2018 ENSO

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has drifted down to -4.3:

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has moved up to -3.8:

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has drifted down to -3.9:

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has moved down to -4.6:

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has moved down to -6.0:

[AbruptSLR]

Per the following weekly NOAA Nino data and the four attached plots (the first two showing NOAA's Upper Ocean Heat Anom & SSTA Evolution, respectively; and the last two BoM plots of the Nino 3.4 and IOD, respectively), the ENSO condition remains neutral:

                     Nino1+2      Nino3         Nino34        Nino4
 Week           SST SSTA    SST SSTA   SST SSTA    SST SSTA

 08AUG2018     20.8-0.1     25.1-0.1     27.1 0.2     29.2 0.5
 15AUG2018     20.9 0.2     25.4 0.4     27.3 0.4     29.5 0.8
 22AUG2018     20.4-0.2     25.1 0.1     27.1 0.3     29.0 0.4
 29AUG2018     20.3-0.3     24.9-0.1     27.0 0.2     29.1 0.4
 05SEP2018     20.1-0.4     25.0 0.1     27.0 0.3     29.1 0.5
 12SEP2018     20.5 0.2     25.2 0.4     27.0 0.3     29.1 0.4
 19SEP2018     20.3-0.1     25.0 0.2     27.0 0.3     29.1 0.4

[AbruptSLR]

The four attached weekly Nino plot thru the week ending Sept 23 2018, were issued today by the BoM and respectively show the Nino 1, 2, 3 & 4 indices.  This data indicates that ENSO conditions remain neutral:

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has moved down to -6.7:

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has moved down to -7.4:

[wolfpack513]

Here we go?!  You can see how quickly SSTs have responded to this week’s WWB. 

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has moved up to -6.9:

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved down to -7.7:

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has moved up to -7.2:

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved down to -7.9:

[Sleepy]

Better late than never, Jamstec:
http://www.jamstec.go.jp/frcgc/research/d1/iod/e/seasonal/outlook.html

Sep. 25, 2018
Prediction from 1st Sep., 2018

ENSO forecast:
The SINTEX-F continues to predict a moderate-to-strong El Niño event that may emerge in fall and reach its peak in winter. This El Niño is more or less of Modoki-type and we need to be careful of its impact that may be different from that of the canonical El Niño.
Indian Ocean forecast:
As predicted earlier, the positive Indian Ocean Dipole (IOD) has actually emerged during July. In particular, we can see the cold sea surface temperature in the eastern pole clearly. The model predicts the positive IOD to continue during the boreal fall. In accord to the positive IOD evolution, sea level anomalies are expected to be negative (positive) in the eastern (western) tropical Indian Ocean. We may observe co-occurrence of a positive Indian Ocean Dipole and an El Niño/El Niño Modoki-like state in the boreal fall and winter seasons of 2018; this is as we observed in 1994 (with El Niño Modoki) or 1997 and 2015 (with El Niño).

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved down to -9.2:

[oren]

The 30-day SOI about to go below -10, with the 90-day SOI threatening to go below -5.

[dnem]

Oren (or ASLR), can you put that in some context?

[AbruptSLR]

Per the following NOAA weekly Nino data, the first two NOAA plots and the last two BoM plots, the ENSO may have just crossed the NOAA threshold for possible El Nino (Modoki) conditions, but for this to be an official El Nino event the Nino 3.4 indict must (on a three-month average) stay about this threshold for five consecutive periods:

                     Nino1+2      Nino3         Nino34        Nino4
 Week           SST SSTA    SST SSTA   SST SSTA    SST SSTA

 01AUG2018     21.2 0.1     25.3 0.0     27.1 0.1     29.1 0.4
 08AUG2018     20.8-0.1     25.1-0.1     27.1 0.2     29.2 0.5
 15AUG2018     20.9 0.2     25.4 0.4     27.3 0.4     29.5 0.8
 22AUG2018     20.4-0.2     25.1 0.1     27.1 0.3     29.0 0.4
 29AUG2018     20.3-0.3     24.9-0.1     27.0 0.2     29.1 0.4
 05SEP2018     20.1-0.4     25.0 0.1     27.0 0.3     29.1 0.5
 12SEP2018     20.5 0.2     25.2 0.4     27.0 0.3     29.1 0.4
 19SEP2018     20.3-0.1     25.0 0.2     27.0 0.3     29.1 0.4
 26SEP2018     20.2-0.3     25.5 0.6     27.3 0.6     29.3 0.6

[AbruptSLR]

The four attached weekly Nino plots thru the week ending Sept 30 2018, were issued today by the BoM for the Nino 1, 2, 3 & 4 indices, respectively.  Collectively, they suggest that we may (or may not) be headed towards a Modoki even this season:

[AbruptSLR]

Oren (or ASLR), can you put that in some context?

dnem,

The linked weatherzone website provides one definition of how ENSO events relate to SOI, while the BoM cites that for La Nina events SOI must be consistently well above +8, and for El Nino events SOI must be consistently well below -8, for several consecutive months (see the attached weatherzone plot):

Title: "Southern Oscillation Index"

http://www.weatherzone.com.au/climate/indicator_enso.jsp?c=soi

Extract: "The Southern Oscillation Index (SOI) is calculated from the monthly or seasonal fluctuations in the air pressure difference between Tahiti and Darwin.

A strongly and consistently positive SOI pattern (e.g. consistently above about +6 over a two month period) is related to a high probability of above the long-term average (median) rainfall for many areas of Australia, especially areas of eastern Australia (including northern Tasmania) - La Niña.

Conversely, a 'deep' and consistently negative SOI pattern (less than about minus 6 over a two month period, with little change over that period) is related to a high probability of below median rainfall for many areas of Australia at certain times of the year - El Niño.

However, it is important to remember that the pattern of relationship between SOI and rainfall (and temperature) can vary depending on the particular season and region. Additionally, the change in SOI over a specified period can be as important in understanding relationships between SOI and rainfall as is the absolute value in SOI."

Regards,
ASLR

[oren]

Oren (or ASLR), can you put that in some context?

Just to add to ASLR's excellent explanation, here are long term charts of the 30-day average SOI and the 90-day average SOI. For context, the 1998 and 2016 events showing nicely as negative areas in the charts were considered "monster El Ninos".
Note: this chart would be more interesting with official El-Nino and La Nina periods highlighted, unfortunately that is beyond my ability.
You can see that -10 for the 30-day SOI is rather low, though still within common random variation. 90-day SOI at -5 is nothing much to write home about. But both are at lows not seen for a year or two. If the SOI goes much lower from here and/or remains consistently low, an EL Nino could develop.

[dnem]

Excellent, thanks guys!

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved down to -10.0:

[Pmt111500]

For those who prefer see the overall ENSO-state in one image, here are the NINO-area graphs in one graph. Tried to scale NINO4 to the others, and did use antialiasing in combining the four to give the graph some inaccuracy :-D . Eyeballing, it looks like the overall NINO areas run some 0,5 degrees hot, but of course this should be calculated from a longer period.

ENSO areas are numbered from right to left, thus inverted their order in the caption, a proper Nino where large positive anomalies on areas 2 and 1 follow areas 4 and 3 can be seen in 2015/03-2016/03.

In the absence of an adjusted baseline (the hot-running 0,5 degrees mentioned) for the oscillation, it's hard to say if a very weak Nina occurs here at all (possibly 2017/08-2018/03). I'd suggest a 12 year running average (of course trailing average) of the whole tropical Pacific as the adjusted (zero) baseline, but I've not done any verification whether it's a good one. Sun's effect should be minimal with this period, though.

[wolfpack513]

A look at 850 wind totals(not anomalies).   Not only a relaxing of the trades but a reversal to westerly winds.

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved down to -10.7:

[Pmt111500]

Added some text to my last, would that make sense to do that?

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved up to -10.2:

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved up to -9.7:

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has drifted down to -9.8:

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved up to -8.7:

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved up to -8.3:

[AbruptSLR]

The first two images were posted today by NOAA show the Eq Pac. Upper Ocean Heat Anom. and the SSTA Evolution, respectively.  The last two image were posted today by the BoM and show the weekly Nino 3.4 and IOD indices respectively thru the week ending Oct 7 2018.  Together with the following weekly NOAA Nino index values thru the week centered on Oct 3, 2018, it looks like there is a good chance that we are headed towards a Modoki-type El Nino event this season:

                     Nino1+2      Nino3         Nino34        Nino4
 Week           SST SSTA    SST SSTA   SST SSTA    SST SSTA

 08AUG2018     20.8-0.1     25.1-0.1     27.1 0.2     29.2 0.5
 15AUG2018     20.9 0.2     25.4 0.4     27.3 0.4     29.5 0.8
 22AUG2018     20.4-0.2     25.1 0.1     27.1 0.3     29.0 0.4
 29AUG2018     20.3-0.3     24.9-0.1     27.0 0.2     29.1 0.4
 05SEP2018     20.1-0.4     25.0 0.1     27.0 0.3     29.1 0.5
 12SEP2018     20.5 0.2     25.2 0.4     27.0 0.3     29.1 0.4
 19SEP2018     20.3-0.1     25.0 0.2     27.0 0.3     29.1 0.4
 26SEP2018     20.2-0.3     25.5 0.6     27.3 0.6     29.3 0.6
 03OCT2018     21.3 0.7     25.6 0.7     27.4 0.7     29.5 0.8

[AbruptSLR]

The four attached images were all issued today by the BoM and show the Nino 1, 2, 3 & 4 indices, respectively, thru the week ending Oct 7 2018.  This data suggests that we are likely headed towards a Modoki El Nino event this season:

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved up to -7.7:

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved up to -6.6:

[Sleepy]

ECMWF plumes for October. Ensembles were on the warm side in all areas for September.

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved up to -6.2:

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved up to -5.7:

[gerontocrat]

A weak El Nino for the winter.

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml

EL NIÑO/SOUTHERN OSCILLATION (ENSO)
DIAGNOSTIC DISCUSSION
issued by
CLIMATE PREDICTION CENTER/NCEP/NWS
and the International Research Institute for Climate and Society
11 October 2018
 
ENSO Alert System Status: El Niño Watch

Synopsis:  El Niño is favored to form in the next couple of months and continue through the Northern Hemisphere winter 2018-19 (70-75% chance).

ENSO-neutral continued during September, but with increasingly more widespread regions of above-average sea surface temperatures (SSTs) across the equatorial Pacific Ocean [Fig. 1]. Over the last month, all four Niño index values increased, with the latest weekly values in each region near +0.7°C [Fig. 2]. Positive subsurface temperature anomalies (averaged across 180°-100°W) also increased during the last month [Fig. 3], due to the expansion and strengthening of above-average temperatures at depth across the equatorial Pacific [Fig. 4]. Convection was increasingly suppressed over Indonesia and around the Date Line [Fig. 5]. Low-level westerly wind anomalies were evident over the western and east-central Pacific, with some of the strongest anomalies occurring over the eastern Pacific during the past week. Upper-level wind anomalies were easterly over the east-central Pacific. Overall, the oceanic and atmospheric conditions reflected ENSO-neutral, but with recent trends indicative of a developing El Niño.

The majority of models in the IRI/CPC plume predict El Niño to form during the fall and continue through the winter [Fig. 6]. The official forecast favors the formation of a weak El Niño, consistent with the recent strengthening of westerly wind anomalies and positive temperature trends in the surface and subsurface ocean. In summary, El Niño is favored to form in the next couple of months and continue through the Northern Hemisphere winter 2018-19 (70-75% chance; click CPC/IRI consensus forecast for the chance of each outcome for each 3-month period).

This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA's National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Forecasts are also updated monthly in the Forecast Forum of CPCs Climate Diagnostics Bulletin. Additional perspectives and analysis are also available in an ENSO blog. The next ENSO Diagnostics Discussion is scheduled for 8 November 2018.

[Sleepy]

A weak El Nino for the winter.

A pretty safe bet without a single model output since only one El Nino that started this late, has passed 1°C and into moderate. That was 86-87, which leads me back to my old pony, the back to back El Nino in 87-88 which was a strong one.

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved up to -5.2:

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved up to -4.7:

[Pmt111500]

ECMWF plumes for October. Ensembles were on the warm side in all areas for September.

There's still quite a while until January, looking like a very weak Nino now.

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has drifted down to -4.8:

[Sleepy]

ECMWF plumes for October. Ensembles were on the warm side in all areas for September.

There's still quite a while until January, looking like a very weak Nino now.

Yes but it's also late for anything stronger if you look at history, as I wrote in 492 above. Should have added again that the 86-87 also was a modoki.

[AbruptSLR]

Per the following NOAA weekly Nino data thru the week centered on Oct 10 2018, the first two NOAA images for the Eq Pac. and the last two images issued today by the BoM for the Nino 3.4 and IOD indices, respectively for the week ending Oct 14 2018; at the moment we are in a weak El Nino condition, but only time will tell if this will qualify as an official El Nino event:

                     Nino1+2      Nino3         Nino34        Nino4
 Week           SST SSTA    SST SSTA   SST SSTA    SST SSTA
 18JUL2018     21.3-0.3     26.1 0.6     27.6 0.4     29.1 0.3
 25JUL2018     21.1-0.3     25.8 0.3     27.4 0.3     29.0 0.3
 01AUG2018     21.2 0.1     25.3 0.0     27.1 0.1     29.1 0.4
 08AUG2018     20.8-0.1     25.1-0.1     27.1 0.2     29.2 0.5
 15AUG2018     20.9 0.2     25.4 0.4     27.3 0.4     29.5 0.8
 22AUG2018     20.4-0.2     25.1 0.1     27.1 0.3     29.0 0.4
 29AUG2018     20.3-0.3     24.9-0.1     27.0 0.2     29.1 0.4
 05SEP2018     20.1-0.4     25.0 0.1     27.0 0.3     29.1 0.5
 12SEP2018     20.5 0.2     25.2 0.4     27.0 0.3     29.1 0.4
 19SEP2018     20.3-0.1     25.0 0.2     27.0 0.3     29.1 0.4
 26SEP2018     20.2-0.3     25.5 0.6     27.3 0.6     29.3 0.6
 03OCT2018     21.3 0.7     25.6 0.7     27.4 0.7     29.5 0.8
 10OCT2018     21.1 0.4     25.6 0.7     27.3 0.6     29.5 0.9

[AbruptSLR]

The four attached weekly Nino indices were all issued today by the BoM thru the week ending Oct 14 2018, & show the Nino 1, 2, 3 and 4 indices, respectively.  This data indicates that we are currently in a weak Modoki-type El Nino condition, and only time will tell whether this season eventually qualifies as an official El Nino event (or not):

[AbruptSLR]

Per the attached plot issued yesterday by the BoM, the 30-day moving average SOI has moved up to -4.3: