Surf Forecasts and Marine Weather - No Hype - Just the Facts!
2 Moderate Southern Hemi Swells Forecast! - Video Forecast HERE (6/9/24)
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: April 23, 2009 9:48 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 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 Hits California Solidly
Quiet Pattern Likely To Follow


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 Thursday (4/23) North and Central California had chest high local northwest windswell at north facing breaks with onshore southwest winds and pretty much a mess. South facing breaks were getting the new southern hemi swell (Swell #1S) at chest high on occasion and on the way up but very inconsistent. Southern California was starting to see a good dose of the Swell #1S with top spots already slightly overhead on the sets and most exposed breaks chest high though very inconsistent. Hawaii's North Shore was getting rather raw north-northeast windswell at head high to a foot or so overhead coming from a weak gale that was north of the Island earlier in the week. The East Shore was getting the same north-northeast windswell at 1 ft overhead at exposed breaks with onshore winds. The South Shore was getting the last little dribbles from the southern hemi at knee to thigh high.  

The forecast for North and Central CA is all focused on southern hemi Swell #1S, which started arriving on Thursday and is expected to peak Friday at 2 ft overhead or so, then on the decrease later Saturday into Sunday.  This remains forecast to be a pretty decent swell, so make the most of it. Southern CA is to be the standout spot for Swell #1S, peaking late Thursday into early Friday at perhaps a few feet overhead on the sets.  Oahu's North Shore is to see that northeast windswell fading on Friday (4/24) and essentially gone by Saturday. Maybe some background waist high energy from across the dateline on Sunday, but odds are low. The East Shore is expected to see that same north windswell, and following the same profile as the North Shore. The South Shore is to move even smaller by Friday and stay there through the weekend into early next week.   

Longterm virtually nothing of interest is forecast in either the North or South Pacific for the next 7 days.  The models continue to hint at possibly a gale at the intersection of the dateline and the Aleutians, but with each new ruin of the models it toggles back and forth between being in the Bering Sea and dipping just barely into the North Pacific, so it is very uncertain if anything will actually result. A little pulse of southern hemi swell is expected in for the South Shore of Oahu Wed/Thurs (4/30),so there's something to look forward to there. Maybe a similar shot for the US West Coast too. but in all it will pale in comparison to the southern hemi swell currently building along the mainland.  


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

North Pacific

On Thursday (4/23) the North Pacific jetstream was fragmented in the east and weak, but in the west a weak trough was pushing west from Kamchatka over the Aleutians Islands.  Winds there were 150 kts offering some limited support for surface level low pressure development.  Over the next 72 hours that trough is to try and hold on, pushing to the dateline with up to 170 kts winds flowing under it.  Then by  Sunday (4/26) it's to reach the dateline and dissipate, though more energy is to pushing towards the dateline from Japan. Beyond 72 hours a generally flat though reasonably energetic flow is forecast tracking northeast from Japan up to and over the Aleutians just west of Alaska then heavily .cgiitting, with a cutoff upper low circulating almost directly over Hawaii, likely making for inclimate weather there. But otherwise there's to be no support for low pressure development.  

At the surface high pressure at 1036 mbs was locked down in the Gulf of Alaska generating a consistent fetch of 15-20 kts north to northwest winds pushing into the Pacific Northwest with a gradient over Cape Mendocino producing up to near 30 kt north winds there resulting in short period windswell from Washington south to Central CA. Low pressure was tracking from off the Kuril Islands towards the dateline with limited 30 kt west winds in it's south quadrant trying to get some traction on the the oceans surface, but without luck yet. Northeasterly windswell from a cutoff low that was circulating 900 nmiles northeast of Hawaii on Mon/Tues (4/21) produced up to 30-35 kt northeast winds and 19 ft seas near 37N 153W was hitting Oahu, but will be fading on Friday.  Over the next 72 hours high pressure at 1036 mbs is to continue holding in the Gulf of Alaska and sinking south affecting the whole way to Cabo San Lucas by Sunday (4/26), producing 20 kt north winds down the coast peaking at 30 kts over Cape Mendocino and producing short period windswell down the Pacific Northwest to Central CA southwards eventually to Baja. The low off the Kurils is to lift northeast reaching the intersection of the dateline and the Aleutians by Sunday (4/26) with more 30 kt west winds forecast  aimed east towards the US West Coast with seas peaking at 23 ft on the dateline at 48N 180W.  This to maybe result in some small 13 sec period swell pushing into the US West Coast late next week.    


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


California Nearshore Forecast
On Thursday (4/23) high pressure at 1036 mbs was in control of the Gulf of Alaska producing 25 kt north winds over Cape Mendocino pushing south to Pt Reyes late and expected to build into the San Francisco/Monterey Bay area by evening, likely bringing much chop to nearshore waters all the way down to Pt Conception. By Friday (4/24) the gradient over Cape Mendocino is to die some (down to 20-25 kts) with windswell fading some, while a shallow area of nearshore 20 kt north winds are to prevail with the high holding strong in the Gulf ridging southward to the Channel Islands by evening with chop likely everywhere except protected breaks in SCal and holding that way into Saturday and building strong by Sunday (4/26). Things are to get even worse on Monday and Tuesday (4/28) nearshore with 20-25 kt northwest winds forecast except in protected breaks in Southern CA. Things to slowly settle down into Wednesday (4/29) but still 15 kt northwest winds expected continuing into Thursday.  Pretty miserable.   

No tropical activity of interest was occurring.


South Pacific

On Thursday (4/23) the South Pacific jetstream was starting to show signs of a a trough building south of Tahiti thanks to a push of winds energy tracking from under New Zealand aimed to the north. Over the next 72 that trough south of Tahiti is to build with up to 120 kt wind building northward offering some odds for gale development. By late Saturday that trough is to peak out while tracking east. Beyond 72 hrs a flat zonal flow is forecast to take over Southwestern Pacific while the trough in the east continues tracking towards Chile, with a possible infusion of additional wind energy to 130 kts late Tuesday (4/28)  and out of the US Swell window by Wednesday (4/29). This trough to possibly offer goods odds for storm development at the surface. 

At the surface on Thursday no swell producing fetch was occurring with a generalize flow of 25 kt west winds tracking the width of  the entire South Pacific near 55S. Over the next 72 hours low pressure is to start building well south of Tahiti, but winds to remain mostly below 35 kts and seas less than 30 ft.   

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: Swell arrived starting early Wed (4/22) with period 20+ secs, with the second pulse arriving Thursday AM again at 20 + sec.  Swell to peak 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: Swell arrived before sunrise early Wed (4/22) with period 20+ secs, with the second pulse arriving Thursday before sunrise again at 20 + sec.  Swell is to peak 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).


Hawaii Background Swell
At the surface on Tuesday AM (4/21) a 980 closed isobar low formed just south of New Zealand producing 50 kt southwest winds at 60S 165E with seas on the increase.  In the evening winds tracked northeast quickly and faded to 40 kts at 56S 178E with 30 ft seas modeled at 57S 174E pushing 30 degrees east of the 193 degree great circle path to Hawaii.  By Wednesday AM (4/22) almost all fetch was gone with residual 28 ft seas modeled at 54S 178W and fading fast, gone by evening. There's some potential for small 16 sec sideband utility swell to reach up into Hawaii late Wed (4/29) with pure swell 2.3 ft @ 16 secs (3.5 ft faces) fading from 2.6 ft @ 15 secs (3.5 ft faces) Thurs AM (4/30). Swell direction 189-193 degrees. 

Southern CA Background Swell
A 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) with 45 kt southwest winds modeled at 65S 175W and seas barely 29 ft over a tiny area at 64S 175W. Winds were gone by evening with 29 ft seas from previous fetch fading at 64S 165W. Sunday AM (4/19) it tried to reorganize with a decent sized fetch of 40 kt southwest winds aimed northeast while pushing northeast through the Southeast Pacific producing a small area of 28 ft seas at 60S 152W, moving to 55S 142W in the evening and down to 26 ft, then fading with winds 35 kts and aimed more  easterly with 26 ft seas at 53S 133W Monday AM (4/20) before dissipating in the evening.  Decent odds for small background southerly swell for Southern CA starting at 2 ft @ 16 secs (3 ft faces) on Tues (4/28) peaking at 2.3 ft @ 15 secs (3.5 ft faces) on Wed (4/29) then down to 2.3 ft @ 14 secs (3 ft faces) Thursday AM coming from 192 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 high pressure is to hold in the Gulf of Alaska into Wednesday (4/29) continuing to generate north wind at near 30 kts near Cape Mendocino and 15-20 kts elsewhere producing some amount  of short period north windswell for the Pacific Northwest down into Baja and most size just south of Cape Mendo aimed at Central CA. Trades to be suppressed over the Hawaiian Islands reducing the probability for east windswell there with upper low pressure in control aloft.

Theoretically another Japan gale is to wind up lifting to the intersection of the dateline and the Aleutians [producing up to 45 kt northwest winds Wednesday (4/29) and generating 32 ft seas just barely south of the Aleutians aimed at the US West Coast.  But odds of that are exceedingly low at this early date.   


MJO/ENSO Update (reference): As of Thursday (4/23) 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 up to 13.7, showing signs of weakness from the 14 day positive streak it was on. The 30 day average was up to 8.67 and the 90 day average was up to 8.56. 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 is on it's way out with easterly anomalies isolated to the Eastern Pacific tracking well into the Atlantic and fading fast while anomalous west winds associated with the Active Phase were holding on the equator north of Australia seeping toward the dateline. This Inactive Phase is to be gone by 4/27 with the new Active Phase building in moderately behind it, pushing to the dateline then and  weakening a little as it tracks east filling the Pacific by 4/30 ad then heading east towards the Atlantic by 5/5.  A new flavor of the Inactive Phase is forecast building in the Indian Ocean by 5/5, but is expected to be weak as it moves east if not totally dissipating before entering the Pacific.  The residual effects of 3 years of La Nina remain in-control in the atmosphere. Cooler than normal surface water off of Central America are gone with normal.neutral water temps back in.cgiay. And below the surface on the equator cool water that had locked down the region are essentially gone, the first time in months, with a steady flow of normal subsurface water tracking from the West Pacific then whole way into Central America. So now we are waiting to see if something will start pushing the warm waters of the West Pacific eastward, kicking us into a warm regime in the equatorial Eastern Pacific.  Regardless, it will still take months before the atmosphere begins to simmer down from the La Nina induce pattern currently in effect. Evidence of this is a huge cool tongue of water extending from Central CA the whole way over Hawaii to the dateline, the result of months of strong high pressure in the Gulf of Alaska.  Expect 2-3 more months of high pressure before a possible neutral pattern takes hold (i.e. no .cgiit in the jetstream over the North Pacific - warmer waters off California). 


South Pacific

Beyond 72 hours the models suggest two gale are to form on Monday (4/27), one in the Southern Tasman Sea and the other well south of Tahiti.  Only 18 hrs of 45 kt south winds is to result in the Tasman Sea before it crashes into New Zealand with seas reaching 35 ft over a tiny area at 45S 158E aimed reasonably well to the north. Maybe some little background swell for Hawaii if this occurs and decent odds for swell for Fiji. 

But the system in the Southeast Pacific is to be much more sizable, with winds to 50 kts Monday evening at 62S 140W aimed pretty well to the north holding into Tuesday AM at 60S 132W.  35 ft seas are forecast Monday PM at 60S 135W and up to 42 ft at 60S 131W Tuesday AM. The fetch is to fade Tues in the evening from 45 kts at 55S 125W with seas to 46 ft at 55S 125W pushing pretty well up the great circle paths to CA  and targeting Central America well.  Seas are to be fading Wednesday AM from 42 ft at 52S 120W.   this looks good assuming one is to beleive the models, which is quite a reach at this early date. 

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

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

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