip resurfacing surgery due to severe pain from deterioration of his hip. Needless to say the procedure is very expensive and his insurance only covers tiny portion of the bill. If you're interested in learning about the procedure or would like to donate to help Jeff out,.cgiease take a look here:

North California Surf Report Works Again: After an extended downtime we finally got the North California Surf Report working again. Thanks for your patience. See it here:

Shark Video: Our friend Curt Myers of Powerlines productions shot this footage of 2 great whites munching on a whale carcass off Devils Slide (south of San Francisco) on Thursday. Kind of interesting to watch. Check it here: (Fixed link)

Wave Model Upgrade Status Report: At this point we believe the installation of the new wave models is complete, with no problems being reported, the server stabilizing and the much requested return of the old style hemispheric Surf Height models now operational (again) and running side-by-side along the new ones. We thank you for your patience and input as we went though this process.  Your feedback helps guide our efforts and ultimately results in a better product for everyone.  Now we're off to start providing better menus to some wave model products most of you probably haven't uncovered yet (site specific graph and text forecasts), updateing the wave model FAQs and then upgrading the Weather Models.  

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

Stormsurf Wave Models Updated: On Friday (2/6) we installed the latest upgrade to our wavemodels. A year in the works, this upgrade essentially is a total re-write of every wave model product we produce. They now take advantage of the new Version 3 of the Wavewatch wavemodel. This version runs at a much higher resolution, specifically 0.0 X 0.5 degrees for the global grib with local products at 0.1667 X 0.1667 degrees, and it uses the hi-res GFS model for wind speeds. And of even more interest, the model now identifies primary swell and windwave variables. As such we now have new model images which displays this data. Also we've included out special 3D topographic land masks into all models. In all it makes for a radical step forward in wave model technology. We'll be upgrading minor components (FAQ, new menu pages etc) for a few weeks to come, but all the basics are available for your use now. Check it out here:

Story About Stormsurf: The folks at SurfPulse (and specifically author Mike Wallace) have written up a really nice article about Stormsurf, complete with some good pics. Learn about how we came to be and a little of where we are going. Check it out here:

Stormsurf Video: Just for fun - here's a clip about Stormsurf that ran on Bay Area TV a while back. Thought you might enjoy it:

Time Zone Converter By popular demand we've built and easy to use time convert that transposes GMT time to whatever time zone you are located. It's ion left hand column on every page on the site near the link to the swell calculator.

Need Chiropractic Help? Visit our friends at Darrow Chiropractic. Not only will Dr. Darrow fix you up, he might give you some big wave surfing tips too! See more here:

Stormsurf Google Gadget - Want Stormsurf content on your Google Homepage? It's si.cgie and free. If you have Google set as your default Internet E.cgiorer Homepage, just click the link below and a buoy forecast will be added to your Google homepage. Defaults to Half Moon Bay CA. If you want to select a different location, just click on the word 'edit', and a list of alternate available locations appears. Pick the one of your choice. Content updates 4 times daily. A great way to see what waves are coming your way! .xml

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Surf Height-Swell Height Correlation Table


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