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Pacific Storm and Surf Forecast
Updated: April 18, 2009 11:22 AM
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 = 2.0 - 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 4/20 thru Sun 4/26
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 #1S Pushing North
Weak Gulf Swell For CA First - Maybe Last One for a Long Time


New Swell Classification Guidelines (Winter)

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.

First of we want to congratulate all the winners of the Billabong XXL awards held last night in Southern CA. A solid contingent of Northern CA folks made it down for the awards including Jeff Clark (presenter Monster Paddle), Grant Washburn and Frank Quirarte. Mike Parsons provided great commentary too. But a big call out to winners who put in time up here in Northern CA, including Derek Dunfee for the Monster Paddle at Mav's on Nov 30th, our friend Twiggy Baker for Biggest Wave of the Year at Tafelberg reef on Aug 9 2008 (outside Dungeons) and Performance of the Year, and the big money to our friend Greg Long for Ride of the Year at Dungeons on July 26. An excellent performance by all and very articulate and thoughtful acceptance speeches by both Greg and Twig. You do the sport of surfing and Billabong proud! A new generation is in-control of the helm.

On Saturday (4/18) North and Central California had shoulder to head high northwest building swell with reasonably clean conditions. Southern California was getting a mix of minimal southern hemi background swell making for surf in the thigh to waist high range. At least it was clean as a whistle. Hawaii's North Shore was getting the last little residuals from a gale that was off Kamchatka with was waist to chest high and clean. The East Shore had waist high.cgius east tradewind generated windswell. The South Shore was knee high or so with background southern hemi impulse energy. 

The forecast for North and Central CA is to see a nice little pulse of swell by late Saturday coming from a gale that pushed from Kamchatka over the dateline and then regenerated off the Pacific Northwest lat this week. That swell is to peak on Sunday then head down in the days to follow. Decent winds expected too. Southern CA to not see too much from either the Kamchatka or the Gulf energy due to the laters very northern angle. Oahu's North Shore is to see only the faintest residual hints of that Kamchatka swell Sunday, with nothing to follow it. Well maybe some northeast windswell Tues/Wed. The East Shore is expected to see slowly fading east tradewind generated windswell through the weekend then basically flat until that northeast windswell shows. The South Shore is to see some sideband swell from a Storm #1S starting Tuesday (4/21) holding into Wednesday.  

Longterm the focus remains down south. In the southern hemi a decent system formed starting Tues (4/14) and rebounded pretty nice Thurs (4/16) with two 24 hour bouts of 40 ft seas aimed pretty well to the northeast in the CA swell window with sideband energy forecast up into the Hawaiian swell window. This is to be the first significant class southern hemi swell of the season for the mainland.


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

North Pacific

On Saturday (4/18) the North Pacific jetstream was a fragmented mess with only a weak trough somewhat distinguishable in the Gulf of Alaska providing little support for low pressure development there. No other areas of interest were indicated. Over the next 72 hours through Tuesday (4/21) maybe a weak trough is to set up off Kamchatka with 130 kt winds feeding into it pushing to the dateline and offering limited support for gale development. Beyond 72 hours there's no clear support for low pressure development.  

At the surface high pressure at 1028 mbs was 600 nmiles off Central CA ridging northeast up into British Columbia generating some modest 15 kt north winds down the coast of Central CA. A second high at 1032 was straddling the northern dateline region. In all there was no swell producing fetch indicated. Over the next 72 hours that high pressure system off California is to fade some with winds fading over nearshore waters. A cutoff low is forecast developing 8 nmiles northeast of Hawaii Mon/Tues (4/21) producing up to 30-35 kt north-northeast winds and 18 ft seas near 37N 150W aimed just a bit well of Oahu. This could be good for some 9-10 sec period windswell for northeast shores Wed/Thurs (4/23) if it occurs.   

Kamchatka Gale
On Saturday PM (4/11) 40 kt west winds were centered just off Kamchatka at 48N 162E and cut off from any track to the US West Coast, but sending some energy down towards Hawaii down the 318 degree path. Sunday winds faded to 35 kts with seas to 28 ft early at 47N 167E as the gale limped east and was almost gone on Monday with only 30 kts winds and 25 ft seas crossing the dateline at 46N 178W pushing down the 302 degree path to North CA. 

 Very limited energy is expected into the US West Coast Saturday (4/18) fading Sunday but being overrun by more local Gulf swell later Saturday into Sunday.

Pacific Northwest Gale
On Thursday (4/16)
weak low pressure at 996 mbs was in the Northern Gulf of Alaska, the remnants of the Kamchatka Gale (above) generating 30-35 kt west winds in it's south most quadrant generating a broad area of 17 ft seas pushing towards the Pacific Northwest.  These seas build to 19 ft in the evening pushing 21 ft Friday AM at 48N 140W, then fading after that. This should result in a nice spurt of 13-14 sec energy pushing towards the Pacific Northwest for late Saturday pushing into Central CA by Sunday AM (4/19) with swell of 5.5 ft @ 12-13 secs (6-7 ft faces) from 307-310 degrees.


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


California Nearshore Forecast
On Saturday (4/18) moderate high pressure at 1028 mbs was 400 nmiles west of San Francisco ridging into southern British Columbia generating a modest northerly flow at 15 kts from Cape Mendocino southward to Pt Conception. But with the high pushing inland, but Sunday those winds are to be all but gone with no change forecast through Wednesday (4/22). But by Thursday (4/23) the next pulse of high pressure at 1032 mbs is to be pushing east from the Gulf bring north winds at 25 kts to Cape Mendocino and covering all of Central CA and down into even southern Southern CA by Friday (including San Diego). Much chop expected. Fortunately it is to back off at least for Southern CA by Saturday (4/25).

No tropical activity of interest was occurring.


South Pacific

On Saturday (4/18) the South Pacific jetstream had a nice trough in.cgiace over the southeast region with 130 kt southwest winds feeding into it but pushing out of the CA swell window and targeting only Peru and locations south of there. Over the next 72 hours a mostly zonal flow (flat west to east) is to set up. Though pockets of winds to 130 kts are forecast, no trough are indicated. Beyond 72 hrs a large a solid trough is forecast forming over the South Central Pacific Thursday (4/23) and maturing on Friday with near 140 kts winds projected pushing well to the north, offering some hope for gale development.

At the surface the broad and fading remnants of Storm #1S were dissipating near 50S 110W, but all winds were 25 kts or less and offering no more swell generation potential. A new storm formed Friday PM (4/17) well south of New Zealand producing a small area of 55 kt south winds at 65S 172E aimed well up the 193 degree path to Hawaii but practically over the Ross Ice Shelf. It was quickly fading Saturday AM (4/18) though with 45 kt southwest winds modeled at 65S 175W and seas barely 29 ft over a tiny area at64S 175W. Winds are to be gone by evening with 29 ft seas from previous fetch fading at 64S 165W. Doubtful any noticeable swell is to result. Over the next 72 hours residuals from the gale are to try and re-organize in the Southeast Pacific Monday but wind are to only reach 35 kts with seas in the 25-26 ft range, not enough to be of notice for our forecast area. 

Storm #1S
A gale started developing under New Zealand pushing east Monday (4/13). by the evening 45-50 kt wind blowing to the northeast were confirmed at 60S 170W with seas building.  The Jason-1 satellite passed over this are and confirmed seas at 30 ft with a single peak reading to 40 ft.

By Tuesday AM pressure dropped to 968 mbs with a decent sized fetch of 50 kt winds confirmed building at 56S 158W starting to get traction on the oceans surface and building in size pushing up the 198 degree path to California and barely unshadowed by Tahiti. 35 ft seas were modeled at 59S 162W. In the evening pressure dropped to 964 mbs with a solid area of 40-45 kt southwest winds at 53S 153W pushing northeast on the 197-198 degree path to California and unshadowed by Tahiti. Seas were modeled up to 42 ft at 56S 155W. The Jason-1 satellite passed over the northeast corner of the fetch an confirmed seas at 37.4 ft where the modeled suggested seas should be 35-36 ft.  The model was right on track if not a foot low.   

By Wednesday AM (4/15) this system was fading with a large fetch of 40-45 kt southwest winds modeled at 53S 145W but the QuikSCAT satellite found only 35-40 kt winds blowing to the north-northeast, pushing right up the 197-199 degree paths to California and unshadowed with seas holding at 39 ft at 52S 147W. In the evening winds were on the way up as the second pulse of this storm got organized.  50 kt winds were confirmed even though models suggested only 35-40 kt at 52S 1451 with 35 ft seas from previous fetch modeled at 50S 140W (191 degrees CA). The Jason-1 satellite passed right over the core of this system at 0Z and reported seas of 33.7 ft with a peak to 40 ft. A second pass over the northwest corned at 06Z confirmed seas at 30.4 ft with a peak to 41 ft where the model indicated 30 ft seas.  So again the model was pretty much right on track. 

Thursday AM (4/16) the gale peaked out 55 kt southwest winds confirmed at 48S 128W aimed 30 degrees east of the 188 degree path to California pushing seas back to 39 ft at 49S 132W. A shrinking area of 45-50 kts southwest winds were fading in the evening at 48S 123W with seas modeled peaking at 43 ft at 48S 123W. 

40 kt winds were modeled continuing into Friday AM with seas fading from 36 ft at 45S 120W and starting to push well east of the CA swell window focusing on Chile and Peru better. 

This storm actually beat what the models called for 5 days ago, a rarity. It produced 108 hours of decent fetch with peaks to near 55 kts, resulting in two 24 hr long spurts of 40 ft seas aimed reasonably well to the north up the 198 and 188 degree paths to California. This is the best we've seen so far this season by a mile and seems entirely likely to produce longer period significant class summer time swell for the US West Coast, the first significant class swell of the 2009 summer season. Side band energy is likely for Hawaii from early in the this storms life (when it was under New Zealand) with healthy size expected into Mexico down to Chile. This system was 4969-6127 nmiles from North CA and 4708-5969 nmiles from SCal. One can expect two distinct swell pulses from this storm relative to California, one from when it was just southeast of New Zealand from a more westerly direction and the second from when it was in the Southeast Pacific, coming from a more southerly direction.  Both to produce energy up to near 20 secs, with peak size in the 17 sec bandwidth.       

North CA: Expect swell pushing into the coast starting early Wed (4/22) with period 20+ secs, with the second pulse arriving Thursday AM again at 20 + sec, peaking late Thursday evening after sunset for the first pulse and 2 PM Friday for the second, then dropping into the 15-16 sec range for Sat (4/25) and 14-15 secs Sunday (4/26).  Peak swell size for the first pulse is expected at 3.5-4.0 ft @ 17 secs (6-7 ft faces with top breaks to peak at 7.5-8.5 ft) from 192-198 degrees with the second pulse perhaps up to 4.0-4.5 ft @ 16-17 secs (6.5-7.5 ft faces with top spots to 8-9 ft) from 180-186 degrees (though that might be a little on the high side).

Southern CA: Expect swell arrival starting well before sunrise early Wed (4/22) with period 20+ secs, with the second pulse arriving Thursday before sunrise again at 20 + sec, peaking late Thursday late afternoon for the first pulse and 6 AM Friday for the second, then dropping into the 15-16 sec range for early Sat (4/25) and 14-15 secs early Sunday (4/26).  Peak swell size for the first pulse is expected at 3.5-4.0 ft @ 17 secs (6-7 ft faces with top breaks to peak at 7.5-8.5+ ft) from 192-198 degrees with the second pulse perhaps up to 4.0-4.5 ft @ 16-17 secs (6.5-7.5 ft faces with top spots to 8-10 ft) from 180-186 degrees (though that might be a little on the high side).


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 virtually no real swell producing fetch is forecast in the North Pacific. Summer is here unless some major change manifests itself with the projected change in the MJO late this month.

MJO/ENSO Update (reference): As of Saturday (4/18) the Madden Julian Oscillation (MJO) was in the Inactive Phase with the ENSO (El Nino Southern Oscillation) index holding in the positive range. The Daily SOI index was 27.33, holding in the 20 range for 10 days now. The 30 day average was up to 7.99 and the 90 day average was up to 8.03. The SOI indicies remained weakly symptomatic of La Nina mainly attributable to the 90 day average. Wind anomalies at the surface and the 850 mb level (approx 1000 ft up) indicated that the Inactive Phase has filled the equatorial Pacific and is now moving east, covering the region from the dateline east to Central America with anomalous west wind seeping well into the Atlantic. The good news is it is past it's peak already while suppressing storm development in the North Pacific. This Inactive Phase is to continue pushing hard east into Central America through 4/22 and into the Atlantic, effectively gone by then. The new Active Phase is building strong behind it in the Indian Ocean, already starting to ease into the far Western Pacific, pushing towards the dateline by 4/22, but weakening as it tracks east. It's to be fading steadily as it tracks over the dateline on 4/27 and into the East Pacific through 5/7 but almost completely dissipated by then. At the same time a new pulse of the Inactive Phase is to be building in the Indian Ocean. The residual effects of 3 years of La Nina remain in-control in the atmosphere, and cooler than normal water off of Central America has gotten only limited reinforcement from the latest push of the Inactive Phase. But below the surface on the equator a persistent patch of cool water (-0.5 degree C) that had locked down the region is essentially gone, the first time in months. The big question is how much effect will this current Inactive Phase of the MJO have on surface and subsurface waters of the East Pacific through the next 3 weeks, and whether the Active Phase behind it comes-on stronger than currently modeled.   Regardless, it will still take months before the atmosphere begins to respond to any warming of the eastern equatorial Pacific Ocean, so expect a continuation of cool and foggy Spring weather in California into early summer. But come summer, if warming develops in the Tropical Eastern Pacific, this could set up up for a decent Fall, and maybe an enhanced late summer southern hemi season.     


South Pacific

Beyond 72 hours the models suggest a rather active pattern down south, though it's all are to be rather small and tracking more east than north courtesy of the zonal flow in the jetstream. A fragmented area of 40-45 kt southwest winds is to try and organize in the Central South Pacific Tues-Thurs (4/23) with pockets of 40-45 kts winds generating seas at 28-31 ft. But that seems a bit optimistic. Nothing else of real interest is indicated.


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

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:

The Kelly Slater Project - A group of dedicated surfers from Cocoa Beach are working to construct a statue of the the home town legend and set it up for all to enjoy near the break where Kelly grew up surfing. Take a look at the statue and read all about it here:

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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