Surf Forecasts and Marine Weather - No Hype - Just the Facts!
Central South Pacific Swell Hitting Hawaii! - Video Forecast HERE (7/14/24)
Buoys | Buoy Forecast | Bulletins | Models: Wave - Weather - Surf - Altimetry - Snow | Pacific Forecast | QuikCAST | El Nino | Tutorials | Great Circles | Video


Stormsurf Mobile App

Create Your Own Surf Forecast
Swell Calculator
Swell Decay Tables
Sea Height Tables
Swell Category Table
Convert from GMT:
 to timezone:

Pacific Storm and Surf Forecast
Updated: July 18, 2010 12:47 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 & 2.0 - 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 7/19 thru Sun 7/25
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 #6S Expected For Early Week in CA
Calm Storm Pattern To Follow for at Least a Week


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 Sunday (7/18) North and Central California was getting more locally generated short period north windswell with waves chest high and clean enough to ride early. Southern California was getting the same windswell at thigh high and clean up north with background dateline swell in the mix down south with sets pushing chest high but linda warbled by early morning southwest winds. Hawaii's North Shore was flat and kinda lumpy early with what looked to be minimal wrap around east windswell trying to make something almost big enough to stand up on, but not quite. The East Shore was getting waist high tradewind generated east windswell and lightly chopped. The South Shore was getting southern hemi swell with waves chest high on the sets and nicely lined up and clean with light trades in effect.

The forecast for North and Central CA is for local windswell northwest to continue pushing in on Monday up to 5.5 ft (face height) with the start of new southern hemi Swell #6 arriving reaching 4 ft late. More of the same expected on Tuesday with windswell 5.5 ft and southern hemi Swell #6S up to 5.5 ft and then more on Wednesday with windswell 5.5 ft and southern hemi swell up to 6 ft. The fade begins on Thursday with windswell dropping from 5 ft and southern hemi swell down to 4.5 ft and fading. Southern California is to see northwest windswell at knee high on Monday with southern hemi swell pushing head high late. Tuesday is to see the southern hemi swell doing it's thing at 1.5 ft overhead late and windswell at thigh high with more on Wednesday with southern hemi swell still 1.5 ft overhead and windswell at knee high. Thursday windswell drops from knee high and southern hemi swell fades from head high. The North Shore of Oahu is to see no rideable surf through the weekend and no change forecast anytime soon.  The East Shore to see perhaps a small push of east tradewind generated windswell Monday at chest to shoulder high fading from waist high.cgius early Tuesday. Small windswell at best on Wednesday then more starts being generated on Thursday at waist high and hanging there for a while. The South Shore is to see New Zealand swell fading from waist high.cgius on Monday then thigh to waist high Tuesday and even less Wednesday before it goes flat.

Up north a quiet weather pattern remains forecast offering no potential for swell production over the next 7 days.  Down south the only hope is that gale that pushed under New Zealand on Sat (7/10) lifting northeast with 32-36 ft seas over a small area but shadowed relative to California, then regenerated while tracking further northeast into late Tuesday (7/13) with up to 40 ft seas modeled. Sideband swell already hit Hawaii on Saturday (7/17) and better size is expected for the US West Coast for the early part of the workweek. After that no swell producing weather systems are forecast for the next week. 


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

North Pacific

On Sunday (7/18) the North Pacific jetstream continued tracking generally over the 45N latitude in the west but very weak, and then ridging some in the East but almost non-existent in terms of wind speeds. A weak trough was over the dateline, but winds were 80 kts offering no support for the development of surface level low pressure development. Over the next 72 hours more of the same is forecast with the dateline trough almost trying to build some, then fading with all it's energy flowing into the ridge in the east (on Wed 7/21) most likely supporting the development of high pressure there rather than low pressure back ont he dateline. Beyond 72 hours the jet is to become fragmented and generally lifting north with whatever energy is present flowing pretty much right over the Aleutians and not offering anything that would be considered supportive of low pressure development of interest.  

At the surface on Sunday (7/18) the normal mid-summer area of high pressure was centered 1400 nmiles west-northwest of Cape Mendocino California at 1032 mbs barely ridging into the coast there generating a small area of 20-25 kt north winds just off the coast and producing minimal short period north angled weak windswell that was reaching down into exposed breaks of Central CA. The high was also generating an area of northeast winds at 15-20 kts that was pushing into the North Shores of the Hawaiian Islands and maybe producing limited easterly windswell there. Over the next 72 hours much of the same is forecast with a broader area of north winds setting up over Cape Mendocino reaching to near 30 kts on Monday (7/19) then slowly backing off to the 25 kts range mid-week (wed 7/21) with trades also continuing over the Hawaiian Islands, though down some Monday-Tuesday then on the upsurge mid-week and likely starting to produce more modest easterly windswell then.  


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


California Nearshore Forecast
On Sunday (7/18) high pressure at 1032 mbs remained positioned 1400 nmiles northwest of Cape Mendocino and was ridging modestly into the US West coast over Oregon forming the usual pressure gradient and north winds over the North CA coast at up to 25 kts.  But no core fetch was reaching south of Point Arena with a generally light if not eddy flow (south winds) in control.  This general pattern is to build into Monday with up to 30 kt north winds up north and a stronger northerly flow pushing into Central CA with likely pretty warbled conditions nearshore. Much of the same is expected on Tuesday (7/20) and Wednesday but with north winds down to 25 kts up off Cape Mendo. Finally on Thursday the gradient is lift north some with a eddy flow taking control of Central CA waters but north winds back up to 30 kts, meaning more north windswell generation likely. By Friday the gradient is to be fading fast with windswell likely on the decrease, though local conditions are to improve more. For the weekend there is no clear sign of any windswell being generated with light eddy winds likely locally. Southern CA is to remain in a light southwest flow throughout.


South Pacific

On Sunday (7/18) a well .cgiit and fragmented jetstream pattern remained in control of the South Pacific with no trough os of interest present and the southern branch of the jet scrapping over the northern edge of Antarctic Ice the entire width of the South Pacific offering no hope to support gale formation down at the oceans surface. Over the next 72 hours no change is forecast. Beyond 72 hours more of the same is expected if not getting a.cgiified with a fully .cgiit jetstream taking over with the southern branch flowing hard west to east over the northern edge of the Antarctic Ice Shelf and completely suppressing support for the development of low pressure at the oceans surface. 

At the oceans surface high pressure at 1036 mbs was off of South America locking down the Southeast Pacific with another high at 1024 mbs east of New Zealand locking the West Pacific down as well.  Over the next 72 hours several area of fetch in he 40-45 kts range are projected, but all are to be tracking fast flat west to east with all fetch aimed due east if not slightly southeast and partially obstructed by the Antarctic Ice Shelf. Beyond 72 hours this same pattern is to hold, suggestive of strong high pressure in the upper levels of the atmosphere.

South Pacific Gale/Swell #6S
A broad area of gale force winds developed in association with e 960 mb low southeast of New Zealand Friday night (7/9) with 45 kt west-southwest winds at 61S 172E building to 45-50 kts Sat AM (7/10) from the southwest to south at 58S 171W then holding at 45 ks blowing almost directly from the south in the evening at 59S 162W. Seas were modeled to 34 ft Sat AM at 59S 178W pushing to 36 ft in the evening at 57S 162W, then fading from 30 ft Sunday AM at 53S 159W. This is on the 189-181 degree tracks to Hawaii and the 206-200 degree tracks to California (and shadowed by Tahiti). Possible swell generation potential for Tahiti, with sideband energy for Hawaii and shadowed and somewhat indirect energy for the US West coast.

Hawaii:  Swell to be dropping from 2.4 ft @ 16 secs (3.5 ft faces) on Monday (7/19) then down the 2.3 ft @ 14 secs on Tuesday (3.0-3.5 ft faces). Maybe residuals of 2 ft @ 13 secs on Wednesday (2.5 ft faces). Swell Direction: 182-191 degrees  

South CA:  Expect swell arrival starting early Monday (7/19) with period 20 secs and and size tiny but building reaching 2.6 ft @ 19 secs late (5.0 ft faces).  Swell to start peaking on Tuesday (7/20) at 2 AM with period 17 secs and size up to 3.6 ft @ 17 secs (6.5 ft faces) but inconsistent.  Swell holding into Wednesday AM (7/21) with pure swell 3.6 ft @ 16 secs early (6 ft faces), with energy from the second part of the storm taking control (see below).  

North CA:  Expect swell arrival starting early Monday AM (7/19) with period 21 secs and and size tiny but building reaching 2.3 ft @ 20 secs late (5.0 ft faces).  Swell to start building on Tuesday (7/20) at 8 AM with period 18 secs and size up to 3.2 ft @ 17 secs later (5.5 ft faces) but inconsistent.  Swell holding into Wednesday AM (7/21) with pure swell 3.6 ft @ 16 secs early (5.5 ft faces), with energy from the second part of the storm starting to take control (see below).     

Part 2

Then a secondary fetch of confirmed 45 kt south to southwest winds started building southwest of Tahiti on Sunday AM (7/11) at 60S 170W and building while tracking east. In the evening a solid fetch of 45-50 kt south to southwest winds was located at 54S 161W and just east of the core of the Tahiti swell shadow at 201 degrees and lifting steadily northeast.  Seas were building from 32 ft at 57S 166W.  At 06Z Monday the model indicated 35 ft seas and the Jason-1 satellite passed right over the core of this area confirming something less, with seas 30.4 ft with a peak reading of 33.8 ft.

On Monday AM (7/12) a solid fetch of 45+ kt south-southwest winds was located at 52S 150W aimed almost right up the 195-196 degree path to California, completely unshadowed. 38 ft seas are modeled at 54S 151W pushing up the 196 degree path to CA. In the evening the fetch shrank a little but built in intensity with 50 kts south winds confirmed at 50S 140W aimed right up the 192 degree path to California.  43 ft seas were modeled at 49S 141W pushing well up the 193 degree path.  The Jason-1 satellite passed right over the core of this fetch and confirmed seas at 38.8 ft (15 reading average) with a peak reading to 41.3 ft, about 3 ft less than modeled.

On Tuesday AM (7/13) the fetch held with a small area of 50 kts south winds modeled at 48S 131W pushing right up the 187 degree path to California. The ASCAT satellite confirmed winds at something less though, looking to be more at 40 kts. A tiny area of 42 ft seas were modeled at 46S 134W. The Jason-1 satellite passed over the western flank of this area and reported a 15 reading average of 35.0 ft with a peak reading to 40.7 ft where the model reported 38 ft.  The model was right on track. By evening the fetch was fading fast with a tiny fetch of 45 kt south winds at 46S 129W aimed due north and 36 ft sea from previous fetch fading at 42S 129W. The Jason-1 satellite passed right over the core of this fetch and reported a 15 reading average significant sea height of 34.2 ft with one peak reading of 39.7 ft, right on track with the models.  

Overall the second pulse of this gale developed pretty close to expectations, with winds in the 45 kt range and unshadowed by Tahiti relative to California but blowing perhaps a bit better up the great circle paths than was originally anticipated.  And the latter part of the storm followed what the wave models predicted almost exactly.  This indicates that there's decent potential for a modest significant class swell to push up into the US West Coast with maybe sideband energy into Tahiti. Hawaii is to be pretty far off and great circle route from the second pulse of this fetch though.

South CA:  Expect swell from the second and best part of this storm to arrive starting Monday (7/19) at 3 PM with period 20 secs and and size tiny but building. Swell to start building decently on Tuesday (7/20) with period 18 secs and size up to 3.2 ft @ 17 secs later (5.5 ft faces).  Swell to peak early Wednesday at 1 AM AM (7/21) with pure swell 3.7 ft @ 17 secs early (6.0 ft faces) and holding decently through the morning. Swell to be fading on Thursday from 3.3 ft @ 14-15 secs (5 ft faces early). Not much left on Friday. Swell Direction: 193-198 degrees       

North CA:  Expect swell from the second and best part of this storm to arrive starting Monday (7/19) at 8 PM with period 20 secs and and size tiny but building. Swell to start building decently on Tuesday (7/20) with period 18 secs and size up to 3.2 ft @ 17 secs later (5.5 ft faces).  Swell to peak on Wednesday at 6 AM (7/21) with pure swell 3.7 ft @ 17 secs early (6.0 ft faces). Swell to be fading on Thursday from 3.3 ft @ 14-15 secs (5 ft faces early). Not much left on Friday. Swell Direction: 190-195 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 high pressure at 1036 mbs is to build slightly and continue ridging into the North California coast generating a decent sized area of 25-30 kt north winds into Thursday (7/22) offering decent odds for local windswell production there with the gradient remaining pretty well to the north leaving local conditions not too bad. Trades are to be peaking over Hawaii at near 20 kts on Thursday too offering increased odds for Northeast windswell along exposed shores. Next week the high is to bloom to 1040 mbs filling the entire Central and East Pacific but pulling away fro the California coast increasing the odds for trades and windswell over the Hawaiian Islands. But by the weekend the high is to rapidly fade and retrograde back tot he dateline with north winds fading along Cape mendocino and trades also fading over the Hawaiian Islands, meaning windswell will likely be falling way back at both locations at that time.


MJO/ENSO Update (reference): As of Sunday (7/18) the Southern Oscillation Index (SOI) remained in positive territory. The daily SOI was at 16.68 and has been positive for 24 days running. The 30 day average was up to 11.06 with the 90 day average at 7.90. This is looking like the Inactive Phase of the MJO was in control.  

Wind anomalies as of Wednesday (7/14) at the 850 mb level (approx 5000 ft up) as defined by models suggested modest west anomalies holding over the far eastern equatorial Pacific reaching from Hawaii to Central America. . But very strong east anomalies were in control from Africa across the Indian Ocean to the dateline and almost to southern South America. The coverage of this area was huge and a very clear signal of a building Inactive Phase of the MJO. The Inactive Phase is to hold through 7/22, then slowly give up a little ground on 7/27, but continuing to hold on well into early August (8/6). This is a very bad sign for later this winter.

We believe the remnants of El Nino are trying to linger in the upper atmosphere for a while longer. But in reality, they are almost gone. The expectation is that we'll fall back into some form of a moderate La Nina Pattern (where the Inactive Phase takes control) for later 2010 into 2011. NOAA seems to support that.cgian too per the latest ENSO update last week. 

Sea Surface Temp anomaly data (7/15) indicates that cooler than normal waters have developed over a moderate strip on the equator from South America drifting west to the dateline and are in fact getting cooler and covering a larger area over time, extending the whole way to almost New Guinea now.  And feeder bands of colder than normal water have developed pushing off the US West Coast and South America reaching to the dateline, only serving to reinforce the existing pattern, suggesting stronger than normal high pressure has built in both hemispheres. Looks like a classic La Nina setup. This is a turn for the worse and only seems to be getting stronger. At the same time a massive buildup of warmer than normal waters continues in the Atlantic almost bleeding into the far Eastern Pacific, of concern to hurricane forecasters there. We'll see if upper level winds support development of hurricane activity or whether residual upper level shear from El Nino will chop the tops of developing systems. Suspect shear will be gone by the heart of hurricane season in the Atlantic.

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 -3 degs below normal. Not good. 

Over the entire Equatorial Pacific trades were blowing all the way to the Philippines and beyond, but only in the normal range. But there has begun to be some signs of slight easterly anomalies developing, which is to be expected given all the other data. This is typical for this time of the year but is likely to change towards an increased easterly flow as Fall approaches symptomatic of La Nina.  Previous we have believed that easterly anomalies usher in La Nina, but this has not been apparent in any data we have seen to date.  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, 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 suggest trade wind anomalies might be a byproduct of the Pacific equatorial current change and not the other way around.  Something to study in the years ahead.     

El Nino is effectively gone and slowly losing it's grip on the global upper atmospheric weather pattern. Still some lingering impact is to continue through the Summer of 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 new  El Nino update.


South Pacific

Beyond 72 hours the South Central Pacific is to be dominated by a generalized high pressure pattern east of New Zealand and a flat west to east flowing jet which will drive all storms systems on that west to east heading minimizing the odds for any fetch to develop aimed to the north. No swell producing weather systems of interest are forecast. 

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

Add a STORMSURF Buoy Forecast to your Google Homepage. Click Here: Add to Google
Then open your Google homepage, hit 'edit' button (top right near graph), and select your location


Local Interest

Powerlines Productions Greatest Hits - Come see excerpts from Powerlines greatest Mavericks movies at the Red Vic in San Francisco on Wednesday July 7th at 2:00, 7:15 and 9:15 PM. Also a sneak peek at their new movie featuring footage of the epic 2009/2010 El Nino winter will be screened. The producers will be on-hand to take your questions.

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

Free Stormsurf Stickers - Get your free stickers! - More details Here

Read all the latest news and happenings on our News Page here

Surf Height-Swell Height Correlation Table


Contact | About | Disclaimer | Privacy
Advertise/Content | Links
Visit Mark Sponsler on Facebook Visit Stormsurf on Instagram Visit Stormsurf on YouTube
Copyright © 2024 STORMSURF - All Rights Reserved
This page cannot be duplicated, reused or framed in another window without express written permission.
But links are always welcome.
Buoys | Buoy Forecast | Bulletins | Models: Wave - Weather - Surf - Altimetry - Snow | Pacific Forecast | QuikCAST | El Nino | Tutorials | Great Circles | Calculator