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Pacific Storm and Surf Forecast
Updated: Thursday, August 20, 2020 5:02 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
3.3 - California & 3.0 - 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 8/17 thru Sun 8/23

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   

Small NZ Swell Hitting Hi & CA
More Forecast Shorterm

On Thursday, August 20, 2020 :

  • Buoy 233 (Pearl Harbor Entrance)/Buoy 239 (Lanai): Seas were 3.0 ft @ 13.3 secs with swell 1.8 ft @ 12.9 secs from 176 degrees.
  • Buoy 106 (Waimea): Seas were 4.2 ft @ 7.7 secs with swell 3.3 ft @ 7.5 secs from 19 degrees. Water temp 81.1 degs.
  • Buoy 46025 (Catalina RDG): Seas were 3.0 ft @ 8.3 secs with swell 1.4 ft @ 13.8 secs from 191 degrees. Wind at the buoy was east at 8-10 kts. Water temperature 70.7 degs. At Harvest Buoy (071) primary swell was 6.3 ft @ 7.6 secs from 310 degrees. At Santa Monica (028) swell was 1.3 ft @ 15.7 secs from 203 degrees. At Oceanside (045) swell was 1.6 ft @ 15.7 secs from 209 degrees. Southward at Point Loma (191) swell was 1.7 ft @ 15.1 secs from 197 degrees.
  • Buoy 46012 (Half Moon Bay)/029 (Pt Reyes): Seas were 5.1 ft @ 5.6 secs with swell 1.8 ft @ 15.4 secs from 201 degrees. Wind at the buoy (012) was north at 18-21 kts. Water temp 52.0 degs (013), 60.8 degs (SF Bar) and 55.9 degs (042).

See Hi-Res Buoy Dashboards (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 Thursday (8/20) in North and Central CA local northwest windswell was producing waves at waist high or so and warbled and mushed and pretty ragged but not chopped. Protected breaks were in the thigh high range and and clean but very soft. At Santa Cruz surf was thigh high and clean and soft and inconsistent. In Southern California/Ventura windswell was producing waves from the northwest at waist to maybe chest high on the peaks and clean and lined up. Central Orange County had set waves at chest to shoulder high on the sets and clean and lined up and nicely rideable on occasion. South Orange County's best summertime breaks had set waves at up to 2 ft overhead high and lined up band clean but with a slight texture on top. North San Diego had sets to head high and lined up and clean but pretty closed out. Hawaii's North Shore was flat and clean. The South Shore was getting fading New Zealand swell with waves at chest high on occasion and clean and lined up when they came. The East Shore was getting minimal east windswell with waves thigh to maybe waist high and almost chopped from modest easterly trades.

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

Meteorological Overview
On Thursday (8/20) minimal locally generated windswell was hitting North and Central CA. There was some minimal southern hemi swell pushing into North CA but it was hitting stronger in Southern CA and fading in Hawaii originating from a weak gale that developed southeast of New Zealand on Tues (8/11) producing up to 34 ft seas aimed east an. And another gale developed south of New Zealand on Fri (8/14) producing 27-28 ft seas aimed northeast for 12 hours adding to the above swell. Another weak system tracked northeast through the Central South Pacific on Sun-Mon (8/16) producing up to 30 ft seas over a small area aimed northeast. That swell is tracking northeast. And after that one more weak gale tracked east through the South Central Pacific on Tues-Wed (8/19) producing up to 32 ft seas aimed due east. So more little swell is possible but nothing solid is suggested. At this point we're just waiting for Fall.

See all the details below...


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

North Pacific

Surface Analysis
On Thursday (8/20) no swell of interest was in the water.

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


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


Tropical Update
Hurricane Genevieve on Thursday AM (8/20) was positioned 50 nmiles west of Cabo San Lucas Mexico with winds 65 kts tracking northwest. It was not in the SCal swell window and at no time was it ever in the SCal swell window. No swell to result.

California Nearshore Forecast
On Thursday (8/20) northwest winds were limited to Central CA nearshore waters at 20-25 kts south of Monterey Bay holding all day offering only minimal support for windchop production there. Winds to be 15 kts or less over North CA water. Friday (8/21) more of the same is forecast with north winds 10-15 kts along the North CA coast and 20-25 kts for Central CA south of Monterey Bay and holding all day with raw local windswell production continuing for southern Central CA. On Sat (8/22) the gradient is to lift north with northwest winds forecast at 15-20 kts for all of North and Central CA early with 20-25 kts north winds building in coverage over North CA later with winds fades to 10 kts over Central CA later. Windswell production building some later. On Sunday (8/23) north winds are forecast at 20 kts for North CA down to Pt Arena with a light eddy flow (south winds) from Pt Reyes southward. On Mon (8/24) north winds are forecast at 20-25 kts limited to Pt Arena northward resulting in windswell radiating south into Central CA with winds light from Pt Reyes southward all day. On Tues (8/25) the gradient is to hold producing north winds at 25 kts for Cape Mendocino but with light winds south of there early but building to 10-15 kts from the north in the afternoon while north winds fade to 20 kts over Cape Mendocino later. Wed (8/26) north winds are forecast at 20-25 kts over a broad area over and off North CA and most of Central CA early holding all day. Windswell production potential on the increase. More of the same on Thurs (8/27) with north winds 20-25 kts over Cape Mendocino early and 10-15 kts south of there to Pt Conception holding through the day.

Total snow accumulation for the week for Squaw Valley, Sugar Bowl, Kirkwood and Mammoth at 0, 0, 0 and 0 inches respectively. Freezing level 14,000 ft or higher for the week.

Snow Models: (Scroll down for resort specific forecasts). Updated!


South Pacific

On Thursday (8/20) the jetstream was well split over the width of the South Pacific with the southern branch pushing east at up to 120 kts on the 60S latitude line over most of the South Pacific and just barely clear of the Ross Ice Shelf but not forming any troughs offering no clear support for gale development. Over the next 72 hours that zonal wind energy is to start falling south over Antarctic Ice focused on the Central South Pacific with a ridge in control over the bulk of the South Pacific on Fri (8/21), fading some in the West Pacific on Sat (8/22) before redeveloping on Sun (8/23). No support for gale development forecast. Beyond 72 hours starting Mon (8/24) the zonal flow is to continue sagging south forming a generalized ridge pushing over Antarctic Ice from a point south of New Zealand eastward over the remainder of the South Pacific offering no support for gale development through Wed (8/26). On Thurs (8/27) the southern branch of the jet is to significantly weaken, no longer forming a ridge, but not offering any support for gale development either.

Surface Analysis
On Thursday (8/20) tiny swell from a gale that developed under New Zealand was still hitting California (see Weak New Zealand Gale below). Secondary swell energy is was also intermixed from another gale that built under New Zealand (see Secondary New Zealand Gale below). And yet another small swell was intermixed originating from New Zealand (see Southwest Pacific Gale below). Another system developed in the same area producing small swell radiating northeast (see Another New Zealand Gale below). And a final system developed southeast of New Zealand (see Final New Zealand Gale below). One more gale followed that but only tiny swell is expected (see South Central Pacific Gale below). Beyond no swell producing weather systems are forecast.

Over the next 72 hours no swell producing fetch is forecast.


Weak New Zealand Gale
A gale started building in the far Southwest Pacific south of Tasmania on Fri PM (8/7) pushing east with 35-40 kt west winds over a small area and seas building. On Sat AM (8/8) southwest winds were 40-45 kts over a small area south of New Zealand with seas 30 ft over a modest area at 56S 162E aimed east-northeast. In the evening fetch was fading with southwest winds 35-40 kts over a modest sized area aimed northeast with seas 32 ft at 53S 176E aimed east-northeast. On Sun AM (8/9) fetch was fading and sinking south from 30-35 kts with seas fading from 27 ft at 53S 175W aimed east. Low odds of any swell resulting for Hawaii or the US mainland.

Southern CA: Swell still decent on Thurs (8/20) at 2.0 ft @ 15 secs (3.0 ft). Swell being reinforced on Fri (8/21) by secondary energy (see below) to 1.8 ft @ 15 secs all day (2.5-3.0 ft). Swell fading on Sat (8/22) from 1.5 ft @ 14-15 secs (2.0 ft). Swell Direction: 213 degrees

North CA: Swell fading some on Thurs (8/20) at 1.6 ft @ 15 secs (2.0-2.5 ft). Swell being reinforced on Fri (8/21) by secondary energy (see below) to 1.5 ft @ 15 secs all day (2.0-2.5 ft). Swell fading on Sat (8/22) from 1.3 ft @ 14-15 secs (2.0 ft). Swell Direction: 213 degrees


Secondary New Zealand Gale
Another gale developed from the remnants of a previous gale (see Weak New Zealand Gale above) on Sun AM (8/9) southeast of New Zealand producing 40 kt west-southwest winds with seas 29 ft over a tiny area at 59.5S 177W aimed east. In the evening fetch pulse from the southwest at 40-45 kts over a small area with seas building to 33 ft at 58.5S 173W aimed east-northeast. On Mon AM (8/10) fetch was fading from 30-35 kts with seas 27 ft over a tiny area at 58.5S 170W aimed mostly east. This system was gone after that.

Low odds of any swell resulting for Hawaii and likely only reinforcing the above swell (Weak New Zealand Gale) in California.


Southwest Pacific Gale
On Tues AM (8/11) a decent sized fetch of 40 kt west winds built just southeast of New Zealand with seas building to 29 ft at 51.5S 175.5W aimed east. In the evening fetch built to 45 kts from the west with seas 35 ft at 52S 160W aimed east but with the fetch starting to fall southeast. On Wed AM (8/12) fetch built to 55+ kts from the west but falling southeast with seas building to 39 ft at 61S 139W aimed southeast and falling southeast having no swell potential radiating northeast. More of the same occurred in the evening with the fetch and seas crashing into Antarctica offering nothing in terms of swell production radiating into the Northern Hemisphere. But the first 18-24 hours of this system had some limited potential.

Hawaii: Swell fading on Thurs (8/20) from 1.6 ft @ 13-14 secs early (2.0-2.5 ft). Swell Direction: 200 degrees

California: This swell to reinforce existing swell above (See Weak New Zealand Gale above).


Another New Zealand Gale
On Fri AM (8/14) a small gale formed southeast of New Zealand lifting northeast producing a modest sized area of 40 kt southwest winds producing 28 ft seas aimed northeast at 56S 170E. In the evening southwest winds were 35 kts lifting northeast producing 26 ft seas at 52S 179W aimed northeast. Fetch dissipated after that on Sat AM (8/15) offer no more swell production potential.

Hawaii: Expect swell arrival on late Fri (8/21) pushing 1.0 ft @ 17-18 secs (1.5 ft). Swell building on Sat (8/22) to 1.5 ft @ 15-16 secs mid-day (2.0-2.5 ft). Swell holding early Sun (8/23) at 2.0 ft @ 14 secs (2.5 ft) then fading. Swell Direction: 195 degrees

Southern CA: Expect swell to arrive weakly on Tues (8/25) building to 1.3 ft @ 15 secs (2.0 ft). Swell dissipating after that. Swell Direction: 213 degrees

North CA: Expect swell to arrive weakly on Tues (8/25) building to 1.2 ft @ 15-16 secs (2.0 ft). Swell dissipating after that. Swell Direction: 212 degrees


Final New Zealand Gale
On Sat PM (8/16) a gale developed southeast of New Zealand producing southwest winds at 40 kts with seas building from 23 ft at 57S 180W aimed northeast. On Sun AM (8/17) fetch continued lifting northeast at 40-45 kts with seas 28 ft over a tiny area at 52S 170W aimed northeast. In the evening the gale tracked well northeast with winds 45 kts from the southwest with seas 30 ft over a small area at 49.5S 160W aimed northeast. Fetch faded Mon AM (8/17) from 35 kts from the southwest with seas fading from 29 ft at 47S 153W aimed northeast. The gale dissipate in the evening with seas fading from 29 ft at 48S 147.5W aimed northeast. Something to monitor.

Hawaii: Swell arrival on Sun (8/23) building to 1.3 ft @ 16 secs later (2.0 ft). Swell peaking early Mon (8/24) at 2.0 ft @ 14-15 secs (2.5-3.0 ft). Swell fading Tues (8/25) from 1.5 ft @ 13 secs (1.5-2.0 ft). Swell Direction: 188 degrees

Southern CA: Expect swell arrival late on Tues (8/25) pushing 1.0 ft @ 17 secs (1.5 ft). Swell building on Wed (8/26) to 1.6 ft @ 15-16 secs early (2.0-2.5 ft). Swell fading on Thurs (8/27) from 1.4 ft @ 14 secs (2.0 ft).Swell Direction: 198 degrees

North CA: Expect swell arrival late on Tues (8/25) pushing 1.0 ft @ 17 secs (1.5 ft). Swell building on Wed (8/26) to 1.6 ft @ 15-16 secs early (2.0-2.5 ft). Swell fading on Thurs (8/27) from 1.4 ft @ 14-15 secs (2.0 ft).Swell Direction: 198 degrees


South Central Pacific Gale
Starting Tues AM (8/18) a gale developed well southeast of New Zealand producing a broad area of northwest winds at 45 kts with seas building to 29 ft at 58.5S 176.5W aimed east. In the evening fetch is to push quickly east and build in coverage at 40-45 kts from the west-northwest with 31 ft seas at 57.5S 162W aimed east-southeast. Fetch moved rapidly east on Wed AM (8/19) over a building area at 40-45 kts with seas 34 ft down at 62S 131W aimed east. The gale pushed east with west winds 35 kt over a large area and seas 31 ft over a broad area aimed east at 58.5S 125W aimed northeast. The gale pushed east of the Southern CA swell window after that. Something to monitor.

Hawaii: No swell expected to result.

Southern CA: Expect swell arrival on Thurs (8/27) pushing 1.3 ft @ 18 secs late (2.0-2.5 ft). Swell Direction: 193 degrees

North CA: Expect swell arrival on Thurs (8/27) pushing 1.0 ft @ 18-19 secs late (1.5 ft). Swell Direction: 193 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 no swell producing fetch of interest is forecast.


South Pacific

Beyond 72 hours a tiny gale is forecast developing south of New Zealand on Thurs (8/27) lifting northeast producing 31 ft seas aimed northeast. Something to monitor but odds low of its formation.


MJO/ENSO Forecast


La Nina Development Continues

MJO/ENSO Discussion
The Madden Julian Oscillation (MJO) 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 equator it is in control of, and in it's Active Phase by slackening if not an outright reversing trade winds while enhancing 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 planet, 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 in the Pacific help support the formation of El Nino. During the Inactive Phase the jet stream tends to split resulting in high pressure and less potential for swell producing storm development. Wind anomalies in the Kelvin Wave Generation Area (KWGA) are key for understanding what Phase the MJO is in over the Pacific. The KWGA is located on the equator from 135E-170W and 5 degs north and south (or on the equator from New Guinea east to the dateline). West wind anomalies in the KWGA suggest the Active Phase of the MJO in the Pacific, and east anomalies suggests the Inactive Phase. In turn the Active Phase strengthens and the Inactive Phase weakens the jetstream, which in turn enhances or dampens storm production respectively in the Pacific.

And the El Nino/La Nino cycle (collectively know as ENSO - El Nino Southern Oscillation) is a less frequent (about once every 7 years) but more impactful cycle that affects world wide weather. Specifically, strong El Nino events promote storm production in the Pacific while La Nina events suppress storm production. These therefore have a significant impact on the production of swell and surf. The paragraphs below analyze the state of the MJO and ENSO in the Pacific and provide forecasts for upcoming activity (or inactivity depending on the state and interaction of these two oscillations).

Overview: A double dip La Nina was in control through the Winter of 2017-2018. But warming started building along the South and Central American coast in early March 2018 associated with two upwelling Kelvin Waves, and continued trying to build over equatorial waters over the Summer and Fall, but not enough to declare El Nino and not coupled with the atmosphere. In January 2019, those warm waters were fading, but then rebuilt late in Feb associated with Kelvin Wave (#3). But as of early June 2019 warm water was fading and by August a tongue of cool water was tracking west on the equator from Ecuador over the Galapagos reaching to a point nearly south of Hawaii. El Nino was dead. A bit of a recovery occurred during Fall of 2019, with weak warm water building in the Nino 1.2 region, but cool water held in a pool off Peru and had not changed until March 2020. By April the cool pool pushed east and by May subsurface cool waters erupted off Ecuador, forming a well defined cool tongue that looked like the start of La Nina, holding into July 2020.

Fall/Winter 2020/2021 = 3.0/3.5 (California & Hawaii)
Rating based on a 1-10 scale: 1 being the lowest (small and infrequent surf conditions), 5 being normal/average, and 10 being extraordinary (frequent events of large, long period swells)

Rationale: It is assumed the PDO has moved to the warm phase in 2014 and that a weak borderline El Nino from 2018 faded out in the Fall of 2019. A La Nina like ocean temperature pattern developed in the equatorial East Pacific in the summer of 2019, then faded and returned to a neutral if not weak warm status during the Winter of 2019-2020 only to return stronger in the Summer of 2020. We have been suspecting a turn towards a La Nina like atmospheric pattern to develop in the late Winter/early Spring of 2020. Our best hope is that moderation from the warm phase of the PDO might tamp down development of a full blown La Nina as we move into 2020. But at this time that does not appear likely. Given all that, for the 2020 there is decent probability for development of La Nina meaning a reduced number of storm days and storm intensity during the summer season, resulting in a below normal level of swell, with swell being below normal duration and period. And by the Fall and early Winter of 2020/21, the number of storm days, intensity and duration of those storms should fade even more, resulting in depressed swell production. This pattern is expected to hold through the Spring of 2021.

KWGA/Equatorial Surface Wind Analysis & Short-term Forecast (KWGA - Kelvin Wave Generation Area - The area 5 degrees north and south of the equator from 170W to 135E)
Analysis (TAO Buoys): As of (8/20) 5 day average winds were solid from the east over the Eastern equatorial Pacific continuing over the Central Pacific and then weak west over the KWGA. Anomalies were light east over the East equatorial and Central Pacific and moderate westerly over the KWGA. (Note: These are 5 day average winds, so they lag what is happening today by about 2 days).
1 Week Forecast (GFS Model): On (8/20) weak east anomalies were building in over all the KWGA today with moderate west anomalies filling the far East Pacific. The forecast calls for east anomalies building over the KWGA and filling 75% of it at the end of the forecast period (on 8/27). Moderate west anomalies are to continue filling the equatorial Pacific east of the dateline for the duration of the forecast period. Support for energy transfer into the jet is fading and will continue on that trend for at least the next week.

Kelvin Wave Generation Area wind monitoring model: West and East

Longer Range MJO/WWB Projections:  
OLR Models: (8/19) A weak Inactive MJO was trying to move into the far West KWGA today. The statistic model indicates the Inactive Phase is to push stronger into the West Pacific 5 days out filling it on day 10 and continuing through day 15. The dynamic model suggests the same thing initially and is corrupt after that.
Phase Diagrams 2 week forecast (ECMF and GEFS): (8/20) The statistical model depicts the Active Phase was weak over the East Pacific today and is to steadily track east over the Central Indian Ocean 15 days out. The GEFS model suggests the Active Phase is to building while tracking over the Atlantic then next 5 days then weakening while pushing into and over the Central Indian Ocean 2 weeks out.
40 day Upper Level Model (assumed to be a statistical mode and 1 week ahead of what is occurring at the surface): (8/19) This model depicts a moderate Inactive MJO was nearly filling the equatorial Pacific today. The forecast depicts the Inactive Phase is to move east through the Central equatorial Pacific and into Central America on 9/18. A weak Active MJO is to follow pushing into the far West Pacific 8/17 moving to the Central Pacific through the end of the model run on 9/28.
4 Week CFS Model (850 mb wind): (8/19) This model depicts an organized Active MJO a day or two past its peak over the KWGA today with weak west anomalies fading fast in the KWGA. The forecast indicates the Active MJO tracking east and fading in the KWGA through 8/26 with west anomalies fading in coverage and gone by the end of that window while east anomalies starting building in the KWGA in one day (8/20) and mostly filling it by 8/26. At that time the Inactive Phase of the MJO to be mostly filling the KWGA and tracking east continuing to lock the KWGA down through the end of the model run on 9/16. Overall a long run of easterly anomalies are to take over the KWGA. Whatever window there is for the MJO to support swell production, it is fading fast.
3 Month CFS Model (850 mb wind): (8/20 - using the 4th/latest ensemble member): This model depicts a weak Active MJO over the KWGA today and past its prime with patches of weak west anomalies trying to hold on as the MJO moves east and out of the KWGA on 8/26. A strong Inactive Phase is forecast traversing the Pacific 8/23-9/19 with another bout of strong east anomalies firmly controlling the KWGA and filling the whole equatorial Pacific and strong over the East Pacific. A strong Active Phase of the MJO is forecast 9/14 through 10/15 with solid west anomalies filling the western 75% of the KWGA while eat anomalies remain in control east of there. A weak Inactive Phase is to follow 9/29-10/23 but with weak west anomalies filling the KWGA. Another modest ACtive MJO is to follow 10/23 through the end of the model run on 11/16 producing modest west anomalies filling the KWGA. The low pass filter indicates a high pressure bias is in control over the dateline today reaching east to a point south of California and is to hold in coverage through the end of the model run with a second contour setting up on 9/11 on the dateline holding through the end of the model run. A single contour low pressure bias is appearing weakly over the Indian Ocean today and is to build in coverage through the end of the model run while its eastern periphery eases east to 160E and over the West KWGA at the end of the model run. East anomalies that have been previously solid in the Indian Ocean for over a year are migrating east into the West Pacific and should track east becoming stationary over the East Pacific early Sept and holding for the foreseeable future. The trend is again turning towards La Nina.

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

Subsurface Waters Temps
TAO Array: (8/20) Today in the far West Pacific the 30 deg isotherm was gone. The 29 deg isotherm was moving east to 171E today. The 28 deg isotherm line was tracking eat at 172W today. The 24 deg isotherm was backtracking to 130W today. Anomaly wise, warm anomalies 0-1 deg C were fading in the West Pacific reaching east to barely 170W with another pocket at +1 deg between 100W to 125W. A river of generally cooler temps were tracking west to east down at 150m traversing the width of the equatorial Pacific. Embedded in that was a building pocket of cooler anomalies at -2 degs located between 110W-170W today and bubbling up to the surface near and around 150W. It appears a conveyor belt of cool water (Cold water Kelvin Waves) was in effect. The hi-res GODAS animation posted 8/16 indicates the cool water bubble at depth was far stronger and larger t erupting to the surface between 105W to 180W. Almost no water water was below the surface or at the surface east of the dateline. In effect a river of cool water was at depth under the entirety of the equatorial Pacific 150m tracking east. The GODAS animation appears to be 1 week behind the TAO data but also is more detailed and accurately modeled.
Sea Level Anomalies: (8/16) Negative anomalies greater than -5 cms with a large embedded area at -15 cms were building over the Central equatorial Pacific between 110W to 175E. Interestingly negative anomalies were dissolving along Ecuador and down into Peru but still covering a large area at -5 cms there and reaching north up to Baja and into Southern CA. No positive anomalies were over the equatorial Pacific, except west of 160E.

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: (8/19) The latest images indicate cold water was holding along Peru tracking northwest building over and off Ecuador some then tracking west on the equator weakening some west of the Galapagos only to rebuild solidly from 120W and west out to the dateline looking like a developing fully in control version of La Nina. Cool anomalies along the coast of Chile up into Peru appearing to be feeding the cool stream. Warm water was off Central America reaching west to the dateline but only north of the equator, remnants of a fading El Nino like pattern. Overall the cool pool on the equator was unmistakable and starting to show signs of rebuilding after previously being stalled.
Hi-res 7 day Trend (8/19): A stream of cooling water was pushing west off Ecuador out to 160W. Small pockets of warming interspersed. The short term trend is looking like development of a large scale cooling trend centered on the dateline.
Hi-res Overview: (8/19) A stream of cool water is entrenched along the coast of Peru lifting northwest to the equator from Ecuador then fading slightly west of the Galapagos, only to rebuild from 120W to the dateline on the equator. Warmer than normal temps were stable north of the equator. Overall the data suggests a building La Nina like pattern.
Nino1.2 Daily CDAS Index Temps: (8/20) Today's temps were rising some at -1.256 degs after previously reaching a new low of -2.138 on 8/13. The trend has been steadily downward since March 26. Overall the trend is towards cooling after having previously been in a warmer range at +0.6 degs between 2/25-3/26.
Nino 3.4 Daily CDAS Index Temps:
(8/20) Temps were starting to fall again at -0.446, previous down at -0.492 on 8/12. Before that temps were stable between 6/27-7/25 at near 0.0. And before that temps were rising after bottoming out down at -0.595 on 5/27. Overall the trend was warming but now appears to be in a steep decline.

Click for Full Sized Image Click for Full Sized Image

CFSV2 Forecast for Nino3.4 Sea Surface Temp (SST) Anomalies & Current SST Anomalies

SST Anomaly Projections
CFSv2 Uncorrected Data (8/20) Actual temperatures were in the +0.65 deg range early this year through March, then started falling down to -0.20 in late-May before stabilized near neutral late June. Then they fell to -0.6 degs in July and early Aug. The forecast depicts a steady downward trend reaching down to -1.25 degs in late Oct. After that temps to start rebuilding steadily up to +0.1 degs in late April. We think the dynamic models might be overstating the magnitude of the coming cooling trend for the equatorial Pacific.
IRI Consensus Plume: The July 19, 2020 Plume depicts temps are at -0.42 degs, and are to fall into Oct to -0.55 degs then moderating and starting to rise some to -0.35 by Jan 2021 and then neutral by March. The low outlier is a dynamic models (NASA GMAO). But a good plethora of models are now suggesting a developing solid La Nina. See chart here - link.

Atmospheric Coupling (Indicating the presence of El Nino in the atmosphere driven by the ocean):
Southern Oscillation Index (SOI) (negative is good, positive bad) (8/20): The daily index was positive today at 26.40. The 30 day average was rising at +6.31. The 90 day average was rising slightly to 0.18, suggesting a neutral ENSO pattern was in control and trending perhaps to La Nina. This index is a lagging indicator.
ESPI Index (like SOI but based on satellite confirmed precipitation. Positive and/or rising is good, negative and/or falling is bad): June -0.67, May -0.46, April 2020 -0.69, March -0.09, Feb +0.65, Jan +0.42, This index was steady positive Aug 2018 through Feb 2020, and now is steady negative, but only weakly so.

Pacific Decadal Oscillation
Per NOAAs index recent values: Jan 2018 +0.29, Feb -0.19, Mar -0.61, April -0.89, May -0.69, June -0.85, July -0.09, Aug -0.43, Sept -0.46, Oct -0.75, Nov -0.78, Dec -0.12, Jan 2019 -0.18, Feb -0.50 Mar -0.23, April +0.10, May +0.14, June -0.11, July +0.44, Aug -0.14, Sept +0.05, Oct -0.96, Nov -0.28, Dec +0.01, Jan 2020 -1.17, This continues to look like the warm phase of the PDO. No consistently solid negative readings have occurred since Feb 2014
The Washington/JISAO index (Jan-Dec): Jan 2018 +0.70. Feb +0.37, Mar -0.05, April +0.11, May +0.11, June -0.04, July +0.11, Aug +0.18, Sept +0.09. No real negative readings have occurred since Dec 2013
The PDO turned from a 16 year negative run (Jan 98-Feb 2014) in early 2014 and has been positive ever since (other than a few months of negative readings in Fall 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 strongly suggests that could be a possibility. 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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Local Interest

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Surf Height-Swell Height Correlation Table


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