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Pacific Storm and Surf Forecast
Updated: April 19, 2008 1:07 PM
Buoys: Northern CA - Southern CA - Hawaii - Gulf of Alaska - Pacific Northwest
Buoy Forecast:
Northern CA - Southern CA - Hawaii - Gulf of Alaska - Pacific Northwest
Pacific Links:  Atmospheric Models - Buoy Data - Current Weather - Wave Models
Forecast Archives: Enter Here
A chronology of recent Mavericks Underground forecasts. Once you enter, just click on the HTML file forecast you want to review (e.g. 073199.html equals July 31, 1999). To view the maps that correspond to that forecast date, select the html file labeled 073199 maps.html
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Swell Potential Rating = 1.0 - California & 1.0 - 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 4/21 thru Sun 4/27
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   

Raw Windswell Hits California
New Zealand Swell Continues for HI, Drifting Into CA too


New Swell Classification Guidelines

Significant: Swell 8 ft @ 14 secs or greater (11+ ft faces) for 8+ hours (greater than double overhead)
Advanced: Swell and period combination capable of generating faces 1.5 times overhead to double overhead (7-10 ft)
Intermediate: Swell and period combination generating faces at head high to 1.5 times overhead (4-7 ft)
Impulse/Windswell: Swell and period combination generating faces up to head high (1-4 ft) or anything with a period less than 11 secs.


On Saturday (4/19) Northern CA surf was pushing double overhead and blown to bits. South facing breaks in Santa Cruz were maybe chest high and clean. waist to waist high and rarely a larger peak ut cleaner. Central California surf (Morro Bay) was a foot or two overhead and blown out bad. Surf in Southern CA from Santa Barbara to just north of LA was up to waist high and reasonably clean. The LA Area southward to Orange County was up to waist high on the sets and a bit textured. South Orange County down into San Diego best breaks were rarely up to chest high and reasonably clean early. The North Shore of Oahu was thigh high. The South Shore was head high with a few bigger sets early and clean. The East Shore was waist high and onshore.

North/Central California was getting slammed by howling north winds and locally generated short period windswell A real mess. Southern California was getting limited locally generated northerly windswell but down south new southern hemi swell was starting to show, rarely. Hawaii's North Shore was small with only minimal background windswell wrapping in. The East Shore had the usual easterly tradewind swell pushing in, though pretty small. The South Shore was the standout spot with southern hemi energy in control and producing solid surf again, though starting to drift downward.

For the future the North and Central California coast to see a stead drop in windswell into early next week, pushing near the flat mark by Tuesday. Maybe some limited southern hemi swell to hit exposed south facing breaks into Monday, but not much. Southern CA this weekend to see some energy from the windswell currently blowing over the northern coast, with southern hemi energy providing better odds at the usual spots into Monday, then fading out. After that nothing immediate is forecast. The North Shore of Oahu might see some limited northwesterly windswell late Saturday peaking Sunday, then settling down to nothing. Southern hemi swell on the South Shore to hold barely into Monday, then be completely gone. Longterm the best odds focus on a gale projected developing on the dateline and just barely south of the Aleutians Sunday tracking southeast through the week, and supposedly rebuilding off California late in the workweek with seas pushing 26 ft. This all looks great on paper but the odds of it actually occurring are remote. At least it's something to watch, because without it the North Pacific is dead. Down south the models suggest a semi-decent gale is to push under New Zealand on Monday (4/21) but fall apart, only to reorganize Wednesday through Friday (4/25) offering some odds for swell targeting both Hawaii and California. We're pessimistic though since the models have been forecasting this for a while now, and as soon as we get sloe to it they push it out further. Guess we'll see what happens. See details below...


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

North Pacific

Saturdays jetstream charts (4/19) for the North Pacific indicated a weak trough over the dateline area pushing into the Western Gulf of Alaska with winds up to 150 kts pushing through it and offering a little hope. A giant ridge was east of there though pushing well up into Alaska. Over the next 72 hours a new little trough is to develop off Kamchatka tracking to the east, pushing over the dateline Monday and then towards the Gulf of Alaska Wednesday (4/23) while getting sheared apart some. This is the only upper feature of interest. Beyond 72 hours that trough is forecast to pus into the Gulf of Alaska and almost get energized Thursday and Friday (4/25) with 110 kt winds flowing under it offering some hope for surface level gale development. Will be interesting if it occurs. Otherwise a huge ridge is forecast forming over the Western Pacific shutting it down hard while traveling east into next weekend.

At the surface today high pressure was in control at 1040 mbs in the northwestern Gulf of Alaska and ridging southeast into the California coast, generating very strong northerly winds at 35 kts over CApe Mendocino down to San Francisco and producing larger raw windswell (by summertime standards). Only minimal 15-20 kt easterly winds were being generated off the south side of this high aimed at Hawaii, offering limited windswell generation potential at best. No other swell source was indicated.

Over the next 72 hours the high pressure system off California is to is to dissipate late Sunday with winds and windswell along the coast fading. A new low is forecast building off Kamchatka Sunday pushing to the dateline Monday (4/21) but winds over exposed waters are only forecast in the 35 kt range, and fading. 23 ft seas possible late Sunday at 47N 175E providing some background swell potential for Hawaii with luck. The low itself is to try and hold on while dropping southeast but winds are to steadily erode to near nothing on Tuesday with seas fading below 20 ft.

A cutoff low formed north of Hawaii at the oceans surface pushing a short bit of 35 kt winds southward towards the Islands early Friday (4/18), offering a little hope for some windswell to result along north facing shores Sunday at 4.7 ft @ 11 secs (5 ft faces), but that's all.


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


California Nearshore Forecast
On Saturday (4/19) strong high pressure at 1040 mbs was ridging into the coast making for very brisk northerly winds along the coast at 30 kts off San Francisco and more further north, but Southern CA remained mostly protected. Large raw summer-time windswell was impacting the coast from Pt Conception northward. The high to shift it's focus south Sunday while fading offering minimal relief in the Bay Area (northerly wind 10-15 kts) but making a mess over Pt Conception and surrounding areas possibly including the northern reaches of South CA. The high to make a slow fade while sitting stationary there into mid-next week, though Southern CA possibly to remain protected by the Channel Islands. Up north first one small and weak low to nudge into Cape Mendocino late Monday with a front dissipating off San Francisco early Tuesday (4/22) providing light wind from Monterey Bay northward. Rain from this system is forecast pushing down the central coast through early Wednesday. And a much stronger low is modeled developing behind, keeping high pressure and wind and bay locally into the weekend. South winds from this system are to not reach any further south than Pt Arena on Friday (4/25) though rain to reach San Francisco early Saturday (4/26) but not any further south. Will believe all this when it happens.

No tropical systems of interest were being tracked.


South Pacific

No swell producing fetch is occurring nor forecast to occur for the next 72 hours.

Solid New Zealand Storm
A system developed under New Zealand Wednesday evening (4/9) with pressure 970 mbs and generating 50-55 kt confirmed winds aimed a bit to the north at 58S 171E. The models indicated seas at 25 ft but the Jason-1 satellite confirmed seas at 31.5 ft at 59S 171E. On Thursday AM (4/10) winds were confirmed at 60 kts at 56S 174W aimed right up the 207 degree path to California but shadowed by Tahiti and 30 degrees east of the 189 degree path to Hawaii. Seas were modeled building from 32 ft at 59S 175E, but we know it was higher than that. Wind faded a bit in the evening while seas caught up, building to 38 ft at 57S 173W. The Jason-1 satellite made a pass over the outer edges of the fetch confirming sea at 38 ft. Wind faded from 45 kts Friday AM with seas up to 41 ft early at 53S 165W (outer edges confirmed at 37.4 ft), then dropped from 37 ft in the evening at 50S 162W. Confirmed 29 ft residual seas were at 46S 158W Saturday morning (4/12) and fading.

In Hawaii swell to be fading from 3.6 ft @ 14-15 secs Saturday (5 ft) and dropping out on Sunday. Swell Direction: 185-190 degrees

California to remain shadowed by Tahiti for the entirety of the storm. First pulse of energy expected late Sunday (4/20) maybe reaching 2 ft @ 16 secs (3 ft faces) at exposed breaks on Monday (4/21).


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 the only potential swell source of interest focuses on the Kamchatka low, which is expected to try and hang on while moving into the Central Gulf of Alaska, then re-energizing due to an improved upper level flow Thursday and Friday (4/25) with winds 30-35 kts pushing 40 kts Friday positioned 750 nmiles off Cape Mendocino and aimed right at the Central CA coast. Seas building to 26 ft. That all seems very far fetched, but is something to watch. No other swell source is indicated.


South Pacific

A gale is modeled to organize under New Zealand starting late Tuesday (4/23) from the remnants of a pre-existing gale that was directly under New Zealand Sun-Mon (4/21). Winds to build over a decent sized fetch area at 48S 178E to near 40 kts aimed well up the 200 degree great circle path to Hawaii late Tuesday pushing to near 45 kts through the day Wednesday near 42S 170W traveling northeast continuing into Thursday near 41S 160W all aimed well towards Hawaii and then California. Seas to 32 ft at 48S 177W Wednesday AM moving to 43S 162W Thursday AM (still 32 ft) and slowly fading into Friday evening. Possible decent swell for Hawaii a week beyond with much less size for the US West coast about 9-10 days out.

Otherwise no swell producing winds 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

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Local Interest

Time Converter - Finally! 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.

Mavericks Contest 2008: View all the action from the 2008 Maverick Surf Contest from Powelines Productions here:

Half Moon Bay Surfers - Attention: There¹s a movement afoot to dredge sand out of the Pillar Point (i.e. Half Moon Bay) Harbor and dump it just south of the jetty, so it will r.cgienish all sand that¹s disappeared between the harbor and HMB. The guy who¹s spearheading the project, Brian Overfelt, has already received a positive preliminary reading from the local harbor commissioners. He¹s making a formal presentation to the Monterey Bay National Marine Sanctuary¹s advisory council this coming Friday (2/15) at Our Lady of Pillar church in Half Moon Bay. (It's on Kelly Ave, just east of the Coast Highway, across the street from Cunha Intermediate School.) starting at 9 AM. More details here:

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:

Grib File Switchover: The old grib1 format wave model datafiles that have been the mainstay of the National Weather service for years now are scheduled to be retired on 1/26. We switched over to the new grib2 files starting with the 00z run of Thurs 1/17. All appears to be running fine. There is no functional change to the content of the models, just that files we receive are now smaller due to improved compression of grib2. But this sets us up to start processing new higher resolution files and building new products in the months ahead. So in all it's a good maintenance level change.

Sharkwater: There's a new feature film called Sharkwater that is hitting theaters November 2nd. Sharkwater is an award winning documentary (22 international film awards including the UN and Cannes) that broke box office records in Canada, opening to bigger numbers than any documentary in history save Fahrenheit 911 and Supersize Me. It is a conservation film that demonstrates that the biggest influence on the air we breathe, and global warming is life in the oceans except life in the oceans is being wiped out. Shark populations have dropped 90% in the last 30 years alone, and the oceans continue to be destroyed because nobody knows that it's happening Learn more here:

Bluewater Gold Rush: The first and only chronicle of the California sea urchin dive fishery. Diving, surfing, comedy, and tragedy on and under the waves of California. "A quintessential tale of California ... dramas of adventure and loss on and under the sea" We read it and it's a great story about the bloom of the urchin diving boom in the 70's and the few lucky souls who were right there when it took off. An easy read that's hard to put down. The trials and success of a 'real' California dream right down to it's core. Check it out here:

Submit your story to 'Surfings Greatest Misadventures: Vol. 2': DEADLINE: January 15th, 2008 Casagrande Press is seeking stories, articles, and essays on the general subject of surfing misadventure for publication in Surfings Greatest Misadventures: Volume 2. We are looking for nonfiction, first-person surf stories of bad judgment calls, pranks, comical/ironic episodes, disaster, attacking predators, misfortune, injury, loss of wit or limb, panic, critical conditions, contest meltdowns, everyday fears, surf trips gone wrong or the out-of-water episodes that surround surfing. We are looking for well-written stories that tell a good tale, reflect a culture, and develop the depth of the characters involved. We also like stories that have a tight narrative tension and a payoff at the end. Open to writers and surfers of any level. There is no fee to submit a story. We will consider previously published stories. To see more info on the first book visit Submit online at

Waveriders Gallery: Check out this collection of high quality artwork all related to waves and the ocean. Surf Paintings, Photography, Posters, Books, Boards and exhibits all produced by a variety of top artists provide a beautiful selection of pieces to chose from. Take and look and see some of the stunning work available from these artists.

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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