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Pacific Storm and Surf Forecast
Updated: Friday, September 17, 2021 5:32 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
4.3 - California & 2.5 - Hawaii
Using the 'Summer' Scale
(See Swell Category Table link at bottom of page)

Probability for presence of largest swells in near-shore waters of NCal, SCal or Hawaii.    

Issued for Week of Monday 9/13 thru Sun 9/19

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   

North Pacific to Start Moving
Southern Hemi Going to Sleep


On Friday, September 17, 2021 :

  • Buoy 233 (Pearl Harbor)/Buoy 239 (Lanai)/Buoy 238 (Barbers Pt) : Seas were 2.9 ft @ 11.8 secs with swell 1.5 ft @ 14.8 secs from 198 degrees. Water temp 79.9 degs (Pearl Harbor 233), NA (Lani 239), 79.7 (Barbers Pt).
  • Buoy 106 (Waimea): Seas were 4.3 ft @ 7.1 secs with swell 3.3 ft @ 6.6 secs from 44 degrees. Water temp 79.2 degs.
  • Buoy 46025 (Catalina RDG): Seas were 3.3 ft @ 15.9 secs with swell 2.6 ft @ 15.3 secs from 187 degrees. Wind at the buoy was southeast at 4-6 kts. Water temperature 66.2 degs, 64.6 (Topanga 103), 62.6 degs (Long Beach 215), 65.5 (Del Mar 153), 70.9 (Pt Loma 191). At Harvest Buoy (071) primary swell was 5.0 ft @ 10.3 secs from 320 degrees. At Santa Monica (028) swell was 1.7 ft @ 14.7 secs from 201 degrees. At Oceanside (045) swell was 1.6 ft @ 18.0 secs from 212 degrees. Southward at Point Loma (191) swell was 2.3 ft @ 14.9 secs from 185 degrees.
  • Buoy 46012 (Half Moon Bay)/029 (Pt Reyes): Seas were 6.2 ft @ 15.4 secs with swell 2.8 ft @ 16.1 secs from 183 degrees. Wind at the buoy (012) was west at 2-6 kts. Water temp 56.5 (Pt Reyes 029), 58.6 (46026), 59.7 degs (SF Bar 142), and 60.6 (Santa Cruz 254).

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 (9/17) North and Central CA had waves at waist to chest high and lumpy and warbled and mushed. Protected breaks were waist to chest high and lined up and clean but soft. At Santa Cruz surf was waist to chest high on the sets and lined up and clean but soft and inconsistent. In Southern California/Ventura waves were waist high or so and lined up and clean but soft. Central Orange County had sets at chest high and lined up and clean. South Orange County's best summertime breaks had sets at 1 ft overhead when they came and lined up and real clean and peeling. North San Diego had sets waves at chest high and lined up and clean but pretty closed out. Hawaii's North Shore was flat and clean. The South Shore was getting very limited swell with waves waist high or so and clean and somewhat lined up but weak and inconsistent. The East Shore was getting waist high east windswell and chopped from moderate east-northeast trades.

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

Meteorological Overview
On Friday (9/17) the last fading remnants of the third pulse of southern hemi swell was fading in California. This swell originated from a gale that formed over the Southeast Pacific on Tues-Wed (9/8) producing up to 40 ft sea aimed northeast. And the last fading remnants of swell were fading in Hawaii originating from a gale that developed in the Tasman Sea with 34 ft seas aimed northeast. Beyond there's no meaningful swell in the water originating from the Southern Hemisphere and no swell producing weather systems are forecast there for the next week. But up north a series of 3 low pressure systems are forecast traversing the North Pacific with the first moving in the Gulf of Alaska on Sat (9/18) with 16-17 ft seas aimed southeast possibly producing windswell for North CA. And 2 more are forecast to follow, with one moving over the North Dateline Region on Sat-Sun (9/19) with 24-26 ft sea aimed east, and another developing in the Northwestern Gulf on Wed-Thurs (9/23) with up to 28 ft seas aimed east. Fall is starting and Summer is over.

See all the details below...


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

North Pacific

On Friday (9/17) the jet was forming a weak trough just off Kamchatka being fed by 130 kts winds offering some limited support for gale development. But east of there over the Dateline the jet ridged north into the Bering Sea then fell southeast over the Central Gulf with winds building to 160 kts forming a decent trough and offering reasonable early season support for gale development. Over the next 72 hours that trough is to push east pushing into Oregon on Sat (9/18) then moving inland later Sun (9/19) no longer supporting gale development. But behind it the entire jet is to fall south tracking east on the 45N latitude line over the North Pacific starting Mon AM (9/20) with winds building to 140 kts pushing off the Kuril Islands forming a trough approaching the dateline and offering decent support for gale development. And east of there winds to be 100-110 kts over the entire North Pacific. A clear change in pattern is suggested. Beyond 72 hours the dateline trough is to build being fed by 160 kt winds on Tues (9/21) with it's apex on the dateline offering good support for gale development. And a second trough is to build east of it in the Central Gulf being fed by 140 kts winds also offering potential. That trough is to move inland over Oregon on Wed 99/22) while the dateline trough builds in coverage filling the dateline region and pushing into the Western Gulf on early Thurs (9/23) being fed by 140 kts winds continuing support for gale development. That trough is to weaken while moving into the Gulf on Fri (9/24) still offering some limited support for gale development. A ridge is to start building over the US West Coast at that time. The change of season is imminent.

Surface Analysis
On Friday (9/18) windswell was possibly being generated associated with a low pressure system developing in the Northwestern Gulf (see Gulf Low Pressure System below).

Over the next 72 hours a gale was developing just west of the dateline in Fri AM (9/17) producing a tiny area of 50 kt west winds and seas building from 24 ft at 43.5N 169.5E aimed east. In the evening west fetch is to be fading from 40 kts with the gale moving over the dateline with 30 ft seas over a tiny area at 45N 176E aimed east. On Sat AM (9/18) the gael is to move east over the North Dateline Region with 35 kt west winds and seas 26 ft at 45.5N 177W aimed east. In the evening the gale is to track east with 35 kts northwest winds and seas 24 ft over a modest sized area at 46N 170W aimed east. More of the same on Sun AM (9/19) with 35 kt west winds in the Western Gulf and 24 ft seas at 47N 170W aimed east. The gael is to fade in the evening with 30 kts west winds and seas fading from 21 ft at 46.25N 161.5W aimed east. the gale is to dissipate from there. Something to monitor.


Gulf Low Pressure System
ON Thurs PM (9/16) a low pressure system was developing in the far Northwestern Gulf of Alaska producing northwest winds at 30+ kts producing 18 ft seas over a tiny area at 50N 168W. On Fri AM (9/17) winds move rapidly southeast at 25-30 kts over a broad area filling the Gulf with seas 16 ft at 47.5N 159W aimed east. Fetch is to ease east in the evening at 25+ kts with seas 15 ft at 46N 150W aimed southeast. On Sat AM (9/18) northwest fetch is to build in the Northeastern Gulf at 30 kts with seas 16 ft at 50N 143W aimed southeast. Fetch is to be fading in the evening with northwest winds 25 kts and seas 17 ft at 47N 140W aimed southeast. The gale is to dissipate after that. Some odds of windswell developing.

North CA: Rough data suggest windswell arrival on Mon (9/20) at 5.5 ft @ 12 secs (6.5 ft). Swell Direction: 300 degrees


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


Tropical Update
No tropical systems of interest were being monitored.

California Nearshore Forecast

  • Sat (9/18) light and variable winds are forecast everywhere through the day. No windswell production forecast.
  • Sun (9/19) northwest winds to be 5-10 kts for North CA early and 10 kts for Central CA (up to 15 kts near Pt Conception) building to 15-20 kts in the afternoon for both North and Central CA. No real windswell forecast. Chop is possible though.
  • Mon (9/20) northwest winds to be 20-25 kts for North CA early and 20 kts for Central CA off the coast early and 10-15 kts nearshore early. Northwest winds holding at 20-25 kts later for North CA but fading to 10-15 kts south of Bodega Bay later.
  • Tues (9/21) northwest winds are forecast at 10 kts early for North CA and 5 kts for Central CA fading to 56 kts in the afternoon both North and South.
  • Wed (9/22) northwest winds are forecast at 5-10 kts for North CA early and calm for Central CA early building for North CA to 15 kts in the afternoon and 10 kts for Central CA.
  • Thurs (9/23) a summer time gradient is to start building with north winds 20-25 kts for North CA early and northwest winds 10-15 kts for Central CA holding all day.
  • Fri (9/24) the gradient is to be limited to Cape Mendocino with north winds 20-25 kts mainly off the coast there and northwest 5-10 kts south of there early.

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

Freezing level 13,500 ft today falling to 11,500 ft on 9/18 then building to 14,000+ ft on 9/19 and holding. Snow level maybe falling to 12,500 ft on 9/26.


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

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


South Pacific

Surface Analysis
On Friday (9/17) fading swell from the last in a series of gale that traversed the South Pacific was lapping into California (see Second South Pacific Gale below). Also the remnants of swell that originated in the Tasman Sea was lapping into Hawaii (see Tasman Sea Gale below).

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


Second South Pacific Gale
Pulse 1 (New Zealand) Another gale started building Thurs PM (9/2) just south of New Zealand with 40-45 kt west to northwest winds with seas building to 29-30 ft over a broad area centered at at 56S 180W aimed east. On Fri AM (9/3) additional west fetch built southeast of New Zealand at 45 kts with 34 ft seas at 58.25S 175.5E aimed east. Fetch pushed east fast in the evening at 45 kts with seas 36 ft at 56.5S 163W aimed east-northeast. On Sat AM (9/4) fetch moved over the Central South Pacific at 35-40 kts with seas fading from 30 ft at 55.25S 145.25W aimed east-northeast.
Pulse 2 (South Central Pacific)
Additional fetch started building in the evening at 45 kts over a broad area aimed well northeast with seas rebuilding from 29-30 ft at 55.25S 164.25W aimed northeast. On Sun AM (9/5) 45 kt southwest winds were pushing over the Central South Pacific with seas 37 ft at 58.75S 159.5W aimed northeast. In the evening southwest winds were 45 kts solid aimed northeast with seas 39 ft at 56.25S 149W. On Mon AM (9/5) 40 kt south to southwest winds were push over the Southeast Pacific and solid in coverage with seas fading from 36 ft at 53S 137W aimed northeast. In the evening fetch was fading from 35-40 kts from the southwest with seas fading from 32 ft at 53S 130W aimed northeast. This system was fading while moving to the far Southeast Pacific with fetch all but gone and seas 31 ft at 50S 125W aimed northeast.
Pulse 3 (Southeast Pacific) A tertiary fetch was building in the South Central Pacific with 50 kt southwest winds and seas building to 35 ft over a small area at 55.5S 156W aimed east. In the evening 55 kt southwest winds are to be over the Southeast Pacific with 41 ft seas at 52S 129.25W aimed northeast. On Wed AM (9/8) 45 kt southwest winds to be on the edge of the CA swell window with 37 ft seas at 52S 120W aimed northeast. producing. In the evening fetch is to be fading from 35 kts on the eastern edge of the SCal swell window with seas fading from 28 ft at 50S 118W aimed northeast. The gale is to be gone relative to CA after that. Something to monitor.

Southern CA: Pulse #3 Fri (9/17) things to start settling down with swell 2.2 ft @ 14-15 secs early (3.0 ft). Dribbles on Sat (9/18) fading from 1.7 ft @ 13-14 secs (2.0-2.5 ft).
Swell Direction
Pulse 3 185 degrees

North CA: Pulse 3 Fri (9/17) things to start settling down with swell 2.2 ft @ 15 secs early (3.0 ft). Dribbles on Sat (9/18) fading from 1.7 ft @ 14 secs (2.0-2.5 ft).
Swell Direction
Pulse 3 183-184 degrees


Tasman Sea Gale
A gale started moving into the Hawaii swell window in the Tasman Sea on Mon PM (9/6) producing 40-45 kt southwest winds with seas 34 ft at 50.25S 151E aimed northeast. On Tues AM (9/7) southwest fetch was fading over a broad area at 35-40 kts filling the South Tasman Sea with 33 ft seas at 50S 157E aimed northeast. In the evening fetch was fading while impacting New Zealand with seas fading from 29 ft at 45S 165E aimed northeast. Swell is radiating northeast towards Hawaii.

Oahu: Dribbles on Fri (9/17) fading from 1.1 ft @ 14-15 secs (1.5 ft). Swell Direction: 215-220 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 another gale is forecast developing in the Northwestern Gulf of Alaska on Wed AM (9/22) with 35 kt west winds and seas 24 ft at 46.25N 170W aimed east. Fetch to build to 40 kts in the evening with 27 ft seas at 46.5N 167.75W aimed east. On Thurs AM (9/23) the gale is to plod east with 35 kts west winds and seas 28 ft at 47.25N 160.25W aimed east. The gale is to rapidly fade in the evening with winds down to 30 kts and seas 23 ft at 48.5N 153.5W aimed east. The gale is to dissipate from there. Something to monitor.


South Pacific

Beyond 72 hours no swell producing weather systems are forecast.


MJO/ENSO Forecast


La Nina Steadily Redeveloping
Summary - Cool water is building across the subsurface equatorial Pacific with no Kelvin Wave induced warm water present. The forecast has improved some though suggesting weak west anomalies taking over the KWGA in October and filling the KWGA after that. A high pressure bias is to control the dateline by early Fall but recent runs of the model suggest that might be temporary, with the high pressure bias out of the KWGA by early Dec. It seems likely blocking high pressure is to hold over the dateline through late Fall, but then the forecast is undefined, but possibly improving as winter takes root.

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. A slow dissolving of La Nina started in March 2021 with 2 Kelvin Waves sweeping east and arriving over the Galapagos in June. Weak warming set up over the equator with no cool waters present. NOAA declared La Nina dead.

Spring/Summer 2021 = 4.0/3.5 (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 that the moderate La Nina from the Winter of 2020/2021 is on the wane and that a return to neutral ENSO state will set up over the Pacific Basin through the summer of 2021. But lingering effects of La Nina are forecast to continue over the Pacific for some time as the upper atmospheric circulation slowly transitions to an ENSO neutral state. This scenario tend to favor the Southeast Pacific, therefore favoring California over Hawaii. To counter that is the forecasted movement of the low pressure bias currently in-flight from the Maritime Continent to the West Pacific over the next 3 months. Still it will take some time for the atmosphere to fully respond, resulting in a slightly less than normal swell production forecast. A somewhat reduced number of storm days and storm intensity is expected as compared to normal over the South Pacific during the early summer season, resulting in a below normal level of swells, with swell being below normal duration and period. But by the Fall and early Winter of 2021/22, the number of storm days, intensity and duration of those storms should start improving as La Nina fades out. The status of the PDO is not known, though it appears to be returning to at least a neutral state, rather than the warm phase as previously projected thereby having no significant positive or negative effect on the long term outlook.

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 (9/16) 5 day average winds were strong from the east over the Eastern equatorial Pacific and strong east over the Central Pacific and strong east over the KWGA. Anomalies were modest east over the East equatorial Pacific and moderate east over the Central Pacific and moderate east over the KWGA. (Note: These are 5 day average winds, versus realtime, so they lag what is happening today (by about 2.5 days).
1 Week Forecast (GFS Model): On (9/17) east anomalies were strong filling the KWGA and weaker but still solidly east reaching eastward to Ecuador over the equator. The forecast calls for east anomalies holding at strong status in pockets for the next week in the KWGA through 9/24 and filling the bulk of the equatorial Pacific Basin through the end of the model run on 9/24. There's no sign of the Active Phase of the MJO. This is an impressively strong and long lasting Easterly Wind Burst.

Kelvin Wave Generation Area wind monitoring model: West and East

MJO/WWB/Wind Projections:  
OLR Models: (9/16) A weak Inactive MJO signal was indicated over the KWGA today. The statistic model projects the Inactive pattern building on day 5 of the model at moderate strength then building to strong strength and holding on days 10 and 15 of the model run. The dynamic model projects the Inactive Phase holding at minimal weak strength on day 5 of the model run then collapsing with a weak Active signal developing on days 10 and holding at weak status over the KWGA on day 15. The 2 models are projecting opposite outcomes. Based on actuals, the statistical model is more realistic.
Phase Diagrams 2 week forecast (ECMF and GEFS): (9/17) The statistical model depicts the Active Phase was weak over the far East Indian Ocean and is forecast tracking to the Central Maritime Continent at very weak status 15 days out. The dynamic model suggests the Active Phase pushing slowly east to the Central Maritime Continent on day 15 of the model run at weak status.
40 day Upper Level Model (assumed to be a statistical mode and 1 week ahead of what is occurring at the surface): (9/16) A strong Inactive Phase (dry air) was indicated over the East Pacific today. The Inactive Phase (dry air) is to track east over Central America on on 9/21 with a weak Active Phase (wet air) forecast developing over the KWGA 9/18 tracking east and weakly filling the equatorial Pacific by 10/1 then moving east and into Central America on 10/11. A moderate Inactive Phase (dry air) is to be moving east over the KWGA on 10/11 moving to the Central Pacific and filling the Pacific at the end of the model run on 10/26.
4 Week CFS Model (850 mb wind): (9/16) This model depicts the Inactive Phase of the MJO was filling the KWGA today with moderate to strong east anomalies in control of the KWGA. The forecast indicates east anomalies and the Inactive Phase holding on the dateline at moderate strength through 9/23 then the Inactive Phase is to move east of the KWGA but east anomalies are to hold on the dateline but weakening. The Active Phase is to weakly develop and push east across the KWGA 9/22-10/7 with west anomalies limited to the western half of the KWGA peaking around 9/30 then east anomalies redeveloping over the KWGA 10/2 and holding through the end of the model run on 10/14.
3 Month CFS Model (850 mb wind): (9/17 - using the 5th ensemble member - the mean of the 4 individual members which are all from the 00Z run - 1 run per day): Today a weak Inactive Phase of the MJO was fading over the east KWGA with modest east anomalies filling the KWGA. The forecast indicates the Inactive Phase is to slowly push east and out of the KWGA on 9/26 with east anomalies moving east centered on the dateline and points east of there starting 9/29. At the same time a weak Active Phase (2 contour lines) is to develop while slowly pushing east entering the KWGA on 9/23 filling the KWGA on 10/4 and holding through 12/6 with west anomalies steadily plodding east filling the KWGA by 11/8 and holding through the end of the model run on 12/15. A modest Inactive MJO pattern is to push into the KWGA on 11/16 slowly pushing east and filling the KWGA at the end of the model run but with west anomalies hold control over the KWGA. The low pass filter indicates a high pressure bias has developed on the dateline and is to hold that position filling the eastern portion of the KWGA east to 130W through 11/25, then starting to lose coverage. A weak second contour is forecast 10/19-11/22. A broad single contour low pressure bias is to develop 10/31 centered over the Maritime Continent at 100E with it's leading edge at 120E then steadily moving east into the KWGA on 11/24 and filling 30% of it at the end of the model run. Today a solid east anomaly pattern that has taken over the KWGA and is to slowly get shoved east and erode as the Active Phase and west anomalies and the low pressure bias try to take root in the KWGA by early Dec. This suggests redevelopment of La Nina for now but possibly fading some come late Fall and early Winter.

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

Subsurface Waters Temps
TAO Array: (9/17) Today in the far West Pacific the 29 degree isotherm was gone, previously at 169E. The 28 deg isotherm line was steady at 174W. The 24 deg isotherm is stable at 125W. Warm water has receded west and has more or less stabilized there. Anomaly wise, warm anomalies +1-2 deg C were building in coverage in the far West Pacific pushing east to 160W with a thin finger extending east just under the surface to 100W. But all the sensors are down between 155W-130W so this analysis is highly suspect. Under that warm pool mostly cool anomalies were in control at 1-2 degs below normal from 150 meters down up to 75 meters down in the east. No Kelvin Waves were obvious and cool water was building in the east at depth. The hi-res GODAS animation posted 9/10 indicates no warm water east of 170W with cool water east of there (where the sensors are inoperable) extending into Ecuador. A solid stream of cool water was pushing up from 150 meters down at 160W and breaching the surface just at the Galapagos. The GODAS animation appears to be 1 week behind the TAO data but also is more detailed and accurately modeled.
Sea Level Anomalies: (9/10) Sea heights were falling over the entire equatorial Pacific with negative anomalies at -5 to -10 cms over the East equatorial Pacific between Ecuador to 160W and with a peak at -15 cms at 135W. All positive anomalies were limited from 160E and points west of there. A warm water 'horseshoe' pattern was developing in the West Pacific. La Nina is making a return.

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: (9/16) The latest images depict a thin steady stream of cool water was present on the equator from Peru tracking up the coast then turning west at Ecuador and building out to 160W. Markedly cooler water was in waves between the Galapagos to the dateline. Cooling was building along Chile and Peru too. A homogenous area of warm water was along Central America up to Southern Baja. Overall this seems to indicate the return of cooling water temps and La Nina. The question is - For how long?
Hi-res 7 day Trend (9/16): A mix of weak warming and cooling waters were in a line from Ecuador out to 140W. Nothing of interest was west of there.
Hi-res Overview: (9/16) A thin stream of cooler than normal water was aligned on the equator from the Galapagos to the dateline. Cooler than normal waters were south of that line down to 20S. Warmer than normal waters were limited to a line north of the equator up to Mexico and along the US Coast up to the Golden Gate. A clear cool outflow is in place pushing from California southwest to the a point over Hawaii's Big Island. It is stable but weak. La Nina appears to be trying to make a resurgence on the equator but fading north of there.
Nino1.2 Daily CDAS Index Temps: (9/17) Today's temps were falling to -0.750 after falling to -0.927 on 9/2 beating the previous peak low reading of -0.746 on 8/15. Before that temps were toggling around neutral 6/13-8/5 except for one dip to -0.411 on 7/8. Prior to that temps peaked on 3/16 when they briefly hit +0.714 degs. The longterm trend has been towards falling back into negative territory.
Nino 3.4 Daily CDAS Index Temps:
(9/17) Today temps were falling hard again at -0.351 after rebounding from a previous low of -0.370 on 8/22, the bottom of a downward trend that held for the previous 7 weeks. Before that temps peaked at 7/1 +0.332, the highest in a year. Temps previously had been steady near -0.222 since early March. Temps bottomed out at -1.654 on 11/3.

Click for Full Sized Image Click for Full Sized Image

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

SST Anomaly Projections
CFSv2 Uncorrected Data (9/17) - Actuals per the model indicate temps were rising in early Nov 2020 after bottoming out at -1.25 degs, building to -0.01 degs in mid-June then starting a steady fade from -0.3 degs in early Aug. The forecast indicates temps to make a dramatic fall reaching down to -1.75 later in November then holding through mid Jan 2022, then pushing up to +0.00 degs in May 2022. This model suggests a return of La Nina conditions this Fall and Winter. There is no indication that El Nino will develop. The PDF Corrected forecast suggests temp falling to -1.40 degs in Nov starting to rise slowly after mid-Jan 2022.
IRI Consensus Plume: The Aug 20, 2021 Plume depicts temps are at -0.41 degs today, and are to fade steadily to -0.57 degrees in Oct holding into Nov, then rising to -0.33 degs in Jan and neutral in March 2022. A weak return of La Nina is expected this Fall and Winter 2021-2022.
See chart here - link.

Atmospheric Coupling (Indicating the presence of El Nino in the atmosphere driven by the ocean):
Southern Oscillation Index (SOI) (negative is good, positive bad - this is a lagging indicator) (9/17): The daily index was rising steady at +14.50 today after peaking at +37.86 on 7/15. The 30 day average was rising to +10.34 today after falling to -3.36 on 6/22, the lowest in a year. It peaked at +19.51 on 1/14. The 90 day average was rising slowly to +9.03 after falling to it's lowest point in a year on 6/9 at +1.06. The 90 day average peaked at +15.75 on 2/23 (clearly indicative of La Nina then). This index is a lagging indicator but suggest La Nina is returning.

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 every 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). 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'). If anything it appears more likely we are still in the cool phase of the PDO.

See imagery in the ENSO Powertool 

Powerlines Jeff Clark Inside Mavericks

Local Interest
Stormsurf Video Surf Forecast for this week. See it Here
For automatic notification of forecast updates, subscribe to the Stormsurf001 YouTube channel - just click the 'Subscribe' button below the video.

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NBC News - Climate Change and Surfing:

Mavericks & Stormsurf on HBO Sports with Bryant Gumbel

Pieces Featuring Stormsurf:

Time Zone Converter By popular demand we've built and easy to use time convert that transposes GMT time to whatever time zone you are located. It's ion left hand column on every page on the site near the link to the swell calculator.

Surf Height-Swell Height Correlation Table


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