ENSO Updates (2007 thru 2023)

[cycloneye]

Climate Prediction Center 9/12/11 Weekly update

La Nina continues to intensify after last week's news of the official comeback of it.

Niño 4= -0.3ºC
Niño 3.4= -0.6ºC
Niño 3= -0.7ºC
Niño 1+2= -0.9ºC



Saved image.

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf

[cycloneye]

The September update of the models has the majority between cold Neutral and La Nina for the next few months.

http://iri.columbia.edu/climate/ENSO/cu ... table.html

Summary
The ending of a moderate to strong La Niña episode in early May 2011 was followed by neutral ENSO conditions until early August, when weak La Niña conditions returned. For the September-November season currently in progress, there is an approximately 52% probability for continuing La Niña conditions, a 48% probability for returning to neutral conditions, and virtually no chance for the development of El Niño conditions. Although weak La Niña conditions are the most likely scenario for the remainder of 2011, a return to neutral conditions is also possible.

General Discussion

In mid-September 2011, the NINO3.4 SST anomaly index was at -0.7 C away from average, indicative of weak La Niña conditions. Sea temperatures below the ocean surface also became somewhat below average during August and so far in September. Zonal wind anomalies in the equatorial Pacific feature a slightly enhanced strength of easterlies, and the Southern Oscillation Index is at slightly above average levels, although still in a neutral range. These observations indicate that the ENSO condition has moved from cool-neutral to weak La Niña between early August and mid-September.

Out of a large set of dynamical and statistical prediction models, 30% of them indicate La Niña conditions during the September-November 2011 season currently in progress, while 70% indicate neutral ENSO conditions. However, based on model predictions and current observations of the ocean surface and subsurface, for the October-December season the probability for neutral conditions is approximately 46%, while the probability for La Niña conditions is 53% and the probability for El Niño development is 1%. By the December-February season 2011/12, the probabilities for La Niña, neutral and El Niño conditions are near 50%, 48% and 2%, respectively.



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[cycloneye]

Climate Prediction Center 9/26/11 update

La Nina gets a bit stronger,now down to -0.8C.


Niño 4= -0.7ºC
Niño 3.4= -0.8ºC
Niño 3= -0.6ºC
Niño 1+2= -0.8ºC



Saved image.

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf

[P.K.]

Doesn't look like this ever got posted.

Pacific approaches La Niña. Positive Indian Ocean dipole develops.

Issued on Wednesday 14 September | Product Code IDCKGEWWOO

Steady cooling of the central Pacific Ocean since early winter has increased the chance of La Niña returning during the last quarter of 2011. Current ENSO indicators are approaching values typically associated with La Niña events.

However, ocean temperatures are yet to reach critical thresholds, while climate model guidance about their future trends is mixed. Some models predict only modest cooling resulting in a borderline-La Niña event, but others predict stronger cooling beyond La Niña thresholds during the southern spring. A minority predict little or no cooling. Taken as a whole, there is an expectation that the trend towards La Niña will continue.

If a La Niña does form, current indicators are that it will be weaker than the strong 2010-11 event. La Niña events raise the odds of above average rainfall across the north and east of the country, but don't guarantee it. The Bureau's National Climate Centre will monitor the situation closely and issue regular updates via this summary.

The latest observations from the Indian Ocean show the development of a positive dipole event, as predicted over the last few months by climate models, including the Bureau's POAMA. Typically peaking in spring, positive dipole modes increase the chance of below average rainfall over southeastern and central Australia.

Next update expected by 28 September 2011 | print version

[cycloneye]

The Aussies are only relying on one model POAMA that doesn't forecast La Nina to return contrary to CPC that rely on all the models plus data. Looks like BoM is playing catchup to CPC.

http://www.bom.gov.au/climate/coupled_model/poama.shtml

[P.K.]

Not really playing catchup. The NOAA definition of La Nina is easier to reach than the BoM's (-0.5C Nino 3.4 as opposed to -0.8C Nino 3.4).

[Ptarmigan]

Eastern Equatorial Pacific Sea Surface Temperature Anomalies
http://jisao.washington.edu/data/cti/

It is related to El Nino Southern Oscillation.

[cycloneye]

Climate Prediction Center 10/6/11 October update

They forecast a weak to moderate La Nina during the Winter months. Right now is in a weak status.

http://www.cpc.ncep.noaa.gov/products/a ... odisc.html

Synopsis: La Niña conditions are expected to gradually strengthen and continue through the Northern Hemisphere winter 2011-12.

During September 2011, La Niña conditions strengthened as indicated by increasingly negative sea surface temperature (SST) anomalies across the eastern half of the equatorial Pacific Ocean (Fig. 1). The weekly Niño indices continued their cooling trend and all are currently at or below –0.5oC (Fig. 2). Consistent with this cooling, oceanic heat content (average temperature anomalies in the upper 300m of the ocean, Fig. 3) remained below-average in response to a shallower thermocline across the eastern Pacific Ocean (Fig. 4). Also, convection continued to be suppressed near the Date Line, and became more enhanced near Papua New Guinea (Fig. 5). In addition, anomalous low-level easterly and upper-level westerly winds persisted over the central tropical Pacific. Collectively, these oceanic and atmospheric patterns reflect the continuation of La Niña conditions.

Currently, La Niña is not as strong as it was in September 2010. Roughly one- half of the models predict La Niña to strengthen during the Northern Hemisphere fall and winter (Fig. 6). Of these models, the majority predict a weak La Niña (3-month average in the Niño-3.4 region less than -0.9oC). In addition, a weaker second La Niña winter has occurred in three of the five multi-year La Niñas in the historical SST record since 1950. However, the NCEP Climate Forecast System (CFS.v1) predicts a moderate-strength La Niña this winter (between –1.0oC to –1.4oC) and CFS.v2 predicts a strong La Niña (less than
–1.5oC), which rivals last year’s peak strength. For CFS forecasts made at this time of year, the average error for December-February is roughly ±0.5oC, so there is uncertainty as to whether this amplitude will be achieved. Thus, at this time, a weak or moderate strength La Niña is most likely during the Northern Hemisphere winter.

[Ptarmigan]

Multivariate ENSO Index (MEI) looks at sea surface temperature and atmospheric pressure related. It determines El Nino or La Nina.
http://www.esrl.noaa.gov/psd/enso/mei/

Here are MEI datasets.
1950 to Present
http://www.esrl.noaa.gov/psd/enso/mei/table.html

1871 to 2005
http://www.esrl.noaa.gov/psd/enso/mei.e ... e.ext.html

[gigabite]

Year over year the Upper Ocean Temperature looks to be up.



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[cycloneye]

The October update of ENSO models forecast Weak La Nina to prevail thru late Winter/Early Spring.

http://iri.columbia.edu/climate/ENSO/cu ... pdate.html

ENSO Update
20 October 2011
Summary
The ending of a moderate to strong La Niña episode in early May 2011 was followed by neutral ENSO conditions until early August, when weak La Niña conditions returned and have been gradually strengthening. For the October-December season currently in progress, there is an approximately 78% probability for continuing La Niña conditions, a 22% probability for returning to neutral conditions, and virtually no chance for the development of El Niño conditions. Weak to moderate La Niña conditions are the most likely scenario for the remainder of 2011, into the first couple of months of 2012.

General Discussion

In mid-October 2011, the NINO3.4 SST anomaly index was at -0.8 C away from average, indicative of weak La Niña conditions. Sea temperatures below the ocean surface have been increasingly below average between August and mid-October. Zonal wind anomalies in the equatorial Pacific feature a somewhat enhanced strength of easterlies, and the Southern Oscillation Index is at slightly above average levels, at a borderline to weak La Niña level. These observations indicate that the ENSO condition continues to be that of weak La Niña, as has been the case since early August.

Out of a large set of dynamical and statistical prediction models, 40% of them indicate La Niña conditions during the October-December 2011 season currently in progress, while 60% indicate neutral ENSO conditions. However, based on model predictions and current observations of the ocean surface and subsurface, for the October-December season the probability for La Niña conditions is approximately 78%, while the probability for neutral conditions is 22% and the probability for El Niño development is near zero. By the December-February season 2011/12, the probabilities for La Niña, neutral and El Niño conditions are near 70%, 29% and 1%, respectively.

[cycloneye]

If the CFS model is right,La Nina will be around thru the late Spring/early Summer timeframe and that could have big implications on the 2012 North Atlantic hurricane season.



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[cycloneye]

It all has to do with the PDO factor to have El Nino or La Nina. Here is a graphic that shows how distributed was El Nino vs La Nina since 1950 to 2011.The PDO has been cold after 2009 when El Nino was present to allow for La Nina to mantain after that for two years in a row. When the PDO has been warm,El Nino has dominated more than La Nina like what occured from 1976 to 1985.Let's see what occurs in 2012 with ENSO and PDO.

[MGC]

Yes, expect more La Nina while the PDO is cold. As long as the AMO continues in the warm phase, and there is no El Nino there sould be plenty of TC activity in the N Atlantic basin....MGC

[cycloneye]

Australian update=The present La Nina will be less strong than the 2010-11 one

http://www.bom.gov.au/climate/enso/

La Niña slowly builds in the tropical Pacific
Issued on Wednesday 9 November | Product Code IDCKGEWWOO

La Niña conditions have strengthened slightly over the past fortnight, with some, but not all, atmospheric and oceanic indicators intensifying. Forecast models surveyed by the Bureau suggest the event is likely to peak towards the end of 2011, and persist into early 2012. It is considered unlikely that the current La Niña will be as strong as the La Niña event of 2010-11.

ENSO indicators continue to remain at or in excess of La Niña thresholds: the tropical Pacific Ocean is cooler than average for this time of year, especially below the surface, while the trade winds, Southern Oscillation Index (SOI) and cloudiness in the tropical Pacific are all at levels consistent with a La Niña event.

[cycloneye]

Climate Prediction Center November update

Weak to Moderate La Nina thru winter but fading after that time.

http://www.cpc.ncep.noaa.gov/products/a ... odisc.html

Synopsis: La Niña is expected to continue through the Northern Hemisphere winter 2011-12.

During October 2011, below-average sea surface temperatures (SST) associated with La Niña conditions strengthened across the east-central equatorial Pacific Ocean (Fig. 1). As a result, the recent weekly SST index values in the Niño-3.4 and Niño-3 regions dropped to near -1.0oC (Fig. 2). Also, the oceanic heat content (average temperature in the upper 300m of the ocean, Fig. 3) remained below-average, reflecting an extensive area of below-average temperatures at depth (Fig. 4). The atmospheric circulation over the global tropics featured strong week-to-week variability during October in response to the Madden Julian Oscillation (MJO). Averaged over the month, convection remained suppressed near the Date Line in association with La Niña, but was near-normal over Indonesia as the MJO acted to offset the increased convection typically associated with La Niña (Fig. 5). In addition, anomalous low-level easterly and upper-level westerly winds shifted into the western Pacific and over Papua New Guinea. Collectively, these oceanic and atmospheric patterns reflect the continuation of La Niña conditions, although modified slightly by the MJO.

A majority of the models now predict La Niña to continue through the Northern Hemisphere winter (Fig. 6) and then gradually weaken after peaking during the November - January period. The models are roughly split between those that predict La Niña to remain weak (3-month average in the Niño-3.4 region less than -0.9oC) and those that predict a stronger episode. Over the last half-century, La Niña events that were preceded by ENSO-neutral conditions during the Northern Hemisphere summer (May-August) were less likely to attain strong amplitude (less than -1.5oC) the following winter. This observation, in combination with the model forecasts, favors a weak-to-moderate strength La Niña during the Northern Hemisphere winter.

[cycloneye]

The November update of ENSO models have La Nina sticking around until the Spring and then Neutral dominating thereafter.Only three models have El Nino by early Summer. Of course,is a long way yet to know for sure what will occur when the 2012 Atlantic Hurricane season starts,how will ENSO be. I think we will have to wait until March or April to see how things are evolving in the Pacific and by then a more clear picture will emerge.



http://iri.columbia.edu/climate/ENSO/cu ... pdate.html

Summary
Weak La Niña conditions re-emerged in August after a brief period of ENSO-neutral conditions following the ending of the significant 2010-11 La Niña. The current event has slowly strengthened and is currently of weak to moderate strength. For the November-January season currently in progress, there is an approximately 74% probability for continuing La Niña conditions, a 26% probability for returning to neutral conditions, and virtually no chance for the development of El Niño conditions. Weak to moderate La Niña conditions are the most likely scenario for the remainder of 2011, into the first couple of months of 2012.

General Discussion

In mid-November 2011, the NINO3.4 SST anomaly index was at -0.9 C from average, indicative of weak La Niña conditions. Sea temperatures below the ocean surface remain below average, and zonal wind anomalies in the equatorial Pacific feature a somewhat enhanced strength of easterlies, although recently there was a notable interruption due to intraseasonal variability. The Southern Oscillation Index is slightly above average, at a borderline to weak La Niña level. These observations indicate weak to nearly moderate La Niña conditions, as has been the case since early October.

Out of a large set of dynamical and statistical prediction models, 67% of them indicate La Niña conditions during the November-January 2011 season currently in progress, while 33% indicate neutral ENSO conditions. Based on model predictions and current observations of the ocean surface and subsurface, for the November-January season the probability for La Niña conditions is approximately 74%, while the probability for neutral conditions is 26% and the probability for El Niño development is near zero. For the January-February-March season 2012, the probabilities for La Niña, neutral and El Niño conditions are near 62%, 35% and 3%, respectively.

[Ptarmigan]

If there is another La Nina following the previous winter's La Nina, it is weaker. However, there are exceptions where the La Nina is stronger than the previous La Nina.

[gigabite]

This is a plot of the 1997 to 2011 nino 3.4 anomaly over the 1983 to 1997 data.
That seems to indicate that there is a 54 percent chance that a change in the
direction of the anomaly is near.
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[cycloneye]

Climate Prediction Center 11/21/11 weekly update has Nino 3.4 down to -0.9C

It is down from the -0.8C that was last week,so in other words,the Weak La Nina is hanging on tough for now.

Niño 4= -0.5ºC
Niño 3.4= -0.9ºC
Niño 3= -1.1ºC
Niño 1+2= -1.2ºC

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf