ENSO Updates (2007 thru 2023)

[Ntxw]

8 days away from October and no August PDO reading yet.

It will probably be below 1 but above 0, if you eyeball NCDC's value to previous months

[Kingarabian]

@ntxw look at this:

[Ntxw]

@ntxw look at this:
http://i.imgur.com/gT0RxHP.png

Tao/triton buoys also can verify that Monday's reading may not be -0.5C or lower. With the gap and the relatively weak readings, we may not get enough to qualify for a weak Nina this year on ONI.

[Ntxw]

Jumped up to -0.4C. La Nada continues...

Nino 1+2 is +0.8C, any opportunity for this to be a traditional la nina (if it even gets there) is probably now nil

[Kingarabian]

PDO down to +0.52.

[Hunabku]

If this westerly wind anomaly east of 180 verifies, positive SOI be damned, La Nada marches on. Sometimes people over emphasize the importance of SOI. That is why we have more indicative and cumulative indexes for measuring ENSO. SOI derives from SLP differences between Darwin and Tahiti, which are around 10 degrees south of the equator. Although it corresponds rather well with changes in equatorial SSTs, it can take a while for SOI averaging to correspond to SST changes.

Looks like it's the MJO behind these forecasted westerly winds.

[Ntxw]

Dropped sharply negative to -0.8C this week

[Macrocane]

Interesting:

"Since mid-September, negative temperature
anomalies have strengthened at depth near the
International Date Line. "

[Ntxw]

Interesting:

"Since mid-September, negative temperature
anomalies have strengthened at depth near the
International Date Line. "

there has been colder subsurface waters. The issue has been when it reaches the surface (upwelling) it's been unable to maintain. For instance there is now forecasted westerly anomalies around 120W in the 3.4 regions coming up which is not Nina like at all moreso Nino. While there is some enhanced trades near the dateline. Remember we are entering climo peak of ENSO events in Oct-Nov-Dec period typically. What you see now is pretty much the most you will get.

[Digital-TC-Chaser]

[cycloneye]

Here is the text of the CPC update of 10/10/16 that has Nino 3.4 down to -0.9C.ONI is at -0.5C.

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

[Ntxw]

That would be the first trimonthly, four more will be needed to qualify as weak Nina

[cycloneye]

 https://twitter.com/EricBlake12/status/785516958473195525




 https://twitter.com/MJVentrice/status/785529749644902400

[Kingarabian]

September PDO came in slightly down to +0.45

[cycloneye]

CPC monthly update at 10/13/16 has 70% chance of La Nina in the fall months and down to 55% in the Winter.

EL NIÑO/SOUTHERN OSCILLATION (ENSO)
DIAGNOSTIC DISCUSSION
issued by
CLIMATE PREDICTION CENTER/NCEP/NWS
and the International Research Institute for Climate and Society
13 October 2016
 
ENSO Alert System Status: La Niña Watch
 
Synopsis:  La Niña is favored to develop (~70% chance) during the Northern Hemisphere fall 2016 and slightly favored to persist (~55% chance) during winter 2016-17.
ENSO-Neutral conditions were observed during September, with negative sea surface temperatures (SSTs) anomalies expanding across the eastern equatorial Pacific Ocean by early October (Fig. 1). All of the Niño regions cooled considerably during late September and early October, with the latest weekly value of Niño-3.4 index at -0.9°C (Fig. 2). Subsurface temperature anomalies also decreased toward the end of the month (Fig. 3), reflecting the strengthening of below-average temperatures at depth in the east-central equatorial Pacific (Fig. 4). Atmospheric anomalies across the equatorial Pacific edged toward La Niña during September, with a stronger tendency toward La Niña late in the month. The traditional Southern Oscillation index and the equatorial Southern Oscillation index were positive. The lower-level winds were near average across most of the basin during the month, but enhanced easterlies were becoming more persistent west of the International Date Line. Upper-level winds were anomalously westerly near and just east of the International Date Line. Convection was weakly suppressed over the central tropical Pacific and was more enhanced over Indonesia compared to last month (Fig. 5). Overall, the combined ocean and atmosphere system reflects ENSO-Neutral during September, but are more clearly trending toward La Niña conditions.

The multi-model averages favor borderline Neutral-La Niña conditions (3-month average Niño-3.4 index less than or equal to -0.5°C) persisting during the Northern Hemisphere fall and continuing into the winter (Figs. 6 and 7). Because of the recent cooling in the Niño-3.4 region and signs of renewed atmospheric coupling, the forecaster consensus now favors the formation of a weak La Niña in the near term, becoming less confident that La Niña will persist through the winter. In summary, La Niña is favored to develop (~70% chance) during the Northern Hemisphere fall 2016 and slightly favored to persist (~55%% chance) during winter 2016-17 (click CPC/IRI consensus forecast for the chance of each outcome for each 3-month period).period).

http://www.cpc.noaa.gov/products/analys ... disc.shtml

[Hunabku]

Great current ENSO synopsis by NOAA - Antici...pation: October 2016 ENSO forecast(https://www.climate.gov/news-features/b ... o-forecast)

Also now the SOI seems to be tanking - that can sometimes happen for the short duration whilst MJO is active – then SOI can climb back again when MJO shifts more suppressive. We shall see

[Hammy]

What are the implications for winter over the Southeast?

[Ntxw]

What are the implications for winter over the Southeast?

Probably not much. This event should it qualify for a Nina will still be very borderline so the effects will not be too different from a cold neutral. Southeast ridges like to poke out during La Nina, so may be a weaker form of that and drought as you have seen in the northern areas of Georgia as a result. Will be colder than last winter though I do believe. Tends to be drier than normal for the southeast.

[Hunabku]

In case y'all were wondering about the amount of SOI tanking - here you go! Look at those daily numbers that started on the 8th, now i'm wondering if this is mostly because of MJO or more indicative of a new trend.

[Ntxw]

In case y'all were wondering about the amount of SOI tanking - here you go! Look at those daily numbers that started on the 8th, now i'm wondering if this is mostly because of MJO or more indicative of a new trend.

http://i.imgur.com/BDX424d.png

It's probably a part of seasonal changes in some part along with the MJO. Still though in previous significant La Nina events you don't see it tank like this often but in weaker events it's not unheard of. Especially heading into peak months of ENSO Oct-Nov-Dec-Jan