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Pacific Storm and Surf Forecast
Updated: Tuesday, December 20, 2016 4:09 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
4.0 - California & 3.3 - 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 12/19 thru Sun 12/25

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   

2nd Dateline Swell Heading East
Stronger Storm Pattern Forecast

On Tuesday, December 20, 2016 :

  • Buoy 106 (Waimea): Seas were 5.6 ft @ 13.3 secs with swell 3.0 ft @ 13.2 secs from 330 degrees.
  • Buoy 46025 (Catalina RDG): Seas were 2.0 ft @ 17.2 secs with swell 1.0 ft @ 16.9 secs from 228 degrees. Wind northeast 4-6 kts. Water temperature 58.3 degs. At Ventura swell was 1.2 ft @ 13.1 secs from 268 degrees. At Santa Monica swell was 0.9 ft @ 17.4 secs from 264 degrees. At Camp Pendleton swell was 0.7 ft @ 13.6 secs from 235 degrees. Southward at Pt Loma swell was 1.9 ft @ 17.4 secs from 292 degrees.
  • Buoy 46012 (Half Moon Bay)/029 (Pt Reyes): Seas were 7.1 ft @ 15.4 secs with swell 4.6 ft @ 15.6 secs from 305 degrees. Wind north 16-18 kts at the buoy. Water temp 52.9 degs.

    46006, 46059, New! Hi-Res Buoy Dashboards (at the bottom of the page)

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.

Surf Heights for Hawaii should be consider 'Hawaiian Scale' if period exceeds 14 secs.

Current Conditions
On Tuesday (12/20) in North and Central CA longer period swell from the North Dateline region was settling down some producing waves in the 3-4 ft overhead range on the sets at exposed breaks and clean with offshore's in control. At Santa Cruz surf was head high or so on the sets and clean and lined up but slow. In Southern California up north surf was thigh high and clean at top breaks. Down in North Orange Co minimal northerly swell was wrapping in at waist high and clean. In San Diego the same swell was waist high and clean early. Hawaii's North Shore was getting north angled sideband swell from the North Dateline region at 2-3 ft overhead and clean and lined up. The South Shore was flat and clean. The East Shore was getting east windswell with waves shoulder high and chopped with moderate east winds.

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

Meteorological Overview
California was getting clean longer period northwest swell originating from the 1st of two storms that recently tracked over the North Dateline region. minimal sideband energy from it was wrapping into Hawaii too. The second of this pair of systems developed in the extreme Northwest Gulf of Alaska Sat-Mon (12/19) producing up to 43 ft seas aimed east then faded some but tracked slowly east through the Northern Gulf Tues (12/22) producing more 28 ft seas aimed east. Another gale is to develop on the Dateline Fri-Sat (12/24) with up to 42 ft seas aimed east. And another gale is forecast for the North Dateline region Sat-Mon (12/26) with seas in the 26-30 ft range aimed east. The Active Phase of the MJO is looking to have the desired effect.

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

North Pacific

On Tuesday AM (12/20) the jetstream was consolidated pushing east off Japan with winds building to 130 kts over the dateline then holding while pushing east and into Oregon. No obvious troughs were present offering no direct support for gale development. Over the next 72 hours more of the same is forecast until Thurs (12/22) when a pocket of winds build to 170 kts just west of the dateline forming a steep trough over the dateline pushing east into the Western Gulf later Fri (12/23). That trough is to be supporting gale development. Also a trough is forecast developing in the Eastern Gulf on Friday too being fed by 150 kt winds falling southeast towards California. Over the next 72 hours starting Sat (12/24) the California trough is to push inland over Central CA with winds 130 kts mainly generating weather for the US West Coast. Back to the west 140-150 kt winds are to be streaming off Japan ridging slightly over the dateline the feeding the preexisting trough over the Western Gulf. That trough is to push east into Sun (12/25) and get rejuvenated off Oregon again pushing into Central CA on Mon (12/26) mostly generating weather. Beyond 72 hours winds are to again build over Japan to 180 kts on Tues (12/27) pushing east towards the dateline but .cgiitting some there, and remaining .cgiit the rest of the way across the Pacific. Still the northern branch is to be energetic across the width of the North Pacific offering potential for gale development.

Surface Analysis
On Tuesday (12/20) swell from storm previously over the North Dateline region was hitting California with remnants fading in Hawaii ( see Solid Kuril Storm below). Another storm formed directly behind it producing yet more swell pushing east (see 2nd North Dateline Storm below).

Over the next 72 hours secondary fetch from the 2nd North Dateline Storm on Tues AM (12/20) was producing 40 kt west winds generating a broad area of 20+ ft seas with a core at 28 ft at 50N 153W (308 degs NCal). Fetch is to be fading in the evening from 30 kts from the west with seas fading from 28 ft at 53N 142W and east of the North CA swell window. This system is to dissipate thereafter. More reinforcing swell is possible for the US West Coast.

A tiny storm is to develop on the dateline Thurs AM (12/22) with 55 kt northwest winds and seas building to 24 ft at 42N 172E. In the evening winds to build in coverage at 50 kts from the northwest with seas building to 33 ft at 41N 178EW aimed well at Hawaii but starting to swing to the east. Fetch to hold Fri AM (12/23) at 50 kts from the west-northwest with seas building to 40 ft at 43N 178W targeting Hawaii and the US West Coast.In the evening fetch is to start fading from 45 kts from the west with seas pushing east at 40 ft at 42N 172W. Sat AM (12/24) fetch is to fade from 35 kts with seas fading from 35 ft at 42N 163W aimed at the US West Coast. Something to monitor.


Solid Kuril Storm
A small storm developed well off the Kuril's on Wed PM (12/14) tracking northeast with winds 45 kt from the west and seas building to 27 ft at 42N 161E. On Thurs AM (12/15) winds built to 55-60 kt from the west but positioned just south of the Central Aleutians on the Dateline with 42 ft seas at 49N 170E targeting mainly the Pacific Northwest and the Central Aleutians. In the evening fetch was fading from 50-55 kts over a solid area south of the Aleutians from the west with seas fading from 47 ft at 51N 178E targeting mainly the Pacific Northwest and starting to impact the Central Aleutians directly. This system was fading out on Fri AM (12/16) with winds dropping from 40 kts just south of the Aleutians and seas fading from 37 ft at 51N 178W. Limited sideband swell is possible for Hawaii with better energy tracking towards the Pacific Northwest.

Hawaii: Residuals fading Tues AM (12/20) from 3 ft @ 12-13 secs (3.5-4.0 ft). Swell Direction: 320 degrees

North CA: Swell peaking Tues AM (12/20) at 5.6 ft @ 16 secs (9.0 ft) and slightly more consistent. Swell fading on Wed AM (12/21) and possibly being overtaken by new stronger swell. Swell Direction: 308 degs (shadowed in the SF Bay Area).


2nd North Dateline Storm
Another gale developed Sat AM (12/17) on the dateline just south of the Aleutians with 45 kt northwest winds and seas on the increase. In the evening winds built to 55-60 kts from the west just south of the Central Aleutians with 40 ft seas at 51N 178E over a modest sized area. On Sun AM (12/18) fetch stalled with 50 kt west winds just south of the Aleutians with seas building to 42 ft at 51N 173W (308 degs NCal) aimed east targeting North CA and the Pacific Northwest. In the evening fetch is to fade from 45 kts from the west in the same location with seas fading from 35 ft over a solid area at 52N 171W (308 degs NCal). On Mon AM (12/19) fetch is to fade from 40 kts from the west with seas fading from 33 ft at 51N 169W with secondary fetch moving in from the west. Solid swell is possible for exposed breaks from Central CA northward and limited sideband swell for Hawaii.

Hawaii: Swell arrival expected Tues (12/20) building to 3 ft @ 17 secs late (5.0 ft). Swell builds some over night peaking Wed AM (12/21) at 4.8 ft @ 15 secs (7.0 ft) early. Swell fading Thurs AM (12/22) from 4.7 ft @ 14 secs (6.6 ft). Swell Direction: 335 degrees

North CA: Expect swell arrival on Wed (12/21) building to 8.4 ft @ 17-18 secs (14.5 ft) and shadowed in the SF Bay Area. Swell fading slowly Thurs AM (12/22) from 7.8 ft @ 16 secs (12.5 ft). Residuals fading Fri (12/23) from 6.4 ft @ 14 secs (9 ft). Swell Direction: 307 degrees


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


Tropical Update
No tropical systems of interest are being monitored.

California Nearshore Forecast
On Tuesday AM (12/20) high pressure at 1030 mbs was 600 nmiles off of Point Conception generating an offshore flow over all of California early. Wed AM northeast winds to continue at 10-15 kts. Winds light northeast early Thurs (12/22) turning north later in the day. Friday AM a new gale is to be building directly off Cape Mendocino with south winds developing from Monterey Bay northward building to 40 kts along the coast at sunset and 55 kt north winds over outer waters with the core of the low over Cape Mendocino at 10 PM. Rain down to San Francisco by 10 AM and Point Conception at sunset continuing overnight. 6-8 inches of snow for Tahoe by 4 PM and much heavier after that. Saturday northwest winds 30 kts early fading to 20+ kts at sunset. Rain and snow continues through the day Saturday fading by sunset. in. A bit of a break is possible on Sunday with north winds fading through the day. No rain forecast. Another front is forecast moving into the Oregon-CA border Sunday evening with south winds pushing into Monterey Bay Mon AM (12/26) with rain south to Santa Barbara at sunset. More snow for Tahoe starting early continuing through the evening. Tuesday (12/27) another low is to queue up off Cape Mendocino with the front impacting the North and Central Coast with rain into Central CA and heavy snow for Tahoe.


South Pacific

Surface Analysis  
No swell of interest was in the water and no swell producing fetch of interest was occurring.

Over the next 72 hours no 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

A broad gale is to develop Fri PM (12/23) just off North Japan with winds 40- 45 kt from the west and seas building to 26 ft at 38N 162E targeting Hawaii. Fetch is to build Sat AM (12/24) to 40 kts from the west-southwest with seas building to 27 ft at 42N 170E again targeting Hawaii well. The gale is to be lifting northeast settling over the North Dateline region on Sun (12/25) with west winds 40 kts and seas 28-30 ft aimed east. It is premature to determine and specific outcome yet.


South Pacific

Beyond 72 hours no swell producing fetch of interest is forecast.

More details to follow...

SST Forecast To Return To Neutral/Normal in 1 Month

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, though most noticeable in the Pacific. 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. Prolonged and consecutive Active MJO Phases help support the formation of El Nino. 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).

Overview: The 2014-2016 El Nino is gone. La Nina has developing but generally weak.

KWGA/Equatorial Surface Wind Analysis & Short-term Forecast:
Analysis (TAO Buoys): As of Monday (12/19) east winds were over the entire equatorial Pacific but calm to light northwest over the Kelvin Wave Generation Area. The KWGA is on the equator from 135E-170W and 5 degs north and south. Anomalies were weak over the equatorial East Pacific and mixed (east and west) over the KWGA. This is a good turn of events. Previous east anomalies over the KWGA were attributable to La Nina and are now being muted/modulated by an Active MJO.
1 Week Forecast (GFS Model): Modest east anomalies were modeled over the dateline but weak west anomalies over the western KWGA. The forecast suggests west anomalies are to fade starting 12/21 with weak east anomalies backtracking west from the dateline taking over the KWGA by 12/25. The first real easterly wind burst from this La Nina started on 9/23 and continued into 12/13, fading some, but likely to return. Easterly anomalies have been consistent, pulsing stronger at times, then weaker, attributable to La Nina and modulated by the MJO.

Kelvin Wave Generation Area wind monitoring model: West and East

Longer Range MJO/WWB Projections:  
OLR Models: As of 12/19 a weak Active MJO signal was present in the West Equatorial Pacific. The statistic model projects it fading while moving east dissipating over the dateline 15 days out. The dynamic model depicts the Active Phase of the MJO is to build slightly and hold into day 10 then fading 15 days out.
Phase Diagrams 2 week forecast (ECMF and GEFS): (12/20) The ECMF model indicates the Active Phase of the MJO is weak and barely discernible in the West Pacific and is to slowly fade over the next 2 weeks. GEFS model depicts mostly the same thing.
40 day Upper Level Model: (12/20) This model depicts a weak Active Phase of the MJO moving over the West Pacific and it is to move east into Central America while weakening on 1/24. A modest Inactive Phase is to develop behind that in the West Pacific on 1/6 tracking east to the East Pacific 1/29. Another Active MJO is to develop over the West Pacific 1/24. This model runs about 2 weeks ahead of what happens at the surface.
CFS Model - 3 month (850 mb wind): (12/20) This model depicts a weak Inactive MJO signal was all but gone over the dateline with modest east anomalies there while the Active Phase of the MJO was building in the far West KWGA and weak west anomalies there also. The Inactive Phase is to fade on 12/29 with the Active Phase building in the West Pacific moving to the dateline through 2/15 with weak east anomalies in.cgiay over the dateline into 1/20. Overall the MJO signal is projected to be very weak and this pattern is to hold as we move deeper into Winter. We suspect La Nina is having the effect of dampening the MJO, and producing weak east anomalies in the KWGA but not producing an outright bias towards the Inactive Phase of the MJO. Likewise the MJO is serving to dampen the effects of La Nina when in the Active Phase.

CFSv2 3 month forecast for 850 mb winds, MJO, Rossby etc

Subsurface Waters Temps
TAO Array: (12/19) Actual temperatures remain stratified with warm water in the West Pacific at 30+ degs C (reaching east to 165E) and the 28 deg isotherm line reaching to 177W and steep, suggesting a hard break between warm water in the west and cool water in the east at depth. This is expected with La Nina in.cgiay. Anomaly wise, warm anomalies at +1-2 degs rule from the West Pacific to 180W.  Neutral to weak negative anomalies are east of there to Ecuador at no more than -1.0 degs, with warmer anomalies building 150 meters down and pushing east daily reaching 135W as of today. The hi-res GODAS animation posted 12/14 depicts this pocket of of cooler water at -1-2 degs below normal in the East Pacific getting weaker. La Nina is in control of the ocean at depth, but not strongly so and weakening and getting shallower.
Sea Level Anomalies: (12/14) Negative anomalies at -5.0 cm with a few small pockets to -10 cm rule the equatorial Pacific from Ecuador to the dateline and 5 degs north and south. And within that, neutral anomalies are developing. This is an upgrade from months past where anomalies were up to -10 cm and suggest La Nina is loosing it's grip at depth.

Surface Water Temps: 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. Regardless of what the atmospheric models and surface winds suggest, actual water temperatures are a ground-truth indicator of what is occurring in the ocean. All data is from blended infrared and microwave sensors.
Satellite Imagery
Hi-res Nino1.2 & 3.4: (12/19) The latest images (1.2 3.4) indicate a very thin and repressed cool pool of water along the immediate coast of Peru but it is contained there migrating nowhere. Warm water is developing solidly just off the coast there and reaching up into Ecuador and the Galapagos. A cool bubble previously between Costa Rica to the Galapagos is holding, or maybe evening starting to rebuild some. A thin cool stream continued from just west of the Galapagos out to 120W, perhaps wider than days past. A broader area of cool temperatures remains from 120W westward to 160W but appears to be fading. La Nina is gaining some control of surface waters of the East Pacific and holding in the Central Pacific suggesting the a westward di.cgiaced La Nina is remains in control.
Hi-res 7 day Trend (12/19): A warming trend continues along Chile and Peru but is fading off Ecuador with a cooling trend between there and the Galapagos. Warming holds from the Galapgos out to 115W. West of there a neutral trend was exhibited with pockets of warming and cooling waters present and a little stronger than in weeks past. The cool pattern in the Central Pacific is nowhere near as prominent as weeks and months previous and is weakening strongly in the East.  
Hi-res Overview:
(12/19) A La Nina cool pool is present over the equator from the Galapagos west to 170E and broadest south of Hawaii. La Nina is holding coverage in the west and loosing coverage in the east.
Nino1.2 Daily CDAS Index Temps: (12/20) Today's temps were steady at +0.395.  
Nino 3.4 Daily CDAS Index Temps: Today (12/20) temps were steady down at -0.676 coming off a recent peak at +0.15 on 12/6. Temps are oscillating warm to cool and back in 2-3 week cycles within a range from -0.3 to -1.0 degs.

Click for Full Sized Image

CFSV2 Forecast for Nino3.4 SST Anomalies

SST Anomaly Projections
CFSv2 Uncorrected Data (12/20) This model suggests La Nina developed from June thru Oct in the -0.55 deg range then started rising to -0.5 on Nov 1 and up to -0.2 degs on Dec 1. The forecast has temps gently rising to -0.1 degs on Jan 1, neutral late Jan, then slowly rising from there to +0.2 degs in March, steady out till Sept. This indicates that La Nina is effectively over and a return to normal temps is expected in Spring.
IRI Consensus Plume: The mid-Dec Plume depicts temps are warming and are now at -0.3 degs. A slow increase in temps is forecast thereafter to neutral 0.0 in March 2017 warming to +0.2 degs in May and holding into the Fall. This is warmer than last months forecast and suggests La Nina is over. See chart here - link. 

Atmospheric Deco.cgiing (Indicating the presence of El Nino in the atmosphere driven by the ocean):
Southern Oscillation Index (12/20): The daily index was rising some today at 23.66 coming off a 7 day mostly negative run. The 30 day average was rising to +2.51. This suggests the Inactive Phase of the MJO has been in control recently driving the SOI upwards. The 90 day average was falling at +0.43. La Nina is trying to hang on, but loosing ground.
ESPI (like SOI but based on satellite confirmed precipitation. Positive is good, negative bad): (12/20) Today's value was falling slightly at  -1.33. A peak low was reached on 11/2 at -1.94 the deepest it had been so far in this event suggesting La Nina was getting better established. But that is changing, with it trending generally upwards (a better direction) and suggesting La Nina is fading.
Pacific Decadal Oscillation: The PDO continues positive, though much weaker lately (as expected with La Nina setting in).
Per NOAAs index recent values (Jan-Oct) are: +0.79, +1.23, +1.55, +1.59, +1.42, +0.76, +0.12 then falling to -0.90, -1.09 and -0.88 in Oct. But in Nov, it was up to +0.53
The Washington EDU index (Jan-Oct) are: +1.53, +1.75, +2.40, +2.62, +2.35, +2.03, +1.25 +0.52, +0.45, +0.56 and up to +1.88 in Nov.
The PDO turned from a 6 year negative run (2008-2013) in early 2014 and has been positive until Aug 2016, the result of a turn towards La Nina. Looking at the long term record, it is premature to conclude that we have in-fact turned from the negative phase (La Nina 'like') to the positive phase (El Nino 'like'), but the data suggests that could be a real possibility. We've been in the negative phase since 1998 through at least 2013 (15 years). By the time it is confirmed (4-5 years out), we will be well into it.

See imagery in the ENSO Powertool


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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