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Pacific Storm and Surf Forecast
Updated: August 13, 2013 9:18 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 = 0.5 - 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 8/12 thru Sun 8/18
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   

Windswell To Build a Little For CA
Windswell to Hold for Hawaii

Swell Classification Guidelines

Significant: Winter - Swell 8 ft @ 14 secs or greater (11+ ft faces) for 8+ hours (greater than double overhead).
- 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/Utility Class: Winter - Swell and period combination generating faces at head high to 1.5 times overhead (4-7 ft).
- 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.
- up to waist high swell. Also called 'Background' swell.

Current Conditions
On Tuesday
(8/13) North and Central CA had surf that was knee to thigh high and clean with some fog in the mix. Down in Santa Cruz surf was flat with a light west ruffle but effectively clean. Southern California up north was flat and clean. Down south waves were knee high or so and clean with a little texture on it. Overall very lake like. Hawaii's North Shore was flat and clean. The South Shore was flat and and clean with trades in effect. The East Shore was getting easterly tropically enhanced windswell at thigh to waist high and chopped from trades.

See QuikCASTs for the 5 day surf overview or read below for the detailed view.

Meteorological Overview
In the North Pacific on Tuesday (8/13) a continuation of a weak pressure pattern was in effect over the Northeast Pacific and no swell producing fetch of interest was occurring
. But at least high pressure appeared to be building in the Central Pacific.

Relative to California no local north fetch of interest was occurring but by Sun (8/18) a weak return of the Cape Mendocino summer pressure gradient is forecast with north winds projected to 25 kts. At least there's some hope for semi-legitimate windswell for Central CA at that time and holding for a few days.  

Relative to the Hawaii easterly tradewinds were blowing at 15 kts, not due to any change in high pressure, but due to semi tropical low pressure tracking west and positioned south of the Islands. Trades to remain in the 15 kt range through the weekend due to this situation, then fading some even as high pressure gets a better grip over the North Pacific. Rideable windswell to continue along exposed east facing shores, at least for the near-term.  

Over the past 7 days no swell producing weather system of interest have occurred in the South Pacific. And looking forward no storms of interest are forecast. A southern hemi swell drought is underway and expected to continue for the foreseeable future. Fall can't start soon enough.   

Details below...

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

North Pacific

Surface Analysis  -  On Tuesday (8/13) the normal East Pacific high pressure system remained weak and ill defined near the mainland and north of Hawaii, but was building at 1024 mbs over and just east of  the dateline. Weak low pressure was trying to organize off Washington at 1004 mbs generating a tiny area of 25 kt west winds aimed at Oregon generating 11 ft seas. No swell of interest to result. A broader gale was in the Bering Sea but landlocked by the Aleutians and of no interest from a swell generation perspective. Relative to Hawaii easterly trades were blowing in the 15 kt range resulting in minimal easterly windswell along along east facing shores. These trades were more a result of ill-defined tropical low pressure tracking south of the Islands rather than of any influence of high pressure.   

Over the next 72 hours weak low pressure is to continue circulating off the Pacific Northwest but getting less organized over time, almost gone by late Fri  (8/16). Winds to not exceed 20 kts Wednesday and beyond with no swell generation potential expected. High pressure to remain generally suppressed along the US West Coast due to the presence of low pressure, though trying to get a nose into the Central CA coast later on Tuesday into Wednesday (8/14) with north winds building to 15 kts along the Southern Central coast perhaps generating bare minimal sloppy windswell, but then fading on Thursday. 

Relative to Hawaii weak high pressure at 1024 mbs is to slowly push east from the dateline reaching a point north of the Islands Friday (8/16) generating a weak easterly flow over the Islands with trades just barely at the 15 kt threshold and tradewind generated east windswell remaining barely in the rideable range. Weak tropical low pressure (not even depression status) is modeled tracking west positioned 300 nmiles south of the Islands at the same time perhaps enhancing trades to the 20 kt range resulting in steady rideable easterly windswell along exposed shores, peaking in-sync with the passage of the lows south of the Islands. But after Friday any trades are to be due to only high pressure north of the Islands. 

Otherwise no other swell producing fetch of interest is forecast.


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


On Tuesday (8/13) what was Super Typhoon Utor was positioned 120 nmiles south of Hong Kong China tracking northwest with winds 95 kts and seas 44 ft. It is to move into mainland China late this evening. No swell is expected radiating into our forecast area.  

No other tropical systems of interest are forecast.  

California Nearshore Forecast
On Tuesday (8/13) a weak local northerly wind flow was in control of the entire California coast with winds 10 kts over outer water and maybe 15 kts near Pt Conception south over the Channel Islands and up at Cape Mendocino. Weak low pressure was trying to build in the Eastern Gulf of Alaska keeping high pressure at bay. Wednesday high pressure is to try and keep a toe in the door relative to Pt Conception with north winds there to 15 kts, but winds less everywhere else. Thursday the low moves too close, with the little high pressure present breaking up and north winds limited to only Pt Conception and only 15 kts at that.  After the low dissipates over the coast Saturday a more normal high pressure pattern is to set up with 15 kt north winds in the afternoon and up to 25 kts near Pt Conception. 25 kt north winds are forecast for Cape Mendocino on Sunday (8/18) with north winds 15 kts pushing down the Central Coast and north windswell on the upswing. By Monday a full eddy flow is to take control of the Central and South Coasts while north winds continue over Cape Mendo at 25-30 kts, then starting to fade later Tues (8/20). Southern CA to remain under a light wind flow for the week.


South Pacific

Jetstream  -  On Tuesday (8/13) the jet was .cgiit over the Southwest Pacific then merged over the Southeast Pacific with a ridge in the northern branch pushing it south into the southern branch. Winds remained weak over the length of the influential southern branch not exceeding even 90 kts. A weak trough was in.cgiay where the jet streams joined in the east, but with winds so light, is was of no real interest.  Over the next 72 hours the same basic pattern is forecast but with a ridge building some south of New Zealand in the southern branch pushing it south and into the Ross Ice Shelf eliminating support for gale development there. The trough in the far east is to continue, with winds building to 120 kts on Wed (8/14) but mostly east of even the Southern CA swell window. Beyond 72 hours the southern branch is to remain di.cgiaced south with another ridge building under New Zealand on Sun (8/18) pushing into the Ross Ice Shelf and building to the east continuing the lockdown on support for gale development over the entire South Pacific. It's as if the southern hemi has decided the season is over. 

Surface  - On Tuesday (8/13) no swell producing fetch of real interest was occurring other than what is noted below. In all, things remained very calm in the Hawaii and California swell windows. 

A gale was developing in the far Southeast Pacific on Tues AM (8/13) producing 40 kt south to southwest west winds aimed barely at Southern CA and better at Chile with 28 ft seas over a tiny area at 58S 120W then quickly racing east by evening with seas to near 30 ft at 54S 112W totally east of even the Southern CA swell window. Maybe a dribble of swell to radiate north towards CA. By Wednesday (8/14) this system is to build but all energy is to target Chile. Nothing else is forecast behind it.

Over the next 72 hrs no other swell producing fetch of interest is forecast. 


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 low pressure is to fall from the Bering Sea into the Northern Gulf on Fri (8/16) generating a generalized westerly wind flow at 20 kts targeting Vancouver Island with 10 ft seas over a small area through Monday (8/19). If this were to occur perhaps minimal windswell would result for Vancouver Island, but that's it. And even that is just a guess by the models. 

Relative to California high pressure is forecast building into the North and Central portions of the state later Saturday (8/17) with north winds building to 25 kts over Cape Mendocino over a small area by Sunday AM with windswell production on the upswing.  This gradient to hold into Tues (8/20) with windswell production continuing. At least there's some hope for something rideable. 

Relative to Hawaii weak high pressure is to hold with easterly trades in the 15 kt range through the weekend (8/18). But again those trades are to be more a function of tropical low pressure passing south of the Islands rather than of any force of the high pressure by itself. By Monday (8/19) the tropical pulses are to come to an end and the easterly fetch afforded by the high pressure is to back off, down to 10 kts or so, with east windswell faltering.

Note: The Madden Julian Oscillation is a periodic weather cycle that tracks east along the equator circumnavigating the globe. It is characterized in it's Inactive Phase by enhanced trade winds and dry weather over the part of the equatorial Pacific it is in control of, and in it's Active Phase by slack if not an outright reversal of trade winds and enhanced precipitation. The oscillation occurs in roughly 20-30 day cycles (Inactive for 20-30 days, then Active for 20-30 days) over any single location on the.cgianet. During the Active Phase in the Pacific the MJO tends to support the formation of stronger and longer lasting gales resulting in enhanced potential for the formation of swell producing storms. During the Inactive Phase the jet stream tends to .cgiit resulting in high pressure and less potential for swell producing storm development. The paragraphs below analyze the state of the MJO in the Pacific and provide forecasts for MJO activity (which directly relate to the potential for swell production).

As of Tuesday (8/13) the daily Southern Oscillation Index (SOI) was down barely to 15.72. The 30 day average was up to 6.67 with the 90 day average down some at 8.86. Overall this is holding stable in weak La Nina territory and not indicative of El Nino and illustrative of a dominance of the Inactive Phase of the MJO.  

Current equatorial surface wind analysis indicated moderate east wind anomalies over the Eastern Maritime Continent fading to neutral over the dateline and continuing south of Hawaii. Neutral anomalies extended from there into the coast of Central America. A week from now (8/21) neutral anomalies are forecast taking over the Maritime Continent continuing over the dateline region turning perhaps lightly east at a point south of Hawaii, then turning neutral on into Central America. In all this suggests a neutral phase of the MJO with the Inactive Phase exiting over the far eastern equatorial Pacific.    

The longer range models (dynamic and statistical) run on 8/12 are in general agreement. Both models suggests no MJO activity was occurring with a neutral pattern over the West Pacific. No change is forecast for the next 15 days while the dynamic model refuses to give up the ghost, with it hinting at just the weakest sign of some Inactive Phase building while tracking east off the Philippines 8-15 days out, but not really worthy of notice. The ultra long range upper level model favors the continuation of some flavor of weak Active Phase of the MJO through the end of August with a weak Inactive Phase building for mid September and even that is to be minimal. Effectively no real MJO signal is projected. 

The more warm water in the equatorial East Pacific means more storm production in the North Pacific during winter months (roughly speaking). Cold water in that area has a dampening effect. As of now (8/12) a very weak La Nina-like pattern continues in the East Pacific on the equator.  A small pocket of cooler water continues in control off the immediate coast of Peru with the outflow from it tracking to the Galapagos, then breaking up with pockets of cooler water radiating west almost to a point south of Hawaii. Today's and the 8/8 imagery suggests the cool pool is a little stronger than the image from 8/5. But this is no different from what has been occurring all summer with the cool pool fluctuating and sporadically spitting occasional larger pockets of cool water westward along the equator and keeping a lid on any legitimate warm water from developing. The sympathetic anomalous cool pool off West Africa appears to be gaining a little ground with a faint cool flow building again almost to South America. It had previously built almost to the coast of South America then retrograded in late June. The African cool pool is a direct reflection of what previously occurred in the Pacific, an unexpected burst of cool water gurgling up off both South America and West Africa simultaneously - a global teleconnection. A.cgiume of slightly cooler than normal water that has been radiating southeast off California for 2 years closed off mid-May, returned in June when the cold pool emerged off Peru and Africa, then fully closed off in July.  As of 8/12 is appears to be rebuilding off the California coast.  But a considerable pocket of warmer than normal waters is building further out, so it's anyone guess whether the local pool we get any traction heading southwest. For now cooler waters over the equatorial East Pacific are under control, but still present, with no sign of a warm pattern developing. In short, we're still under some weak influence of La Nina or at least a neutral pattern biased cold.  

Subsurface waters temps on the equator indicate a neutral temperature pattern. Warm water from the West Pacific previously migrated east over top of a cold pool - eliminating it's impact and continues holding.

Projections from the CFSv2 model run 8/13 indicate water temps have been hovering near neutral since January within only a +-0.25 deviation. Recent runs of the model have consistently been suggesting a slow trend towards water temps moving positive (up to +0.3 degs C) by Nov 2013 and near +0.6 C by April 2014. But for the immediate future a neutral pattern is expected. So overall the immediate outlook remains nothing stellar, but trending towards something that would be considered right on the threshold of warm, by Spring 2014, assuming one were to believe the model. This is good news. If anything the ocean is in recharge mode, with cold water dispersing and temperatures gradually on the rise again in fit's-and-starts. Historically, if a warm water buildup indicative of any kinda of El Nino pattern were to occur in 2013, it would have started building in Feb-Mar. That is clearly not the case for this year. Expect a neutral pattern for Winter of 2013-2014 with perhaps a slightly warmer pattern for 2014. 

We are in a neutral ENSO pattern with neither a solid El Nino or La Nina imminent. But a weak prevalence of the Inactive Phase of MJO seems to be biasing the weather global pattern. This is a better.cgiace than previous years (2010-2011, 2011-2012 and 2012-2013) under the direct influence of La Nina, but we're still not in a pure neutral pattern either. We're still recovering from the 2009-2010 El Nino. Longer term the expectation is there will be at least one to two years of neutral temperatures ultimately converging in a stronger warmer pattern and possible El Nino 2-3 years out (2015 or 2016). And historically, this is the 'normal' pattern (a few years of false starts post La Nina before a legit El Nino forms).

See imagery in the ENSO Powertool and more details in the  El Nino Update Last Updated 10/6/12 


South Pacific

Beyond 72 hours a weak pressure pattern is to continue typical of the late stages of winter in the Southern Hemi with no swell producing fetch of interest 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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