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Pacific Storm and Surf Forecast
Updated: Tuesday, October 17, 2023 2:32 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 & 4.0 - Hawaii
Using the 'Winter' Scale
(See Swell Category Table link at bottom of page)

Probability for presence of largest swells in near-shore waters of NCal, SCal or Hawaii.    
Issued for Week of Monday 10/16 thru Sun 10/22
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   

Swell #1 - ET Bolevan Hits Hawaii
Swell Propagating Southeast

Tuesday, October 17, 2023 :

  • Buoy 238 (Barbers Pt)/Buoy 239 (Lani): Seas were 4.9 ft @ 15.4 secs with swell 3.6 ft @ 16.2 secs from 209 degrees. Water temp 81.1 (Barbers Pt), 81.0 (Pearl Harbor 233), 81.1 (Lani 239).
  • Buoy 187 (Pauwela): Seas were 6.4 ft @ 13.3 secs with swell 2.6 ft @ 22.0 secs from 323 degrees. Water temp 79.5 degs
  • Buoy 106 (Waimea)/Buoy 202 (Hanalei): Seas were 7.4 ft @ 22.2 secs with swell 3.7 ft @ 20.4 secs from 321 degrees. Water temp 80.4 degs
  • Buoy 46025 (Catalina RDG): Seas were 4.9 ft @ 6.7 secs with swell 2.2 ft @ 13.5 secs from 231 degrees. Wind east at 4-6 kts. Water temperature 69.1 degs, 61.2 (Harvest 071) 66.2 (Topanga 103), 64.2 (Long Beach 215), 67.5 (Oceanside Offshore 045), 65.8 (Del Mar 153), 68.7 (Torrey Pines Outer 100). At Harvest Buoy (071) primary swell was 5.6 ft @ 15.6 secs from 291 degrees. At E. Santa Barbara (46053) swell was 2.1 ft @ 13.9 secs from 224 degrees. At Santa Monica (028) swell was 2.8 ft @ 7.8 secs from 263 degrees. At Oceanside (045) swell was 1.8 ft @ 13.3 secs from 205 degrees. Southward at Pt Loma (191) swell was 1.7 ft @ 13.4 secs from 223 degrees. Water temperature was 66.0 degrees (Imperial Beach).
  • Buoy 029 (Pt Reyes): Seas were 7.9 ft @ 13.3 secs with swell 4.6 ft @ 12.7 secs from 281 degrees. Wind northwest at 12-14 kts (46026) and 12-14 kts (1801589). Water temp NA (Bodega Bay 46013), 60.4 degs (Pt Reyes 029), 59.9 (San Francisco 46026), 60.1 (SF Bar 142), 61.9 (1801589) and 61.0 (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 Tuesday (10/17) in North and Central CA waves were head high to 1 ft overhead and lined up and clean but a bit warbled and hidden in dense fog. Protected breaks were waist to chest high on the sets and lined up and clean but soft and socked in with fog. At Santa Cruz surf was chest to head high with some bigger peaks and lined up and clean with decent form but with a little intermixed warble. In Southern California/Ventura waves were chest high with bigger sets and clean and lined up with decent form when they came but soft. Central Orange County had sets at chest to head high and reasonably lined up and clean with decent form and light fog. South Orange County's best summertime breaks had sets at chest high and lined up and clean with good form but inconsistent with 1 wave sets. North San Diego had sets at chest to head high and lined up and clean with decent form and a bit foggy. Oahu's North Shore was getting the leading edge of Swell #1 (ET Bolevan) with waves 10 ft and clean and powerful and coming up steadily. The South Shore had sets at chest to head high and lined up and clean. The East Shore was getting wrap around energy from the northwest with waves waist to chest high and nearly clean with only a light onshore flow early.

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

Meteorological Overview
On Tuesday (10/17) the main story was the arrival of Swell #1 in Hawaii that evolved from the Super Typhoon Bolevan that tracked north off Japan then turned extratropical while recurving over the lower dateline region on Sun-Mon (10/16) with up to 54 ft seas aimed east then faded while tracking northeast through the Gulf of Alaska early Tues (10/17). Long period swell is building in Hawaii and forecast to push southeast towards the US West Coast. Otherwise in California remnant swell was fading originating from another solid gale that developed that off the Kuril Islands tracking east-northeast on Wed-Thurs (10/12) with 46 ft seas over the North Dateline region then faded in the far Northwestern Gulf on Fri (10/13). A 'real' Fall pattern is materializing. A weak gael is forecast to fall southeast from the dateline into the Gulf Fri-Mon (10/23) producing 18 ft seas targeting Hawaii. And small southern hemi swell is hitting Hawaii's south shores with reinforcements directly behind.

See all the details below...


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

North Pacific

On Tuesday (10/17) the jet was consolidated ridging some off Japan then falling into a trough in the Western Gulf being fed by 140 kts winds offering continued support for gale development before lifting northeast and pushing into British Columbia. A nice jetstream pattern continue. Over the next 72 hours the Gulf trough is to slowly lose energy and pinch off in the Eastern Gulf well off California on Thurs (10/19) losing support for gale development. Beyond 72 hours a big ridge is forecast developing over the far Northwest Pacific on Fri (10/20) with the jet lifting up over Kamchatka then falling hard southeast through the Central Bering Sea and far Northwestern Gulf forming a trough over the Gulf Sat (10/21) being fed by 120-130 kts winds offering some support for gale development north of Hawaii. But by late Sun (10/22) that trough is to pinch off with a weak jetstream flow tracking off Japan and lifting gently east-northeast up to British Columbia on Tues (10/24). The jet will need some time to regroup though winds are forecast rebuilding to 130 kts over Japan on Tues (10/24).

Surface Analysis
On Tuesday (10/17) swell from a storm previously over the North Dateline region was fading California (see North Dateline Gale below). And of more interest was swell impacting Hawaii and bound for the US West Coast originating from an extratropical storm that developed from the remnants of what was Super Typhoon Bolevan over the Dateline (see Swell #1 - ET Bolevan below).

Over the next 72 hours all eyes are to be on Swell #1 - ET Bolevan.

But starting Thurs PM (10/19) a low pressure system is to start building over the North Dateline region producing northwest winds at 30 kts aimed southeast. Seas 18 ft at 47.5N 175E aimed east. On Fri AM the low is to weaken while falling southeast producing 30 kt northwest winds and seas 18 ft at 45N 180W aimed southeast. In the evening the low is to moved to the far Western Gulf with 25 kt northwest winds targeting Hawaii well and seas 16 ft at 41N 173W aimed southeast. The low is to rebuild Sat AM (10/21) 900 nmiles northwest of Hawaii producing 30 kts northwest winds and seas barely 18 ft at 37N 170W. The low is to start fading north of Hawaii in the evening producing 25 kt northwest winds and seas with 16 ft seas at 35N 165W aimed southeast. The low is to stall there and circulate producing another fetch of north winds at 35 kts on Mon AM (10/23) producing 19 ft seas at 45N 163W aimed south, then dissipating. Windswell possible for Hawaii.


North Dateline Gale
Starting Tues PM (10/10) a gale developed off the Southern Kuril Islands with 45 kt west winds over a small area starting to get traction on the oceans surface while lifting east-northeast with seas building from 20 ft at 37N 159E aimed east. On Wed AM (10/11) west and northwest winds built to 50 kts with seas 27 ft at 43.5N 168E aimed east. The gale was racing east-northeast in the evening with 55 kt west winds approaching the North Dateline region with seas 43 ft at 47N 177E aimed east. On Thurs AM (10/12) the storm was just south of the Central Aleutians over the dateline with 50 kt west winds over a solid area with seas 46 ft at 49.5N 175W aimed east. In the evening fetch is to be fading from 35-40 kts as the gale continue east just south of Aleutians with seas fading from 37 ft at 52N 170W aimed east free and clear of land. On Fri AM (10/13) residual fetch is to hold over the North Dateline region with fetch fading with 30-35 kt west winds and seas fading from 25 ft at 48N 168W aimed east. The gale is to dissipate from there. Something to monitor.

North CA: Swell fading Tues (10/17) from 3.6 ft @ 14 secs (5.0 ft). Swell Direction: 303-307 degrees and shadowed in the SF Bay Area.

Southern CA: Swell continues on Tues (10/17) at 1.6 ft @ 14-15 secs (2.0-2.5 ft). Swell fading on Wed (10/18) from 1.7 ft @ 13-14 secs (2.0-2.5 ft). Swell Direction: 307-311 degrees



Swell #1 - Extra Tropical Storm Bolevan
On Sun AM (10/8) Tropical Storm Bolevan was developing 1,600 nmiles west of the Philippines with winds 45 kts tracking northwest. On Wed AM (10/11) Bolevan turned to Super Typhoon Status turning north and building positioned 1,200 nmiles west of Taiwan with winds 155 kts.
On Thurs AM (10/12) Super Typhoon Bolevan turned northeast 800 nmiles south-southeast of Tokyo Japan with winds 155 kts. In the evening seas were 61.8 ft at 25N 147E. On the evening the Jason-3 satellite passed directly over the center and reported seas over a 15 reading average of 34.2 ft with one reading to 38.3 ft but with alot of data drop outs (given heavy rain).

By Fri AM (10/13) Bolevan was accelerating northeast 600 nmiles southeast of Tokyo with winds 135 kts. Seas were supposedly 69 ft at 28.75N 151E aimed northeast up the great circle paths to Hawaii and California and 2784 and 4236 nmiles respectively. In the evening seas were 61.5 ft at 32,75N 156,75E aimed northeast.

On Sat AM (10/14) Bolevan was 1,200 east of North Japan with winds 75 kts turning extratropical while accelerating more. Seas were 49 ft at 37.5N 163.5E. The Jason-3 satellite made a pass over the west quadrant of the storm at 13Z and report a 15 reading average at 36.7 ft with one reading to 42.5 ft where the model reported seas 38 ft. The model was doing a good job. In the evening Bolevan started making the transition into an extratropical storm with winds 55-65 kts from the west and seas 47.3 ft at 41.25N 171.25E aimed east building to 54.9 ft at 06Z at 42.5N 175E.

On Sun AM (10/15) ET Bolevan was on the dateline with winds 55-60 kts from the west and and seas 53.4 ft at 42.75N 179.25E aimed pure east. at 18Z seas were 51.3 ft at 42.5N 177.5W aimed east. The storm continued on a easterly heading in the evening with winds 50 kts moving east of the dateline with seas 49.1 ft at 42N 174.25W aimed east. And at 06Z seas were 48.5 ft at 42.5N 171W aimed east.

On Mon AM (10/16) ET Bolevan was starting to fall southeast over the Western Gulf with winds fading to 45 kts and seas 46.5 ft at 41.5N 166.75W aimed east. At 18Z seas were 42.3 ft at 40.75N 162.75W In the evening fetch is to be fading fast as the gale moves into Central Gulf with 35 kt west winds and seas fading from 38 ft at 41N 158.5W aimed southeast.

By Tues (10/17) the remnants of extratropical storm Bolevan are to be fading in the Central Gulf 1250 nmiles north-northeast of Hawaii with 35 kt west and northwest winds and seas 32 ft at 41.5N 150.75W aimed southeast, Bolevan to dissipate from there while tracking northeast bound for Central Canada. Something to monitor for Hawaii and California.

Large long period swell is in the water streaming east and southeast.

Oahu - Expect swell arrival on Mon (10/16) building at sunset with early arriving energy at 22-25 secs and swell size in the 2-3 ft range (5-6 ft). Swell building overnight. Swell building Tues (10/17) with period 22 secs early slowly dropping to 20 secs at sunset. Rough estimate late-morning is swell 5 ft @ 20-22 secs (10-11 ft Hawaiian) and exceedingly thick with alot of water moving around and swamping anything but deep water breaks later. Do not venture into the ocean if you are not a pro. Swell peaking just past sunset at 10 ft @ 18-20 secs (18-22 ft Hawaiian). Swell solid on Wed (10/18) with pure swell dropping from 8-10 ft @ 16 secs (12.8-16.0 ft). Swell Direction: Weakly 290-315 degrees but most energy coming from 319-330 degrees

North CA: Expect swell arrival on Wed (10/18) building to 4 ft @ 21 secs near sunset. Swell building overnight peaking near sunrise Thurs (10/19) at 9.6 ft @ 18-19 secs (17-19 ft) and holding solidly through the day with period dropping to 17 secs late. Swell fading on Fri (10/20) from 7.5 ft @ 15 secs early (11.0 ft). Residuals on Sat (10/21) fading from 4.5 ft @ 12-13 secs (5.5 ft). Swell Direction: 290-296 degrees focused on 295 degrees

Southern CA: Expect swell stating to show at the buoy Wednesday (10/18) afternoon and size small in the 2-3 ft @ 22-23 secs range outside the Channel Islands and 1.5 ft @ 23 secs nearshore at the most exposed breaks (3.5 ft). Swell building as period hits 20 secs sunrise Thurs (10/19) and continuing to build through mid-day with swell peaking then through sunset at 4.5 ft @ 18-19 secs (8.0 ft) with top deep water exposed breaks to maybe 5.5 ft @ 18-19 secs (10 ft). Swell holding Fri AM (10/20) at 4.0 ft @ 16-17 secs early (6.5 ft) at exposed breaks. More breaks to be rideable as period drops. Residuals fading Sat AM (10/21) from 2.5 ft @ 14-15 secs (3.5 ft). Swell Direction: 298-301 degrees

Note: There is a higher than usual uncertainty on the forecast due to lack of significant Jason-3 coverage and issues with the GFS Wave model.


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


Tropical Update
No tropical systems of interest were being tracked.

California Nearshore Forecast

  • Wed AM (10/18) high pressure starts fading with northwest winds 15 kts for all of North and Central CA mainly off the coast and 10 kts nearshore early. In the afternoon northwest winds are to fade at 10 kts for all of North and Central CA. No precip forecast.
  • Thurs AM (10/19) northwest winds to be 10 kts for North CA early and 5 kts for Central CA. In the afternoon northwest winds to be 5-10 kts for all of North and Central CA.
  • Fri AM (10/20) northwest winds to be light and variable at 5 kts for all of North and Central CA early. in the afternoon winds to turn southwest at 10 kts for North CA and 5 kts for Central CA as low pressure starts building off Cape Mendocino.
  • Sat AM (10/21) light southwest winds are forecast at 5-10 kts for North CA early and west at 5 kts for Central CA. In the afternoon northwest winds are forecast at 5 kts for North and Central CA. The low is to be moving closer to Cape Mendocino. Rain for North CA late evening.
  • Sun AM (10/22) west winds re forecast at 5 kts for North and Central CA early. The low is to be dissolving just off North CA. In the afternoon high pressure arrives with north winds 10-15 kts for all of North and Central CA and 20 kts for all of Southern CA. Light rain for NOrth Ca down to Monterey Bay early with lingering spotty showers through the afternoon.
  • Mon AM (10/23) high pressure takes control with northwest winds 20-25 kts for all of North and Central CA early but light for Southern CA. In the afternoon northwest winds build to 25 kts for all of North and Central CA.
  • Tues AM (10/24) the gradient starts to lift north some with northwest winds 25 kts for Cape Mendocino and 20 kts for the rest of North and all of Central CA early. In the afternoon north winds to be 30-35 kts for North Ca and northwest 15-20 kts for Central CA and 20 kts solid off the coast.

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 respectively.

Temperatures for the Pacific Crest Trail and Tioga Pass Road intersection (8,700 ft): 55 degrees through Fri night (10/20) then cooling Sun-early Tues (10/24) with temps at freezing. A warming trend starts later Tues (10/24) with temps generally 45-50 degrees during the day 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

Surface Analysis
On Tues (10/17)
swell from a small gale previously south of New Zealand was hitting Hawaii (see New Zealand Gale below).

And swell from another gale that developed southeast of New Zealand was tracking northeast targeting Hawaii (see Another New Zealand Gale below)

Over the next 72 hours a gale is forecast developing under New Zealand on Wed AM (10/18) producing 35-40 kts southwest winds and seas forecast at 32 ft at 58.25S 163.5E. in the evening fetch is to be fading from 30-35 kts aimed northeast with seas 27 ft at 54.25S 179.25W. Fetch to fade from there. Maybe some small swell to radiate northeast.


New Zealand Gale
On Mon AM (10/9) a gale started developing while tracking northeast under New Zealand producing 35 kt southwest winds over a solid area with seas 27 ft at 51S 170E aimed northeast and mostly shadowed by New Zealand. In the afternoon a broad fetch of southwest winds were 35 kts just southeast of New Zealand with seas aimed northeast at 27 ft at 52.75S 169.25E aimed northeast. On Tues AM (10/10) south winds were 30 kts with 23 ft seas fading at 48.75S 178.72W aimed northeast. The gale dissipated from there. Maybe some small swell to result for Tahiti and Hawaii.

Oahu South Shore: Swell building some on Tues (10/17) pushing 1.5 ft @ 15-16 secs (2.0-2.5 ft). Swell fading on Wed (10/18) from 1.5 ft @ 14 secs early (2.0 ft). Swell Direction: 200 degrees


Another New Zealand Gale
On Tuesday PM (10/10) another gale developed south of New Zealand producing 40-45 kt west winds with seas 27 ft at 55S 165.5E aimed northeast. On Wed AM (10/11) the gale was track east producing 40-45 kt southwest winds over a tiny area southeast of New Zealand with seas 29 ft at 56.75S 175E aimed east-northeast. In the evening southwest winds were 35-40 kts with seas 29 ft at 54S 180W aimed northeast. The gale held while easing east on Thurs AM (10/12) with 35-40 kt southwest winds and seas 29 ft at 61.5S 175W aimed northeast. The gale faded in the evening.

Oahu South Shore: Expect swell arrival on Wed (10/18) building to 1.3 ft @ 17 secs late (2.0 ft). Swell building on Thurs (10/19) to 1.7 ft @ 15-16 secs (2.5 ft). Swell fading Fri (10/20) from 1.8 ft @ 14-15 secs early (2.5 ft). Residuals on Sat (10/21) fading from 1.4 ft @ 13 secs (1.5-2.0 ft). Swell Direction: 192 degrees


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




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

North Pacific

Beyond 72 hours no swell producing weather systems of interest are forecast.


South Pacific

Beyond 72 hours starting Sat AM (10/21) another small gale is forecast developing under New Zealand with 45 kt southwest winds and seas 35 ft at 56.25S 173.75E aimed northeast. In the evening the gael is to continue tracking east with 40+ kt southwest winds and seas 35 ft at 55S 176.25W aimed northeast. On Sun AM (10/22) fetch is to fade from 40 kts from the southwest with seas 32 ft at 52.75S 167.25W aimed northeast. Something to monitor.


MJO/ENSO Forecast


El Nino Steadily Building
Kelvin Waves #4, #5 and #6 Erupting - NINO3.4 SSTs reflect El Nino
1 Kelvin Wave traversed the Pacific in Dec '22 with a 2nd in Jan-Feb and a 3rd and 4th in March-April, a 5th in May and a 6th in August. But after the last Active MJO in mid-to-late May (resulting in Kevin Wave #5), the MJO stalled. Finally the Active Phase restarted in later July Producing Kelvin Wave #6 which is erupting off Ecuador now. Sea Surface Temperatures in the east are warm and holding, and slightly expanding. And another Active Phase of the MJO is developing now (mid-Oct) likely starting to produce Kelvin Wave #7 which is pushing east. All these Active MJO/Kevin Wave pairs are backfilling warm water off Ecuador and helping push the atmosphere towards El Nino. And El Nino is finally starting to be evident in the atmosphere as evidenced by the SOI, OLR. ocean current, and wind anomalies.

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 (10/16) 5 day average winds were strong from the east over the East equatorial Pacific and moderate east over the Central Pacific and calm over the KWGA. Anomalies were neutral over the East equatorial Pacific and moderate west over the Central Pacific and moderate 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): (10/17) Modest east anomalies were over the western half of the KWGA today but with strong west anomalies over the dateline and points east of there. The forecast indicates east anomalies retrograding steadily and receding west from the KWGA and gone on 10/21 (4 days from now) with strong west anomalies building from the dateline over the West KWGA steadily and filling it through the end of the model run on 11/2. This continues looking very interesting.

Kelvin Wave Generation Area wind monitoring model: West and East

MJO/WWB/Wind Projections:  
OLR Models: (10/16) A modest Inactive MJO was over the KWGA. The statistic model indicates the Inactive MJO (cloud free air) is to build some on day 5 building to moderate to strong status on day 10 and holding on day 15 of the model run. The dynamic model depicts the Inactive Phase holding at weak to modest strength through day 5 then collapsing to neutral starts for days 10 and 15.
Phase Diagrams - 2 week forecast (CA and GEFS): (10/17) The statistical model depicts the Active signal was modest over Africa. The forecast indicates it is to move to the Indian Ocean 15 days out and split between weak and moderate. The dynamic model indicates the Active signal meandering over Africa at weak status for the next 2 weeks unchanged.
40 day Upper Level Model (assumed to be a statistical mode and 1 week ahead of what is occurring at the surface): (10/17) A neutral MJO pattern was indicated over the KWGA today. The forecast has a very weak Inactive Phase (dry air) tracking east and over the KWGA 10/22-11/11 then moving east of the KWGA while a weak Active (wet air) pattern sets up over the KWGA 11/16 through the end of the model run on 11/26. But the extreme weakness of this suggest an El Nino pattern is in play now.
4 Week CFS Model (850 mb wind): (10/16)
Today a neutral MJO was over the KWGA but with modest west anomalies over most of the KWGA except weak east anomalies over the West KWGA associated with a fading negative Equatorial Rossby Wave almost gone over the KWGA. The forecast has the Rossby Wave fading out on 10/19 with east anomalies gone on 10/20. After that west anomalies are to quickly build to strong status starting 10/17 centered on the dateline and building over the entirety of the West KWGA by 10/21 and in control holding from there through the end of the model run on 11/13. Of note: Moderate east anomalies started building over the Indian Ocean on 9/2 and are now at strong status today and forecast holding through 11/2 then fading some but still near strong status through the end of the model run on 11/13. That coupled with building west anomalies in the West Pacific suggest massively falling air occurring somewhere near 90E (East Indian Ocean). This is likely the falling branch of the Walker Circulation. The Indian Ocean Dipole is currently strong positive and building (the falling branch of the Walker Circulation). We're at the precipice of the start of a real El Nino pattern according to this model.
3 Month CFS Model (850 mb wind):
(10/17) - 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 Active Phase was weakly pushing into the KWGA with weak to modest west anomalies in control. A weak Inactive Phase is forecast 10/18-11/2 but with moderate to strong west anomalies in control. West anomalies to to fade some 10/28 into 11/9 to modest strength. The Active Phase is to then build 11/7-12/4 with strong west anomalies filling the KWGA. A solid Inactive Phase develops 11/15 in the far west KWGA filling it the end of the model run on 1/14/24 but with west anomalies holding at modest to moderate strength while easing east to 165W. Also note that east anomalies started building at 70E (West Indian Ocean) on 9/7 and are forecast building through 11/5, holding through 12/13 then moderating some and holding through the end of the model run. This strong east and west anomaly pattern looks very much like falling air centered over the East Indian Ocean (110E) and the the downward branch of the Walker Circulation/+IOD. Outgoing Longwave Radiation (OLR) suggests cloud activity took over the KWGA weakly on 6/24 and started building in earnest June 25 and then more solid starting Sept 15 and is continuing to build today. It is forecast building strongly from here forward but especially starting 10/12. Conversely clear skies started building over the Maritime Continent in mid-May and have continued solidifying today and are forecast building from here forward especially starting 10/10. This also suggest a fall and rising air pattern associated with the change in the Walker Circulation. The low pass filter indicates a broad low pressure bias is established over the KWGA centered at 180W with 3 contour lines (starting 7/14). A 4th contour line is to develop Nov 2. A 5th contour line is scheduled to develop on 12/12. The high pressure bias has dissolved and is no longer in the Pacific but started to build over the Maritime Continent on 10/2. A second high pressure contour is to develop on 12/4. 7/18 was the start of a major positive change in the development of El Nino with advent of the Active Phase of the MJO and west anomalies and that momentum is growing stronger each passing day. It appears a strong El Nino is finally starting to develop in a classical sense.

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

Subsurface Waters Temps
TAO Array: (10/17) Today in the far West Pacific the leading edge of the 30 deg isotherm was easing east to 169W (previously 169W). The 29 degree isotherm was easing east to 157W (previously 162W). The 28 deg isotherm line was easing east to 145W (previously 140W) and looks like east winds that had been hitting it are abating. The 24 degree isotherm extended the whole way across the Pacific and was steady at 39m (25m 4 days earlier and at one point down to 65m) in the far East. Anomaly wise, warm anomalies at +2 deg C started in the far West Pacific at 173E associated with newly developing Kelvin Wave #7 centered at 172W pushing east in a continuous stream feeding into Kelvin Wave #6 and other previous Kelvin Waves that have formed a broad pocket of +3-5 degs anomalies over the East Pacific starting at 137W (152W on 9/11). +4-5 degree anomalies were tracking east now at 124W (previously 138W). The warm pool in the east (originating from Kelvin Waves #6, 5, 4...) is discharging to the surface while being backfilled by more warm water/Kelvin Wave #7. There's about 3 months of warm water backed up off the Ecuadorian Coast (previously 2 months) today with a stream of warm water backfilling into it. The hi-res GODAS animation posted 10/10 indicates a large very warm stream of +1-2 degs anomalies extending west to east starting at 175E and over a large section of the subsurface equatorial Pacific (Kelvin Wave #7) and building while tracking east with 2 deg anomalies from 130W and points east of there and +4-5 degs anomalies from 121W and points east of there originating from Kelvin Waves #6, #5 and #4 erupting into Ecuador. A steady stream of +1-2 degree anomalies were falling off the Maritime Continent merging with the preexisting warm stream. In other words, this image suggests a steady flow of warm water flowing east from the Maritime Continent suggesting Kelvin Wave #8 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: (10/10) Sea heights were positive across the equatorial Pacific starting at 160E at +0-5 cms extending east into Ecuador. +5 cm anomalies were in the east from 175E east into Ecuador with 2 pockets of +10 cm anomalies imbedded to the south. Positive anomalies extending north into Central America up to the southern tip of Baja and south to North Peru. This means no cool water was at depth. Per the Upper Ocean Heat Anomaly Histogram (10/5) warm water is building at +0.5 degs from 175E and points east of there. +1.00-1.50 degs were in a building pocket between 175W to 149W and fading in the east limited to 112W to 94W over the East Pacific and shrinking in coverage while migrating east. A pocket of near neutral to slightly negative anomalies was between 140-160E and shrinking. The warm water flow had backed off some with nothing to force more warm water east (i.e. no Active MJOs occurring) in July. But a new Kelvin Wave is now in flight. 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: (10/16) The latest images depict a strong warm signal along the coasts of Peru and Ecuador now out to 125W (previously 115W) and building in strength and coverage. There are sign that a moderate warm signal is building further west on the equator out to 170W (previously 155W). The warm pool is now growing westward after previously losing coverage. Lesser heat extended west to the dateline and beyond. Heat also extends north up to Central Baja and south down into Patagonia. There is a very clear El Nino signal with the classic El Nino triangle in-place and rebuilding towards as strong as it was months past, but over a larger area. The last remnants of La Nina are gone on the equator but remnants are still evident in a fading cool pool from a point well off Southern Baja from 130W west to a point south of Hawaii at 175W. The Cool Pool is slowly collapsing. La Nina is all but gone now atmospherically over the Pacific.
Hi-res 7 day Trend (10/16): A small thin stream of pockets of warm anomalies were aligned on the equator from the Galapagos west to the dateline. Otherwise mostly neutral temps prevailed. Perhaps some energy is being added to the warm surface pool. A warming trend had been well entrenched over the East Pacific since Nov 1 2022 with no cooling waters over the equatorial East Pacific since 12/15.
Hi-res Overview: (10/11) Warmer than normal waters are filling the East Pacific off Chile, Peru, Ecuador and north up to Mexico with strong warming in many pockets from 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. And the La NIna enhanced cool pool off California is fading and drifting west, while weakening.
Nino1.2 Daily CDAS Index Temps: (10/17) (The official OISST temp record runs about +0.2 degrees higher). Today's temps were stabilizing but down at +1.778 after steadily fading down to +1.527 (10/6) (previously +2.10 - 9/17) and have been falling since 8/31 when they were up to +3.073 after rising to +3.164 (8/18) 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:
(10/17) (OISST runs about +0.2 degrees higher). Today temps were rising at +1.294 after falling down to +1.149 (10/11). . Weekly OISST were at +1.5 the past 3 weeks (through 10/11) after being up to +1.7 degs the week before and +1.6 degs 3 weeks in a row prior (starting 8/30) putting us in minimal strong El Nino status. 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.

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 Data (Nino3.4 Region)
Previous - Temps bottomed out at at -1.25 degs in early Nov 2020, 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, and +1.05 mid July reaching up to +1.30 degs early Aug peaking at +1.6 degs in Sept.
Forecast (10/17) - Temps are to hold at +1.5 degs into mid-Nov, then rising fast to +1.90 degs in Dec and Jan and solidly in strong El Nino territory before starting a slow fade thereafter. The PDF Corrected forecast suggests temps are forecast falling to +1.40 degs in mid-Nov then rising to +1.70 degs in Dec and Jan. According to this version of the model we are building into a mid to upper level strong El Nino.
IRI Consensus Plume: The Sept 20, 2023 Plume (all models) depicts temps are +1.671 degs today and it's the 6th month above the La Nina threshold. Temps to rise steadily from here forward up to +1.838 degrees in November then fading from there. The dynamic model suggest temps peaking at +2.073 in Nov while the statistic models show +1.410 degrees. The dynamic models are running much hotter than the statistic models. The CFS model is on the low end 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 (10/17) the Daily Index was negative at -5.55 and has been negative for 58 days (starting 9/16). It was positive the previous 7 days, then negative the previous 29 days (7/14-8/11) with a peak down to -37.30 on 7/25.The SOI has effectively been negative since 7/12. 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 some at -9.28 after falling to -15.70 on 9/23. It 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 -11.62 and turned negative the first time in years on 5/12. Recent max lows were -11.85 on 10/15, -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:

Mavericks & Stormsurf on HBO Sports with Bryant Gumbel

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Surf Height-Swell Height Correlation Table


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