2015 El Niño?

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has drifted up to -17.6:

[AbruptSLR]

Per the attached plot issued today by the University at Albany, the 5S-5N 850-hPa Wind Anom forecast from Sept 30 to Oct 7 2015; confirms that the up-coming strong WWB even will last at least from Oct 3 thru Oct 5, and should clear help to strengthen the current strong El Nino event:

[AbruptSLR]

The first attached image issued today by the BoM indicates that the 30-day moving average SOI has moved up to -17.1.

The second attached image as from the BoM shows the Eq Pacific Sub-surface Temp. and Temp Anom. for Sept 28 2015; indicating that warm water is quite deep in the Eastern Eq. Pacific; which indicates to me that the currently westward moving oceanic Rossby waves will soon be reinforcing the current EKW.

[citrine]

Oxfam predicts food insecurity in Africa due to El Nino:

Entering Uncharted Waters: El Niño and the threat to food security
http://www.oxfamamerica.org/explore/research-publications/entering-uncharted-waters-el-ni%C3%B1o-and-the-threat-to-food-security/

[AbruptSLR]

Oxfam predicts food insecurity in Africa due to El Nino:

Entering Uncharted Waters: El Niño and the threat to food security
http://www.oxfamamerica.org/explore/research-publications/entering-uncharted-waters-el-ni%C3%B1o-and-the-threat-to-food-security/

citrine,

Welcome to the 2015 El Nino! thread.  The following quote and first accompanying image shows that not only does this year's El Nino threaten food supplies in Africa but also in India, New Guinea and in many parts of Latin America.

Extract: "El Niño has also already reduced the Asian monsoon over India, and is raising the odds of a prolonged drought in East Asia, coinciding with the planting and early development of the main rice crop in Indonesia; if world prices for rice increase there could be knock-on effects
on poor urban consumers in import-dependent West African countries. In Papua New Guinea, 1.8 million people have been affected by drought already and El Niño will make this worse."

The second attached image from the University of Albany show the 5S-5N 850-hPa Wind Anom forecast from Oct 1 to 8 2015, indicating that a strong Westerly Wind Burst, WWB, should last from Oct 3 thru Oct 6, which will drive more warm water into the Eastern Tropical Pacific.

The third attached image shows NOAA's SSTA map for Oct 1 2015, which shows a cool spot near Easter Island, which indicates to me that the upwelling Rossby waves have reach at least this far west, and should collide with the new WWB driven eastward downwelling EKW pulse by the end of October, within the Nino 3.4 zone thus likely driving our current strong El Nino into a Super El Nino status.

Best,
ASLR

[Clare]

The El Nino warnings here for NZ farmers have been ramped up considerably with this advisory. On the North Is east coast where I live we have already had low winter rainfall ('til last week, when we got a reprieve which should help delay things a bit) & we can get terrible drought conditions. Farmers will be looking to sell stock etc. The NZ economy could potentially take a big hit.
I am readying lots of mulch for my vege garden as we will likely get water restrictions. 

Strongest warning yet for horror summer El Nino
6:26 PM Thursday Oct 1, 2015"New Zealand has today received the strongest warning yet that it's gazing down the barrel of the worst El Nino summer since the calamitous 1997/98 event that cost the country hundreds of millions of dollars. The severe drought caused by the 1997/98 El Nino was later estimated by the New Zealand Institute of Economic Research to have caused a loss to agriculture of $618 million - or close to one per cent - to GDP."
http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=11522259

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has dropped down to -17.8:

[AbruptSLR]

The first attached Earth nullschool map issued today for the 850-hPa & MSLP for Oct 4 2015, show the unusual mechanism that driving the up-coming strong WWB.

The second attached University at Albany 5S-5N 850-hPa Wind Anom forecast from Oct 2 thru 9 2015; shows that this unusual WWB mechanism will extend this strong WWB from Oct 3 to beyond Oct 9 2015.  This will certainly strengthen our current El Nino into a Super status by the end of October (or by early November).

[AbruptSLR]

Per the following linked Weather Network article a Super El Nino has an ONI  (three-month average) value greater than +2.0C

http://www.theweathernetwork.com/us/news/articles/climate-and-environment/risk-of-record-setting-super-el-nino-rising/54173/

Extract: "First, the index used by NOAA to track the strength of El Niño, known as Oceanic Niño Index (ONI), is based on the average sea surface temperature anomalies over a three-month period. If ONI is 0.5oC (0.9oF) or higher, that is counted as an El Niño event, above 1.0oC (1.8oF) is a moderate event, above 1.5oC (2.7oF) is strong, and above 2.0oC (3.6oF) is very strong (or "super"). Weekly values in the model runs, however, can get lost in a three-month average. Thus, it's the longer-term look at the event that matters, not the short-term updates."

Therefore, to refine my statements about a possible Super El Nino, I mean that the SON 2015 (and possibly/probably the ASO 2015) ONI could be over +2.0C.

And you can track the ONI values here:
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml

[Lord M Vader]

If one extrapolate the ONI index for July-August-September, a reasonable outcome would be an ONI-number of +1,6. I agree that it seems likely that the ONI value should exceed +2,0 for SON.

Given that the imminent strong WWB materializes I think it would be possible to see an ONI-value for the period OND to be about +2,5... Such  high value would exceed the 1997-1998 El Niño event...

//LMV

[AbruptSLR]

Given the following weekly Nino 3.4 values, it appears probable that the ASO ONI value will be above +2.0C:

                     Nino1+2      Nino3          Nino34       Nino4
 Week           SST SSTA    SST SSTA    SST SSTA   SST SSTA
 05AUG2015     23.6 2.6     27.6 2.3     28.9 1.9     29.6 0.9
 12AUG2015     22.8 2.0     27.3 2.2     28.9 2.0     29.6 0.9
 19AUG2015     22.4 1.7     27.2 2.2     28.9 2.1     29.7 1.1
 26AUG2015     22.6 2.0     27.3 2.3     29.0 2.2     29.7 1.1
 02SEP2015     22.7 2.2     27.3 2.4     28.9 2.1     29.7 1.0
 09SEP2015     22.5 2.0     27.4 2.6     29.0 2.3     29.7 1.0
 16SEP2015     23.0 2.6     27.6 2.7     29.0 2.3     29.8 1.1
 23SEP2015     23.2 2.7     27.5 2.6     29.0 2.3     29.8 1.1

[werther]

Let me make a follower's contribution too. FWIW, the daily figures as presented through Tropical Tidbits are going through the roof. Big WWB as forecast?

[AbruptSLR]

Let me make a follower's contribution too. FWIW, the daily figures as presented through Tropical Tidbits are going through the roof. Big WWB as forecast?

werther,

I have found that the Tidbits daily values have a fair amount of noise, so I recommend waiting for the NOAA numbers on Monday as these directly contribute to the ONI numbers.

Best,
ASLR

[gregb]

Perhaps more evidence of a strengthening El Nino and the source of the beautiful weather we are experiencing here in the NW.

[AbruptSLR]

The attached plot issued today by the BoM indicates that the 30-day moving average SOI has dropped down to -18.5:

[Bruce Steele]

gregb, Doesn't look like " the blob " of old. Seems talk of the blob fighting back the El Nino will fade quickly if that low holds out for long. There is even a prediction of rain this weekend here in Central Calif. 

[bigB]

The 1st, 2nd, and 3rd attached images show the daily Nino 1+2, 3, and 3.4 indices respectively (courtesy Levi Cowan). As of October 2nd at 18z, all 3 of these regions were warming, with the Nino 3 and 3.4 regions reaching new all time highs (per this dataset). This is largely thanks to the current reversal of trades over the Western and Central equatorial Pacific.

The 4th attached image is a comparison of tropical Pacific SSTA for October 2nd, 1982 (top), 2015 (center), and 1997 (bottom). Per this data, we remain ahead of the 1982-83 event, but behind the 1997-98 event (in the E PAC).  I don't see any reason why this event won't continue to be comparable to the 1982-83 and 1997-98 super events, at least through October. If one looks at the SSTA maps (here: http://cci-reanalyzer.org/Reanalysis_daily/) for any other event since 1979, the 1982-83, 1997-98, and 2015-16 events are truly in a league of their own. 

PLEASE NOTE: The SSTA map for 2015 was generated from high resolution daily OISST.v2 data, while the maps for 1982 and 1997 were generated from CFSR data (slightly lower resolution). The climatological base period used for the 2015 map is slightly different than the climatological base period used for 1982 and 1997 maps. However, not enough to make a notable difference.

[bigB]

Ahh, the good ol' CDAS daily Nino indices vs. NOAA CPC (OISST.v2) Nino indices.

Perfect. I made the following attached images a while back (for another forum/El Nino thread) to show how the weekly NOAA CPC (based on weekly OISST.v2 data) Nino indices compare to the daily CDAS/tropical tidbits Nino indices. The weekly NOAA CPC values tend to run warmer in the Nino 1+2 and 3 regions, slightly warmer in the Nino 3.4 region, and pretty even in the Nino 4 region. The overall trend between the two datasets is relatively similar.

NOTE: I'm not sure if plotted the NOAA CPC values correctly, but close enough!!! The daily CDAS indices are fun to watch as long as one remembers to focus on the trend rather than a particular daily value. The weekly CPC (or OISST.v2) indices can run up to a week behind, so the CDAS daily indices can used as a rough estimate of what's to come.

[AbruptSLR]

First, this Long Paddock Station Daily SOI was -49.70 today, indicating strong forcing from the atmosphere to support a growing El Nino:

3 Oct 2015 1011.72 1016.55 -49.70 -19.93 -16.70

https://www.longpaddock.qld.gov.au/seasonalclimateoutlook/southernoscillationindex/30daysoivalues/

Second, the attached image shows that the WWB is weakened relative to yesterday, but remains strong.

[bigB]

ONI data just released...

http://www.cpc.ncep.noaa.gov/data/indices/

Per the NOAA ONI (based on ERSST.v4 data), the JAS ONI value came in at +1.46 deg C. On the ONI chart, it will show up as +1.5 deg C.

The Monthly ERSST.v4 value for September came in at +1.67 deg C .

The monthly OISST.v2 value for September has not yet been released, but will likely be +2.3 deg C.

Note: Per NOAA CPC, ONI values may change up to two months after the initial "real time" value is posted. Therefore, the most recent ONI values should be considered an estimate.

However, if they do change, it's usually not much.

VERY IMPORTANT NOTE: I did a little research and number crunching, and here's what I found. Per the NOAA CPC ONI, only 7 El Nino events since 1950 have achieved strong status (ONI value of +1.5 or greater). 86% of those events increased by at least +0.5 deg C after the July-August-September 3 month season. The 87-88 El Nino event makes up the 14% that did not. Here's a list of events since 1950 that have achieved strong status (in chronological order): 57-58, 65-66, 72-73, 82-83, 87-88, 91-92, and 97-98. Now the 2015-16 event (that makes 8 ), though it's not set in stone as ONI values can change up to 2 months after they are initially released. Nonetheless, the odds of this event achieving at least one ONI value of +2.0 deg C are very high based on historical data. REMEMBER, 6 of 7 past strong El Nino's have gone on to increase by at least +0.5 deg C after the JAS ONI value. The only reason the 87-88 event didn't increase after September, is because it had already peaked. This event clearly has not peaked. I personally suspect this event could reach an ONI value of +2.0 deg C by SON, but it's more likely to be the OND.

EDIT: The only reason I don't think we'll reach an ONI value +2.0 by ASO, is because the monthly ERSST.v4 (which the ONI is based on) value for August came in at +1.51, while the September value came in at +1.67. That means the October value would need to come in at +2.82 in order for the ASO ONI value to be +2.0.

Also, the weekly NOAA CPC values are based on OISST.v2 data, thus they do not contribute to the ONI (different datasets). OISST.v2 data runs much warmer than ERSST.v4 data.

[AbruptSLR]

The first attached image shows the Earth 850-hPa Wind & MSLP Map for Oct 3 2015, showing the beginning of a several day major WWB near the Eq. Pacific International Dateline (note that the trade winds are dead).

The second image was issued today by the BoM & indicates that the 30-day moving average SOI has dropped down to -20.4:

[AbruptSLR]

The first image shows the UatA 5S-5N 850-hPa Wind Anom forecast from Oct 4 to 11 2015, showing that the current WWB is strengthening (compared to yesterday) and will clearly strengthen the current EKW into the super category, and possibly setting the stage for a Godzilla El Nino (a ONI above 2.5) in the NDJ timeframe.

The second image shows the current Earth nullschool 850-hPa Wind & MSLP Map, showing the strength of the current WWB (& the weakness of the trade winds).

The third image shows today's Earth nullschool forecast for Oct 6th 2015 of the Surface Wind & MSLP Map; which illustrates my personal greatest worry, that the currently strong (& strengthening) El Nino event will increase the frequency with which the Amundsen Bellingshausen Sea Low, ABSL, will be positioned (as illustrated) to advect warm Circumpolar Deep Water, CDW, directly into the Amundsen Sea Embayment, ASE, which may trigger the collapse of the residual Thwaites Ice Tongue, and also accelerate the next major calving of the Pine Island Ice Shelf.  Such destabilizations of ASE marine glaciers could trigger an abrupt rise in sea level starting with the main phase collapse of the West Antarctic Ice Sheet circa 2030-2040.

Edit: The fourth image shows today's Earth nullschool forecast for Oct 6th 2015 of the Surface Wind & Temperature Map (see the third image for comparison); which shows how surface heat is drawn direct from the South Pacific in to the ASE (in this case, and the West Antarctic in general), during strong El Nino events.

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has dropped down to -21.8:

[deep octopus]

Per NOAA, over the last week, Niño 1+2 regions warmed to 2.8 C, the Niño 3 region warmed to 2.8 C and the Niño 3.4 region warmed to 2.4 C.

                Nino1+2      Nino3        Nino34        Nino4
 Week          SST SSTA     SST SSTA     SST SSTA     SST SSTA
26AUG2015     22.6 2.0     27.3 2.3     29.0 2.2     29.7 1.1
 02SEP2015     22.7 2.2     27.3 2.4     28.9 2.1     29.7 1.0
 09SEP2015     22.5 2.0     27.4 2.6     29.0 2.3     29.7 1.0
 16SEP2015     23.0 2.6     27.6 2.7     29.0 2.3     29.8 1.1
 23SEP2015     23.2 2.7     27.5 2.6     29.0 2.3     29.8 1.1
 30SEP2015     23.4 2.8     27.6 2.8     29.1 2.4     29.7 1.1

Attached is the SST anomaly chart by OSPO for October 5th.

[jbatteen]

A very typical El Nino upper air pattern over the continental US has resulted in the warmest September on record in Minnesota.

For those who chose to do outdoor activities in the fall, September cooperated for the most part with the warmest September on record statewide.

September 2015 was the warmest September on record for the State of Minnesota for records going back to 1895. The preliminary statewide average temperature was 65.1 degrees or 5.8 degrees above the 1981-2010 normal. The old record was 63.0 degrees in September 1897. The warm September was mainly driven by warm overnight minimum temperatures.

The overall weather pattern for September was summer-like with wind patterns favoring warm moist air from the south and few Canadian cold fronts. Fall penology for leaf color seems to be delayed about a week.

Below is a table showing how individual cities ranked for average temperatures in September 2015.

 


City        Ave   Dep from   Rank
            Temp  Normal   
--------------------------------------
Twin Cities  67.9  +5.9     4th warmest
St. Cloud    64.8  +6.2     4th warmest
Duluth       61.5  +5.9     warmest
Int. Falls   59.0  +5.4     5th warmest
Rochester    66.2  +5.3     2nd warmest
La Crosse    69.3  +6.5     warmest
Sioux Falls  67.1  +5.8     3rd warmest (tie)
Fargo        65.6  +6.5     warmest
 

Last modified: October 1, 2015

http://www.dnr.state.mn.us/climate/journal/1509_warm_september.html

[AbruptSLR]

As the current El Nino event still appears to be strengthening, the Nino 3.4 2.4C value that DO just reported makes me wonder whether a Godzilla El Nino could develop by the OND 2015 timeframe.  In this regards:

The first image shows the UatAlbany 5S-5N 850-hPa Wind Anom forecast from Oct 5 to 12 2015; showing that the current WWB remains strong and that the forecast in this area remains aggressive for strengthening the current El Nino.

The second image shows the NOAA Subsurface Eq Pac Temp Anom for Sept 30 2015, showing that the upwelling phase was occurring by that date and that it was upwell relatively warm water.

The third image shows the NOAA Eq Pac Upper Ocean Heat Evolution issued Oct 5 2015, confirming that the current EKW is now in an upwelling phase.

The fourth image shows NOAA's ONI plot from 1950 thru JAS of 2015, indicating that as bigB said the JAS ONI is now (subject to revision) +1.5C.

[AbruptSLR]

The first two plots were issued today by the BoM for the week ending Oct 4 2015, showing the Nino 3.4 (+2.13) and the IOD (+1.17), respectively.  The IOD value in particularly, raises concerns that the current El Nino event may be strengthening for some time to come.

The third and fourth images are from Tropical Tidbits issued Oct 5 2015, which I present as a follow-up from last weeks discussion about how variable Nino 3.4 daily values (see the third image) can be, as the Tidbit daily Nino 3.4 value is down to +2.279 even through the WWB has been blowing for days and the fourth image shows that the 7-day differential SSTA in the Nino 3.4 zone has been warming up.  This illustrate why is better to use weekly, monthly or ONI values to track long-term trends (unless you want to have fun watching daily values).

[Lord M Vader]

You were just a little faster than me ASLR in posting similar pics. However, I find it intriguing that a possible new EKW may be coming. Take a close look at the picture showing the Ocean Heat Content (OHC), which ASLR also posted, and you will find a warming region just east of the Dateline. The main question is what that will mean for the next months given the current massive WWB? One distinct possibility is that we by November will enter the stage of "Godzilla El Niño"...

Another interesting thing that the CPC/NOAA forecast depicts is that the Western Pacific will be warming by AMJ 2016. It also doesn't look like a La Niña would be to develop but I don't know...

//LMV

[AbruptSLR]

The four attached plots for the Nino 1, 2, 3 & 4 indices, respectively, were all issued today by the BoM for the week ending Oct 4 2015, and they all indicate a strengthening El Nino event.

[deep octopus]

Speaking of upper air patterns, a few days ago I worked up some correlation analyses using (you guessed it) NCEP/NCAR Reanalysis tools. Specifically, I examined the correlated link between the Niño 3.4 index and zonal winds at the 200 hPa atmospheric level. The following attachments show this relationship for the months of November, December, January, and February, which I figure are months of greatest interest in terms of identifying the oceanic teleconnections with the atmosphere. Indeed what we see is a typical marker of El Niño, which is a split jet stream, particularly noticeable along North America. Along Central America and the southern United States is a strong upper level westerly pattern, along the central plains a strong upper level easterly pattern, and skirting the Arctic basin is another strong upper level westerly pattern. We might imagine in the void between these anomalies, then, the approximate paths of the extended subtropical jet  pattern along the southern U.S. and northern Central America, and then the polar stream along southern edge of Canada. North of the polar jet stream is cold air, which is less likely to plunge into the central plains during El Niño winters. Stormy, cooler weather is more prominent in the south.

Perhaps nothing new, but an interesting visualization I've wanted to better understand myself. Notice the anomalies also strengthen as winter wears on.

[AbruptSLR]

Speaking of upper air patterns, a few days ago I worked up some correlation analyses using (you guessed it) NCEP/NCAR Reanalysis tools. Specifically, I examined the correlated link between the Niño 3.4 index and zonal winds at the 200 hPa atmospheric level. The following attachments show this relationship for the months of November, December, January, and February, which I figure are months of greatest interest in terms of identifying the oceanic teleconnections with the atmosphere. Indeed what we see is a typical marker of El Niño, which is a split jet stream, particularly noticeable along North America. Along Central America and the southern United States is a strong upper level westerly pattern, along the central plains a strong upper level easterly pattern, and skirting the Arctic basin is another strong upper level westerly pattern. We might imagine in the void between these anomalies, then, the approximate paths of the extended subtropical jet  pattern along the southern U.S. and northern Central America, and then the polar stream along southern edge of Canada. North of the polar jet stream is cold air, which is less likely to plunge into the central plains during El Niño winters. Stormy, cooler weather is more prominent in the south.

Perhaps nothing new, but an interesting visualization I've wanted to better understand myself. Notice the anomalies also strengthen as winter wears on.

DO,

Thanks for the interesting analysis.  What caught my eye is the large telecommunication of heat from the tropical Pacific to West Antarctica in the November timeframe.  We could be in for a very dynamic ice mass loss in the ASE by the end of November 2015.

Best,
ASLR

[Lord M Vader]

According to Philip Klotzbach, September Niño 3.4 was 0,07^oC warmer than 1997!

See: https://twitter.com/philklotzbach

According to Jan Null, the anomaly for Niño 3.4 in September was +2,28..

See: https://twitter.com/ggweather/status/651086606271676416/photo/1

//LMV

[AbruptSLR]

Per following data and attached plot issued today by the BoM, the 30-day moving average SOI has drifted down to -21.9:

20150905,20151004,-21.9

[bigB]

(unless you want to have fun watching daily values).

Indeed I do.    As long as one focuses on the trend rather than a single daily value. I proved how the trend in daily CDAS/tropical tibbits data reflects the trends in weekly CPC values. The weekly CPC values for the week centered on September 30th, reflect the recent uptick in daily CDAS data (that started Sep 25th).

[AbruptSLR]

The first attached image shows the UatA 5S-5N 850-hPa Wind Anom forecast for Oct 6 to 13 2015, showing that while the recent strong WWB has now come to an end, the westerly winds near the Equatorial International Dateline remain relatively high for the duration of the forecast.

The second image shows how the ENSO variance has been increasing with time; which increases the likelihood that we may experience a Godzilla El Nino this year (as compared to projections tied to historical statistics).

[James Lovejoy]

October 3rd NOAA updated the MEI Multivariate ENSO Index.
Highlights:  "Compared to last month, the updated (August-Spetember) MEI has increased by 0.16 standard deviations to +2.53, or the 2nd highest ranking, surpassed only in 1997 at this time of year. This new peak value of the current event ranks third highest overall at any time of year since 1950, closing in on 1982-83 and 1997-98 with 'Super El Niño' values around +3 standard deviations."  See attached.

For the complete update, go to http://www.esrl.noaa.gov/psd/enso/mei/

[Sigmetnow]

Will the warm Pacific Ocean result in Hurrican Oho going Where No Hurricane Has Gone Before?
http://www.weather.com/storms/hurricane/news/tropical-storm-oho-hurricane-northwest-british-columbia

[AbruptSLR]

The attached plot issued today by the BoM indicates that the 30-day moving average SOI drifted down to -22.0:

[gregb]

The monthly release of the NASA model is out (attachment 1). As has been the case for most of the year, the GMAO model still has the 3.4 region peaking near the 3C mark. Recent runs of the CFSv2 model now seem to be responding to the WWB activity of the last few weeks (attachment 2) and is now heading up towards 3C too. The PDF-corrected output of CFSv2, while still showing some upward movement, is quickly diverging from the other models, and now predicts temperatures below those that already exist (attachment 3). NCEP might need to work up a new climatology baseline after this event.

[Lord M Vader]

Our current WWB will restrengthen soon if the current forecast for the next 7 days holds... Courtesy: University of Albany

One interesting feature is that a minor "WWB" will emerge in the far Eastern Pacific... The odds for a "Godzilla El Niño" is certainly increasing more and more...

//LMV

[AbruptSLR]

Today's first attached image from the University at Albany 5S-5N 850-hPa Wind Anom forecast from Oct 7 to 14 2015; indicates a high likelihood of two new strong WWB's just west of the Equatorial International Dateline; which if they occur could serve to push our current El Nino into the Godzilla category (ONI over 2.5C or MEI up to 3.5 standard deviations) by the December to January timeframe.

Furthermore, I attach the second image of the April 1997 Super Typhoon Isa storm track to remind readers that this one WWB probably accounts for the rapid rise and rapid drop-off of the 97-98 Super El Nino; possibly making this event more atypical than the 82-83 Super El Nino event, and that if our current El Nino is tracking the 82-83 type of El Nino, then a Godzilla El Nino event in 2015-16 seems likely.

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has moved down to -22.8:

[gideonlow]

ASLR -- Can you explain this in more detail?  The typhoon was in April and looks like it would have driven a strong WWB for several days.  As powerful as it was, I don't see how it could have contributed to the demise of the event nearly a full year later.  The cycle from WWB/downwelling to EKW transit to upwelling of warm water in the East completes in about 4 months, right?  If memory serves (and based on the Stormsurf ENSO discussions I've been reading since 1997), Westerly anomalies continued well into the Fall of 1997.  I suspect I am missing something here.  Thx!

I attach the second image of the April 1997 Super Typhoon Isa storm track to remind readers that this one WWB probably accounts for the rapid rise and rapid drop-off of the 97-98 Super El Nino

[AbruptSLR]

ASLR -- Can you explain this in more detail?  The typhoon was in April and looks like it would have driven a strong WWB for several days.  As powerful as it was, I don't see how it could have contributed to the demise of the event nearly a full year later.  The cycle from WWB/downwelling to EKW transit to upwelling of warm water in the East completes in about 4 months, right?  If memory serves (and based on the Stormsurf ENSO discussions I've been reading since 1997), Westerly anomalies continued well into the Fall of 1997.  I suspect I am missing something here.  Thx!

I attach the second image of the April 1997 Super Typhoon Isa storm track to remind readers that this one WWB probably accounts for the rapid rise and rapid drop-off of the 97-98 Super El Nino

gideonlow,

I suspect that what you are missing is that the ENSO phenomena is a classic example of what chaos theory calls a "strange attractor".  Once a sufficiently strong perturbation occurs (like Super Typhoon Isa), as series of positive feedback mechanisms can be triggered resulting in resonance of several Earth Systems resulting in as series of EKW downwelling/upwelling pulses that led to the 97-98 Super El Nino.  However, you need to remember that once the Western Pacific Warm Water Pool is sufficiently depleted that the "strange attractor" behavior can feed a series of negative feedbacks resulting in a following strong La Nina event (thus completing the ENSO cycle).  Therefore, when Super Typhoon Isa moved an atypically large amount of warm water to the Eastern Tropical Pacific, it triggered increase local evaporation that knocked down the trade winds that contributed to two more pulses of the EKW (on say about 4 month cycles), leading to an early peak of the 97-98 Super El Nino (ie the MEI for this event peaked in September 1997).  After September the atmosphere stopped reinforcing the ocean, thus while it took another four months of the oceanic EKW to dissipate (continuing to January 1998), the lack of reinforcement from the atmosphere and the partial depletion of the warm water pool, lead to the following La Nina event.

Best,
ASLR

[AbruptSLR]

The first attached image by the UatA today shows the 5S-5N 850-hPa Wind Anom forecast from Oct 8 to 15 2015; indicates that the up-coming WWBs have merged in to once very strong WWB beginning today.

The second image issue today by the Earth nullschool shows the Earth 850-hPa & MSLP Map for Oct 8 2015, indicating both that the strong WWB has already started and also that the SOI will be strongly negative today.

[AbruptSLR]

The attached (& linked) NASA plot of the Jason-2 satellite residual sea level values for Oct 1 2015; shows that both: (a) the EKW has strengthened from the prior NASA residual sea level plot; and (b) the large volume of warm water parallel to the equator & off the coast of Mexico is likely feeding the series of atmospheric low pressure systems that are migrating westward across the north side of the Tropical Pacific and that are creating the series of strong WWBs that may boost our current strong El Nino into at least a Super and possibly a Godzilla status:

https://sealevel.jpl.nasa.gov/images/latestdata/jason/2015/20151001G.jpg

[AbruptSLR]

As a round-up of a few related parameters:

The first image shows NOAA's Eq Pac Upper Ocean Heat Anom circa Oct 8 2015; showing that this value appears to be increasing again, indicating that the downwell phase of the current EKW is current gaining strength.

The second image shows BoM's Equatorial International Dateline cloud cover through about Oct 8 2015, showing abnormally high cloud cover; which indicates that the atmosphere is still reinforcing the current downwelling EKW phase.

The third image shows NOAA SSTA map for Oct 8 2015, showing that the recent cool spots in the Eastern Equatorial Pacific area are dissipating; which means more evaporation providing more positive feedback from the ocean into the atmosphere.

[AbruptSLR]

Per the attached plot issued by the BoM today, the 30-day moving average SOI has remained constant at -22.8:

[AbruptSLR]

The first image shows a nullschool Earth 850-hPa Wind & MSLP Map indicating that both the NH & the SH are working together to produce a WWB of high intensity.

The second image shows the UatA 5S-5N 850-hPa Wind Anom forecast from Oct 9 to 16 2015, indicating that the current and recent WWBs have been so strong that they have refined their scale.

[Tor Bejnar]

These update automatically, so having them near the top of the page may be convenient.

I remain curious why the starting value in these graphs appears to be less than the values reported elsewhere for the 'initial conditions' period.