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Pacific Storm and Surf Forecast
Updated: July 14, 2010 6:41 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 = 2.5 - California & 1.5 - 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 7/12 thru Sun 7/18
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 Pushing North Towards HI & CA
Calm Storm Pattern To Follow


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 Wednesday (7/14) North and Central California was getting the tail end of swell originating from the dateline with waves head high to 1 ft overhead and slightly textured early.  Southern California was getting weak wrap around windswell with maybe some background dateline swell up north at maybe thigh high and windblown. Down south there was some indications of the dateline swell pushing waist to maybe chest high and textured. Hawaii's North Shore had descended back into near flatness though occasional waist high.cgius sets were coming through with clean conditions.  The East Shore was getting waist high tradewind generated east windswell and lightly chopped. The South Shore was getting background southern hemi swell with waves chest high.cgius on the sets and pretty lined up on occasion with light trades in effect.

The forecast for North and Central CA is for local windswell taking control on Thursday providing weak chest high surf with maybe a little southern hemi background swell underneath at thigh high late and continuing at thigh high on Friday with waist high.cgius local windswell on top.  Saturday local windswell is to build to chest high with maybe waist high background southern hemi swell underneath, and then maybe to shoulder high windswell on Sunday with fading thigh high southern  hemi swell intermixed. Southern California is to see barely noticeable weak southern hemi background swell fading Thursday, then be reinforced by more of the same on Friday with waves to waist high. Saturday and Sunday is to see more waist high unremarkable background southern hemi swell with maybe thigh high north angled local windswell intermixed at exposed breaks  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 no east tradewind generated windswell until Saturday, when it rebuilds to thigh high.cgius and maybe waist high.cgius on Sunday. The South Shore is to see southern hemi swell fading a little on Thursday at waist to chest high early and then waist high Friday. New swell from under New Zealand arrives later Saturday at chest high with more period than others before it,  holding on Sunday, then sliding down. 

Up north a quiet weather pattern is forecast offering no potential for swell production over the next 7 days.  Down south a gale 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, though less in reality. Modest swell to result initially for Hawaii by Saturday (7/17) and then better size for the US West Coast by Monday (7/19).  After that no swell producing weather systems are forecast. 


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

North Pacific

On Wednesday (7/14) the North Pacific jetstream continued tracking generally flat west over the 45N latitude but very weak, almost non-existent over the dateline, then rebuilding some pushing into British Columbia. Winds ranged from 70-110 kts. No troughs were present offering zero odds to support surface level low pressure development. Over the next 72 hours more of the same is forecast but with a trough building just west of the dateline with 110 kt winds flowing into it Friday into early Saturday offering limited support for low pressure development, but with the energy quickly lifting northeast and dissipating. Beyond 72 hours the jet is to be dominated by a ridge developing over the Western Gulf of Alaska likely supporting high pressure at the oceans surface and not doing anything for what normally would be considered real swell production. 

At the surface on Wednesday (7/14) the normal summertime area of high pressure remained centered about 900 nmiles west-northwest of Cape Mendocino California at 1032 mbs barely ridging into the coast there generating a small area of 25 kt north winds just off the coast and producing minimal short period north angled weak windswell down into exposed breaks of Central CA. In general, unremarkable. The high was too far northeast to have any impact on trades over the Hawaiian Islands. Over the next 72 hours much of the same is forecast with 20-25 kt north winds continuing off Cape Mendocino maybe breaking up a little later Friday (7/16). trades to maybe build a little later Friday at 15 kts solid pushing into the Hawaiian Islands with easterly windswell still remaining below any real level of interest.  


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


California Nearshore Forecast
On Wednesday (7/14) high pressure at 1032 mbs remained positioned 900 nmiles west of Cape Mendocino and was ridging lightly into the US West coast over Oregon forming the usual pressure gradient and north winds over the extreme North CA coast at 25 kts.  But no fetch was reaching south of Cape Mendo with a generally light if not eddy flow (south winds) in control.  This general pattern is to hold through early Friday with only little variation day to day.  Secondary north fetch at 15 kts is forecast over Point Conception. Then late Friday the gradient is to work it's way south some with 25 kt north winds still holding up north, but 15 kt north winds are to start sweeping down much of the outer Central CA coast, likely adding a fair amount of warble and bump to nearshore surface conditions and getting more pronounced by late Saturday into Sunday (7/18).Next week the gradient itself is to dip south with 15-20 kts winds over all Central CA waters, with chop or at least lump in control making a mess of the surf into Tuesday (7/20) and high pressure build strong over the balance of the Northeast Pacific all the way to the dateline. This suggests the Inactive Phase of the MJO is to take dominance and local northwest wind and chop at exposed breaks from Pt Conception northward are to be the norm.  


South Pacific

On Wednesday (7/14) a generally .cgiit and fragmented jetstream pattern remained in control of the South Pacific with the remnants of a pervasive trough trying to hang on over the Southeast Pacific. There was some limited support for gale development in this trough. Over the next 72 hours that trough is to be getting undercut by energy running west to east along the northern edge of the Antarctic Ice Shelf pretty much shutting the trough down by Thurs (7/15) and then dissipating totally while moving east out of the California swell window over the weekend. Beyond 72 hours a fully .cgiit jetstream is to take 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 the remnants of the gale that made Swell #6S was fading fast on the eastern edge of the California swell window winds winds down to 30 kts and basically worthless now.  A new gale was developing just southeast of it at 960 mbs generating another fetch of 35-40 kt southwest winds but nothing of real interest. High pressure at 1028 mbs was building in east of New Zealand locking the West Pacific down.  Over the next 72 hours persistent 35 kt southwest fetch is to hold over the far Southeast Pacific, perhaps generating 26 ft seas aimed well to the north, but not enough to produce a swell of more than 14 secs, which will likely decay significantly on the long trip north. 

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:  Expect swell pushing into the south shore of Oahu starting Saturday (7/17) with period 19 secs and pushing 2 ft @ 18 secs at sunset (3.5 ft faces with sets to 4 ft at top spots). Swell to start peaking as period hits 17 secs at 6 AM Sun (7/18) and holding through the day as period falls to 16 secs.  Pure swell to be 2.6 ft @ 16-17 secs (4.0-5.0 ft faces).  Swell to be dropping from 2.4 ft @ 15 secs (3.5 ft faces) on Monday (7/19). 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 3.2 ft @ 17 secs (5.5 ft faces) but inconsistent.  Swell holding into Wednesday AM (7/21) with pure swell 3.0 ft @ 16 secs early (5 ft faces), and slowly settling down.  

North CA:  Expect swell arrival starting early Monday AM (7/19) with period 21 secs and and size tiny but building reaching 2.6 ft @ 20 secs late (5.0 ft faces).  Swell to start peaking on Tuesday (7/20) at 8 AM with period 17 secs and size up to 3.2 ft @ 17 secs (5.5 ft faces) but inconsistent.  Swell holding into Wednesday AM (7/21) with pure swell 3.0 ft @ 16 secs early (5 ft faces), and slowly settling down.     

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 average0 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.  Detailed surf forecast coming shortly. 


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 1032 mbs ridge a little more into the North California coast generating a broader area of 25 kt north winds offering better odds for local windswell production there, but with the gradient also sinking south into nearshore Central CA waters, making a pretty sloppy mess of things into Monday (7/19). But with the broadening of the high, trades to start building into Hawaii at 15 kts over the weekend 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 with decreasing the odds for windswell initially along the California coast. 


MJO/ENSO Update (reference): As of Wednesday (7/14) the Southern Oscillation Index (SOI) remained in positive territory. The daily SOI was up to 23.08 and has been positive for 20 days running. The 30 day average was up to 8.52 with the 90 day at 7.38. This is looking like the start of a modest run of the Inactive Phase of the MJO.  

Wind anomalies as of Wednesday (7/14) at the 850 mb level (approx 5000 ft up) as defined by models suggested light west anomalies holding over most of the equatorial Pacific to the dateline with light east anomalies limited to the Indian Ocean and extreme Western Pacific. This suggests the Active Phase of the MJO was still trying to hold on over the Eastern Pacific and had actually expanded it's coverage, not dying as fast as previous forecast. The Inactive Phase was trying to build in the Indian Ocean, but was not making any headway. Regardless, the Active Phase is to fade quickly through 7/23 while the Inactive Phase builds over the  Western Pacific and into the East at the same time, then weakly in control of the entire Pacific by 7/26, fading slowly into August 3.    

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 light to 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 (7/12) 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 the west to east heading and minimize the odds for any fetch to develop aimed to the north. And even at that, only minimal gale force winds are forecast and nearly over Antarctic Ice. Given the time of year the Antarctic Ice pack has built almost to it's furthest extent north, reaching up to between 65-62S.  In short, no swell producing fetch of interest is 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

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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.

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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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