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Pacific Storm and Surf Forecast
Updated: September 10, 2009 9:40 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 = 3.3 - California & 3.5 - Hawaii
Using the 'Winter' 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 9/7 thru Sun 9/13
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   

Swell Hits Hawaii - Moving Towards CA
Last Pulse of Follow-On Swell Energy Radiating from 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 Thursday (9/10) North and Central California had waist high background surf of indeterminate source or maybe a little more with light winds and fog early. Southern California was dead flat and textured up north but with a few individual up to chest high sets at top spots down south coming from the tropics and windy mid-day. Hawaii's North Shore had sets pushing 2 ft overhead mid-day and on the way up, new swell coming from the dateline storm. Trades were a bit stiff out of the northeast. The East Shore report was unavailable. The South Shore again had a little more swell than expected, coming out of the south with sets pushing waist to chest high and clean conditions. 

The forecast for North and Central CA is for northwest windswell coming out of the Gulf on Friday to waist high or so. Then swell from a storm that has moved from the dateline up into the Gulf of Alaska is to start hitting on Saturday pushing near double overhead and then a bit less on Sunday (3+ ft overhead) and a tad more northerly.  Southern California is to see some swell from this system too by mid-Saturday pushing head high late (better at top spots) and holding near that level all Sunday.  The North Shore of Hawaii is already starting to see some rideable swell from the Dateline/Gulf system expected to peak at 4 ft overhead early Friday dropping to 2-3 ft overhead on Saturday and a little less on Sunday and far more northerly. The East Shore might even see some size from this one Sunday and Monday. The South Shore is to remain near flat till late Friday when some small background swell might hit at waist high or so holding well into next week. 

For now the best thing expected is from that gale that built on the dateline tracking quickly into the Gulf of Alaska then fading out on Friday. It's to be good enough to push swell into Hawaii (already occurring) and then have follow-on energy emanating from the Gulf to keep swell in the water though the weekend in the Islands and set up equal sized swell from Central CA by the early weekend continuing into early next week. In all a nice prelude to Fall is expected. Another much weaker gale is forecast for the Central Gulf Sun-Thurs (9/17) providing something to ride focused on the Pacific Northwest down into Central CA, but size to be minimal. With the ascendancy of the Inactive Phase of the MJO over the East Pacific now, we expected a minor pause in the action till maybe 9/21.  But after that, the machine should fire up again, but better. 


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

North Pacific

On Thursday (9/10) the North Pacific jetstream a nice trough was present over the Northern Gulf of Alaska with 170 kt winds pushing downs it's western flank targeting the US West coast.  A ridge was over the dateline with another trough over the Kuril Islands. The Gulf trough was providing good support for a gale under it. Over the next 72 hrs the gulf trough is to fade a little and pinch off, but then reinforcing energy is expected to start dropping into it on Sunday from the Bering Sea with more 170 kt winds building just south of the Eastern Aleutians likely helping to support more gale development there focused on the Pacific Northwest.  The trough over the Kuril Islands is to remain landlocked.  Beyond 72 hours the Gulf trough is to slowly fade, but not entirely with some form of low pressure development continuing there through Tues (9/15). And yet another trough is forecast building in the Western Gulf Thurs (9/17) with 120 kt winds pushing down into it, likely helping to support low pressure development there. In all, not a bad pattern, especially for early Sept. 

At the surface on Thursday (9/10) a gale low was in the Northern Gulf of Alaska with pressure 972 mbs and supporting 35 kt northwest winds, producing 23 ft seas (see Dateline/Gulf Storm below). Otherwise weak high pressure at 1020 mbs was just north of Hawaii elongated west to east but not really generating any swell producing wind. Another broad low pressure system was landlocked over the Kuril Islands and Kamchatka, offering northing of interest. Over the next 72 hours both these low pressure systems are to lift north and dissipate while  high pressure at 1024 mbs builds some 900 nmiles north of Kauai elongated again on the west to east axis.  No fetch of interest is to result.  It's just filling the void left behind by the exiting lows.  At this point the Dateline/Gulf Storm is to be of most interest. 

Dateline/Gulf Storm
A storm developed on the dateline Tues AM (9/8) from energy that spun off of Tropical Storm Dujuan (off Japan) with pressure 984 mbs forming a pressure gradient with high pressure south of it, generating confirmed winds at 50-55 kts aimed due east at 39N 178W aimed right up the 292 degree path to Central CA with some degree of 45 kt fetch (unconfirmed) pushing towards Hawaii down the 319 degree path. 30 ft seas were modeled at 40N 179E. Tuesday evening fetch dropped to the 45-50 kt range but covering a larger area at 40N 170W aimed right up the 288 degree path to Central CA with decent fetch aimed down the 331 degree path to the Islands. 32 ft seas were modeled at 40N 175W heading mostly due east. 

The fetch faded in strength on Wednesday AM with 40-45 kt winds confirmed at 40N 163W aimed right up the 287 degree path to Central CA and still with decent energy pushing towards Hawaii down the 348 degree path. 29 ft seas were modeled at 40N 163W.  The Jason-1 satellite passed over the back quadrant of this area reporting seas of 26.4 ft with ah peak to 30.5 ft where the model depicted only 24 ft seas.  So the model was running on the low side (good news). By evening the whole focus shifted east away from Hawaii with a large fetch of 40-45 kts northwest winds set up at 40N 153W generating more 29 ft seas at 40N 156W, though some energy is still likely pushing towards the Islands. The Jason-1 satellite reported average seas on the back end of this fetch at 24.7 ft with one peak reading at 29.9 ft, besting the model which indicated 22-23 ft seas for the same area.  This is good news. 

Thursday AM (9/10) residual 30-35 kts fetch was at 45N 152W with the core of the gale moving up into the northern Gulf. 23 ft seas were modeled at 40N 150W aimed right down the 296 degree path to Central CA. The Jason-1 satellite passed over the leading edge of this fetch and reported seas at 27.4 ft with a peak reading of 35.8 ft, beating the heck out of the model which only showed 23 ft seas for the same area. More good news. The final push of 30 kts winds is forecast in the evening with 24 ft seas at 46N 150W tracking towards the Pacific Northwest down into Central CA. 

Even some residual 22 ft seas are forecast into Friday AM (9/11) at 46N 150W targeting mostly the Pacific Northwest. 

Based on the models this was a nice early season little storm, and a bit early and strong for anything but an El Nino Fall. So from an El Nino perspective things were right on track. And looking at the Jason-1 data, it appears that this system actually did better than what the models suggested.  The QuikSCAT data also suggested the same, with wind speeds consistently a little higher than what hindcast versions of the model suggested, and actuals better than the forecasts. So this is pretty typical of El Nino years, that is, the models tend to undercall it versus the more familiar pattern of the models overcalling it (during la Nina years). So the bias, at least for this system, is in our favor. Otherwise it produced 48 hours of 40-45 kts winds with a 24 hrs spike in the 50 kts range, good for 17 sec period swell with a nice bit of 15 sec follow on energy and more in the 13-14 secs range relative to Central CA.  Hawaii's focus will be the initial pulse of 17 secs energy, especially given their close proximity.  No significant class potential here, but solid utility classs well is expected for all locations. 

Hawaii:  Expect swell arrival Thursday afternoon (9/10) with swell building to 6.6 ft @ 17 secs (10 ft faces) and holding through the evening.  By Friday AM swell of 7.2 ft @ 14 secs is forecast (10 ft faces) holding decently into mid-afternoon, then heading down an little. Continued follow-on energy from the initial push to continue Saturday (9/12) with swell 6.6 ft @ 11-12 secs (7.0-7.5 ft faces)  fading from 6 ft @ 10-11 secs on Sunday (6.0-6.5 ft faces) coming more from the north.  Swell Direction: 320 degrees initially moving to 350 degrees on Sunday. 

North CA:  Expect swell arrival starting Saturday (9/12) at 5 AM with swell period 17-18 secs and size coming up steadily, reaching 6 ft @ 16 secs early afternoon (9-10 ft faces).  Swell to hold steady then period dropping some over night.  By Sunday AM (9/13) swell is to continue at 6.5 ft @ 14 secs (9 ft faces) and starting to swing a little more out of the north, with more westerly energy still lurking underneath. Swell to be down to 6 ft @ 11-12 secs on Monday AM (6-7 ft faces).  Swell Direction: 285-292 initially, turning towards 300-305 degrees on Sunday.    

South CA:  Expect swell arrival starting Saturday (9/12) at 1 PM with swell period 17-18 secs and size coming up steadily, reaching 3 ft @ 16 secs at sunset (5 ft faces - with tops exposed spots near NCal levels).  Swell to hold steady with period dropping over night.  By Sunday AM (9/13) swell is to continue at 3.5 ft @ 14 secs (5 ft faces) and starting to swing a little more out of the north, with more westerly energy still lurking underneath. Swell to be down to 3 ft @ 12 secs on Monday AM (3-4 ft faces).  Swell Direction: 290-297 initially, turning towards 305-310 degrees late on Sunday.    


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


California Nearshore Forecast
On Thursday (9/10) a gale low in the Gulf of Alaska was helping to suppress high pressure development nearshore, and supporting a calmer local wind regime. That is to break down on Saturday (9/12) but a trough associated from what was the Gulf gale is to hold over the coast through Sunday (9/13), holding high pressure at bay and keeping winds generally light. By Monday (9/14) another gale is forecast for the Gulf with a front pushing up close to the Pacific Northwest,  again suppressing significant winds along the CA coast and holding into Thurs (9/17). After that there's some sense that high pressure will try and make a stand with north winds starting to build over Cape Mendocino at 25 kts with lesser winds down the length of the Central CA coast at 15 kts.  But more low pressure is expected for the Gulf, likely making short work of the highs influence. 


The Inactive Phase of the MJO is in control of the Eastern Pacific expected to continue influencing the area through 9/22 and likely hampering odds for tropical storm formation.  But a more favorable pattern is to follow: 

Hurricane Linda as located 1000 nmiles southwest of Pt Conception California drifting northwest with sustained winds 65 kts. this motion is expected to continue with a slow degradation in strength forecast, down to depression status Saturday AM (9/12). Some degree of minimal swell is lapping into Southern CA shore right now from this system, but size is minimal.  That size to hold into Friday, the fade out. given the swell being generated in the Gulf of Alaska, this is only incidental energy.


South Pacific

At the surface on Thursday (9/10) high pressure at 1032 mbs was just east of New Zealand ridging south almost to the Ross Ice Shelf and effectively cutting off the storm track from the Indian Ocean eastward. No swell producing weather systems were in.cgiay in the US swell window. Over the next 72 hours a storm is forecast building in the deep Southeast Pacific  Saturday (9/12) with winds 50-55 kts at 60S 120W holding into Sunday.  Seas are forecast up to 40 ft at 60S 105-110W, well east of the SCal swell window. All fetch is to be aimed almost due east, targeting Southern Chile. Little to no energy is expected to be pushing north towards California, though some swell will likely start pushing northeast towards Central and moreso, South America. 


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




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

North Pacific

Beyond 72 hours high pressure is to retrograde, taking up shop over the dateline while another weak gale is forecast developing in the Northern Gulf of Alaska on Sunday (9/13) generating 30 kts winds in the Western Gulf aimed at the US West coast. This low is to hold if not push a little east generating varying degrees of 20-25 kt northwest fetch through Tues (9/15) producing seas of 15-18 ft, likely resulting in some degree of 10-11 secs period windswell pushing towards the US West Coast for later in the week.  Another patch of similar low pressure is forecast for the Western Gulf on Thursday (9/17) likely resulting in the same strength fetch and seas. But no other swell producing fetch is forecast.   

MJO/ENSO Update (reference): As of Thursday (9/10) the Madden Julian Oscillation (MJO) was in the Inactive Phase, and reasonably strong. The ENSO (El Nino Southern Oscillation) index remained barely negative. The Daily SOI index was at -1.96. The 30 day average was up to 0.41 and the 90 average was up to 1.04.  The SOI index was on the rise, typical of the Inactive Phase of the MJO.

Wind anomalies at the 850 mb level (approx 5000 ft up) as defined by models indicated that strong easterly anomalies are starting to subside  over the entire Eastern equatorial Pacific starting weakly over the dateline and peaking in velocity from south of Hawaii into Central America. This was the tail end this event and is expected to slowly subside loosing coverage through 9/19. But of more interest, the models also indicate that western anomalies associated with a building Active Phase of the MJO were taking firm root over the entire width of the Indian Ocean, almost extending out into the far western Pacific. As the Inactive Phase pushes over Central America the Active Phase is to be starting to exit the Indian Ocean pushing into the Western Pacific on 9/14 reaching to the dateline by 9/24 then slow fading through through at least the end of the month. All this looks nice, though no strong anomalies are indicated, just 'average'. But the question remains: How far off the mark are the models, and will the Westerly Anomalies develop stronger than currently forecast and hold longer? It's too early to tell, but our guess remains that this might be the case.  The good news is the easterly anomalies associated with the current Inactive Phase didn't even develop until they reached the East Pacific, leaving the prime area for Westerly Wind Burst development (and Kelvin Wave formation) untouched. Such a scenario only aids the development of El Nino. 

Sea Surface Temp anomaly data (9/10) indicates only subtle change over the past month, 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 holding at 2.0 deg C above normal in the east. This is suggestive of a moderate El Nino.  But the expanse of the warmer waters has increased some solidifying there grip north up the coast of Baja Mexico and Southern CA, but still retreated from the Central California coast. There is also more coverage over the dateline region pushing east, suggesting the warm pool is in fact building not in intensity but in area. This would likely have a stronger effect on the environment over the long term. Cooler than normal waters (-2.0 deg C) remain mirrored streaming off Africa and pushing east reaching South America. Typical of stronger Classic El Ninos of the past. . 

Below the surface on the equator major changes have evolved. A steady flow of 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. And if anything that pattern has built. 2-3 deg warmer than normal waters are in control from 155W extending the whole way into Central America in one non-stop contiguous stream. Most impressive. The Kelvin Wave we have been tracking earlier in the month near 165W is embedded in that stream pushing into Central America. arrival was forecast at 9/27, and that continues to look to be the case. This Kelvin Wave was the result of a Westerly Wind Burst (WWB) in the West Pacific that occurred on 7/25-8/2. This is exactly the sort of situation we've been looking for and is critical to the formation of a legitimate El Nino. Next up is we'll be looking for another WWB and assocaited Kelvin Wave from the Active Phase of the MJO schedule for alter this month.  

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 by 8/20, continuing steady 8/31. But on 9/3 more fully blowing west winds were indicated and were holding into 9/10 extending from the west to 170E with a solid westerly anomaly in.cgiay. This is the result of a tropical system (Dujuan) in the West Pacific, classic El Nino symptoms.  This is good news and might continue to gently feed the subsurface warm water flow pushing east. At a minimum it suggests reinforcements for the existing Kelvin Wave pattern already in.cgiay. 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. All data suggests this will not be a strong El Nino, more likely a moderate one. NOAA's most recent update today forecasts 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, but a far stronger signal is now in.cgiay and looks to continue. 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 current data indicates that the warm pool will continue to build.

The next milestone we're looking for is development of the next Active Phase of the MJO, expected sometime near the 3rd week of Sept. The models (as of 9/10) indicate it is forming as expected. Also water temps need to hold if not build (as is happening now). A final confirmation should be possible in late-Sept. In the mean time, the current Inactive Phase currently in-progress faltered as it passed over the West Pacific, a good thing in that it allowed the prime area for Westerly Wind Bursts to remain unscathed, allowing the warm pool to continue to build. 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, a gentle but steady push/momentum in-favor of storm development rather than the manic frenzy of a strong El Nino, but without all the weather associated with a strong event. So in many ways a moderate El Nino is more favorable from a surf perspective. As of right now things remain 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 the only pe.cgiexing indicator. But we're becoming more disposed to think the SOI of more of a lagging indicator, at least for this event.    


See more details in the new  El Nino update.


South Pacific

Beyond 72 hours the models suggest some degree of unsettled weather is forecast off the Southern tip of Chile, but all is to outside the California swell window. No swell potential forecast for US interests. 

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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