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Pacific Storm and Surf Forecast
Updated: Friday, August 18, 2023 2:15 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
2.5 - California & 2.1 - 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 8/14 thru Sun 8/20
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   

First SE Pacific Swell Hitting CA
Second Behind It - All Eyes on Hurricane Hilary

Friday, August 18, 2023 :

  • Buoy 238 (Barbers Pt)/Buoy 239 (Lani): Seas were 3.5 ft @ 9.1 secs with swell 2.7 ft @ 9.5 secs from 200 degrees. Water temp 80.1 degs (Barbers Pt), 80.2 (Pearl Harbor 233), 80.1 (Lani 239).
  • Buoy 106 (Waimea)/Buoy 202 (Hanalei): Seas were 3.4 ft @ 11.8 secs with swell 1.9 ft @ 11.4 secs from 309 degrees. Water temp 79.5 degs
  • Buoy 46025 (Catalina RDG): Seas were 2.6 ft @ 12.0 secs with swell 1.2 ft @ 13.6 secs from 201 degrees. Wind northwest at 0-2 kts. Water temperature 68.2 degs, 69.1 (Topanga 103), 63.9 degs (Long Beach 215), 66.6 (Oceanside Offshore 045), 64.6 (Del Mar 153), 67.3 (Torrey Pines Outer 100). At Harvest Buoy (071) primary swell was 1.9 ft @ 14.7 secs from 205 degrees. At E. Santa Barbara (46053) swell was 0.8 ft @ 10.1 secs from 275 degrees. At Santa Monica (028) swell was 1.3 ft @ 13.7 secs from 202 degrees. At Oceanside (045) swell was 1.9 ft @ 13.8 secs from 196 degrees. Southward at Pt Loma (191) swell was 2.0 ft @ 13.8 secs from 186 degrees. Water temperature was NA degrees.
  • Buoy 46012 (Half Moon Bay) Out of Service /029 (Pt Reyes): Seas were 4.6 ft @ 9.1 secs with swell 3.4 ft @ 8.6 secs from 313 degrees with southern hemi swell 1.7 ft @ 13.5 secs from 196 degrees. Wind east-southeast at 2-4 kts (46026). Water temp NA (Bodega Bay 46013), 61.5 degs (Pt Reyes 029), 59.7 (San Francisco 46026), 60.4 (SF Bar 142), 63.5 (Pt Santa Cruz 254) and 61.7 (Monterey Bay 46042).

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 Friday (8/18) North and Central CA waves were thigh to waist high and somewhat lined up but warbled from south wind. Protected breaks were thigh high and clean and soft. At Santa Cruz surf was waist high on the sets and lined up and clean with decent form but soft. In Southern California/Ventura waves were thigh to waist high and lined up if not closed out but clean with some warble intermixed. Central Orange County had occasional sets at thigh to waist high and lined up coming from the south but soft and breaking just off the beach. South Orange County's best summertime breaks had sets at chest to shoulder high and lined up with decent form but warbled from a modest northwest wind. North San Diego had sets at waist to near chest high and lined up and cleaner but soft and a bit closed out. Oahu's North Shore had some waist high plus sets with some form and clean and soft but lined up. The South Shore had a few sets at thigh high and clean. The East Shore was getting no rideable surf and lightly chopped from easterly trades.

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

Meteorological Overview
On Friday (8/18) small southern hemi swell was hitting California originating from a small gale that developed on the eastern edge of the CA swell window on Thurs (8/10) producing 25 ft seas over a small area aimed north. And another gale developed in the upper reaches of the Southeast Pacific on Mon-Tues (8/15) producing 25-26 ft seas aimed north. And yet a third gale developed on the southern edge of the California swell window Tues PM (8/15) into Wed AM producing 27 ft seas aimed east-northeast. So a strong of tiny southern hemi swells are forecast. But after that the southern hemi goes quiet. And up north nothing is happening yet. Hurricane Hilary is developing while tracking north up along the Baja Coast forecast to impact North Baja offering a small window for swell into exposed breaks in Southern CA. Otherwise we continue monitoring the development of El Nino.

See all the details below...


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

North Pacific

Surface Analysis
On Friday (8/18) no swell was in the water and none was forecast to be generated.

Over the next 72 hours no swell production is forecast.


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


Tropical Update
Hurricane Hilary on Fri AM
(8/18) was located 300 nmiles south-southwest of Cabo San Lucas Mexico with winds 125 kts (144 mph) tracking north-northwest at 9 kts and in the Dana Point swell window (30 nmiles of exposed fetch on the storms east quadrant) 1300 nmiles away on the 160 degree track up to Malibu/Long Beach (154 degs) with 60 nmiles of exposed fetch but shadowed north of Malibu by the Channel Islands. Seas estimated at 50 ft. Hilary is to peak in the evening with winds 130 kts (150 mph) slowly making a track more to the north and 900 nmiles out and still in the Dana Point/Long Beach swell window at 160 & 154 degrees respectively. By Sat PM (8/19) Hilary is to become shadowed by Baja (Natividad and Isla Cedros) with winds 100 kts (115 mph) turning almost due north. Swell production is to be done after that relative to exposed breaks in Southern CA . Beyond Hilary is to continue on a near north track while fading with winds down to minimal hurricane status (65kts - 75 mph) Sun PM (8/20) and poised to move onshore near Ensanada Mexico then tracking just inland of San Diego late Sunday night and well inland over the South Central Valley Monday AM. Relative to California the main concern is heavy rain mostly east of the storms center in Southern CA and the High Sierra in the Sun- Mon (8/21) timeframe.

Southern CA: Expect swell arrival on starting Sunday afternoon (8/20) building to 3.4 ft @ 15-16 secs later (5.0 ft). Residuals on Mon AM (8/21) fading from 3.6 ft @ 9-10 secs (3.5 ft). Swell Direction 154-160 degrees.

California Nearshore Forecast

  • Sat AM (8/19) the pressure gradient returns with northwest winds 20-25 kts over Cape Mendocino but with calm winds from Bodega Bay southward. In the afternoon northwest winds are to hold at 20-25 kts for Cape Mendocino but with northwest winds 5 kts for the rest of North and all of Central CA. Windswell building some. Light winds for Southern CA. Rain possible for Southern CA in the afternoon as Hilary approaches from the south.
  • Sun AM (8/20) northwest winds fade from 20-25 kts well west of Cape Mendocino but with a weak eddy flow (south winds) for most of North CA and all of Central CA early. Northeast winds 5-10 kts early for Southern CA from Long Beach southward. In the afternoon northwest winds build to 15 kts for all of North and Central CA with northeast winds building from 13-17 kts for Southern CA as Hilary approaches. Northeast winds 15 kts for Dana Point southward around 11 PM. Rain possible all day for Southern CA building into the late afternoon and early evening. Heavy rain from Pt Conception southward around 11 PM with light rain building north of Monterey Bay and over the Sierra to a point south of Tahoe.
  • Mon AM (8/21) Hilary is to be well inland with northwest winds 30 kts for Cape Mendocino (local gradient) but some flavor of southerly winds 5-10 kts for the rest of North and Central CA and southwest winds 10-15 kts Southern CA. In the afternoon northwest winds to be 10 kts for Cape Mendocino and a south flow at 5 kts for the rest of North and Central CA. Light winds for Southern CA. Windswell fading north of Pt Conception. Rain for Southern and Central CA north to Monterey Bay early and covering the Sierra early then fading in the afternoon. Maybe light showers for the San Francisco area in the evening.
  • Tues AM (8/22) a weak pressure and wind pattern is forecast with south winds 5 kts or less early for North and Central CA early. In the afternoon no change is forecast. No rain forecast.
  • Wed AM (8/23) northwest winds to be 10 ks for Cape Mendocino and northwest 5 kts for the rest of North and Central CA early. In the afternoon no change is forecast.
  • Thurs AM (8/24) northwest winds to be 10 kts for Cape Mendocino and 5 kts from the northwest for North and Central CA early. In the afternoon northwest winds to be 10 kts for all of California.
  • Fri AM (8/25) northwest winds to be 5-10 kts for all of California early. Northwest winds building to 15 kts in the afternoon around Pt Conception.

Total snow accumulation for the next 10 days respectively for Squaw Valley, Sugar Bowl, Kirkwood and Mammoth are projected at 0, 0, 0, and 0 inches.

Temperatures for the Pacific Crest Trail and Tioga Pass Road intersection (8,700 ft): 55 degrees but dropping to 45 degrees Mon-Tues (8/22) then back to 45-55 degrees beyond.

- - -

Tioga Pass/Pacific Crest Trail intersection forecast: Temps - Freeze Level
More locations here (scroll down to 'Resort Snow Forecasts>Central CA or North CA Caltrans & Backcountry')

Snow Models: (Scroll down for Resort specific forecasts).


South Pacific

On Friday (8/18) the jet was extremely split over the width of the South Pacific with the influential southern branch running due east down on the 70S latitude line over the Ross Ice Shelf and heading east from there with no troughs indicated. The northern branch was running east on the 30S latitude line with winds to 150 kts in pockets with no troughs offering no support for gale development. Over the next 72 hours more of the same is forecast with a strong ridge pushing south in the southern branch of the jet on Wed (8/23) continuing to reinforce the split pattern offering nothing and getting reinforced yet again on Fri (8/25).

Surface Analysis
On Friday (8/18) small swell from a gale previously in the upper reaches of the Southeast Pacific was starting to show in Southern CA (see Southeast Pacific Gale below).

Over the next 72 hours no swell producing weather systems are forecast. Swell from another gale previously in the Southeast Pacific is to be radiating northeast (see Another Southeast Pacific Gale below).

Also another gale previously developed below it but no swell is expected to result (see Deep Southeast Pacific Gale below).


Southeast Pacific Gale
On Wed PM (8/9) a small gale tried to start building in the upper reaches of the Southeast Pacific producing 35-40 kts south winds and seas building from 22 ft at 40S 129W aimed north. On Thurs AM (8/10) 40 kts south winds were in play with seas 24-25 ft at 42S 130W aimed north. Fetch faded in the evening from 30 kts over a broad area aimed north with seas fading from 23 ft at 38S 130W aimed north. Limited swell is tracking north.

Southern CA: Expect swell arrival on Fri (8/18) building to 2.1 ft @ 15 secs (3.0 ft) late AM. Swell fading Sat AM (8/19) from 2.0 ft @ 13-14 secs early (2.5 ft). Swell Direction: 196 degrees

North CA: Expect swell arrival on Fri (8/18) building to 2.0 ft @ 15 secs (3.0 ft) late. Swell Fading Sat AM (8/19) from 2.0 ft @ 14 secs early (2.5-3.0 ft). Swell Direction: 195 degrees


Another Southeast Pacific Gale
On Mon AM (8/14) a gale developed in the upper reaches of the Central South Pacific producing a small area of south winds at 30-35 kts aimed north. Seas building. In the evening south winds continued almost stationary at 35-40 kts aimed north with seas 23 ft developing at 37S 143W aimed north. On Tues AM (8/15) south winds were easing east at 30-35 kts with seas 26 ft at 34.25S 139.25W. Fetch was fading in the evening from 30 kts from the south with seas 23 ft at 32S 133W aimed mostly east at Chile. A quick fade followed. Possible small swell to develop radiating north towards California.

Southern CA: Expect swell arrival on Tues AM (8/22) building to 1.6 ft @ 15-16 secs later (2.0-2.5 ft). Swell building Wed (8/23) at 2.0 ft @ 14 secs (2.5-3.0 ft). Swell fading on Thurs (8/24) from 1.9 ft @ 13 secs early (2.5 ft). Dribbles on Thurs (8/25) fading from 1.7 ft @ 12-13 secs (2.0 ft). Swell Direction: 198 degrees

North CA: Expect swell arrival on Tues AM (8/22) building to 1.5 ft @ 15 secs later (2.0-2.5 ft). Swell building Wed (8/23) to 2.0 ft @ 14 secs (2.5-3.0 ft). Swell fading on Thurs (8/24) from 2.0 ft @ 13 secs early (2.5 ft). Dribbles on Thurs (8/25) fading from 1.6 ft @ 13 secs (2.0 ft). Swell Direction: 197 degrees


Deep Southeast Pacific Gale
A gale started to develop Tues PM (8/15) just off Antarctic Ice over the Southeast Pacific and south of another gale producing 45 kt southwest winds with seas 25 ft at 63.75S 137W aimed east-northeast. Fetch was fading on Wed AM (8/16) from 35-40 kts with seas 27 ft at 61S 124W aimed east-northeast. Fetch dissipating down to 30 kts in the evening with seas fading from 24 ft at 62S 119W aimed east-northeast. Doubtful any swell will radiate north into our forecast area.


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 weather systems of interest are forecast.


South Pacific

Beyond 72 hours there is some remote hope for a gale developing in the deep Southeast Pacific on Fri (8/25) producing 29 ft seas at 57S 131W aimed northeast. Will monitor. Otherwise no swell producing weather systems of interest are forecast.


MJO/ENSO Forecast


El Nino Moving Forward Steadily Now
Kelvin Waves #3, #4 and #5 Erupting - NINO3.4 SSTs well in El Nino Territory and Slowly Rising
1 Kelvin Wave traversed the Pacific in Dec '22 with a 2nd in Jan-Feb and a 3rd and 4th in March-April and a 5th in May. But after the last Active MJO in mid-to-late May, the MJO stalled, until Possibly restarting in Aug. Sea Surface Temperatures in the east are very warm and holding, but not expanding. The atmosphere is showing only the weakest signs of being coupled with the ocean mainly in ORL and surface currents. Fortunately, another Active MJO is getting limited traction (8/1) and seems to be creating one last Kelvin Wave that will help push the atmosphere towards El Nino.

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: In 2019 warm equatorial waters were 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. A bit of a recovery tried to occur during Fall of 2019, with weak warm water building in the Nino 1.2 region, but cool water held in a pool off Peru. By April 2020 a cool pool was starting to build, forming a well defined cool tongue that evolved into La Nina, with it fully developing through July 2020. That pattern continued until late Fall 2022 when trades started fading and by early 2023 multiple Kelvin Waves were in flight with significant warming developing over the East Equatorial Pacific. La Nina was dead on 3/18/2023 with El Nino apparently developing. But it was not coupled with the atmosphere as of 7/20/2023.

Summer 2023 = 3.7 (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: A 3 year La Nina started fading in Jan 2023 and was gone by April. 3 Active MJO's produced 3 Kelvin Waves with the 3rd in that series poised to start erupting off Ecuador now (May 2023). The CFS model is predicting steady west anomalies from here forward and the leading edge of the low pressure bias on the dateline and forecast to nearly fill the Pacific during June. We are in a state of transition from ENSO neutral to El Nino during the summer of 2023. As a result we will be moving from a period of reduced number of storm days and storm intensity during the early part of Summer towards a period of enhanced storm production starting Late July and beyond, getting fairly intense come Fall. This should result in a slightly below normal level of swells, with swells being below normal duration and period over early Summer. But by late July 2023, the number of storm days, intensity and duration of those storms should start improving as El Nino starts getting a solid footprint on the atmosphere. The net result is we're currently thinking a near normal number of swells with normal size and duration is to result, but all focused sometime after late July 2023. The swell pattern will be normal to somewhat below normal before July and above normal after July 23. And By Sept, the El Nino footprint should be solid. Of course this is all highly speculative at this early and based mostly on the CFS model and it's projection of a building ENSO footprint getting solid by Sept.

KWGA/Equatorial Surface Wind Analysis (KWGA - Kelvin Wave Generation Area - The area 5 degrees north and south of the equator from 170W to 135E)
Analysis (TAO Buoys): As of (8/17) 5 day average winds were strong from the east over the East equatorial Pacific and moderately strong east over the Central Pacific and light west over the KWGA with the dividing line at 170E. Anomalies were neutral over the East equatorial Pacific and neutral to west over the Central Pacific and light west over the KWGA. (Note: These are 5 day average winds, versus realtime, so they lag what is happening today (by about 2.5 days).
2 Week Forecast (GFS Model): (8/18) Light west anomalies were over the West KWGA today with east anomalies building solidly over the dateline. The forecast indicates east anomalies taking over modest to moderate strength 8/19-8/25 with no west anomalies of interest. Starting 8/26 weak west anomalies are to return a modest strength filling the KWGA holding through the end of the model run on 9/3. The GEFS depicts west anomalies returning weaker. The ECMWF shows west anomalies returning decently by 8/24 So perhaps a small burst of easterly anomalies are possible for 6-7 days starting now then back to westerly anomalies.

Kelvin Wave Generation Area wind monitoring model: West and East

MJO/WWB/Wind Projections:  
OLR Models: (8/17) A neutral to weak Inactive MJO was over the KWGA. The statistic model indicates no change through day 15 of the model run. The dynamic model depicts the same but with the Inactive MJO slightly stronger.
Phase Diagrams - 2 week forecast (CA and GEFS): (8/16) The statistical model depicts the Active signal was weak over the Atlantic and is to track east to the Central Indian Ocean and very weak 15 days out. The dynamic model indicates the same thing.
40 day Upper Level Model (assumed to be a statistical mode and 1 week ahead of what is occurring at the surface): (8/18) A weak Active (wet) pattern was barely present over the West Pacific today. The forecast has the Active Phase (wet air) gone with remnants over the for East Pacific 8/23 then gone by 9/2 while a new modest Inactive Phase (dry air) starts develop over the far West KWGA on 8/28 tracking slowly east and not east of the KWGA until 9/22 moving to the East Pacific at the end of the model run on 9/27. A weak Active signal (wet air) is to be moving over the west KWGA 9/22 building through the end of the model run.
4 Week CFS Model (850 mb wind): (8/17)
Today the Active MJO was depicted over the far East Pacific with moderate to strong west anomalies there but a mix of east and west anomalies over KWGA. A small Westerly Wind Burst occurred started 7/14 and is continuing to this date. The forecast indicates west anomalies gone on 8/19 as an equatorial Rossby Wave produces east anomalies through 8/25. After that moderate to strong west anomalies are forecast filling the KWGA starting on the dateline 8/24 then filling the KWGA 8/29 and beyond through the end of the model run on 9/14.
3 Month CFS Model (850 mb wind):
(8/18) - using the 5th ensemble member - the mean of the 4 individual members which are all from the 00Z run - 1 run per day):
Today the Inactive Phase was building over the KWGA but with weak west anomalies still in play filling the KWGA. The forecast has a weak Inactive Phase passing over the KWGA through 8/15 with west anomalies fading some mainly in the west KWGA 8/20-8/29 with weak east anomalies in control then. But west anomalies are to hold on the dateline through the period and start building in coverage 8/29. After that the Active Phase returns on 9/12 holding through 10/21 with strong west anatomies taking over the KWGA 9/13-10/15. Weaker but still sold west anomalies to hold through the end of the model run on 11/15. Outgoing Longwave Radiation (OLR) suggests cloud activity took over the KWGA on 6/24 and is holding if not building starting 8/15 and solid moving forward. If anything clear skies started building over the Maritime Continent 7/16 and are forecast building from here forward. The low pass filter indicates a broad low pressure bias is established over the KWGA centered at 175E with 3 contour lines (starting 7/14) and it's leading edge well east of the dateline at 135W today (it started pushing east on 2/15). The primarily contours leading edge is to slowly ease east to 122W (Up to the California coast) at the end of the model run with it's center easing east to 178E and a 4th contour line developing briefly around 9/27. The high pressure bias was south of California at 120W and is to dissipate on 10/15. 7/18 was the start of a major positive change in the development of El Nino with a advent of the Active Phase of the MJO and west anomalies. It appears a borderline strong El Nino is developing.

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

Subsurface Waters Temps
TAO Array: (8/18) Today in the far West Pacific the leading edge of the 30 deg isotherm steady at 171W (previously 175W). The 29 degree isotherm was steady at 157W (previously 160W). The 28 deg isotherm line was steady at 146W (previously 143W). The 24 degree isotherm extended the whole way across the Pacific but was getting a little deeper today at 30m (previously 25m and at one point down to 65m) in the far East. Anomaly wise, warm anomalies at +2 deg C were in the far West Pacific associated with newly developing Kelvin Wave #6 centered at 175W pushing east in a continuous stream with +3-4 degs anomalies over the East Pacific starting at 130W (145W on 7/20). +4 degree anomalies were barely hanging on. The warm pool in the east is discharging to the surface. There's about 2 months of warm water backed up off the Ecuadorian Coast today with a stream of warm water backfilling into it. The hi-res GODAS animation posted 8/6 indicates a large very warm stream of +1-2 degs anomalies extending west to east starting at 145E and over the whole subsurface Pacific and building while tracking east with 2 deg anomalies from 138W and points east of there and +4-5 degs anomalies from 117W and points east of there erupting into Ecuador. +2 degree anomalies were falling off the Maritime Continent merging with the preexisting warm stream with a new pocket of 2-3 degs anomalies centered at 160E (Kelvin Wave #6). In other words, this image suggests a steady flow of warm water flowing east from the Maritime Continent suggesting perhaps another Kelvin Wave is developing. No cool anomalies were indicated. El Nino is developing. The GODAS animation is 1 week behind the TAO data but also is more detailed and accurately depicted since its satellite based.
Sea Level Anomalies: (8/6) Sea heights were positive across the whole equatorial Pacific at +0-5 cms and a little thinner at 150E. +5 cm anomalies were in the east from 145W east into Ecuador with a second pocket in the west from 165E-175W (Kelvin Wave #6). Positive anomalies extending north into Central America up to the southern tip of Baja and south to Chile. This means no cool water was at depth. Per the Upper Ocean Heat Anomaly Histogram warm water continues at +1.00-2.00 degs over the East Pacific from 113W and east of there. A broad pocket of near neutral temps was in place west in the West Pacific (130E-160E) with a broad pocket of warming at +0.5-+1.0 degs anomalies from 160E to 113W. The warm water flow had backed off some with nothing to force more warm water east (i.e. no Active MJOs occurring). But that pattern is changing for the better now. Otherwise there's been no change since mid March, a steady flow of warm water pushing east.

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 Qualitative Analysis: (8/17) The latest images depict a strong warm signal along the coasts of Peru and Ecuador and rebuilding after fading some 3 weeks ago affected by east winds blowing solidly over this area. Lesser but still serious heat continued west to about 140W. Lesser heat extended west to the dateline and beyond. Heat also extends north up Mexico reaching Central Baja and south down into Patagonia. There is a very clear El Nino signal with the classic El Nino triangle in-place. The last remnants of La Nina are gone on the equator but remnants are still evident mainly from a point well off Pt Conception west to a point south of Hawaii. The Cool Pool is finally collapsing. La Nina is all but gone now atmospherically over the Pacific.
Hi-res 7 day Trend (8/17): A string of pockets of warming waters were on the equator from Ecuador west to 135W. This is a good sign. It's not surprising there's no clear warm signal along Ecuador because temps are already so warm they can't get any hotter. A neutral trend was along the coasts of Chile and Peru. The pattern of adding energy to the warm surface pool is stable but not inching forward. A warming trend had been well entrenched over the East Pacific since Nov 1 with no cooling waters over the equatorial East Pacific since 12/15 except for the time frame from 4/23 to today. And strong warming is developing off California. This possibly signals the demise of the cool upwelling 'La Nina hangover' pool.
Hi-res Overview: (8/17) Warmer than normal waters are filling the East Pacific off Chile, Peru, Ecuador and north up to Mexico with strong warming in many pockets along the immediate cost of Peru and Ecuador out to 110W and building. And the classic El Nino tongue of more intense warming is building considerably over the equator west to the dateline and beyond. Everything is now looking like El Nino. But the La NIna enhanced cool pool off California persists, though weaker. Very perplexing. It's a clear sign of the negative PDO and it is not budging.
Nino1.2 Daily CDAS Index Temps: (8/18) (Coral Reef temps run about +0.2 degrees higher). Today's temps were rising to +3.164 after being up to +2.925 on 8/10 after rising at +3.074 degs (8/7) after being up to +3.391 (on 7/20) and had been rising from +2.906 (starting 7/3) rising from +2.451 after peaking at +2.7926 on 6/13 and have been up in the +2.0 to +3.0 degs range since 4/1 having previously peaked at +2.891 (4/13). Previously temps reached +2.302 degrees on 4/6, +1.732 degs (3/22), up from +0.462 since 2/28. Temps had reached as high as +1.076 on 2/19 and were previously steady at +0.848 since 2/7. Previously they started steadily rising 11/13 when they were around -1.5 degs C.
Nino 3.4 Daily CDAS Index Temps:
(8/18) (Coral Reef anomalies run about +0.2 degrees higher). Today temps were rising at +1.120 and on a slow upwards trajectory. Temps first time above 1.0 degs was on 8/7 after being up to +0.967 (8/1) up from +0.873 degs (7/25) after peaking at +0.985 (7/18). Previously temps were rising slightly at +0.882 (7/9) after being steady at +0.794 4-5 days and that after being steady at +0.895 (3 days near 6/25) after being in the +0.712 range the previous 9 days after previously rising to +0.975 on 6/9. We are now 31 days into a trend of being above the El Nino threshold (for the 2nd time). Temps reached the El Nino threshold for the first time on 5/17 at +0.507 then quickly fell over the next 10 days down to +0.378 (5/26). Previous peaks of +0.318 on 4/30 besting the previous peak at +0.199 on 4/21. Temps have been steadily increasing hitting 0.0 on 4/12 and were then more or less steady the previous 4 weeks. Temps previously rose to -0.402 on 2/23. Temps rose above the La Nina threshold (-0.5 degs) on 2/22 and had been rising slowly since 2/12 when they were about -1.0 degs C. They had been in the -1.0 deg range since at least Nov 2022.

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

SST Anomaly Projections
CFSv2 Data (Nino3.4 Region)
Previous - Temps rose in early Nov 2020 after bottoming out at -1.25 degs, up to -0.01 degs in mid-June 2021 then fading to -1.05 degs in mid-Nov then rebuilding to -0.7 in mid Feb 2022 then fading to -1.1 degs in May before starting an upward climb peaking in mid-June at -0.65 degs and mid July at -0.55 degs. A steady decline set in after that falling to -1.00 degs in Aug and Sept rising to -0.8 degs mid Oct then falling to -1.0 in Nov but then slowly rising to -0.75 degs in Jan 2023 and up to -0.5 degs (above the La Nina threshold) on 2/12. Temps rose to +0.50 degs mid-May and were at +0.9 degs in mid-June, reaching +1.15 degs early Aug.
Forecast (8/18) - Temps are are to slowly rise to +1.20 degs in mid-Aug and +1.35 degs mid Sept, then start rising quickly, to +1.75 degs in Oct and +2.05 degs in Nov and solidly in El Nino territory. The PDF Corrected forecast suggests temps are forecast holding at +1.15 degs into mid-Aug then steady at +1.10 in Sept, then rising to +1.45 degs in Oct and +1.65 degs in Nov-Dec. According to this version of the model we are building into a strong El Nino through the Summer. But max temps are down from previous runs.
IRI Consensus Plume: The August 18, 2023 Plume (all models) depicts temps are +1.432 degs today and it's the 5th month above the La Nina threshold. Temps to rise steadily from here forward up to +1.682 degrees in Oct and 1.716 in November then fading from there. The dynamic model suggest temps peaking at +2.060 in Nov while the statistic models show +1.122 degrees. The dynamic models are running much hotter than the statistic models. The CFS model is right in the middle of the dynamic model range.
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 - all but the Daily Index was a lagging indicator):
Today (8/18) the Daily Index was positive at +3.70 and mass been mixed postive and negative the last 7 days. It had been negative the previous 29 days (7/14-8/11) with a peak down to -37.30 on 7/25. It was positive the previous 21 days then was negative 11 days prior and positive 5 days previous then negative for 27 days previous ending 6/6 with a peak down to -29.32 on 5/31, -64.63 on 5/24 and -31.31 on 5/12. Previously readings were toggling between +10 and -10 for 13 days, but negative the 15 days previous to that, positive the 6 days prior to that after being mostly negative 25 days before that. It fell to -19.40 on 4/2. -17.44 on 2/22, the beginning of a change from which no return seemed likely. It was up to +21.85 on 2/10 and +55.74 on 12/22 and were in the +20 range the previous 22 days.
The 30 day average was rising at -11.93 and fell below the neutral point on 7/26. It rose above positive 7/3-7/25. It previously fell to -19.64 on 6/5 had been falling to -4.13 on 4/4 (lagging indicator driven by the Active Phase of the MJO) after falling to -0.52 on 3/22 previously falling to +4.18 on 11/27 and peaking at +21.57 (10/16) after supposedly peaking at +19.66 on 9/28. It was down to +6.89 on 7/29. It peaked at +20.34 (5/12) the highest in a year and beating last years high of +19.51 (1/14).
The 90 day average was rising some at -7.47 and turned negative the first time in years on 5/12. Recent max lows were -8.90 on 8/8 and -7.57 on 6/6. It previously peaked at +14.63 on 2/20, +15.61 on 10/25 and +12.92 on 8/11 and that after peaking at +18.40 (7/2) beating it's previous peak of +16.86 (5/31), the highest in a year. It previously peaked at +9.80 (9/21) after falling to it's lowest point in a year at +1.06 (6/9). The 90 day average peaked at +15.75 (2/23/21 - clearly indicative of La Nina then). This index is a lagging indicator but suggests that the Active Phase occurring now is starting to drive the index down, hopefully with no upward trend in sight for at least a year.

Pacific Decadal Oscillation
The PDO theoretically turned from a 16 year negative run (Jan 98-Feb 2014) in early 2014 and was positive till Dec 2019, but has been negative ever since, driven by recent La Nina conditions. In May-July 2021 it was the most negative its been in the -1.80 to -2.04 range since Sept 2012 (-2.99) and then fell to -3.16 in Oct 2021 (the lowest since July 1933) then settled at -2.72 in Nov and Dec 2021. Looking at the long term record, it seems likely we are still in the Cool Phase of the PDO (La Nina 'like') with no signs of moving to the positive/warm phase (El Nino 'like').

See imagery in the ENSO Powertool 

Powerlines Jeff Clark Inside Mavericks

Local Interest
Stormsurf Video Surf Forecast for this week. See it Here
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NBC News - Climate Change and Surfing:

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Surf Height-Swell Height Correlation Table


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