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Pacific Storm and Surf Forecast
Updated: Wednesday, September 23, 2020 5:30 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 & 2.3 - 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 9/21 thru Sun 9/27

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 Swell Pushing to CA
Solid SPac Swell Heading North - More Possible To Follow

BUOY ROUNDUP
On Wednesday, September 23, 2020 :

  • Buoy 233 (Pearl Harbor Entrance)/Buoy 239 (Lanai): Seas were 2.9 ft @ 14.3 secs with swell 1.2 ft @ 16.6 secs from 220 degrees.
  • Buoy 106 (Waimea): This buoy is currently not operating (ceased service at 9/15 - 19Z). Water temp 81.0 degs.
  • Buoy 46025 (Catalina RDG): Seas were 2.2 ft @ 17.2 secs with swell 1.1 ft @ 15.9 secs from 217 degrees. Wind at the buoy was variable at 0-4 kts. Water temperature 68.2 degs. At Harvest Buoy (071) primary swell was 1.6 ft @ 16.5 secs from 199 degrees. At Santa Monica (028) swell was 1.5 ft @ 16.5 secs from 208 degrees. At Oceanside (045) swell was 1.3 ft @ 17.0 secs from 208 degrees. Southward at Point Loma (191) swell was 1.4 ft @ 16.5 secs from 207 degrees.
  • Buoy 46012 (Half Moon Bay)/029 (Pt Reyes): Seas were 3.7 ft @ 10.0 secs with swell 1.7 ft @ 15.9 secs from 214 degrees. Wind at the buoy (012) was northwest at 10-14 kts. Water temp 53.8 degs (013), 59.7 degs (SF Bar) and 56.3 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).
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/Utility Class: 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.

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

PACIFIC OVERVIEW
Current Conditions
On Wednesday (9/23) in North and Central CA local northwest windswell was producing waves at thigh high on the sets and clean and lined up but just too small. Protected breaks were thigh high and clean but weak. At Santa Cruz waves were waist to chest high on the sets and clean and lined and occasionally almost fun looking. In Southern California/Ventura waves were waist to almost chest high on the sets and peeling and clean. Central Orange County had set waves at chest to head high coming from the south and clean and lined up but a little soft. South Orange County's best summertime breaks had set waves at chest to head high and super clean and peeling but soft. North San Diego had sets at chest high and clean and lined up and peeling. Hawaii's North Shore was flat and clean. The South Shore was still getting southern hemi swell with set waves chest to head high and lined up and clean but inconsistent. The East Shore was getting minimal east windswell with waves thigh high and lightly chopped early from modest east trades.

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

Meteorological Overview
On Wednesday (9/23) small southern hemi swell was hitting Hawaii and California having been previously generated by a gale that tracked under New Zealand Fri-Sat (9/12) with up to 43 ft seas aimed east. And another system developed under New Zealand on Sat (9/19) tracking east through the deep Central and Southeast Pacific into Tues (9/22) producing seas up 41 ft aimed east. Up north a gale was starting to fade after having tracked from the far Northwestern Gulf Mon-Wed (9/23) with 27-28 ft seas aimed well east and southeast. There's some suggestion of maybe another weak system to follow in the Northeast Gulf on Tues (9/29) with possibly 2 more behind that approaching from the dateline. So Fall looks to be ready to arrive, and not a moment to soon. That said, a small system is forecast under New Zealand Mon-Tues (9/29) with up to 35 ft sea aimed well north. So the South Pacific isn't going to sleep just yet.

See all the details below...

 

SHORT- TERM FORECAST
Current marine weather and wave analysis plus forecast conditions for the next 72 hours

North Pacific

Overview
Surface Analysis
On Wednesday (9/23) swell was radiating southeast from a gale previously in the Northwestern Gulf of Alaska (see Northwestern Gulf Gale below).

Over the next 72 hours no additional swell production is forecast.

Northwestern Gulf Gale
A low pressure system started traversing the far Northwest Pacific on Sat PM (9/19) tracking just south of the Aleutian Islands producing a small area of up to 27 ft seas at 51N 173W aimed east on Sun PM (9/20) but not getting interesting till Mon AM (9/21) when the low is to start falling southeast some over the Eastern Aleutians producing 35 kt northwest winds with seas building in coverage at 27 ft at 49.5N 167.5W aimed southeast. In the evening northwest winds increased in coverage at 35 kts with seas building to 28 ft at 47.5N 160W aimed southeast. On Tues AM (9/22) the gale was fall southeast over the Central Gulf of Alaska producing 35 kt northwest winds over a decent sized area with seas 27 ft at 46N 156W aimed southeast. The gale built some in coverage in the evening while tracking east with 35-40 kt northwest winds and seas 29 ft at 45.5N 151.5W aimed southeast. On Wed AM (9/23) northwest winds were 35 kts over the Central Gulf approaching the Pacific Northwest with seas fading from 27 ft over a solid area at 44N 144W aimed southeast. Fetch is to be fading in the evening from 30 kts with seas fading from 22 ft at 45.5N 136.5W aimed southeast. The gale is to dissipate from there. This forecast has held pretty decent for days now and is likely to produce swell.

North CA: Expect swell arrival late Thurs (9/24) building to 7.5 ft @ 15-16 secs (10.5 ft). Swell continues on Fri (9/25) at 7.5 ft @ 14-15 secs (10.5 ft) early. Residuals fading on Sat (9/26) from 5.2 ft @ 13 secs early (6.5 ft). Dribble on Sun (9/27) at 5.5 ft @ 10-11 secs (5.5 ft). Swell Direction: 299-305 degrees

Southern CA: Expect swell arrival on Fri (9/25) mid-AM to 3.7 ft @ 15-16 secs (5.5 ft) at select exposed breaks. Swell holding through the day. Swell fading on Sat (9/26) fading from 3.1 ft @ 13-14 secs early (4.0 ft). Residuals on Sun (9/27) fading from 2.3 ft @ 11-12 secs (2.5 ft). Swell Direction: 303-309 degrees

 

Placeholder

Tropical Update
No tropical system are being monitored.

California Nearshore Forecast
On Wednesday (9/23) northwest winds were 10 kts or less except 15 kts near Big Sur early building to 15 kts for all of Central CA in the afternoon. South winds to be building into the afternoon at 15-20 kts for Cape Mendocino. On Thurs (9/24) northwest winds are forecast at 15-20 kts for Central CA south of Monterey Bay early and northwest 10 kts for North CA early building to 10-15 kts for all of North CA and 20 kts for all of Central CA later. Rain for Cape Mendocino mainly early. On Fri (9/25) northwest winds are forecast at 15 kts for North CA early and 20 kts for Central CA early building to 20+ kts for all of North and Central CA later. Sat (9/26) northwest winds are forecast at 20 kts for all of North and Central CA pushing 25 kts for Ncal later. Sunday (9/27) northwest winds to be 20-25 kts streaming down North CA, but near calm all day over Central CA. Monday (9/28) the gradient and north winds to be 25-30 kts for Cape Mendocino early and clam south of there with the north fetch fading in coverage later with light winds everywhere but the CA-OR border later. Tues (9/29) a light winds flow is forecast all day for North and Central CA. On Wed (9/30) northwest winds are forecast at 10 kts early for North and Central CA building to 10-15 kts later.

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 next 10 days.

Snow Models: http://www.stormsurf.com/mdls/menu_snow.html (Scroll down for resort specific forecasts). Updated!

 

South Pacific

Overview
Jetstream
On Wednesday (9/23) the southern branch of the jet was running zonally from west to east on the 57S latitude line over the entirety of the South Pacific with winds to 150 kts over the Southeast Pacific offering some support for gale development. Over the next 72 hours the jet is to steadily weaken and start falling south over the entirety of the South Pacific pushing over the Ross Ice Shelf offering no support for gale development. Beyond 72 hours the jet is to start falling hard southeast on Sun (9/27) southeast of New Zealand pushing down into Antarctica offering no support for gale development from there and points east of there. But on Saturday into Sun (9/27) in the Tasman Sea and up to a point south of New Zealand a new trough is to start building with the jet pushing hard north at 130 kts offering a good environment for gale development. That trough is to push east filling the area under and southeast of New Zealand on Mon PM (9/28) being fed by 110-120 kts winds still offering good support for gale development. But that trough is to rapidly fade on Tues (9/29) with support for gale development diminishing. Still remnants of the trough are to linger while moving east into the Central South Pacific late on Wed (9/30).

Surface Analysis
On Wednesday (9/23) swell from a New Zealand gale was impacting California while fading out in Hawaii (see Stronger New Zealand Gale below). And another gale developed under New Zealand tracking east with swell from it propagating northeast (See South Pacific Gale below).

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

 

Stronger New Zealand Gale
A new gale started building southwest of New Zealand on Fri PM (9/11) producing 45-50 kt west winds over a decent sized area with seas to 43 ft at 56.5S 158E.5 aimed east (218 degs SCal, 216 degs NCal and shadowed by NZ for HI). On Sat AM (9/12) west-southwest winds were pushing east over a decent sized area at 40-45 kts with seas 44 ft at 57.5S 169E aimed east (213 degs SCal and shadowed by Tahiti, 212 degs NCal and unshadowed, 197 degs HI). In the evening fetch was aimed better northeast at 35-40 kts with seas fading from 39 ft at 58S 180W aimed east-northeast (209 degs SCal and still shadowed, 208 degs NCal and shadowed by Tahiti, 192 degs HI). On Sun AM (9/13) fetch was fading from 30 kts over broad area aimed northeast with seas fading from 33 ft at 57S 170W aimed northeast (206 degs SCal and unshadowed, 205 degs NCal and still shadowed, 186 degs HI). The gale was gone after that. Some small swell is possible for California with tiny sideband swell for Hawaii.

Southern CA: Swell fading Wed (9/23) from 1.7 ft @ 16 secs (2.5 ft). Swell dropping on Thurs (6/24) from 1.3 ft @ 15 secs early (2.0 ft). Swell Direction: 213 degrees

North CA: Swell fading Wed (9/23) from 1.6 ft @ 16 secs (2.5 ft). Swell dropping on Thurs (6/24) from 1.3 ft @ 15 secs early (2.0 ft). Swell Direction: 213 degrees

 

South Pacific Gale
A gale started developing under New Zealand just off the Ross Ice Shelf on Sat PM (9/19) producing a 40-45 kt southwest winds resulting in seas at 38 ft aimed east at 59.5S 179.5W tracking east. On Sun AM (9/20) southwest winds were 40 kts over a solid area with seas building to 39 ft at 60S 172W aimed east-northeast. In the evening southwest winds built to 40-45 kts over a broad and solid area aimed east-northeast with seas 40 ft at 59.5S 162.5W aimed east-northeast. On Mon AM (9/21) 40 kt west-southwest winds were covering a large area with seas 40 ft at 59S 150W aimed east-northeast. Fetch was fading in the evening while pushing east at 40 kts from the west still over a solid area with seas fading from 36 ft at 57.5S 137W aimed east. On Tues AM (9/22) fetch was fading over the far Southeast Pacific with seas 33 ft at 58S 120W aimed east. In the evening a lingering fetch of west winds to hold at 40-45 kts barely in the SCal swell window with seas 28-30 ft at 53S 119W aimed east. This system continued tracking east offering energy only up into Chile. Something to monitor.

Hawaii: Expect swell arrival on Sat (9/26) building to 1.1 ft @ 19 secs late (2.0 ft). Swell building some on Sun (9/27) to 1.4 ft @ 17 secs (2.0-2.5 ft). Swell holding on Mon (9/28) at 1.4 ft @ 15-16 secs (2.0-2.5 ft). Swell all but gone on Tues (9/29). Swell Direction: 195 degrees

Southern CA: Expect swell arrival on Sun (9/27) building to 1.3 ft @ 23 secs at sunset (2.5 ft). Swell building on Mon (9/28) to 2.5 ft @ 20 secs later (5.0 ft). Swell building on Tues (9/29) to 3.0 ft @ 18 secs mid-day (5.0-5.5 ft with sets to 6.5 ft). Swell solid on Wed (9/30) building to 3.3 ft @ 16-17 secs (5.5 ft with sets to 6.5-7.0 ft). Swell Direction: 198 degrees

North CA: Expect swell arrival on Sun (9/27) but not rideable yet with period 23-24 secs late. Swell building on Mon (9/28) to 2.0 ft @ 20-21 secs later (4.0 ft). Swell building on Tues (9/29) to 2.5 ft @ 18 secs late (4.5 ft with sets to 5.5 ft). Swell solid on Wed (9/30) at 2.6 ft @ 16-17 secs (4.0-4.5 ft with sets to 5.5t). Swell Direction: 197 degrees

 

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

 

QuikCAST's

 

LONG-TERM FORECAST
Marine weather and forecast conditions 3-10 days into the future

North Pacific

Beyond 72 hours another small gale is forecast developing in the far Northeastern Gulf of Alaska on Mon PM (9/28) with 30-35 kt west winds and seas building to 20 ft at 27N 155W aimed east. The gale is to track northeast Tues AM (9/29) with 40-45 kt west winds over a small area and seas building to 25 ft at 51N 151W aimed east and moving east of the North CA swell window. The gale is to be fading off the South Alaskan Coast in the evening 30-35 kts southwest winds targeting only Alaska with 26 ft seas at 55N 146W aimed north. Low odds of sideband swell radiating towards the Pacific Northwest down into North CA. Something to monitor.

Another small gale is forecast developing 1000 nmiles north of Hawaii on Wed (9/30) with 35 kt west winds and seas to 20 ft or so near 40N 162W aimed east.

And yet another is forecast evolving from a tropical system east of Japan on Wed (9/30) producing 45 kt westerly winds and seas to 40 some feet at 41N 160E aimed east. There's no odds of this system developing at this early date.

 

South Pacific

Beyond 72 hours a gale is forecast developing south of New Zealand on Sun AM (9/27) producing a broad area of 30-40 kt south winds and seas starting to develop. In the evening a broad fetch of 45 kt south winds is forecast just off the edge of the Ross Ice Shelf producing seas building to 28 ft late at 59S 172E aimed north. No change on Mon AM (9/28) with 45 kt south winds holding in place and seas 35 ft at 56.5S 172E aimed north. Fetch is to fade some in the evening with 40-45 kt south winds and 31 ft seas at 54S 176E aimed north-northeast. On Tues AM (9/29) fetch is to be fading from 35 kts over a large area aimed north with seas fading from 30 ft at 53S 173E aimed north. The gale to fade out from there. Something to monitor.

 

MJO/ENSO Forecast

 

Cold Water and La Nina Firmly In Control

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.

LONG-RANGE PACIFIC STORM AND SWELL GENERATION POTENTIAL FORECAST
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 (9/22) 5 day average winds were strong from the east over the Eastern equatorial Pacific continuing over the Central Pacific and strong from the east over the KWGA. Anomalies were weak east over the East equatorial building to modest east over the Central Pacific and then building in coverage moderate east 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 (9/23) moderate plus east anomalies were filling the KWGA today and extending east to a point south of California on the equator. The forecast calls for east anomalies holding at moderate to strong status filling the KWGA through the end of the model run on 9/30. Support for energy transfer into the jet is weak and is expected to continue that way if not weakening more for at least the next week.

Kelvin Wave Generation Area wind monitoring model: West and East

Longer Range MJO/WWB Projections:  
OLR Models: (9/22) A weak Active MJO signal was over the KWGA today. The statistic model indicates the Active MJO pattern is to hold at weak status on day 5 fading some on day 10 then gone on day 15. The dynamic model suggests the exact same thing.
Phase Diagrams 2 week forecast (ECMF and GEFS): (9/23) The statistical model depicts the Active Phase was weak over the Maritime Continent today and is to collapse while tracking east into the West Pacific and near nothing at day 15. The GEFS model suggests much the same but with the Active Phase at weak status on day 15 over the West Pacific.
40 day Upper Level Model (assumed to be a statistical mode and 1 week ahead of what is occurring at the surface): (9/22) This model depicts a weak Active MJO was over the Central Pacific today with a very weak Inactive Phase over the KWGA. The weak Active pattern is to push into Central America on 10/12 having only limited benefit to storm production. The Inactive Phase of the MJO is to push east with a stronger pulse following over the KWGA on 10/17 with the 2 joining forces filling the equatorial Pacific 10/22 then pushing east to the East Pacific at the end of the model run on 11/1.
4 Week CFS Model (850 mb wind): (9/22) This model depicts no coherent MJO signal today but with moderate east anomalies filling the KWGA and all of the equatorial Pacific. The forecast indicates no MJO is forecast for the future with east anomalies weakening some over the KWGA 9/27-10/6 with perhaps a pocket of west anomalies briefly appearing in that window. But by 10/6 east anomalies are to start rebuilding reaching strong status a few day later and holding through the end of the run on 10/20. Overall a long run of easterly anomalies remain forecast in the KWGA.
3 Month CFS Model (850 mb wind): (9/23 - using the 4th/latest ensemble member): This model depicts a weak Active Phase of the MJO starting to build over the KWGA today but with east anomalies from a previous Inactive Phase of the MJO still controlling the KWGA. The Active Phase is to weaken while pushing east and gone on 9/30 producing no west west anomalies. A weak Inactive MJO signal is forecast 10/7-10/27 with mostly weak to modest east filling the KWGA but with stronger east anomalies setting up east of the dateline filling the area of Ecuador. The Active Phase is to return in earnest on 10/27 coherently traversing the KWGA through 11/25 producing modest to moderate west anomalies filling the KWGA and those anomalies moving over the East Pacific but not overtaking east anomalies south of California to Ecuador on the equator. A weak Inactive Phase is to follow 11/18 tracking east through the end of the model run on 12/21 but with with weak to modest west anomalies holding in the KWGA but with strong east anomalies t holding over the East equatorial Pacific. The low pass filter indicates a high pressure bias is firmly in control over the dateline today with 2 contour lines reaching east to a point south of California and is to continue through the end of the model run while perhaps easing east some with the western edge of the high pressure bias slowly moving east through the period positioned at 170E at the end of the model run. A single contour low pressure bias is over the Indian Ocean today and is to build in coverage through the end of the model run with its eastern periphery easing east to 160E at the end of the model run. But its core is to show no signs of moving east locked over the Indian Ocean. East anomalies that have been previously solid in the Indian Ocean for over a year are migrating east through the West Pacific today and should continue tracking east then stabilizing setting up over the East Pacific late Sept and holding for the foreseeable future. The trend is turning towards La Nina. The good news is that at least at this early date, this might end up being a short lived event.

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

Subsurface Waters Temps
TAO Array: (9/23) Today in the far West Pacific the 30 deg isotherm was gone. The 29 deg isotherm was stable at 165E today. The 28 deg isotherm line was retrograding to 172W today. The 24 deg isotherm was stable at 133W today. Anomaly wise, warm anomalies +0-1 deg C were steady and perhaps trying to ease east some moving from the West Pacific 1to 153W at depth today. There was a large pocket of cooler anomalies at -3 degs filling the entire area east of there and bubbling up to the surface over that entire area. The hi-res GODAS animation posted 9/15 indicates the cool water bubble at depth was stronger and larger erupting to the surface from 160W eastward to Ecuador with a core to -4.5C but with cool anomalies even west to there to 170E. Warm anomalies were below the surface over the far West Pacific reaching east to 165W at depth (150m). The GODAS animation appears to be 1 week behind the TAO data but also is more detailed and accurately modeled.
Sea Level Anomalies: (9/15) Negative anomalies were forming a wave pushing west from the Galapagos to 160W with negative anomalies -5 to -15 cms. Negative anomalies were weak but still present along the coast of Peru up into Ecuador at -5 cms and then reaching north up to Baja and into Southern CA. No positive anomalies were over the equatorial Pacific, except from the dateline and points west of there.

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: (9/22) The latest images indicate cold anomalies were on the equator from Ecuador west to the dateline and solid in density over that entire and large area. Markedly cold anomalies were imbedded between the Galapagos to 135W. Cool anomalies were also holding along the coasts of Chile and Peru. This clearly indicates a well developed version of La Nina. Warm water was all but gone off Central America north of the equator. 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 (9/22): A warming trend was positioned on the equator from just west of Ecuador over the Galapagos and west to 120W, but then with a cooling trend from there to 160W.
Hi-res Overview: (9/22) A stream of consistent cool water is well entrenched from Chile up to Peru and Ecuador then tracking west on the equator out to the dateline. A clear La Nina signal is depicted.
Nino1.2 Daily CDAS Index Temps: (9/23) Today's temps were rising slightly to -1.571 degs after previously reaching a momentary low of -2.138 on 8/13. The trend has been steady but quite cold since June.
Nino 3.4 Daily CDAS Index Temps:
(9/21) Temps were steady today dropping to -0.945, the lowest so far in the La Nina event. The previous low was -0.733 on 9/10. Temps have been on a steady decline since 7/25. Before that temps were stable between 6/27-7/24 at near 0.0. And before that temps were rising after bottoming out down at -0.595 on 5/27. Overall the trend 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 (9/22) 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 stabilizing near neutral into late June. They began falling again in July down to -0.80 mid-Aug. The forecast depicts a steady downward trend from here reaching down to -1.75 degs in late Nov holding in early Dec then beginning to rise in later Dec, rebuilding up to +0.00 degs in May. We think the dynamic models might be overstating the magnitude of the coming cooling trend for the equatorial Pacific, but maybe not too much.
IRI Consensus Plume: The August 21, 2020 Plume depicts temps are at -0.52 degs today, and are to fall in early Nov to -0.60 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 modest 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 - this is a lagging indicator) (9/23): The daily index was positive today at 7.43. The 30 day average was steady today at +8.99. The 90 day average was rising to 6.58, suggesting a neutral ENSO pattern was in control and trending towards 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 

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External Reference Material: El Nino Southern Oscillation (ENSO), Madden Julian Oscillation (MJO), Pacific Decadal Oscillation (PDO), Southern Oscillation Index (SOI), Kelvin Wave


Powerlinessurf Jeff Clark Inside Mavericks

Local Interest

Stormsurf Video Surf Forecast for the week starting Sunday (9/20):
https://www.youtube.com/watch?v=h2T9NFUBAFs&feature=youtu.be&hd=1
For automatic notification of forecast updates, subscribe to the Stormsurf001 YouTube channel - just click the 'Subscribe' button below the video.

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NBC News - Climate Change and Surfing: https://www.nbcnews.com/mach/science/climate-change-good-surfing-other-sports-not-so-much-ncna1017131

Stormsurf and Mavericks on HBO Sports with Bryant Gumbel https://www.youtube.com/watch?v=luQSYf5sKjQ

Mavericks Invitational Pieces Featuring Stormsurf:
http://www.bloomberg.com/video/how-to-predict-the-best-surfing-waves-EsNiR~0xR5yXGOlOq2MqfA.html
http://www.cbsnews.com/videos/surfs-up-for-mavericks-invitational-in-calif/

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.

Surf Height-Swell Height Correlation Table

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