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Pacific Storm and Surf Forecast
Updated: April 28, 2009 8:09 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 = 1.0 - California & 1.0 - 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 4/27 thru Sun 5/3
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   

Gulf of Alaska to Wake Up Some
Solid South Pacific Storm Forecast - Aimed At S. America


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 Tuesday (4/28) North and Central California had weak waist to chest high local north windswell with light onshore winds and textured conditions. Southern California has limited thigh to waist high northwest short period windswell at exposed breaks up north and chopped but cleaner as one traveled south. Hawaii's North Shore was flat and onshore. The East Shore was getting the same north-northeast windswell at waist high at exposed breaks. The South Shore was effectively flat with maybe some knee high east windswell wrapping into exposed breaks and clean.

The forecast for North and Central CA indicates some little southern hemi background swell is to be moving in for Wednesday and Thursday at waist high or so. Southern CA is to see the same southern hemi background swell moving in later Tuesday at waist high (showing on the buoys already) and holding through Wednesday, then nearly gone by sunrise Thursday. Oahu's North Shore is to see some some background windswell from the dateline showing up at 1 ft overhead on Wednesday and holding into Thursday. Maybe some background waist high energy from across the dateline on Sunday too. The East Shore is to be flat by Wednesday and stay there. The South Shore is see some background southern hemi swell by  Wednesday at waist to chest high holding into Friday.   

Longterm a small gale pushed off Japan on Monday (4/7) pushing to the dateline Tuesday and fading with seas never over to 20 ft, good for background swell for the Islands Sat-Sun (5/3) at 3.5 ft @ 12 secs. But the remnants of that gale are to fire up on the dateline Thursday/Friday pushing well into the Gulf of Alaska with seas to 26 ft aimed decently at both the Islands and the mainland, likely fueled by the Active Phase of the MJO. That fetch is to simmer in the Central Gulf on into the weekend and early next week producing more 20 ft seas, likely setting up more shorter period swell into mid-next week. Down south the models continue hinting at a decent storm building south of Tahiti mid-week tracking straight east with seas to 44 ft, but little if any fetch is to be aimed north, limiting odds for swell pushing up into the California swell window. But for Central and South America, this one might be worth the effort. 


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

North Pacific

On Tuesday (4/28) the North Pacific jetstream had a decent consolidated flow of 150 kts winds pushing off Japan arching over the dateline then dipping south to a point just north of Hawaii before .cgiitting and falling apart with the remnants pushing into Central CA and a branch pushing up into Alaska. No real support for gale development yet but the building trough just north of Hawaii was interesting. Over the next 72 hours that flow is to hold and ease east with most energy over the dateline, possibly helping to set up low pressure at the oceans surface by Thursday. Beyond 72 hours the pattern is to hold with a solid singular flow of energy tracking almost flat from Japan over the dateline to a point a ways west of California by Friday (5/1) with winds holding at 160 kts in the Western Gulf and a trough trying to organize. Gale development likely. The flow is to fully push onshore over Central CA late Saturday into Sunday looking very winter-like. A trough is to persist in the Gulf slowly drifting east into early next week and support low pressure development at the oceans surface there.   

At the surface weak low pressure was approaching the dateline centered over the Aleutians at 988 mbs with limited 30 kt west and northwest winds in it's southwest sector. 20 ft seas were modeled at 43N 165E likely good for limited background swell for the Islands at 3.5 ft @ 12-13 secs ( 4 ft faces) on Saturday-Sunday (5/3). A near neutral pressure pattern was off California offering no windswell potential and no trades were blowing over the Hawaiian Islands.  Over the next 72 hours a new low pressure system is to form on the dateline just south of the Aleutians generating 30-35 kt west winds in it's south quadrant Thurs-Fri (5/1) generating a small area of 26 ft by Friday AM at 43N 172W pushing to 42N 165W by evening and fading fast. Possible small 14 sec period swell for the North Shore by Sunday (5/3) fading from 13 secs into Monday and into the US West Coast starting late Sunday up north. 

Also last Sunday (4/26) low pressure was over the dateline in the Bering Sea generating a small fetch of 25 kt northwest winds just south of the Aleutians producing 19 ft seas there as it has since late Saturday. This should be good for some small swell pushing into Oahu on Wednesday (4/29) at 5.5 ft @ 12 secs (6-7 ft faces) from 327 degrees and holding into Thursday.


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


California Nearshore Forecast
On Tuesday (4/28) an isolated area of north winds was centered off Pt Conception, driven by weak high pressure at 1024 mbs off the US West Coast. On Wednesday a new little patch of high pressure is to be rebuilding in the Gulf pushing down to Baja with 25 kt northwest winds forecast late over Pt Conception reaching up to Monterey Bay and south into Baja. This is to hold Thursday, maybe retreating a little late as low pressure tries to build in the Gulf. Modest south winds are forecast for San Francisco northward on Friday (5/1), continuing Saturday and reaching to Pt Conception Sunday as the front pushes down the coast. Rain pushing into the San Francisco area early Friday turning south to near Pt Conception late, then drying out on Saturday before another weaker pulse hit down to San Francisco on Sunday. 

No tropical activity of interest was occurring.


South Pacific

On Tuesday (4/28) the South Pacific jetstream was .cgiit over the West but was pulling together south of Tahiti with winds 120 kts pushing east.Maybe a little support for gale development was trying to organize. Over the next 72 that trough south of Tahiti is to push east to the edge of the US swell window Wednesday (4/29) but with 130 kts winds flowing through ti offering better odds for gale development. Reinforcing energy is expected in that area on Thursday too, continuing gale development on the edge of the US swell window.  Beyond 72 hrs yet more energy is forecast in the jet with winds to 150 kts feeding into this trough and pushing towards Chile with the vector aimed more southeast than even east and well beyond the US swell window. A weak pattern is to remain over the West Pacific until Tuesday (4/5) when a trough is forecast forming under New Zealand with 130 kts winds pushing hard north there offering potential for gale development.  

At the surface on Tuesday a gale was trying to organize southeast of New Zealand and on the edge of the Ross Ice Shelf. 35-40 kt southwest winds were building expected to reach 45 kts by evening at 62S 162W. Seas on the increase. Over the next 72 hours this storm is to be the only ting of interest. By Wednesday AM a solid fetch of 45-50 kts southwest winds are forecast at 61S 149W aimed right up the 194 degree path tot California. Seas building from 32 ft at 62S 150W. In the evening a most solid fetch of 45-50 kt southwest winds are forecast at 60S 133W aimed 40 degree east of the 186 degree path to California and taking aim more on Central America. Sea building to 38 ft at 59S 140W. Thursday AM the storm is to deepen to 948 mbs with 55 kts winds forecast at 65S 133W and free and clear of ice and aimed 40 degree east of the 186 degree path to CA with seas to 41 ft at 55S 130W. That fetch is to fade to the 45-50 kt range in the evening and nearly pushing out of the California swell window at 60S 123W aimed way more east then north. 40 ft seas forecast at 57S 120W.   On Friday (5/1) 45 kt pure east winds are to be pushing out of the California swell window towards Chile with 36 ft seas at 55S 112W fading from  32 ft in the evening at 58S 103W bound for Chile.

Current data suggests some limited sideband swell from this one reaching up to exposed breaks in Southern CA if this storm forms as forecast, but that remains only a guess at this early date.

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 residual low pressure energy is forecast pushing into the Central Gulf of Alaska Sunday-Monday (5/4) producing a limited fetch of 30-35 kt northwest winds in the Western Gulf heading east generating a fragmented area of 20 ft seas near 40N 152W on Monday  building to 23 ft at 41N 146W on Tuesday (4/5) and providing decent sized possible follow on 12-13 sec period energy for US West Coast down into  Hawaii mid-next-week (if this occurs).


MJO/ENSO Update (reference): As of Tuesday (4/28) the Madden Julian Oscillation (MJO) was in the Active Phase with the ENSO (El Nino Southern Oscillation) index dropping well into the negative range. The Daily SOI index down to -24.95, providing 3 days in a row of negative readings (after 26 days of positive values). The 30 day average was down to 8.81 and the 90 day average was down to 8.14. 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 Active Phase was firmly taking control, stronger than originally expected with westerly anomalies covering the entire equatorial Western Pacific to the dateline and seeping east of there. It is to be weakening a little as it tracks east filling the Pacific by 4/30 and then heading east but still having an effect over the entire Pacific through 5/7.  A new version of the Inactive Phase is forecast building in the Indian Ocean by 5/2, but is expected to be weak as it moves east if not totally dissipating before entering the Pacific between 5/10-17.  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 if not verging on slightly warmer than normal. 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 over the dateline and then breaking the surface near 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.  This bout of the Active Phase should help that process along. Regardless, it will still take months before the atmosphere begins to simmer down from the La Nina induce weather pattern. But, for the first time since November 2008, a consolidated jetstream pattern is forecast over the North Pacific, a early sign of recovery if it holds. Conversely a huge cool tongue of water extending from Central CA the whole way over Hawaii to the dateline remains in.cgiace, the result of months of strong high pressure in the Gulf of Alaska resulting in brisk north winds down California turning to northeast winds over Hawaii generating massive upwelling.  Expect 1-2 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 no additional swell development in the South Pacific. But a big push of energy is expected to start seeping into the South Pacific from under Australia  a week out possibly feeding into a trough forecast in that area. The short of tis is there is some hope, but that's a long ways off. 

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:

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New Wave Model Facts: Click HERE to read more about the new wave models. Important info.

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