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Pacific Storm and Surf Forecast
Updated: April 13, 2010 8:15 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 = 2.0 - California & 2.0 - 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 4/12 thru Sun 4/18
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   

High Pressure Dominates North Pacific
Southern Hemi to Perhaps Stir


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 Tuesday (4/13) North and Central California was getting Gulf windswell in the 1-2 ft overhead range with modest onshore winds and pretty warbled. Southern California was getting some wrap around windswell from the north intermixing with very small and very southerly angled southern hemi swell at waist to chest high or so pushing head high at top spots. Conditions remained a bit raw up north but reasonably clean down south. Hawaii's North Shore was getting new dateline swell with waves 3-5 ft overhead on the sets, but trades were blowing pretty hard. The East Shore was getting 2-3 ft overhead wrap around energy with easterly windswell on top and chopped. The South Shore was getting no surf of interest.

The forecast for North and Central CA is for a mix of Gulf swell and local windswell in the head high range Wednesday with south angled southern hemi swell only at the most exposed breaks in the head high range. More of the same on Thursday and then fading on Friday. Saturday Gulf swell fades from chest high with waist high.cgius southern hemi swell in the mix then Gulf swell fades Sunday and southern hemi swell holds. Southern California is mainly southern hemi swell from here on out, at shoulder to head high Wed, then shoulder and fading Friday and very south angled.  A new pulse is expected for Saturday more from the southwest at  chest high and holding Sunday. The North Shore of Oahu is to see fading dateline swell at 3 ft overhead on Wednesday and 1 ft overhead Thursday with chest high leftovers on Friday. Maybe 4 ft overhead north angled windswell on Saturday and fading some Sunday. The East Shore to see northeast swell from the Gulf at shoulder to head high on Wednesday and then the usual trade wind generated east windswell beyond, ratcheting up Fri/Sat. The South Shore is to see  some thigh high background southern hemi swell on Wed-Fri.

Looking at the models not a whole lot is forecast to happen.  A gale is forecast tracking just south of the Aleutians on Friday with 26 ft seas and fading as it moves into the Gulf of Alaska through Monday (4/19).  Maybe some little swell to result for the Islands and the US West Coast, but not much.  Nothing else is on the charts.  Down south the storm pattern is all aligned west to east, mostly not allowing any swell energy to radiate north.


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

North Pacific

On Tuesday (4/13) the North Pacific jet was .cgiit from the dateline eastward with the northern branch riding east pretty much right over the Aleutians across the width of the Pacific.  It was offering no support for gale development.  Over the next 72 hrs a cutoff upper low is to develop just off the coast of the Pacific Northwest while the main flow of energy follows the Aleutians eastward into Alaska and Canada. Again, no obvious support for gale development is suggested. Beyond 72 hours the cutoff low is to persist and actually suck in the main flow of the jet, with a sizable trough setting up in the Eastern Gulf of Alaska by Sun (4/18) with 180 kts winds falling down into the trough. Decent support for gale development possible then. But winds speeds are to quickly ramp down with the trough moving fast to the east, nearly onshore over Northern CA by late Monday. But behind it the jet is to start sagging south tracking over the 40N latitude and starting to look a bit more like it has all winter, with something that almost resembles a trough over the dateline on Tues (4/20).   

At the surface on Tuesday (4/13) high pressure at 1032 mbs remained locked over the dateline ridging east into the Gulf of Alaska and pretty much eliminating any odds for gale development anywhere in the greater North Pacific.  Over the next 72 hours that high is to loose a little coverage but still remain a dominant force with it's core on the dateline pushing a bit east. and forming a pressure gradient with an upper low off the US West Coast on Thurs (4/15) generating 30 kt north winds 600 nmiles north of Hawaii possibly setting up 10 sec period windswell for the Islands.  At the same time a gale low is to be tracking east through the Bering Sea Thurs-Fri (4/16) generating 26 ft seas on the dateline just south of the Aleutians. The gale is to fade as it pushes into the Gulf of Alaska on Saturday generating only 2 ft seas. Limited swell possible earlier next week for the US West Coast.  


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


California Nearshore Forecast
On Tuesday (4/13) the weak leading edge of a huge pool of high pressure running from the dateline up into the Gulf of Alaska was barely brushing the Central CA coast generating northwest winds in the 10 kt range, and of no real impact. No real change is expected Wednesday or Thursday as upper low pressure off the US West coast hold the high at bay. If anything, that low pressure trough is to get better traction down at the oceans surface relative to CA on Friday (4/16) with some circulation developing and light south winds starting to impact the Northern CA coast by afternoon and continuing perhaps down to Central CA on Saturday. A weak front is possible brushing the coast Sunday with more modest south winds and light rain over the state reaching down into Southern CA and continuing into  Monday. High pressure is to coming rushing in on Tuesday (4/20) with 20+ kt northwest winds in control all the way down into Southern CA then. 


South Pacific

On Tuesday (4/13) no real swell producing weather systems of interest were occurring.  Upper level high pressure was having an obvious affect on the region east of New Zealand pushing all weather systems on a very west to east track, not allowing any fetch to push much to the north.
Over the next 72 hours no swell producing fetch of interest is forecast with that pattern holding into Saturday (4/17). 

Previously the models had suggested a storm forming well southeast of New Zealand on Sat (4/10) with 55k southwest winds pushing somewhat northeast, but that system actually turned more on a west to east path providing limited if no fetch aimed north. No swell of interest expected to result. Seas did reach 40 ft at 06Z Sat (4/10) at 60S 160W. 

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 there's some suggestion that high pressure is to fade some and a more favorable pattern might set up. Low pressure is to develop on the dateline late Sunday (4/18) down at 40N with 40 kts northwest winds and gently lifting northeast Monday producing 45 kt west winds into Tuesday pushing towards Northern Canada. Possible sideband swell for Central CA northward with more energy into the Pacific Northwest, but that is far from guaranteed.     

MJO/ENSO Update (reference): As of Tuesday (4/13) the Southern Oscillation Index (SOI) was holding in the positive range and still symptomatic of the Inactive Phase of the Madden Julian Oscillation. The daily SOI was up to 15.50.  The 30 day average was up to 6.97 (It bottomed out for the winter on 2/16 at -24.82) with the 90 day average up to -8.83 (bottomed out at -14.2 on 3/14). El Nino maxed out on 2/15. 

Wind anomalies at the 850 mb level (approx 5000 ft up) as defined by models indicated completely neutral anomalies over the entire equatorial Pacific, suggesting neither the Inactive or the Active Phase. This should neither feed nor hinder storm generation potential.  But with Spring moving in, it's difficult to estimate exactly what the impact will be. At this point were monitoring the MJO more for signs of Active Phase dominance in the critical March-May time frame (versus monitoring for storm support) to see if this Midoki El Nino can hang on for another year, or whether we fall back into a La Nina Pattern (where the Inactive Phase takes control). 

Sea Surface Temp anomaly data (4/12) indicated no dramatic change from previous weeks, with warmer than normal waters consolidated on the equator more towards the dateline and less in the vicinity of the Galapagos Islands, but not gone from South America and if anything, building slightly (likely the result of a recent impact by a Kelvin Wave). Erosion of warmer waters over the Galapagos is expected, symptomatic of the fading of El Nino. 

Below the surface on the equator a Kevin Wave attributable to the previous Active Phase of the MJO was fading. On 4/13 a tongue of warmer than normal water was in.cgiace extending east from 120W into Central America averaging 3 deg C above normal with a small core at 4 C at 110W. This is expected to fuel or at least extend El Nino symptoms into summer, but is likely the last Kelvin Wave we are going to see. 

Over the entire Equatorial Pacific trades were blowing all the way to almost the Philippines, but only in the normal range. This looks like the normal Springtime transition typical for this time of the year. 

El Nino is slowly loosing it's grip and it's affects on the global atmospheric weather pattern. Still some impact is to continue into the Summer of 2010. This suggests that the spring storm pattern be enhanced in the North Pacific, but also the early summer storm track in the South Pacific too.  This has not been a strong El Nino, more of a solid moderate one. A respectable accumulation of warm surface water in the equatorial East Pacific and a solid pool of warm subsurface water remains in.cgiace, but seems to be eroding some suggesting El Nino has maxed out. But the atmosphere is already being strongly influenced by the warm water buildup over the past 6 months, and it will not return to a normal state for quite some time. 

At this point were mainly monitoring to determine whether this El Nino will degrade into La Nina (which typically happens after stronger El Nino's), or whether it will hold in some mild El Nino-like state for several years in a row. This would be the best outcome, but far from expected.  The months of Mar-June normally are when the transition takes.cgiace.    


See more details in the new  El Nino update.


South Pacific

Beyond 72 hours the models indicate a new gale developing under New Zealand on Fri PM (4/16) tracking northeast with a small area of 45 kt southwest winds at 50S 180W by Saturday AM (4/17) with 32 ft seas building at 58S 165E. Those winds to hold in the evening and lift more northeast to 43S 175W with 34 ft seas at  50S 180W. The gale to be fading Sunday AM (4/18) but 36 ft seas to be covering a good sized area at 48S 170W.  More fetch is to hold in the the same area through the weekend with up to 40 ft seas at 50S 160W on Sunday evening.  Interesting if this occurs.

There's suggestions another one might form behind it too next week.

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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Stormsurf Hi-Res Coastal Precipitation Models Upgraded Though a bit late in the season, on 3/20 we i.cgiemented the same basic technology used in our new snow/ski models into the coastal hi-res precipitation models. So now you can not only determined whether rain is forecast for your area, but also snow. And not just light, medium or heavy snow like most sites, but the exact snowfall amount (in inches) for each 3 hr frame of the animation. Here's a sa.cgie, but now this approach is used in all our precipitation models.

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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.

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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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