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Pacific Storm and Surf Forecast
Updated: Saturday, September 23, 2017 12:25 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
1.2 - California & 1.0 - 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 9/25 thru Sun 10/1

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   

No Swell Expected
Windswell the Only Hope


On Saturday, September 23, 2017 :

  • Buoy 106 (Waimea): Seas were 4.2 ft @ 11.1 secs with swell 2.4 ft @ 11.1 secs from 316 degrees.
  • Buoy 46025 (Catalina RDG): Seas were 3.7 ft @ 6.2 secs with west windswell 3.0 ft @ 6.0 secs from 268 degrees. Wind at the buoy was east at 4-6 kts. Water temperature 67.8 degs. At Ventura (Buoy 111) swell was 1.4 ft @ 8.7 secs from 255 degrees. At Santa Monica (028) swell was 2.1 ft @ 6.1 secs from 265 degrees. At Camp Pendleton (043) swell was 2.3 ft @ 6.3 secs from 264 degrees. Southward at Pt Loma (191) swell was 3.5 ft @ 6.3 secs from 292 degrees.
  • Buoy 46012 (Half Moon Bay)/029 (Pt Reyes): Seas were 6.8 ft @ 10.0 secs with Gulf windswell 5.5 @ 9.5 secs from 311 degrees. Wind at the buoy was north 12-14 kts. Water temp 61.2 degs.

    46006, 46059, 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 Saturday (9/23) in North and Central CA lingering residual Gulf windswell was hitting exposed breaks producing surf at chest to maybe head high and clean but unremarkable. Protected breaks were waist to chest high and clean. At Santa Cruz windswell was trying to wrap in with surf knee to thigh high and clean and gutless. In Southern California up north waves were thigh high and clean. In North Orange Co northwest windswell was producing waves thigh to waist high and clean but weak. In South Orange Co waves were thigh to maybe waist high and weak and textured. In San Diego surf was waist to maybe chest high on the sets and clean. Hawaii's North Shore was better than expected with rare sets in the chest to shoulder high range and clean. The South Shore was flat and clean. The East Shore was getting east windswell at thigh to waist high and heavily textured early from easterly trades.

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

Meteorological Overview
On Saturday (9/23) residual windswell from the Gulf of Alaska was still hitting California making for some rideable waves but nothing more. For Hawaii limited sideband windswell from the Gulf of Alaska was hitting the North Shore. The models suggest no obvious groundswell producing weather systems are to develop for the next 7 days either in the North or South Pacific. Windswell remains the best option for the short term, then even that fades away.

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

North Pacific

On Saturday AM (9/23) the jetstream was tracking east off North Japan on the 37N latitude line with winds up to 130 kts in one small pocket over the dateline almost trying to form a trough then splitting over the Central Gulf of Alaska with most energy ridging northeast pushing into Central Canada with the southern branch pushing over Central Baja. There was weak limited support for gale development in the dateline proto-trough. Over the next 72 hours
the same general pattern is to hold into Tues (9/26) with the jet tracking east off Japan with winds to 120 kts feeding the same semi-trough now repositioned east over the Western Gulf of Alaska offering very weak support for gale development in lower levels of the atmosphere. East of there the jet is to be ridging north and pushing into Southern Alaska. Beyond 72 hours the trough is to peak on Wed (9/27) being fed by up to 140 kts winds offering limited support for gale development while lifting north and pinching off into Thursday. Back to the west the jet is to start ridging north while building with winds 170 kts by Sat (9/30) tracking northeast off Japan pushing over the Western Aleutians tracking up into the Bering Sea, then falling hard south at 130 kts forming a pinched trough 700 nmiles northwest of Hawaii before ridging again to the northeast pushing up into British Columbia. There's to be little to no support for gale development in the pinched trough.

Surface Analysis
On Saturday (9/23) no groundswell was hitting either Hawaii or California. Residual windswell from a gale previously in the Gulf of Alaska was fading along the Pacific Northwest and California Coast and mixing with locally produced north windswell (in CA).

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

For windswell relative to California: High pressure at 1026 mbs is centered 750 nmiles west of North CA ridging weakly into into the North California coast generating a weak pressure gradient over North CA and north winds 20 kts resulting in limited north windswell for North and Central CA. The gradient and north winds to continue into Sun (9/24) covering a slightly larger area making for small short period northerly windswell again for North and Central CA. Monday the gradient is to build more with north winds 25 kts over North CA with windswell increasing some with the gradient starting to lift north on Tues (9/26) moving over the CA-OR border late with windswell size starting to fade in North and Central CA. North winds and the gradient are to be gone after that with no windswell forecast.

For windswell relative to Hawaii: East trades are to fall below the 15 kt threshold east of the Islands on Sat (9/23) and are not expected to exceed the threshold for the coming week offering no support for windswell production.


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


Tropical Update
No tropical systems of interest were occurring and none were forecast.

California Nearshore Forecast
On Saturday (9/23) high pressure at 1026 mbs was trying to ridge into the North and Central CA coast generating a weak pressure gradient and north winds at 20 kts over the area from Cape Mendocino nearshore then extending south to Big Sure but positioned 150 nmiles off the coast with light local winds nearshore from Bodega Bay southward. More of the same is forecast Sunday with north winds 20 kts over Cape Mendocino down to a point well off Big Sur a but light nearshore from just south of Pt Arena southward. The gradient is to build more over North CA on Mon (9/25) with north winds 25+ kts then lifting north Tues (9/26) with north winds still 25 kts early limited to Cape Mendocino drifting north with calm to northwest winds 5-10 kts elsewhere over the entire state. Light winds everywhere on Wed-Fri (9/29) 10 kts or less. North winds possibly building some Sat (9/30) to 15 kts over Cape Mendocino and Pt Conception.

South Pacific

Surface Analysis  
On Saturday (9/23) no swell from the South Pacific was hitting California or Hawaii and none was in the water tracking north.

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


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




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

North Pacific

Beyond 72 hours there low odds of a a low pressure system developing 1200 nmiles north of Hawaii on Thurs (9/28) producing up to 35 kt west winds on Fri (9/29) while lifting northeast through the Gulf with northwest winds building to near 45 kts over a tiny area later Friday, then continuing northeast fast on Sat (9/30) producing 40 kt northwest winds before moving into the Central Canadian coast in the evening. Seas building to 22 ft on Sat AM (9/30) at 46N 140W targeting the Pacific Northwest down to maybe Central CA. Low odds of any of this actually materializing.

For California a weak local pressure and wind pattern is forecast offering no potential for generating windswell.

For Hawaii trades are to be light, below the 15 kt threshold, with no rideable east windswell projected.

South Pacific

Beyond 72 hours no swell producing fetch is forecast.

More details to follow...


La Nina Pulse Fading - But the Damage is Done

The Madden Julian Oscillation 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.The paragraphs below analyze the state of the MJO in the Pacific and provide forecasts for MJO activity (which directly relate to the potential for swell production).

Overview: La Nina started developing in early 2016, but westward displaced and generally weak. And by March 2017, it was gone with suspicious warming developing along South America and over the Galapagos to a point south of Hawaii. By May the atmosphere returned to a neutral configuration and is holding.

KWGA/Equatorial Surface Wind Analysis & Short-term Forecast:
Analysis (TAO Buoys): As of Fri (9/21) the 5 day average indicated east winds were over the entire equatorial Pacific and moderate over the Kelvin Wave Generation Area. Anomalies were neutral over the East Pacific and weak easterly over the KWGA.
1 Week Forecast (GFS Model): (9/23) Moderate east anomalies were modeled building over the core of the KWGA. East anomalies are to be building back to strong status 9/24 holding through 9/29 then fading to moderate at the end of the model run on 9/30. This is not the Inactive Phase of the MJO, but is a full pulse of La Nina completely squashing the MJO. This is not conducive to storm development in the greater Pacific Basin.

Kelvin Wave Generation Area wind monitoring model: West and East

Longer Range MJO/WWB Projections:  
OLR Models: As of 9/22 a neutral MJO pattern was in control of the KWGA. The statistical model depicts a dead neutral pattern holding for the next 2 weeks. The dynamic model depicts the same thing but with a weak Inactive/Dry pattern trying to develop in the far West Pacific the last 5 days of the model run.
Phase Diagrams 2 week forecast (ECMF and GEFS): (9/23) The ECMF model depicts the Active Phase of the MJO weak and incoherent and is forecast to stay that way, perhaps becoming weakly defined in the West Pacific 4 days out, only to collapse a few days later. The GEFS model depicts the same thing.
40 day Upper Level Model: (9/23) This model depicts a very weak Inactive/Dry Phase over the Central Pacific with a neutral pattern everywhere else. The Inactive Phase is to track east into Central America on 10/13. Another weak Inactive Phase is to follow in the West Pacific 10/11 easing east to Central America into the end of the model run on 11/2. This model runs about 2 weeks ahead of what happens at the surface.
CFS Model - 3 month (850 mb wind): (9/23) This model is having technical difficulties. It depicts a strong version of the Inactive/Dry Phase of the MJO building over the KWGA with the Active Phase moving east and out of the KWGA with modest east wind anomalies over the far West Pacific. Those anomalies are to fade even as the Inactive Phase tracks east over the West Pacific through 10/8. After that a very weak pattern is forecast through 11/1 with neutral wind anomalies forecast. After that the the Active Phase build 11/8 with west anomalies in control holding through 11/25, fading with a weak Inactive Phase building with west anomalies still in control through the end of the model run on 12/21. None of this is believable. The low pass filter indicates a very weak La Nina signal is in control of the KWGA and is to hold till 10/25, then building in coverage but quickly drifting east and out of the KWGA by the end of November. There's some sense the pattern is to start shifting east early November entirely east of the dateline. Best guess is a very weak directionless and low energy weather pattern biased towards La Nina redeveloping in Fall of 2017. It will take 5 years for the Pacific to recharge from the 2014-16 El Nino.

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

Subsurface Waters Temps
TAO Array: (9/23) A pattern change set up in August, with warm water retreating to the west and cooler water building in the east. Today in the far West Pacific water temps had fallen to 29 degs centered at 160E. The 28 deg isotherm line is steady at 174W. The 24 deg isotherm is stable at 125W today but shallow at 60 meters deep at 140W. Anomaly wise a clear change is present in the East Pacific with warm water gone and turning neutral to weakly negative +0.0 to -1.0 degs at the surface and up to -3.0 degs at depth at 140W indicative of La Nina. Warm anomalies are isolated to the West Pacific at +1.0 degrees down to 100 meters deep with the dividing line between cool and warm at 170W. The hi-res GODAS animation posted 9/15 depicts the same thing, but with more cool water east and less warm water in the west. It looks like the cool water pocket at depth in the East Pacific is poised to erupt to the surface while east winds push all warm surface waters of the equatorial Pacific to the West Pacific. The GODAS image appears to be about 1 week behind the TAO data.
Sea Level Anomalies: (9/15) Negative anomalies are in control at -5 cms from 170W to Ecuador with a large pocket of -10 cm anomalies now present between 110W-160W suggesting a building cool pool at depth. This is not good.

Surface Water Temps: The more warm water in the equatorial East Pacific means more storm production in the North Pacific during winter months (roughly speaking). Cold water in that area has a dampening effect. Regardless of what the atmospheric models and surface winds suggest, actual water temperatures are a ground-truth indicator of what is occurring in the ocean. All data is from blended infrared and microwave sensors.
Satellite Imagery
Hi-res Nino1.2 & 3.4: (9/22) The latest images (1.2 3.4) indicate a clear cold pattern has developed on the equator. Upwelling is strong nearshore along Peru and Ecuador tracking solidly northwest then building in density over the Galapagos and flowing steadily west from there on the equator and well defined out to 160W. There is no breaks in the cool stream over this entire area. This looks very much like a classic La Nina signature. Cooling in the heart of the Nino3.4 region is building.
Hi-res 7 day Trend (9/21): A neutral temperature trend is along Peru off Ecuador and the Galapagos becoming warmer from there out to 120W with fragmented cool and warm pockets interspersed out to 160W.
Hi-res Overview:
(9/21) A clear La Nina cool stream is present starting off Southern Chile pushing north up Peru then turning northwest off Ecuador building strongly while tracking west from the Galapagos to 140W and moderate out to the dateline. This pattern outlines the South Pacific high pressure system well which is assumed to be stronger than normal. There is no sign of warm anomalies in the Nino 1.2 or Nino3.4 regions. Otherwise waters of all oceans of the planet are warmer than normal other than the aforementioned stream. We now assert that climatology needs to be updated to reflect the new reality of warming ocean temperatures over the entire planet.
Nino1.2 Daily CDAS Index Temps: (9/23) Today's temps were steady at -1.31, down markedly from 2 weeks ago.
Nino 3.4 Daily CDAS Index Temps: Today (9/23) temps have bottomed out and are rising slowly at -0.611. The long arc suggests a clear downward trend.

Click for Full Sized Image

CFSV2 Forecast for Nino3.4 SST Anomalies

SST Anomaly Projections
CFSv2 Uncorrected Data (9/23) The forecast has temps falling steadily from -0.5 degs early Sept to -0.7 in early Oct and down from there to -1.5 in Dec. Then the trend is to turn upwards rebounding to -0.35 in April and neutral in June 2018. This suggests a legit La Nina now expected for the Winter of 2017-2018. The CFS SST images (9/11) continues to suggest a modest La Nina cool pattern building on the equator off the Galapagos in Sept and building steadily into Jan/Feb 2018. A full on La Nina is setting up.
IRI Consensus Plume: The mid-Sept Plume updated (9/19) depicts temps forecast to fade -0.4 degs in Sept, and fading to -0.6 degs in Nov, slowly rising from there turning neutral in April 2018. See chart here - link.  The NMME consensus for Sept average indicates temps -0.75 degrees below normal Nov-Jan 2018 then rebounding to normal in April. It sure looks like La Nina is on the way. The CFSv2 is the outlier, colder than all other models. Still, given all the oceanic signals, we a tending to side with it more than the other models.

Atmospheric Coupling (Indicating the presence of El Nino in the atmosphere driven by the ocean):
Southern Oscillation Index (9/23): The daily index was positive again at 6.36, rebounding from a 6 day negative run. The 30 day average was falling at 3.75. The 90 day average was rising at +4.39. This suggests a turn towards La Nina.
ESPI (like SOI but based on satellite confirmed precipitation. Positive is good, negative bad): (9/23) The index was falling again at -1.31 (up from -2.20 on 6/28/17 but still suggesting a turn towards La Nina). Last years La Nina reached -1.94 on 11/2/16. We're deeper than that now. So the index is about as negative as it was at the peak of last years (2016) La Nina. At this time it looks like La Nina is returning for a double dip/2 year La Nina (not unusual). This index is a forerunner of what happens in the ocean by 2-3 months in developing El Nino and La Nina events.

Pacific Decadal Oscillation: The PDO continues positive, though much weaker lately (as expected with La Nina setting in).
Per NOAAs index recent values (Jan-Dec): Jan 2017 = +0.10, Feb = +0.04, March = +0.12, April=+0.52, May=+0.30, June=+0.19, July= -0.50, Aug= -0.68. This continues to look like the warm phase of the PDO discounting the recent La Nina dip. No consistently negative readings have occurred since Feb 2014
The Washington EDU index (Jan-Dec): Jan 2017 = +0.77, Feb = +0.70, Mar = +0.74, April=+1.12, May=+0.88, June=+0.79, July=+0.10. No negative readings have occurred since Dec 2013
The PDO turned from a 16 year negative run (Jan 98-Feb 2014) in early 2014 and has been positive ever since (other than a few months of negative readings in Fall 2016, the result of a turn towards La Nina). Looking at the long term record, it is premature to conclude that we have in-fact turned from the negative phase (La Nina 'like') to the positive phase (El Nino 'like'), but the data strongly suggests that could be a possibility. By the time it is confirmed (4-5 years out), we will be well into it.

See imagery in the ENSO Powertool


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

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