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Pacific Storm and Surf Forecast
Updated: April 5, 2009 5:11 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 = 3.0 - California & 3.0 - 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 4/6 thru Sun 4/12
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   

Real Swell for US West Coast from the Gulf
Swell for Storm Off Japan for Hawaii Too


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.

On Sunday (4/5) North and Central California surf was head high and clean, a nice break from the non-stop winds of late. This was mostly residual local windswell though there was some background energy under there originating out by the dateline. Southern California was getting more of that swell, really the swell that hit Northern CA on Saturday, with waves waist high but top spots chest to head high on the sets and clean down south. Hawaii's North Shore was getting sideband energy from a gale that formed north of the Islands heading east on Thursday/Friday with longer period but smaller size, with waves in the waist to maybe chest high range and northeast trades a bit on it. The East Shore had more head high east tradewind generated windswell courtesy of high pressure northeast of the Islands. The South Shore was near flat with no southern hemi swell to speak of.  

North and Central CA is actually in a good.cgiace, with 2 swells forecast over the next 5 days. First up is swell from the Gulf for Monday/Tues, then swell from off Japan for Thursday and beyond. Details below. Make the most of this opportunity. Southern CA is to see a portion of both of these swells too making for fun rideable surf through the week (see QuikCast). On Oahu's North Shore swell from the Gulf gale is to fun sized on Monday with swell still 3.7 ft @ 12-13 secs early, but fading. No need to worry, cause much more size is expected to start showing late and building more on Tuesday reaching double overhead, then fading Wednesday (see details below). The East Shore is expected to continue with some form of modest easterly trade wind generated windswell, but fading by next weekend. The South Shore is expected to get in on the action too with a little pulse of southern hemi background swell arriving late Monday and providing something rideable at least through Wednesday.

Longterm another gale is forecast in the North Pacific tracking just south of the Aleutians into the Gulf starting mid-week offering some limited swell potential for mainly the US West Coast. But after that things are looking to quiet down. Nothing of real interest is expected this week out of the southern hemi.  


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

North Pacific

On Sunday (4/5) the North Pacific jetstream remained .cgiit on the dateline with the northern branch ridging north through the Western Gulf of Alaska then dipping into a steep trough off California. Only this trough offering any support for low pressure development. Over the next 72 hours through Wednesday (4/8) that trough is to slowly fade and push inland over Central CA. Otherwise a laconic flow is to prevail in the northern branch of the North Pacific jet, rising steadily north off Japan and then dipping a shade through the Gulf of Alaska. Beyond 72 hours another trough is to build in the Gulf and drop south along the US West Coast on Thursday (4/9) moving into Central CA on Friday while a big ridge builds in the Gulf. Back to the west a completely fragmented and weak jet is to develop offering no support for gale development.

At the surface strong high pressure at 1032 mbs was positioned 900 nmiles north of Hawaii and a fraction of the size is was earlier last week. It was serving only the generate easterly trades over the Hawaiian Islands at 20 kts, but without the depth of days before. Weak low pressure at 1008 mbs was 600 nmiles west of San Francisco generating 25 kt north winds off it's western flank aimed due south, but offering no swell production capacity for either the mainland or Hawaii. Over the next 72 hours no real change is forecast other than the high loosing strength, dropping to 1028 mbs and the low off California weakening more and drifting east, moving over San Francisco on Wednesday, perhaps brining some rain with it. North winds along the US West Coast appear to remain suppressed for a while, perhaps giving the ocean a slim chance of warming up.


Gulf Gale
Thursday AM (4/2) a new gale was forming in the Western Gulf of Alaska, just beyond the dateline. 40-45 kts winds were confirmed in it's southern quadrant at 46-48N 171W, north of the 296 degree path to NCal. By evening it had pressure of 992 mbs with 45-50 kt west winds confirmed in it's south quadrant at 46N 165W and 23 ft seas building aimed well at the US West Coast. 45 kt northwest winds were moving into the Gulf Friday AM (4/3) at 46N 156W with 26 ft seas at 45N 162W aimed down the 296-297 degree paths to NCal. Barely 40 kt northwest winds were confirmed in the evening at 48N 152W with seas to 28 ft in it's south quadrant at 45N 151W aimed well at the US West Coast, then moving into the Eastern Gulf on Saturday AM (4/4) with 35 kt northwest winds fading and 25 ft seas at 43N 148W while dropping southeast towards Central CA. In the evening 23 ft seas were modeled at 40N 145W. The Jason-1 satellite passed almost directly over the fetch and confirmed 22.6 ft seas at 38.9N 147W, right in line with the models. Sunday 30-35 kt northwest winds were just 600 nmiles off San Francisco with seas in the 20 ft range and the leading edge of the low starting to push into the coast late. The core of the low is to never move onshore, but is to wither just off the coast through late Tuesday.  South winds and rain is expected for Central Ca in association with this system Mon-Wed (4/8) with potential for snow at higher elevations.

Expect swell arrival in the Pacific Northwest on Sunday (4/5) and into Central CA (San Francisco) starting at 11 PM Sunday peaking early Monday (near 3 AM) with swell about 7.5 ft @ 16 secs (10-11 ft faces) from 290-297 degrees. 

Japan Storm
A storm was forming off Japan Thursday (4/2) with 50-55 kt northwest winds and 26 ft seas modeled late at 38N 154E pushing well towards Hawaii down the 302 degree great circle path. On Friday AM (4/3) west winds at 45 kts with seas up to 36 ft at 38N 160E targeting Hawaii well and even pushing energy towards the US West Coast up the 296 degree path (NCal). By evening winds to be dropping from 40 kts with seas peaking at 37 ft at 38N 166E aimed at NCal (3300 nmiles away) down the 295 path and Hawaii (2100 nmiles away) down the 309 degree path. The Jason-1 satellite passed directly over the core of the fetch and confirmed seas at only 30.6 ft with one spurious peak reading at 39 ft. This was considerably less than what the model suggested. 30 kt west winds were fading fast Saturday AM (4/4) with seas fading from 36 ft early at 41N 171E, down to barely 29 ft at sunset at 41N 175E. The Jason-1 satellite passed over the western side of the peak seas at 18Z Saturday and confirmed seas at 27.8 ft @ 40.6N 168E with a peak reading to 32.2 ft where the modeled suggested seas of 28 ft. So the model was right on target this time.   

Hawaii: Expect a decent pulse of 18 sec period swell to reach Hawaii's North Shore late Monday (4/6) with most consistent size on starting 2 AM Tuesday (4/7) as period turns to 17 secs. Swell to peak at 6.6 ft @ 16-17 secs right before sunrise and hold decently through the morning (10 ft faces) coming from 305 degrees .

North CA: Expect inconsistent 17 sec period energy is to reach into Central CA starting late Wed (4/8) at 8 PM peaking into Thurs (4/9) AM at 5.2 ft @ 16 secs (8 ft faces) from 295-296 degrees. Very inconsistent.      

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


California Nearshore Forecast
On Sunday (4/5) low pressure at 1006 mbs was 600 nmiles west of San Francisco not yet reaching the coast with calm winds nearshore. The low is to sink south and inch closer on Monday but still be off the coast, with light east winds forecast for both Central and NCal. Finally on Tuesday south winds and light rain to hit, reaching even Southern CA. But the core of the low is to inland on Wednesday with light high pressure building in behind and rain fading. A moderate north wind pattern is expected to build in by late Thursday north of Pt Conception at 15 kts holding through the coming weekend with rain Thursday in NCal pushing south to Southern CA Friday while clearing north, then clearing in the south by Saturday.

No tropical activity of interest was occurring.


South Pacific

Remnants of the Second New Zealand Gale (see details below) are trying to congeal in the Southeastern Pacific on Sunday AM (4/5) producing a small fetch of confirmed 50 kt almost south winds at 48S 138W aimed 15 degrees east of the 194-197 degree path to CA and east of the Tahiti swell shadow, expected to hold into the evening at 46N 128W aimed up the 184 degree path to CA. 35 ft seas are forecast Sunday evening at 45S 132W with the momentum pushing them more east than north. 30 ft seas are forecast Monday AM at 43S 125W. Beyond the fetch is to all turn to the east to southeast on Monday AM (4/6) and fading. 27 ft seas are pretty well east bound for Peru from 42S 115W in the evening. This system to fade there after. Possible very southerly angled swell pushing up into California 7-8 days later (Mon 4/13).   


First New Zealand Gale
On Sunday (3/29) an elongated fetch of 35-40 kt west winds were under New Zealand associated with a 960 mbs low in the deep Southwest Pacific and generated 30 ft seas at 55S 158E south of the Tasman Sea and shadowed from Hawaii and the US by New Zealand. By Monday AM that gale was fading with 35 kt southwest winds aimed better to the northeast, then fading from 30 kts by Tuesday AM. Seas were modeled at 30 ft Mon AM (3/30) at 54S 176E and holding at 30 ft in the evening at 54S 179W. The Jason-1 satellite passed over the eastern edge of the fetch at 06Z Tues and reported seas of 25.8 ft with a peak to 34.8 where the model suggested seas of 27-28 ft. This was about on-track.  One more reading of 28 ft occurred Tuesday AM (3/31) at 52S 180W then dissipating. Possible modest 17 sec southern hemi swell is possible for the Islands 7 days later (late Mon 4/6 with swell 1.6 ft @ 17 secs dropping to 1.6 ft @ 16 secs on Tues resulting in 2.5-3.0 ft faces from 195 degrees) and Thursday (4/9) for CA (1.6 ft @ 16 secs - 2.5 ft faces from 210 degrees).

Second New Zealand Gale
Another gale tried to get going under New Zealand Wednesday (4/1) producing a modest area of 40 kt wind at 60S 180W Wed PM aimed somewhat to the northeast, but dissipating into Thursday AM. 28 ft seas were modeled  Wed afternoon (3/31) at 60S 170W pushing to 29 ft Thursday AM (4/2) at 58S 177W then down to 26 ft in the evening at 55S 165W. Possible sideband swell for the Islands starting Fri (4/10) at 2 ft @ 16 secs (3 ft faces) down to 2 ft @ 14.5 ft on Sat (3 ft faces) from 188 degrees. This swell was barely unshadowed (Tahiti swell shadow) for CA.with smaller energy limping in Sun (4/12) with swell 1.6 ft @ 19 secs (3 ft faces) from 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 hours a gale low is forecast to build on the dateline just south of the Aleutians Wednesday (4/8) tracking east with 45 kt west winds, then fading in the GUlf on Friday. Additional low pressure energy to join up with the remnants in the Gulf, possibly generating more 35 kt winds there but mostly aimed northeast towards northern Canada. Limited potential for swell development pushing towards the US West Coast. High pressure north of Hawaii is to start pushing east and ridging lightly in to the US West Coast Fri/Sat (4/11) then pushing inland over the PAcific Northwest on Sun (4/12). Only very limited windswell production possible in CA.

MJO/ENSO Update (reference): As of Sunday (4/4) the Madden Julian Oscillation (MJO) was barely in the Active Phase with the ENSO (El Nino Southern Oscillation) index neutral. The Daily SOI index was back down to 4.11 (36 days in a row near neutral). The 30 day average was up slightly to 1.44 and the 90 day average was down to 6.66. This was almost exactly what has happened for the past 3 years in a row, where the SOI dives south in mid-March. Will be interesting to see if it holds there as it did last year for 6 moths almost fueling an El Nino, or rebounding as it did on 2007 to lick off the current La Nina episode. The SOI indicies remained barely symptomatic of La Nina mainly attributable to the 90 day average, but clearly La Nina has taken a big hit over the past month. Wind anomalies at the surface and the 850 mb level (approx 1000 ft up) indicated a fading westerly flow from just east of the dateline into Central America, covering the entire Eastern Equatorial Pacific and indicative of the fading Active Phase of the MJO.  This is likely the last push of it and is likely the main influence in helping the recent 2 gales in the North Pacific, and may be helping the formation of gales under New Zealand and regions east of there. A strong pulse of the Inactive Phase is building over Indonesia and Northern Australia ready to burst east into the Western Pacific if not already doing it, likely contributing to the demise of Spring storms in the West Pacific.The INactive Phase is to be sagging over the dateline by 4/9, then holding there while slowly fading and easing east reaching Central America on 4/16 and fading through the end of the month. A new Active Phase is forecast to build behind it in the Indian Ocean through the month, but not reach the Pacific. The residual effects of 3 years of La Nina remain in-control, with cooler than normal water trying to hold west of Central America. But that took a pretty good hit over the week of 3/30 with warmer than normal waters now barely built-in there at the surface. And below the surface the equatorial subsurface warm pool of water that has been repressed back west of the dateline worked it's way east to 137W, a major step forward.  The big question is how much effect will this next 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 strong. Suspect we will loose some ground by the middle to end of the month. 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 no swell producing systems 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

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:

Help Out a Fellow Mavericks Surfer: Our friend Christy Davis is going through some tough times. His 14 year old daughter has been diagnosed with leukemia and she is currently undergoing chemotherapy. The prognosis is good but we'd all like to help him out with medical expenses not covered by insurance. If you would like to donate, send an email to us here or send it to Christy directly at: Chris Davis PO Box 628 Moss Beach, CA 94038

Swell #2 Mavericks Videos from Powerlines Productions: Check out the action on both Saturday and Sunday (11/30) from that massive swell of 12-13 ft @ 25 secs. Filmed by Curt Myers and Eric Nelson. Really thick! See this and more.cgius the movie Ride-On 12/11 at the Old Princeton Landing or the Red Vic Moviehouse in San Francisco 12/19-23. &

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:

Pictures from Swell #1 - The first real significant class swell of the season produced a bit of action at Mavericks. See pictures here

Big Surf Up North - the First swell of the Fall 2008/2009 season brought a few large raw waves to the North CA Coast. Check out the details here:

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:

STORMSURF Local Wave Models Upgraded - We significantly upgraded the local waves models on Sunday (6/8). All now utilize our newly developed high-resolution 3D shaded relief topography for mapping landmasses. Coastlines are now accurate down to the individual pixel providing near photographic realism. Mountains and hills are all shaded and accurate to within the same single pixel specification. Cities are overlaid as before, but now we've added major highways and rivers too (for many locations). Some good exa.cgies of this new technology can be viewed here:
- View the reefs north of Tahiti and notice their contribution to the 'Swell Shadow' relative to California - Tahiti
- Notice the detail of the coast in and around Vancouver Islands and Washington State - Pacific Northwest
- See the details of inland waterways of the US Northeast Coast - Virginia
- Details of the Mentawai Island and Nias

And all the local models can be found either on our homepage or from the wavemodel page (bottom half of the page).

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.

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

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


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