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Pacific Storm and Surf Forecast
Updated: Tuesday, December 15, 2020 6:18 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
4.0 - 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 12/14 thru Sun 12/20

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   

Continuous Gulf Swell Forecast
Southern Hemi to Pulse

On Tuesday, December 15, 2020 :

  • Buoy 233 (Pearl Harbor Entrance)/Buoy 239 (Lanai): Seas were 3.4 ft @ 7.7 secs with swell 2.5 ft @ 7.5 secs from 178 degrees.
  • Buoy 106 (Waimea): Seas were 7.2 ft @ 13.3 secs with swell 6.3 ft @ 12.9 secs from 325 degrees. Water temp 79.5 degs.
  • Buoy 46025 (Catalina RDG): Seas were 5.4 ft @ 11.4 secs with swell 2.9 ft @ 10.4 secs from 274 degrees. Wind at the buoy was northeast at 16-20 kts. Water temperature 60.3 degs. At Harvest Buoy (071) primary swell was 10.8 ft @ 15.1 secs from 310 degrees. At Santa Monica (028) swell was 2.1 ft @ 13.4 secs from 262 degrees. At Oceanside (045) swell was 1.8 ft @ 14.6 secs from 261 degrees. Southward at Point Loma (191) swell was 3.5 ft @ 13.6 secs from 276 degrees.
  • Buoy 46012 (Half Moon Bay)/029 (Pt Reyes): Seas were 10.1 ft @ 15.4 secs with swell 6.0 ft @ 14.5 ft from 304 degrees. Wind at the buoy (012) was northwest at 10-14 kts. Water temp 51.4 degs (013), 52.5 degs (SF Bar) and 53.2 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 Tuesday (12/15) in North and Central CA waves were 3-4 ft overhead and a bit lumpy, unorganized and washing around though winds were light early. Protected breaks were 1-2 ft overhead and clean and lined up but still a bit unorganized, likely due to king tide. At Santa Cruz surf was 1 ft overhead and clean but a bit lumpy and unorganized again due to tide. In Southern California/Ventura waves were head high and lined up and glassy and peeling and looking pretty good. Central Orange County had set waves at head high and lined up and clean but soft and playful. South Orange County's best summertime breaks had sets at waist high and clean and lined up but mostly weak. North San Diego had sets at 1-2 ft overhead and lined up and clean but a bit on the soft side. Hawaii's North Shore was still getting swell with waves 2 ft overhead and more at top breaks and lined up but a little warbled at exposed breaks. The South Shore was near flat and clean. The East Shore was getting some wrap around energy from the northwest with waves waist high and heavily warbled from modest east trades.

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

Meteorological Overview
On Tuesday (12/15) swell was fading but still hitting California from a gale that tracked through the Gulf of Alaska off North CA on Sat (12/12) with seas building to 36 ft then pushing 39 ft as it moved over the Northeastern Gulf on Sun (12/13). And swell is hitting Hawaii and bound for the US West Coast from another gale that tracked from north of Hawaii to the Northeastern Gulf Sun-Tues (12/15) with seas building to 47 ft aimed east. And another gale developed and lingered just off the Northern Kuril Islands Sun-Mon (12/14) producing 35 ft seas aimed east targeting primarily Hawaii. After that nothing obvious is forecast. A weak gale is to develop in the Gulf on Thurs-Fri (12/18) producing 35 ft seas aimed east. And another tiny gale is to be tracking east through the Central Gulf Fri- Sun (12/20) producing up to 38 ft seas aimed east. And a broader system is to be developing the Northwest Pacific Sun-Tues (12/22) producing 28-32 ft seas aimed east while pushing into the Northwestern Gulf and fading. Rideable swell is expected, but nothing over the top.

See all the details below...


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

North Pacific

On Tuesday (12/15) the jet was well consolidated pushing east off Japan over the dateline to the dateline with winds 180 kts solid then weakly splitting just over the dateline with most energy continuing east in the northern branch of the split heading towards the Pacific Northwest with a trough over the Central Gulf offering some support for gale development there. The southern branch of the split was pushing towards the equator. Over the next 72 hours no real change is forecast but with the split point easing east to a point north 1,000 nmiles north of Hawaii on Fri (12/18) with another weak trough tracking east through the Northern Gulf on Friday perhaps offering some support for gale development there as winds fade to 160 kts off Japan. Beyond 72 hours the jet is to be reinvigorated on Sat (12/19) as winds build to 210 kts off Japan pushing to the dateline on Sun (12/20) carving out a broad trough off the Kuril Islands with an inferred split point again developing north of Hawaii. The trough and split are to push east into Tues (12/22) with the split moving to 150W and the well defined trough over the dateline and still being fed by 190 kts winds. A fairly impressive jetstream pattern is forecast 180 hours out.

Surface Analysis
On Tuesday (12/15) swell from the first in a pair of Eastern Gulf Gales was fading in California (see First Eastern Gulf Gale below). And swell from a gale previously over the North Dateline region was fading in Hawaii (see North Dateline Gale below). And another Eastern Gulf Gale was producing swell pushing east right behind targeting California (See Second Eastern Gulf Gale below). And one more gale previously tracked off the Kuril Islands producing swell targeting Hawaii (see Kuril Gale below).

Over the next 72 hours a small gale is forecast developing over the Central Gulf of Alaska on Thurs AM (12/17) producing 40 kts west winds and seas building from 26 ft at 42.5N 162W aimed east targeting the US West Coast. In the evening the gale is to track east with winds building to 50 kts and seas 34 ft at 45.5N 151.5W aimed east focused on the Pacific Northwest. On Fri AM the gale is to lift northeast off British Columbia with 45 kt west winds ands seas 34 ft at 48N 141W (310 degs NCal) aimed east. The gale is to be moving inland in the evening. Small swell is possible for the US West Coast.

Also on Fri AM (12/18) another tiny gale is to start building in the far Western Gulf of Alaska with 55 kt west winds and seas building from 30 ft at 43N 175W aimed east. In the evening the gale is to track east with 50-55 kt west winds and seas 39 ft at 43.5N 164W aimed east. On Sat AM (12/19) the gael is to be tracking east through the Central Gulf with 40 kts west winds and seas 32 ft at 43.5N 155W aimed east. In the evening the gale is to be poised off the Pacific Northwest coast with 40 kt west winds and seas 32 ft at 46.5N 142.5W aimed east. This system to fade after that. Modest swell for the US West Coast possible.


First Eastern Gulf Gale
A gale started developing Fri AM (12/11) 900 nmiles north of Hawaii with a small area of 45 kt west winds and seas building from 18 ft at 35N 159W aimed east. In the evening a small fetch of 55 kt west winds was pushing east-northeast with seas building to 29 ft at 38N 150.5W aimed east. On Sat AM (12/12) fetch was lifting northeast off the North CA coast with northwest winds 45-50 kts and seas 36 ft at 40N 143W aimed east. In the evening the gale stalled forward motion and eased north some with 45-50 kt west-northwest winds and seas building to 39 ft at 45N 140.5W aimed east. Fetch eased north some Sun AM (12/13) off the Pacific Northwest with 45 kt west winds and seas 39 ft at 49.5N 140W aimed east. Fetch was fading while lifting north in the evening with 40 kt west winds and seas fading from 28 ft up at 52N 140W aimed east. The gale dissipated from there.

North CA: Swell fading on Tues (12/15) fading from 8.1 ft @ 14 secs (11 ft). Swell Direction: 280-290 degrees initially moving to 310+ degrees


Weak North Dateline Gale
On Wed AM (12/9) a small gale was developing over the North Dateline region producing 30-35 kt northwest winds and seas building from 18 ft at 44N 171E aimed southeast. In the evening northwest winds were building at 40-45 kts just west of the dateline and over a small area aimed southeast with seas 25 ft at 47N 174E aimed southeast. On Thurs AM (12/10) fetch was lifting north slightly at 35-40 kts from the west with seas 27 ft south of the Central Aleutians at 47N 175E aimed southeast. This system held position in the evening with 35 kt northwest winds and seas 26 ft at 47N 176E aimed southeast. More of the same occurred Fri AM (12/11) with 30-35 kt northwest winds steady and seas 25 ft at 47N 179E aimed southeast. Winds weakened in the evening to 30 kts with 22 ft seas at 49N 179E aimed southeast. The gale was gone on Sat AM (12/12). Small northerly angled swell is possible for Hawaii and even less for the US West Coast.

Hawaii: Swell fading on Tues (12/15) from 4.2 ft @ 12-13 secs (5.0 ft). Swell dissipating later in the day. Swell Direction: 325-330 degrees


Second Eastern Gulf Gale
Another tiny gale developed 950 nmiles north of Hawaii on Sun AM (12/13) with 45 kt west winds and seas building from 30 ft at 35.5N 165W aimed east. The gale tracked east-northeast in the evening with 40 kts west winds over a small area and seas 30 ft at 37.5N 158.5W aimed east. The gale pushed northeast Mon AM (12/14) while building with 55 kt northwest winds and seas 39 ft over a building area at 43.5N 150W aimed east. In the evening winds faded to 50 solid while the gale lifted northeast with seas building to 47 ft at 46.5N 141.5W aimed east. The gale was pushing up to British Columbia Tues AM (12/15) with 40 kt west winds and seas fading from 42 ft just off North Vancouver Island at 49N 138W and north of the CA swell window. More solid but local swell to result primarily for California and the Pacific Northwest. Something to monitor.

Hawaii: Sideband swell arrived on Tues (12/15) holding at 4.7 ft @ 12-13 secs(5.5 ft). Swell fading on Wed (12/16) from 3.4 ft @ 11-12 secs (3.5 ft). Swell Direction: 325-330 degrees

North CA: Expect swell arrival on Wed (12/16) before sunrise peaking at sunrise at 11.6 ft @ 17 secs (19-20 ft) then fading some through the day. Swell fading on Thurs (12/17) from 6.5 ft @ 13 secs (8.5 ft). residuals on Fri (12/18) fading from 7.5 ft @ 12 secs (8.5 ft). Swell Direction 280-298 degrees with most energy north of there at 300-312 degrees and shadowed in the SF Bay Area

Southern CA: Expect swell arrival on Wed (12/16) building through the day to 4.2 ft @ 16 secs at the most exposed breaks (6.5 ft). Swell fading on Thurs (12/17) from 3.9 ft @ 15 secs (5.5 ft) and gone by sunset. Swell Direction: 286-304 degrees with most energy even north of that.


Kuril Gale
On Sun AM (12/13) a gale developed off the Kuril Islands producing 45+ kt northwest winds and seas building from 28 ft at 41N 164E aimed east. In the evening 40-45 kt west winds were holding position with an expanding area of 34 ft seas building at 45N 168E aimed east. Fetch lifted north and was fading Mon AM (12/14) from 30-40 kts with seas fading from 32 ft at 48.5N 168E aimed east. The gael fading from there. Some swell for Hawaii.

Hawaii: Expect swell arrival on Thurs (12/17) pushing 5.0 ft @ 15 secs (7.5 ft) late AM. Another pulse expected Fri AM (12/18) at 4.8 ft @ 15 secs early (7.0 ft) fading through the day. Residuals on Sat (12/19) fading from 4.1 ft @ 13-14 secs (5.5 ft). Swell Direction: 315-325 degrees.


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


Tropical Update
No tropical weather system of interest were being monitored.

California Nearshore Forecast
On Tues (12/15) light north winds are forecast for North CA early and north 10-15 kts for Central CA early turning south at 10 kts for Cape Mendocino after sunset and holding north 10 kts from Pt Reyes to Monterey Bay and north 10-15 kts south of there to Pt Conception. Light rain for Pt Arena and point north of there fading overnight. Wed (10/16) south winds are forecast building through the day for North CA to 30 kts for Cape Mendocino late and 5 kts at the Golden Gate with light northwest winds 5 kts for Central CA all day. Rain developing over all of North CA in the evening. Thurs (12/17) northwest winds are forecast at 15-20 kts all day for North CA and northwest 10-15 kts for Central CA early building to 20 kts later. Rain for all of North and Central CA early fading at sunset. Snow developing before sunrise for Tahoe down to Yosemite and holding while pushing further south through the day then fading at sunset. On Fri (12/18) northwest winds are forecast at 10-15 kts early for North CA and Central CA early holding at 15 kts steady through the day but fading to 5-10 kts for Cape Mendocino later. No precip forecast. Sat (12/19) light winds are forecast for North CA maybe trending southerly for Cape Mendocino late. Northwest winds are forecast for all of Central CA at 15 kts early fading to 10 kts later. On Sun (12/20) weak high pressure is to hold over CA with light winds for North CA early and north winds 10-15 kts early holding through the day. On Mon (12/21) light winds are forecast over all of North and Central CA maybe pushing 10 kts near Monterey Bay early fading to 5 kts later. Tues (12/22) light north winds are forecast at 5-10 kts early pushing 15 kts south of Monterey bay to Pt Conception later. South winds building to 15 kts for Cape Mendocino later. Light rain for Cape Mendocino late.

Total snow accumulation for the week for Squaw Valley, Sugar Bowl, Kirkwood and Mammoth at 8 inches, 12 inches, 8 inches, and 4 inches respectively.

Freezing level mostly 10,000 ft for the next 7 days except falling to 4000 ft on 12/17.

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


South Pacific

Surface Analysis
On Saturday (12/5) no swell was in the water and no swell producing weather systems were occurring. But a small storm did produce some seas of interest (See New Zealand storm below)

Over the next 72 hours no swell producing weather systems are 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 starting Sun AM (12/20) a broad gale is forecast developing mid-way between Japan and the dateline producing 40-45 kt west winds over a fragmented area and seas 28 ft at 41N 165E aimed east. In the evening the gale is to push east with 35-40 kt west winds and seas 30 ft at 43N 175E over a building area. The gale is to stall Mon AM (12/21) with 30-35 kt west winds and seas 29 ft at 42N 176E aimed east. More of the same in the evening with seas fading from 24-30 ft at 40N-47N 175W aimed east. the gael to fade from there. Something to monitor.


South Pacific

Beyond 72 hours a gale is unbelievably developing under New Zealand on Tues AM (12/15) with 35-40 kt southwest winds and seas building. In the evening a solid fetch of 45 kts southwest winds are forecast with seas building to 33 ft at 59S 173E aimed northeast. On Wed AM (12/16) the gael is to be lifting northeast with 45-50 kts southwest winds and seas building to 42 ft at 58S 177W aimed east-northeast. In the evening the gale is to be fading with 35-40 kts southwest winds and seas fading from 39 ft at 55S 168W aimed northeast. The gale to fade from there. Will monitor.



MJO/ENSO Forecast


La Nina Neither Building Nor Fading

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 (12/14) 5 day average winds were strong from the east over the Eastern equatorial Pacific continuing over the Central Pacific and again strong from the east over the East KWGA fading and turning strong westerly in the Southwest KWGA. Anomalies were neutral over the East equatorial Pacific continuing neutral over the Central Pacific and moderate to strong easterly over the East KWGA fading to neutral and turning westerly in the West 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 (12/15) moderate east anomalies were filling the KWGA and reaching east to a point south of California. The forecast calls for moderate plus strength east anomalies filling in more coherently over the KWGA over the next 5 days and solid filling the KWGA through the end of the model run on 12/22. East anomalies are to hold over the East Pacific on the equator and if anything building in more coherently east to a point south of California.

Kelvin Wave Generation Area wind monitoring model: West and East

Longer Range MJO/WWB Projections:  
OLR Models: (12/14) the Active Phase of the MJO is present over the West KWGA today. The statistic model projects it building in coverage while easing east and holding at modest strength through the end of the model run on day 15. The dynamic model suggests the same thing.
Phase Diagrams 2 week forecast (ECMF and GEFS): (12/15) The statistical model depicts the Active Phase was weak over the East Maritime Continent today and is to track east to the West Pacific and getting steadily weaker and non-existent on day 15. The GEFS model suggests the Active Phase is to track to the West Pacific while generally holding strength except for a dip in strength at day 7.
40 day Upper Level Model (assumed to be a statistical mode and 1 week ahead of what is occurring at the surface): (12/6) No Update. This model depicts a weak Active Phase (wet air) over the East Pacific tracking east while fading pushing into Central America on 12/21. A modest Inactive Phase was over the West Pacific and is to push east and into the Central America on 1/5. A weak Active Phase is to push into the West Pacific on 1/10 easing east at the end of the model run on 1/15. .
4 Week CFS Model (850 mb wind): (12/14) This model depicts no MJO signal over the KWGA today with mostly moderate east anomalies over the core of the KWGA. The forecast indicates weak to modest east anomalies are start taking better hold over the KWGA through 12/21, then building to moderate strength through 12/28, then building to strong status and holding through the end of the model run on 1/11. The low pass filters coverage of high pressure over the KWGA is to be holding steady through the end of the model run.
3 Month CFS Model (850 mb wind): (12/15 - using the 4th/latest ensemble member): This model depicts the Inactive Phase of the MJO was all but gone from the KWGA today with neutral to weak east anomalies in control. The Inactive Phase is to push east and out of the KWGA by 12/16 with mostly weak east anomalies holding in the KWGA. A weak Active Phase was starting to push into the Western KWGA today and is to track east through 1/12 producing weak west anomalies in the KWGA. A strong Inactive MJO is to return 1/13 holding to 2/8 with strong east anomalies in the KWGA and filling the East Pacific again. A strong Active Phase is to return 1/24 holding through 2.27 with very modest west anomalies filling the KWGA and strong west anomalies in the far West KWGA. This is an upgrade. 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 with it's western periphery easing east to 160E at the end of the model run. A third contour line is to appear on 12/15 with a fourth on 1/17 holding through the end of the model run. A single contour low pressure bias is over the Indian Ocean today and is to build in coverage holding through the end of the model run and its eastern periphery easing east to 150E at the end of the model run. East anomalies that have been previously solid in the Indian Ocean for over a year previous migrated east through the West Pacific to the East Pacific on 10/1 and then stabilized there. For now the trend is towards a building La Nina.

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

Subsurface Waters Temps
TAO Array: (12/15) Today in the far West Pacific the 30 deg isotherm was gone. The 29 deg isotherm was building slightly to 163E today. The 28 deg isotherm line has rebuilding from 170E to 175E today. The 24 deg isotherm was steady at 140W today. Anomaly wise, warm anomalies +2 deg C were locked steady in the West Pacific pushing east to 160W at depth and moving no further east. A broad cooling pattern was controlling the entire equatorial Pacific with anomalies -3 degs C in the far East, but otherwise temps generally -1 deg C over the entire equatorial Pacific at depth. The hi-res GODAS animation posted 12/9 indicates a strong cool pattern over the East Pacific at depth but with warming easing east to 150W. The GODAS animation appears to be 1 week behind the TAO data but also is more detailed and accurately modeled.
Sea Level Anomalies: (12/9) Negative anomalies were forming a wave pushing west from the Galapagos to 180W peaking at barely -15 cms at 110W and -10 cms solid from Ecuador to 155W. Negative anomalies were -10 cms along the coast of Peru up into Ecuador and then -5 cms reaching north up to Baja and into South and North CA. Looking at the big picture, negative anomalies were forming a massive triangle from Cape Mendocino south to Southern Chile and west out to the intersection of the dateline and the equator. 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: (12/14) 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. Colder anomalies were barely imbedded in that flow in places but no longer distinct. And the overall cool pool does not look as cold as weeks and months past. Cool anomalies were also holding along the coasts of Chile and Peru. This clearly indicates a well developed version of La Nina filling the entire equatorial Pacific and down into Chile. But the overall cool intensity of that pool appears to have stabilized if not losing some of its intensity. Perhaps we are past the peak of this event.
Hi-res 7 day Trend (12/14): Temps were still warming along Chile and Peru reaching west to the dateline but again not a solidly as days past. A small cooling stream was present over the Galapagos out to near 110W with a 2 tiny pockets of cooling west of there. No whole scale warming pattern was depicted, but neither was significant cooling occurring.
Hi-res Overview: (12/14) 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 and west to New Guinea. But the trail of markedly cool anomalies previously imbedded in that flow is gone. Perhaps the peak of La Nina has been reached.
Nino1.2 Daily CDAS Index Temps: (12/15) Today's temps were falling to -0.748on after previously rising to a peak of -0.595 on 12/11. This area has been on a seesaw rising trend since early October. Temps were previously down to -2.138 on 8/13. The longterm trend has been steady but quite cold since June.
Nino 3.4 Daily CDAS Index Temps:
(12/15) Temps were gently rising to -1.028 today after bottoming out at -1.654 on 11/3, beating the previous low of -0.945 on 9/22. The previous low before that was -0.733 on 9/10. Temps have been on a steady decline since 7/25. 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 (12/12) Today the model indicates temps at -1.15 degs. The forecast depicts temps holding at -1.15 degs to mid-Jan then beginning to rise, rebuilding up to -0.50 degs mid-June and stabilizing there (still in minimal La Nina territory). This is becoming a 2 year event in that even if temps were to return to 0/normal it would take 3-5 months for the upper level circulation to respond in kind.
IRI Consensus Plume: The Oct 21, 2020 Plume depicts temps are at -1.10 degs today, and are to hold into Dec, then moderating and starting to rise some to -0.89 by Jan 2021 and then neutral by June. Most models are suggesting a moderate to La Nina returning to Neutral in the late Spring. 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) (12/15): The daily index was up some at +19.88. The 30 day average was rising at +11.09. The 90 day average was rising some at 8.73. 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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