Swell Classification Guidelines
Significant: Winter - Swell 8 ft @ 14 secs or greater (11+ ft faces) for 8+ hours (greater than double overhead).
Summer - 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).
Summer - 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.
Summer - up to waist high swell. Also called 'Background' swell.
On
Sunday, August 16, 2015
:
- Buoy 165 (Barbers Point): Seas were 3.8 ft @ 12.5 secs with swell 1.5 ft @ 13.4 secs from 201 degrees.
- Buoy 46025 (Catalina RDG): Seas were 3.6 ft @ 6.0 secs with swell 1.2 ft @ 15.4 secs. Wind northwest 10-12 kts early. At Santa Barbara swell was 2.0 ft @ 7.7 secs from 264 degrees. At Santa Monica swell was 1.2 ft @ 14.0 secs from 192 degrees. Southward from Orange County to San Diego swell was 1.5 ft @ 13.7 secs from 184 degrees.
- Buoy 46012 (Half Moon Bay): Seas were 4.9 ft @ 7.0 secs with swell 1.2 ft @ 14.3 secs. Wind northwest 14-18 kts. Water temp 61.0 degs. Note:
The hi-res Pt Reyes Buoy has been defunded and decommissioned. Funding comes from the CA Parks Dept. We're working to obtain info to e.cgiore ways to reactive this buoy.
PACIFIC OVERVIEW
Current Conditions
On Saturday (8/15) in North and Central CA at best breaks local north windswell was producing surf in the waist high range and clean with generally nice conditions. Down in Santa Cruz surf was knee to thigh high on the sets and inconsistent and clean but weak. In Southern California up north local windswell was producing occasional sets with waves in the thigh to waist high range and textured but reasonably lined up. Down south waves were waist high on the sets and textured breaking mostly just off the beach. Hawaii's North Shore was flat with some sideshore texture on it. The South Shore was getting bare minimal southern hemi background swell with waves thigh to waist high or so and clean at best breaks. The East Shore was getting tradewind generated east windswell with waves waist high and chopped from east trades.
See QuikCASTs for the 5 day surf overview or read below for the detailed view.
Meteorological Overview
For the North Pacific no large scale non-tropical swell producing weather systems were occurring. The remnants of Tropical Storm Molave were just west of the dateline but no fetch of interest was present resulting in no swell production. Two Tropical Storms were in the far West Pacific and not doing anything of interest just yet, but both are forecast to develop strongly. Regarding windswell, relative to California high pressure was starting to ridge into the North California coast and starting to generate the usual pressure gradient and small north windswell down into Central CA, expected to peak on Sun-Mon (8/17) then fade some only to return later in the workweek. For Hawaii, east windswell continues but is expected to be fading some Sunday (8/16) and then gone later Monday. For the southern hemisphere a .cgiit upper level flow continues to suppress storm production over the bulk of the South Pacific with no swell in the waters and none forecast. Maybe a small gale to actual develop under New Zealand on Wed (8/19) producing up to 28 ft seas, but that's it. Otherwise the El Nino base state continues to develop. We're continue waiting for the start of transition to a Fall influenced weather pattern.
SHORT- TERM FORECAST
Current marine weather and wave analysis.cgius forecast conditions for the next 72 hours
North Pacific
Overview
Surface Analysis
On Saturday (8/15) no swell producing fetch that wasn't tropical was occurring over the greater North Pacific (see Tropical Update section below for tropical details). High pressure at 1032 mbs was in the Gulf of Alaska starting to ridge into the North California coast generating a small but developing pressure gradient and north winds to 25 kts over Cape Mendocino with 15 kts winds down to Pt Conception with small north windswell starting to materialize at exposed breaks. For Hawaii the same high pressure system was generating trades at 15 kts east of and over the Islands, though with not 100% coverage in that area. limited east windswell was the result on exposed east shores. There's also low to almost no odds of tiny swell resulting for Hawaii from what was Tropical Storm Molave approaching the dateline on Thurs-Fri (8/14) (see Tropical Update below).
Over the next 72 hours relative to California the Gulf high pressure system is to continue ridge onshore Sun-Mon (8/17) with the pressure gradient growing moderately in coverage over North CA generating 25-30 kt north winds over and off Cape Mendocino with windswell peaking during that winds down into Central CA. The gradient is forecast to lift north and weaken Tues-Wed (8/19) with 20-25 kts winds migrating up off the Coast of Oregon and only 15 kts winds forecast near Cape Mendocino, with windswell fading significantly down into Central CA as a result. Relative to Hawaii trades driven by the same high pressure system to barely hang on in patches east of the Islands early Sun at 15 kts producing very limited east windswell and then even that to fade out. Fetch associated with the high is to all be well north of the Islands after that.
North Pacific Animations: Jetstream - Surface Pressure/Wind - Sea Height - Surf Height
Tropical Update (as of 12Z Sat 8/15)
TS Molave - On Thurs AM (8/13) minimal Tropical Storm Molave was tracking east-northeast off Central Japan almost mid-way to the dateline. Winds were only at 40 kts generating 13 ft seas per the official forecast and 22 ft per the model at 35N 158E. Winds held in the evening with seas to 20 ft at 36N 162E. The model suggested winds rebuild briefly Fri AM (8/14) to 50 kts with seas 24 ft at 38N 167E. The WindSAT satellite made a partial pass over the storm at 06Z Fri AM and confirmed winds at 40 kts, a little less that what was modeled. Per the models Molave faded with winds dropping from 38 kts in the evening (0z) with seas 24 ft @ 39N 171E. The WindSAT satellite made a pass over the storm at 19Z suggesting only 30-35 kt west winds. So the model was overhyping the winds and seas in this storm. Still, the track is encouraging and suggests El Nino is trying to feed the jetstream some, but not alot yet regardless of all the hype.
No swell of interest is expected to result for Hawaii or the US West Coast. But, just for fun, assuming some 13 sec energy does materialize, it would arrive in Hawaii (2,000 nmiles out) as follows. No odds for swell in CA being 3200 nmiles out. Monitor the buoys as an exercise:
Hawaii: Swell arrival on Tues (8/18) at 5 AM with period 13 secs from 306 degrees
Tropical Storm Goni: This system was 100 nmiles north east of Guam tracking west northwest with winds 45 kts and building, expected to continue on this track with winds to 115 kts on Tues PM (8/18) positioned 700 nmiles south of Southern Japan or 500 nmiles east-southeast of Taiwan. A slow fade to set in there after with Goni modeled impacting the southern end of Taiwan on Fri (8/21). No recurvature to the northeast is forecast.
Tropical Storm Atsani: Of far more interest is this system. Currently it is positioned 1,100 nmiles east-northeast of Guam tracking west-northwest with winds 45 kts. Steady strengthening is forecast with this system turning progressively more to the northwest. Atsani is to peak on Wed AM (8/19) with winds 130 kts at 20.5N 152.5E and making a gentle turn more northerly. Per the GFS model this system is to be on a northward heading at 25N 151E on Fri AM (8/21) with winds holding solid at 91 kts and seas 51 ft in it's east quadrant aimed north, and continuing that track into the weekend with seas 53 ft Sat AM (8/22) with winds 92 kts. The experimental 2 week hi-res FIM model suggests this system is to turn northeast on Mon (8/24) with winds still at hurricane force reaching a point a bit west of the dateline on Wed (8/26) and briefly stalling with winds at 65 kts and turning extratropical. It is to theoretically continue east-northeast from there while slowly loosing strength, pushing into the northwestern Gulf of Alaska south of the Eastern Aleutians on Fri (8/28) with winds 45 kts and dissipating from there. Certainly and interesting tease. But the models are notoriously inaccurate regarding tropical systems and especially a week or more into the future. Still, this system bears watching.
California Nearshore Forecast
On Saturday (8/15) high pressure at 1032 mbs was in the Gulf of Alaska ridging into North CA forming a gradient and generating north winds at 25 kts along the coast of Cape Mendocino with a near eddy flow from Pt Arena southward. The gradient and north winds to build Sunday at 25-30 kts with a weak eddy flow nearshore south of Pt Reyes, holding Monday, then fading Tues (8/18) as the high retrogrades with north winds down to 20 kts late. High pressure is to still be influencing the picture and pushing east again on Thursday with the gradient rebuilding over Cape Mendocino at 25+ kts with 20 kt north winds down to Pt Arena but winds light south of there. the gradient to hold if not build to 30 kts late Friday then rapidly dying Sat (8/22) down to 20 kts late over North CA.
South Pacific
Overview
Jetstream
On Saturday AM (8/15) the jetstream continued very .cgiit with the southern branch ridging hard south pushing into Antarctica southeast of New Zealand then running east slowly rising but never escaping Antarctic Ice until it got just east of the southern tip of South America. No troughs were indicated offering no support for gale development. The northern branch of the jet was tracking east as it has all summer from a point north of Northern New Zealand on the 28S latitude line with winds 140 kt winds in one pocket south of Tahiti but less everywhere else. A bit of a trough was south of Tahiti supporting formation of cutoff low pressure at the surface there and helping drive the SOI down some. From there the northern branch fell southeast merging with the southern branch forming a large ridge well off off the Chilean Coast. There was no support for gale formation by the jet in lower levels of the atmosphere. Over the next 72 hours more of the same is forecast but with the track of the southern branch of the jet moderating some over time and lifting north to 68S, but still totally over Antarctic Ice running due east and tracking under the southern tip of South America. Ice. A steep trough is forecast forming south of Tasmania on Sun (8/16) pushing well to the north but with no real wind energy in it offering little to support gale formation and then getting cut off by Monday. If anything, a new ridge is to start developing well southeast of New Zealand on Tues (8/18) pushing the jet in the Southwest Pacific down to 72S and back over Antarctica proper. In the northern branch the cut off trough south of Tahiti is to wash out with perhaps high pressure starting to build at the surface driving the SOI up some. Beyond 72 hours a new trough is to form south of New Zealand on late Tues (8/18) fed by 130 kt winds and trying to make progress into the greater Southwest Pacific late Wed (8/19) but quickly moderating while a big ridge develops east of there pushing the southern branch well into Antarctica. Limited odds to support gale development in the New Zealand trough. No real change is forecast in the northern branch except for a small trough forecast south of Tahiti on Wed (8/19) again perhaps supporting weak low pressure down at the surface nudging the SOI down some. A far greater trough is forecast forming in the northern branch northeast of New Zealand on Sat (8/22) perhaps tracking east and again pushing the SOI negative with luck.
Surface Analysis
On Saturday AM (8/15) high pressure at 1020 mbs was still positioned between the .cgiit jetstream flow southeast of New Zealand ridging south to 60S driving the storm track south over Antarctic Ice. Secondary high pressure was falling southeast from Southeast Australia ridging under New Zealand. Also high pressure was 1032 mbs was off Southern Chile. All this was driving the storm track well south of normal. No winds of 35 kt or greater were occurring anywhere over the South Pacific except in the far Southeast Pacific just west of the southern tip of South America, where 40 kt northwest winds were pushing towards Antarctica. Otherwise a cutoff low was between the .cgiit jetstream flow south of Tahiti helping to push the SOI into negative territory, but getting ready to exit the area. Over the next 72 hours The cutoff low south of Tahiti is to fade, but with a new cutoff low forming south of Tahiti starting late Tues (8/18).
Small South Pacific Gale
A small gale developed Wed PM (8/5) southeast of New Zealand producing 40 kt west winds and seas to 28 ft at 58S 162W aimed east. Those winds started fading Thurs AM (8/6) from 35 kts with seas fading from 26 ft at 57S 150W.
California: Low odds of swell arrival on Sun mid-day (8/16) with period 15 secs. Swell Direction: 200 degrees
South Pacific Animations: Jetstream - Surface Pressure/Wind - Sea Height - Surf Height
LONG-TERM FORECAST
Marine weather and forecast conditions 3-10 days into the future
North Pacific
Beyond 72 hours high pressure in the Gulf of Alaska is to again start ridging into North California on Thurs AM (8/20) reinvigorating the pressure gradient there with and north winds building back to 25 kts, pushing barely 30 kts on Friday then fading from 25 kts early Sat (8/22). 15 kt northwest winds to be pushing down into the Central CA coast. Windswell to build some in response to the winds over the North Coast. Relative to Hawaii spotty trades are to hold at 15 kts east and north of the Islands starting Wed (8/19) and continuing into the weekend. With luck some bare minimally rideable windswell to result along exposed east shores.
South Pacific
Beyond 72 hours a weak gale is to build south of New Zealand on Wed AM (8/19) producing 40 kt west-southwest winds and 30 ft seas at 60S 158E. Fetch is hold in the evening easing east with seas building to 34 ft at 58S 167E. More 40 kts fetch is to continue Thurs AM (8/20) but aimed to the northeast with 33 ft seas at 55S 177E. Fetch to turn more northerly in the evening fading from 35 kts with 30 ft seas at 53S 174W. A quick fade to follow. If this were to come to pass some modest southwest swell would result for Tahiti, Hawaii and the US West Coast. No other swell source is indicated.
Also the cutoff low south of Tahiti is to track slowly east helping to keep the SOI negative into late Thurs (8/20), then moving east of the area. Another weak low to develop in the same area on Sat (8/22).
Details to follow...
MJO/ENSO Update
Galapagos-Ecuador SST Anomalies Crashing
Strong Kelvin Wave Building Just West of There
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 equatorial Pacific it is in control of, and in it's Active Phase by slack if not an outright reversal of trade winds and enhanced 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.cgianet, 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 help support the formation of El Nino. During the Inactive Phase the jet stream tends to .cgiit resulting in high pressure and less potential for swell producing storm development. 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: A strong El Nino is developing. It began its lifecycle in late 2013 as a primer WWB and Kelvin Wave developed. Then in early 2014 a historically strong push by the Active Phase of the MJO resulted in a large Kelvin Wave, and anomalies continued in the Spring into early Summer transporting more warm water eastward. But the cycle faltered in July due to a protracted bout of the Inactive Phase of the MJO which enabled the upwelling phase of the Kelvin Wave cycle to manifest driving cooler water east, muting warm water buildup along the Ecuador coast. Still the warm water pipe remained open, but surface temperatures near the Galapagos never recovered and any atmospheric momentum was lost. Then in early 2015, another historically strong push from the MJO occurred, effectively a repeat of the early 2014 event, invigorating the warm water transport process and, adding more heat to an already anomalously warm surface pool off Ecuador. That pool has been building steadily in spurts ever since. The paragraphs below describe the current status of various El Nino indicators, followed by a few paragraphs that tie all the pieces together and provide our analysis of what is to come.
(1st paragraph in each section is new/recent data and is typically updated with each new forecast. 2nd paragraph, where present, provides analysis and context and is updated only as required).
Atmospheric Co.cgiing Index's (lagging indicators rather than driving oceanic change): As of Thurs (8/13):
Daily Southern Oscillation Index: Was falling at --31.70, adding another 4 days below -10 and coming 3 days after a 17 day run of numbers below -10 with 10 days of that below -20.
30 Day Average: Was falling from -18.55, responding to the 10 day negative dip above. It was it's lowest point in years on 7/18/15 at -20.49.
90 Day Average: Was falling slightly at -12.21. It has been at or below -10.0 since early July and bottomed out at it's lowest reading in year on 8/5 at -14.17.
Trend (looking for negative SOI numbers, indicative of the Active Phase of the MJO or El Nino): The near term trend based on the daily average was indicative of a building El Nino base state. The longer term pattern was indicative of a steadily building El Nino base state.
SOI Trend - Darwin (looking for high pressure here): High pressure was over Southeast Australia at 1028 mbs helping to drive the SOI negative. A slow fade is forecast setting in on Mon (8/17) with lower pressure building over East Aus on Thurs (8/20). But modest high pressure to return thereafter at 1016 mbs through Sun (8/23).
SOI trend - Tahiti (looking for low pressure here): An upper trough was supporting modest low pressure south of Tahiti on Sat (8/15), but that is expected to be r.cgiaced by weak high pressure Sun-Mon (8/17) fading, with weak low pressure returning on Tues-Thurs (8/20). Weak high pressure is again forecast Friday with low pressure trying to get a foothold by Sun (8/23)
SOI 1 week Forecast: The net result is to be a steady negative SOI into the weekend, then rising Sun-Tues (8/18) before falling again through Thurs (8/20), then rising again.
SOI Analysis: During El Nino, the SOI functions as a measure of how well the ocean and atmosphere are co.cgied. Current numbers suggest good but not great co.cgiing. that will likely change for the better as the El Nino base state builds as we move into Fall. A consistent 90 day average of -18 is our target, indicative of a strong El Nino.
Southern Hemi Booster Index (SHBI) Analysis: South winds have again returned to East Aus offering some support for the SHBI (which is theorized to supercharge a developing El Nino). South and southeast wind anomalies have been building in this region off and on for weeks now (previous run 7/29-8/10, this run 8/13-8/15). South winds are forecast continuing into Sun (8/16), fading, then redeveloping on Mon-Wed (8/19), then fading though 8/23. The SHBI appears to positively influencing El Nino development, but we have no hard numbers to confirm.
ESPI (like SOI but based on satellite confirmed cloud cover): (8/15) Today's value is +2.53 and has been steady in the +2.5 range since 8/10. We just started following this index. Historically the peak of the '82 El Nino was +2.2 and the '97 event +2.85. This suggests the '15 El Nino is already very well co.cgied with the atmosphere, more so than some of the other indices indicate.
Equatorial Surface Wind Analysis & Short-term Forecast: As of Sat (8/15):
7 Day Models: Models are not updating. Owner is working to rehost on a new server.
Analysis from TAO Buoys: Down at the surface the TOA array (hard sensors reporting with a 24 hr lag) indicated strong south winds (not anomalies) at 160E giving way to modest west winds on the dateline. The GFS model suggests south winds at 14 kts between 150E-155E giving way to calm winds east of there (5 kts or less). Anomaly wise - Strong southwest anomalies continued from 165E to 180W in the heart of the KWGA, then turned to moderate west anomalies from there to 165W. Normal winds continued east of there. This west winds pattern continues impressive but looks to be fading now. These west anomalies are purely a function of the El Nino base state enhanced by a small Rossby Wave, but that is all but gone now. These anomalies remained virtually unchanged for the past 25 days (7/19-8/15) and followed directly behind a very strong WWB burst (third of the year) that was associated with a robust Active Phase of the MJO (historically strong) 6/24-7/17 (nearly 2 months of west anomalies or stronger).
1 Week Forecast: Decreasing weak west anomalies are to hold from the dateline and points east in the KWGA. But the CFS model continues to hint at weak east anomalies developing in the Western KWGA on 8/17 and holding at least through 8/22 and possible 9/9 associated with the Inactive Phase of the MJO. Still west anomalies to continue from the dateline eastward. Something to monitor for.
A huge WWB occurred in March followed by a second smaller one (9 day duration) in early May with weaker but still solid west anomalies continuing after that through 6/10. Anomalies faded to neutral for 8 days through 6/18 as the Inactive Phase of the MJO interfered with the pattern (the first such event of the year), then weak westerlies started again on 6/18. A significant WWB, the strongest of the year so far, starting on 6/26 peaking near 7/4 but held nicely through 7/17 (22 days), the result of a historically strong Active Phase of the MJO which produced a strong and large Kelvin Wave, the third this year and the strongest by far. Moderate westerly anomalies redeveloped thereafter until 7/29 when a Rossby Wave started interacting with the building El Nino base state, enhancing the westerly flow, developing a mini-WWB at 175E through 8/5. And westerly anomalies continue through today (8/15). That is nearly 2 months of non-stop anomalies if not out and out west winds (6/26-8/15). West wind anomalies at the surface are the hallmark of the Active Phase of the MJO and El Nino and drive Kelvin Wave production.
Kelvin Wave Generation Area monitoring model here
Longer Range MJO/WWB Projections: As of 8/15:
OLR Models: Indicate a dead neutral MJO signal over the West Pacific. The Statistic model suggests a weak MJO pattern is to hold for the next 15 days. The Dynamic model depicts and even stronger dead MJO signal for the next 15 days. In essence no MJO influence is forecast. This is typical of the pattern when an El Nino base state strengthens.
Phase Diagrams 2 week forecast (ECMF and GEFS): They suggest the Active Phase of the MJO is weak and collapsed and is to not return.
40 Day Upper Level Model: It depicts a weak Active MJO pattern fading while tracking east over the Central Pacific. A moderate Inactive Phase is to develop in the far West Pacific 8/20 tracking east through 9/19. This makes sense given the CFS forecast for weak east anomalies in the far west KWGA for the next few days if not 3 weeks. It is suspected a little bit of destructive interference to develop regarding surface west anomalies west of the dateline from this weak Inactive Phase. The stronger El Nino base starts it's influence from the dateline heading east.
CFS Model beyond 1 week (850 mb): A weak Inactive MJO influence is forecast 8/17-9/24, but westerly winds are to persist minimally from the dateline east. Some positive enhancement from Rossby waves might result for a few days around 9/4 and then again on 9/14 through 9/24, with a major push of the Active Phase of the MJO remaining scheduled starting Sept 25 in the far West Pacific holding till 11/13. No easterly anomalies are forecast for the long term.
The general consensus by the models is that we are to hold in a neutral to slightly Inactive MJO pattern for the next 4-5 weeks, then perhaps giving way to the Active Phase. In reality, a pure El Nino base state is at.cgiay driving current west anomalies and not expected to change much. Westerly anomalies, regardless of their source, are all that's required to push warm water to the east.
CFSv2 3 month forecast for 850 mb winds, MJO, Rossby etc
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.
Satellite Imagery
Low-res: On (8/13) first impressions continue indicating a moderate and somewhat decently defined El Nino pattern in.cgiace covering the entire equatorial Pacific. But compared to previous imagery (7/16), the pattern remains diffuse. There has been no increase in concentration of warm waters and if anything, the entire pattern looks less defined. Temperatures in the NINO1.2 region as of the latest image appear to be weakly loosing concentration, but not getting cooler. Along the West African Coast, cool water continues holding there. Very warm water continues off the US West Coast and if anything building while extending west the whole way to Japan but unrelated to this years El Nino, but possibly attributable to the building warm phase of the PDO. Slightly cool water is over Australia. Slightly warm water continues near Madagascar.
Hi-res Nino1.2: (8/15) Very bad news is developing here with anomalies rapidly fading east of 100W. Only limited pockets of +2.5 deg or greater anomalies are left, rapidly in decline starting 8/13, And this pocket is working it's way west over the Galapagos and tracking west from there. The upwelling phase of the Kelvin Wave cycle is here, or at a minimum a heavy backdraft from a huge Kelvin Wave building just east of the Galapagos is occurring. Peak temps occurred between the Galapagos and Ecuador on 7/14, then faded between 7/14-7/30 (and is reflected in the low res imagery too - see above). From 7/31-8/13 temps between Ecuador and the Galapagos stabilized then crashed starting 8/14.
Hi-res NINO 3.4: (8/15) Conversely a much different picture is in.cgiay here with unbroken +2.25 degs anomalies advecting west from a previous Kelvin Wave that impacted the Galapagos now reaching to 158W today, the furthest west so far. But the total thickness of the stream (coverage) is slightly less than days past (i.e. the stream is getting stretched while moving west with no backfill from the Galapagos occurring). Previously they reached to 133W as of 7/16 and then 138W (7/31) pushing to 149W on 8/10. This is advection west of warm water resulting from eruption of the 1st and 2nd Kelvin Waves earlier this year.
Galapagos Virtual Station: This station reported temps at +2.4 degs today (8/15) increasing from the low point of 2.0 degs on 8/10. Previously a solid reading occurred on 5/23 at +4.59 degs suggesting the first Kelvin Wave generated in Jan-Mar had arrived, then built to +5.45 degs on 6/14. Temps faded from that high peak down to +4.1 degs in late June then rebuilt up to +4.94 on 7/17. Then a fade set in, down to +3.1 degs as of 7/31 and bouncing from +3.1-3.5 through 8/7, then falling dramatically to 2.0 on 8/10. Much more warm water is poised at depth just off Ecuador (see below) and required immediately.
Other Sources
TAO Data: +1.0 anomalies are in control over most entire equatorial Pacific, the warmest in years, presumably advecting west from the Galapagos covering the entire area west to the dateline. A previous pool of +1.5 deg anomalies on the dateline has vanished. There is an embedded area of +2.0-2.5 deg anomalies extending from the Galapagos to 145W with +1.5 deg anomalies reaching to 150W (holding) Overall the warm water signature is holding but not migrating west any. This is likely the peak for a few months.
Nino1.2 Index Temps: (8/15) Temps are steadily fading, down to +1.7 degs, presumably the result of the backdraft occurring off Ecuador. Previously temps hovered at +2.1 degrees early June then spiked reaching +3.0 degs on 7/3, faded then spiked again on 7/13 at +3.0 degs and yet again at +3.0 degs on 7/22. Temps fell to +1.9 degrees on 7/27 and have been steadily fading from there.
Nino 3.4 Index Temps: Temps are up some today at +1.83, having just beat the previous all time peak (so far) for this year event on 8/10 at 1.8 degrees. Water temps previously held in the +1.0-1.3 deg range since mid-April, then started building pushing +1.5 degs on 6/30, held then crept up, peaking at +1.75 degs on 7/19 and +1.7 degs on 7/29 and then peaking at +1.8 of 8/10.
If one is to make a direct comparison of the 2015 event to '97 at this time of year based on water temp alone, there is no comparison. '97 imagery leaves this years event in the dust. This is not unexpected given the freight train consistency of WWBs leading up to the '97 event. This years event is building, but at a slower pace and in fit's and starts, but with an underlying deliberateness just the same. Total coverage of warm waters in the current imagery still remains respectable, but the depth of concentration is not in the league of '97. And as of today, a clear and significant downgrade is occurring in the Galapagos area, as evidenced by the apparent drop-off of NINO 1.2 water temps, the hi-res satellite data and the hi-res temp trend imagery for the past 7 days. This is likely the result of a pause in upwelling of warm water in that region, a break between the first and second Kelvin wave eruptions and the third poised just off Ecuador. This could be true Upwelling Phase of the Kelvin Wave cycle. But we suspect it just a backdraft or pull back of warm waters ahead of a massive Kelvin Wave set to erupt in the Ecuador region in the next week. But, the point is, until that eruption occurs, these cooler water will advect west and eventually negatively impact temps in the NINO3.4 area, driving it down too. There appears to be.cgienty of water poised in the subsurface reservoir, and if anything, is building driven by the strength and duration of the most recent WWB (late June) when the resulting Kelvin Wave hits (peak temps in Nino 1.2 expected 10/4). Still given the current pause in warming near the Galapagos, no additional expansion of the warm pool is expected in the short term. This is the opposite of what would be expected if one were trying to compare 2015 to '97. Still, this pause is temporary, with much warming, the biggest yet of this event, still in the pipe.
Subsurface Waters Temps
TAO Array: (8/15) On the equator and under the dateline (160-180W) temperature anomalies have rebuilt significantly. 29 deg temps are between 165E to 140W with a pocket of 30 deg temps pooled up at 152W, 70 meters down. +2.0 degs anomalies are fully bulging from the dateline eastward and +4 deg anomalies taking root from 152W eastward (holding), the direct effects of the massive June-July WWB. A large warm reservoir at +5-7 deg above normal is poised to erupt into Ecuador. That reservoir is holding coverage with peak +7 degs anomalies centered at 110W (holding) and +5 deg anomalies extending east from 141W to Ecuador (holding). This pocket is a mixture of warm water from a WWB in early May merging with water from the most recent strong WWB in late June-July. The pipe is open with more warm water rushing in and very warm water poised to erupt into the Galapagos.
Sea Surface Height Anomalies (SSHA): Data from 8/11 depicts 0-+5 cm anomalies over the entire equatorial Pacific starting at 175E with a expansive core at +15 cm from 110-150W (holding). No anomalies were from the Galapagos to Ecuador. This is most impressive. All this is indicative of a wide open pipe with a large Kelvin Wave in flight in the mid-Pacific poised to merge with a subsurface reservoir poised off Ecuador. This is a classic major El Nino setup, not a standard El Nino.
Upper Ocean Heat Content: As of (8/11) this data drives the point home. It indicates +0.5-1.0 deg anomalies are tracking east between 180W and the Galapagos (holding). +1.0-1.5 degs are from 171W eastward. +1.5 deg anomalies are doing the same easing east from 155W. All these sectors are sliding east slightly. A pocket of +2.0 degs anomalies are at 151W-->108W (holding) with a large pocket of +2.5 deg anomalies between 146W-->118W (holding). A pocket of cooler 0.5-1.0 degs anomalies is holding between the Galapagos and Ecuador (from 91W-80W) and not moving east. this is the backdraft pool.
A strong Kelvin Wave impacted the Ecuador Coast in May-June with a second somewhat weaker one impacting it in June. And now a third is setting up, the strongest of all an getting stronger with each update. The pause in warming near Ecuador is evident in the subsurface data too, suggestive of a break between successive strong Kelvin Waves. And that gap is not getting smaller (i.e. moving east). If anything, it is holding, and appears to be influenced by backdraft from the expanding 3rd Kelvin Wave developing west of it. We're beginning to be disposed to say that a Upwelling Phase of the Kelvin Wave cycle is occurring. Still no 'cooler than normal' waters are expected to result, just a pause in the steady incremental increase in surface warming. But that will likely have an affect on the overall heat signature at the surface, reducing it some in the short term (as is currently occurring in Nino1.2). We've calculated Kelvin Wave arrival using satellite data to identify the leading edge of it and using 2 and 3 m/sec travel speeds. The eruption should be poised to occur now. But based on satellite and other data, no eastward movement of the leading end of the Kelvin Wave is occurring. This suggests is is still organizing east of the Galapagos.Regardless, the subsurface configuration suggests there are 2.5 months of warm water in this reservoir (till Nov 1) and some of that water is extremely warm. And with an expected pause now setting up in the KWGA of westerly anomalies, the question becomes, is this third Kelvin Wave the final one, or will another follow? We al hope the answer is more is on the way. but that is entirely dependent upon how strong the El Nino base state really is. Historically this is a great setup if we can just get through the short term 'pause' and then get another WWB behind that.
North Pacific Jetstream: As of Sat (8/15) a weak flow was continuous across the North Pacific roughly centered at 50N. A bit of a .cgiit was occurring from the dateline westward. This is not impressive but suggests some weak influence by El Nino is occurring by virtue of the jet being present at all south of the Aleutians. More of the same is forecast over the coming week but with a trough forecast developing in the Northern Gulf Sun (8/23) pushing the jet there down to 48N and the southern branch of the .cgiit in the west building down at 40N . But as of right now it's unremarkable.
Pacific Counter Current: As of 8/6 the current continues solid and building. The current is pushing strongly west to east over the west equatorial Pacific filling the Kelvin Wave Generation Area then lifting a bit north of the equator and still solid from 160W to 120W before fading out. A pocket of modest east anomalies was over the immediate Galapagos. Anomaly wise - Strong west anomalies were spread on the equator over the West Pacific to the dateline, then lifting a bit north of the equator from the dateline to 130W, then fading but continuing to 100W. Light west to east anomalies were also south of the equator from the dateline to 110W. This is fairly impressive, suggesting this event is getting legs. Compared to the '97 El Nino at this time, today's image actually beats the imagery for '97. This is the first time this has happened.
SST Anomaly projections (CFSv2 model - PDF Corrected): For the model run 8/15 for the Nino 3.4 region, peak temperatures have stabilized. It suggests water temps are at +1.6 deg C (verified at 1.62 degs today) and are to steadily warm continuing to +1.9 degs by Oct peaking at +2.0 degs by Nov, then dropping off. Even given the current pause occurring In Nino1.2, and considering the size of the new Kelvin Wave forming subsurface, we suspect this projection is on the low side. The mid-July consensus Plume suggests development of a strong El Nino with peak temps (depending on model type) spread between 1.5-2.0 degs above normal. See the chart based version here - link.
Analysis: In late 2013 into 2014 the Active Phase of the MJO and successive Kelvin Waves warmed waters over the Eastern equatorial Pacific and primed the atmosphere out of a 15 year La Nina biased pattern that had been in.cgiay since the demise of the '97-98 Super El Nino. It is assumed some greater force was dictating the change from a cool regime to warmer pattern, (the PDO). This warming and teleconnection continued building in 2015 with two Kelvin Waves arriving in Ecuador warming surface waters well into El Nino territory and a third, the strongest so far, in flight now. Preceding this Kelvin Wave is a pocket of less warm water. But with a large warm reservoir lodged just west of the Galapagos and the third Kelvin Wave directly behind, warming is expected to resume shortly. At this time we believe the classic El Nino feedback/teleconnection loop is in effect, with the atmosphere and the ocean are well co.cgied.
A si.cgie glance at the SST Anomaly charts suggest a well developed El Nino pattern is in.cgiay. The big question then becomes: How strong will this El Nino become? That is purely a function of the strength and duration of westerly anomalies in the Kelvin Wave Generation Area. And the frequency of those events is dictated by the character of the El Nino. All El Nino events are different. The pace of the WWBs and Kelvin Waves, their duration, depth and speed all help to define any given ENSO event. The '97 event was fast paced and furious, with no breaks, transitioning from La Nina to the strongest El Nino ever (by some measures) in a quick 7 month window starting 4/23 peaking on 11/26 (+2.69 deg). The '82 El Nino took longer to build starting in May and peaking in late Jan of '83 (+2.8 degs) (data OISSTv2). Other strong events in '72, '86, and '91 had dissimilar profiles. The point being, there is no exact te.cgiate for a strong El Nino other than they tend to form in the Spring and peak during the following Winter. And regarding the exact micro-details of each WWB, the resulting Kelvin Wave speed and arrival time in Ecuador etc, all vary though fall into the general guidelines established above. Given the false start of this El Nino in 2014 (and for that matter the other false start in 2012), this event has taken it's sweet time getting organized. But it's been struggling against an atmospheric bias towards La Nina driven by the cool phase of the PDO. We believe the atmosphere is trying to transition to the warm phase of the PDO, but is still fighting momentum from the cool phase, hence elongating this El Nino's lifecycle. And regarding the 'warm blob' off the Pacific Northwest, we believe that is more a symptom of the developing warm PDO, and will get punctured by incoming storms once El Nino gets traction and the jetstream energizes in the late Jan/early Feb 2016 timeframe. Winds from storms cause mixing and upwelling, which in turn cool surface waters. Of course that assumes this El Nino event develops into at least Strong if not Super status.
The longer it takes El Nino to develop, the thought is it will take proportionally longer to dissipate. That is, once El Nino atmospheric momentum takes hold, and if it takes longer to make that transition, it will be more stubborn and take longer to dislodge. There is no scientific data to support that thesis, it's just an opinion. But if the Active Phase of the MJO does develop in the Sept/Oct timeframe as predicted by the CFS model, and if a significant Kelvin Wave results, it would not arrive in Ecuador till ~Jan 1, 2016, and not disburse till a month later (Feb). That said, the character of this event is not at all like '97, but is starting to show signs of developing slower, like '82. And that would not be a bad thing, in that it could slow the inevitable transition to La Nina until later in the winter of 2016-2107.
Finally the discussion of 'atmospheric co.cgiing' needs to be considered. How much affect is El Nino having on the atmosphere? That is ultimately what impacts the jetstream and fuels winter storm development. The SOI is one such indicator. Changes in surface wind in the equatorial West Pacific another. But it is the total effect of El Nino on a wide variety of indicators, and the weighting of those indicators into a single number that can be used to track this event against others. This approach provides a clearer picture, where tracking an individual condition in the absence of others leads to a less comprehensive view. NOAA has developed just such an index, the Multivariate ENSO Index. It is used for research purposes, but is useful for our need too. It is conservative, has a pedigree, and has been hindcast tested against previous ENSO events. Per the MEI, the top 5 events since 1950 in order are: '97, '82, '91, '86, and '72 with '97 and '82 classified as 'Super El Nino's' because they reached 3 standard deviations (SD) above normal. '91 and '86 were at about 2.2 and 2.1 respectively with '72 peaking at 1.8 SD's above the norm. The current ranking (July) for 2015 is 1.97 SD (65). At this same time in '97 the ranking was 2.85 SD (66) and in '82 it was 1.7 SD (61). So we're slightly above the '82 event but well below '97, or comfortably on track for this time of year to move into Super El Nino territory. And even more interesting, the MEI for July actually went down (0.09 SD) from last month. Suffice it to say were are somewhere between '82 and '97 in term of of atmospheric co.cgiing.
So where does it go from here? Having a MEI that today is equivalent to two other Super El Nino events is no guarantee that this years event will eventually evolve into a Super El Nino. We still have 1.0 SDs to go. Though looking at the record back to 1950 for other events that have similar values in July, the odds favor that outcome. Still, the argument goes back to monitoring WWB and Kelvin Waves. That ultimately is the best leading indicator of what's to come. The more west anomalies, the more warm water gets pushed down into the pipe and the rest turns into an assembly line process with a more or less fixed outcome. Said another way, it appears an evolving El Nino base state is in control and building which in turn should dampen any future Inactive Phases of the MJO cycle and/or potential for easterly anomalies. This is required for a major El Nino to develop. So the current concern is focused on the pause in warming in the Nino 1.2 region and it's eventual impact as it advects into the Nino3.4 region. But again, with a very vigorous Kelvin Wave locked and loaded in the pipe poised to erupt near Ecuador in the next few weeks, it seems the nearterm outcome is certain. The future concerning more and stronger WWBs is unknown, but we are betting on the CFSv2 being largely on the right track with the El Nino base state slowly having greater influence over time and being enhanced by the MJO and Rossby Waves at times. And that doesn't count the change of seasons scheduled to start in early Sept, again favoring enhancement of the El Nino base state and the MJO. We just need to get though the next 3 weeks.
So for now we're tracking towards an El Nino that will end up somewhere between the 82' and '97 event, with very good atmospheric momentum in.cgiay, and that's a good.cgiace to be. We'll continue monitoring the North Pacific jetstream and will be looking for tropical activity in the West Pacific to recurve northeast moving towards the Gulf of Alaska, and for swell to result from such systems in later August and Sept. To us, those are the sure signs of deep changes in the atmosphere influenced by El Nino. Until then, continue on your training routines and complete.cgians to procure additional boards. And if you own beachfront property in California, pay your insurance premiums.
See imagery in the ENSO Powertool
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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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