E.N.S.O. Discussion

[summer blizzard]

AMO was negative in November-December for the first time since 2011. 

https://www.esrl.noaa.gov/psd/data/correlation/amon.us.long.data

We do now have a cooler profile in the western Pacific sub-surface and eastern Pacific albeit warm anomalies persist in the central Pacific sub-surface. How this develops could impact our summer in terms of GLAAM. 

The Nino has definitely peaked at the surface with 3.4 recording values between 0.3 and 0.7 during January however i don't expect a radical shift. 

We continue to see a Nino standing wave with pulses travelling across the Pacific from time to time. 

..

Worth saying that the PDO is still neutral-negative (perhaps having an impact on the abnormal Nino pattern - +SOI in Dec-Jan).

..

The current wave travelling through the central Pacific should allowing for a lag produce a blocking signal at the mid to high lattitudes from about now (5th Feb) through to pretty much the end of the month. I would buy the runs showing blocking near the UK over those which are zonal. 

[Qusar]

 

 

[damianslaw]

The forecasted possible moderate El Nino hasn't come to fruition then, Not sure going forward how ENSO might influence the pattern through early Spring - but it seems to be taking a very bit part in influencing proceedings at the moment. I think moderate-strong El Ninos help increase chances of colder patterns in Spring, but not sure on that. 1998 springs to mind..

Could do with something shaking the static pattern of the last 12 months - any signs what this might be.. slow moving patterns have become the order of the day and its all been very very very benign. 

[BornFromTheVoid]

Looks like we're at the beginning of another El Nino
 

 

[North-Easterly Blast]

At the most this year's El Nino has only turned out to be a weak event; it reached only around +0.9 in late 2018 and has declined back to +0.5 since the start of this year, so at the moment it is hardly anything that you could classify as an El Nino.

[BornFromTheVoid]

7 minutes ago, North-Easterly Blast said:

At the most this year's El Nino has only turned out to be a weak event; it reached only around +0.9 in late 2018 and has declined back to +0.5 since the start of this year, so at the moment it is hardly anything that you could classify as an El Nino.

Many of the ENSO calls are based on the ONI index, whereby the 3.4 anomaly has to remain over +0.5 for 5 consecutive overlapping 3 month periods, so it takes a little while for one to be called officially and we've probably just passed that threshold.
Additionally, the subsurface heat anomaly has been growing again over the last few weeks and there are some very strong westerly wind bursts coming up, all of which should help sustain or strengthen the current weak Nino conditions

[summer blizzard]

Having done a bit of reading as persistent as the cool eastern anomoly at the sub-surface has been it seems that this is likely to be temporary and offset by an eastward moving Kelvin wave (the warm anomolies) so i thought i would look at summer periods which were second year positive.

1958

1969

1977

1987

1991

1994 (excluded because late 92 was a flopped Nina, this was essentially one very long Nino event)

2003

2015

I went for Q3 since that was the first positive quarter in 2018.

1958 was the tail end of a strong Nino.

1969 was long weak to moderate Nino starting about when ours did the prior year so that could be a good analogue.

1977 was again essentially a long weak Nino so could be a good analogue.

1987 was another that fits timing wise but got stronger around this time in (2019) so it may be something to watch for. 

1991 was a building event that saw a late starting Nino with years of neutral-positive before and after. I do not consider it a good analogue since our event has taken the more normal approach.

2003 was essentially a neutral buffer year between the events of 2002 and 2004, low confidence in this one. 

2015 was similar to 1987 on a stronger scale in that a weak event starting the prior winter got much stronger.

..

With that in mind there are essentially two camps i have most confidence in..

1) 1969 and 1977 were long but fairly weak events

2) 1987 and 2015 were events that just continued to build

..

It is worth saying that 1991 and 2003 aside, summer was generally poor in all those years.

 

 

[karyo]

On 23/02/2019 at 19:51, summer blizzard said:

Having done a bit of reading as persistent as the cool eastern anomoly at the sub-surface has been it seems that this is likely to be temporary and offset by an eastward moving Kelvin wave (the warm anomolies) so i thought i would look at summer periods which were second year positive.

1958

1969

1977

1987

1991

1994 (excluded because late 92 was a flopped Nina, this was essentially one very long Nino event)

2003

2015

I went for Q3 since that was the first positive quarter in 2018.

1958 was the tail end of a strong Nino.

1969 was long weak to moderate Nino starting about when ours did the prior year so that could be a good analogue.

1977 was again essentially a long weak Nino so could be a good analogue.

1987 was another that fits timing wise but got stronger around this time in (2019) so it may be something to watch for. 

1991 was a building event that saw a late starting Nino with years of neutral-positive before and after. I do not consider it a good analogue since our event has taken the more normal approach.

2003 was essentially a neutral buffer year between the events of 2002 and 2004, low confidence in this one. 

2015 was similar to 1987 on a stronger scale in that a weak event starting the prior winter got much stronger.

..

With that in mind there are essentially two camps i have most confidence in..

1) 1969 and 1977 were long but fairly weak events

2) 1987 and 2015 were events that just continued to build

..

It is worth saying that 1991 and 2003 aside, summer was generally poor in all those years.

 

 

Thanks for the analysis. Personally i couldn't care less about summer weather in the UK, I am more interested in the effect to the hurricane season. Does el nino always have a suppressing effect on the Atlantic hurricane season?

[summer blizzard]

On 01/03/2019 at 10:38, karyo said:

Thanks for the analysis. Personally i couldn't care less about summer weather in the UK, I am more interested in the effect to the hurricane season. Does el nino always have a suppressing effect on the Atlantic hurricane season?

The further east the event, the greater the suppression but yes, a subdued season is more likely than a highly active one albeit the state of the event at the time will have an impact.

..

In ENSO related news it looks like March could potentially be a top 10 month for +ENSO values in 3.4. 

2016 28.90

1983 28.66

1992 28.66

1998 28.62

1958 28.27

1987 28.27

1966 28.21

2010 28.18

2019?? (28.2 speculated)

 

Now looking at the list above it is worth saying two things..

1) Only 1987 and 1958 went on to be full year second winter Nino events. The other 6 years (25%) went negative. 

2) Of the 24 summer months in that list, only one (July 1983) was more than 1C above average.

..

So essentially the data suggests that it is still too early in the year to judge whether we retain a Nino throughout and also that our potential summer analogues do not look all that good. 

 

[BornFromTheVoid]

Latest ENSO update from NOAA: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

Nino likely to last through spring and summer, and a 50% chance of still being around come years end.

ONI index is following 2015 quite closely, and with the warm pool continuing to grow, the above probabilities seem very much plausible.

[Gray-Wolf]

There are those punting for another major in 2019/20 which seems a little too close on the heels of the 20125 event? I thought we had an average of 25 years between major Nino's?

Let us see if we pick up some westerlies to halt the trades over the coming months?

[summer blizzard]

 

57 minutes ago, Gray-Wolf said:

There are those punting for another major in 2019/20 which seems a little too close on the heels of the 20125 event? I thought we had an average of 25 years between major Nino's?

Let us see if we pick up some westerlies to halt the trades over the coming months?

You mean easterlies rather than westerlies. 

I'm still wary of modeling for the later half of the year personally simply because they tend to be somewhat reactionary. We saw a standing wave develop quite coherently in February (it remains persistent) which is why we have seen a surge recently but these things don't always last and we do have a wave at the sub-surface of cool anomolies. 

As per my post above there are routes to keep the Nino and forecasts could be correct but at the same time the majority of years with the event going now degenerate to cold-neutral by years end. 

[BornFromTheVoid]

4 minutes ago, summer blizzard said:

 

You mean easterlies rather than westerlies. 

I'm still wary of modeling for the later half of the year personally simply because they tend to be somewhat reactionary. We saw a standing wave develop quite coherently in February (it remains persistent) which is why we have seen a surge recently but these things don't always last and we do have a wave at the sub-surface of cool anomolies. 

As per my post above there are routes to keep the Nino and forecasts could be correct but at the same time the majority of years with the event going now degenerate to cold-neutral by years end. 

The warm pool in the subsurface has grown at an impressive rate this year, as shown in the report linked above.

The SOI has plummeted to values not seen since 2016 also: http://www.bom.gov.au/climate/current/soi2.shtml


Nothing is a certainty with the climate, but the signals for a proper Nino this year continue to grow from what I can see.

[summer blizzard]

1 minute ago, BornFromTheVoid said:

The warm pool in the subsurface has grown at an impressive rate this year, as shown in the report linked above.

The SOI has plummeted to values not seen since 2016 also: http://www.bom.gov.au/climate/current/soi2.shtml


Nothing is a certainty with the climate, but the signals for a proper Nino this year continue to grow from what I can see.

The sub-surface warmth is primarily concentrated around 180W and East however while last year there was no real cool anomaly to speak of, there is now a more coherent wave under the western Pacific. 

This won't stop the Nino strengthening through spring and into summer but it may play a bigger role later in the year strength dependent. 

[BornFromTheVoid]

3 minutes ago, summer blizzard said:

The sub-surface warmth is primarily concentrated around 180W and East however while last year there was no real cool anomaly to speak of, there is now a more coherent wave under the western Pacific. 

This won't stop the Nino strengthening through spring and into summer but it may play a bigger role later in the year strength dependent. 

Nino will likely be considered to have started in October last year once the JFM ONI index is updated, so for it to stretch out a full year is good going in itself. Building strength into 2020, like the 2015/2016 Nino is unlikely, as that was an exceptional event. But by Autumn so many things will have changed that the deep cool anomaly may not even be a player!

[knocker]

Quote

El Niño ALERT; likelihood of El Niño in 2019 increases

The El Niño–Southern Oscillation (ENSO) is currently neutral. The Bureau's ENSO Outlook has moved to El Niño ALERT.

This means the chance of El Niño developing in 2019 has increased to approximately 70%, around triple the normal likelihood.

Tropical Pacific sea surface temperatures have touched on El Niño thresholds for the past three weeks, while waters below the surface are also slightly warmer than average. Signs of El Niño in the atmosphere are less clear. While values of the Southern Oscillation Index (SOI) are currently within El Niño bounds, the index is likely to weaken in the coming days. Large swings in the SOI are not uncommon during the southern hemisphere monsoon season. Additionally, trade winds have been closer to normal over the past fortnight after a period of weakened trades in the western tropical Pacific.

Most international climate models suggest sea surface temperatures in the central tropical Pacific Ocean are likely to remain at El Niño levels into winter. Sustained warmer than average ocean waters would increase the likelihood of coupling between the atmosphere and ocean, which would typically cause changes in Australian and global weather patterns. However, current outlooks have less skill for the period beyond May, and therefore predictions for the latter months should be viewed with some caution.

http://www.bom.gov.au/climate/enso/?utm_source=tw&utm_medium=org&utm_campaign=sm-0009-0022&utm_content=Br&hootPostID=2529c3c4f502cc762036cb19ab1bfabd

[karyo]

Interesting enso update from CFSv2. It shows that the current weak el nino may not have much mileage left. Peaking around June (still as a weak event) before entering enso neutral territory by August. This can have implications on the hurricane season so I will be watching with interest for future updates.

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf 

Edited April 15, 2019 by karyo

[knocker]

 

Edited April 25, 2019 by knocker

[summer blizzard]

Having figured out where the charts come from i thought the progression would be cool to illustrate (ignored Jan since it was very similar to February)..

Essentially what this shows is that after struggling a bit at the surface late last year it got a second wind because of a large underlying warm pool around the dateline which is surfacing about now. What it also shows however is that the Nino event may be bowing out in the next few months, there is now no major feed for it and a larger expanse of cool anomolies which will themselves try make the surface as time goes on. 

My analogue pack earlier in thread did suggest that 75% of events at our strength in March end the year negative, that may come to fruition. 

[knocker]

 

Edited May 2, 2019 by knocker

[knocker]

 

Edited May 2, 2019 by knocker

[karyo]

13 hours ago, knocker said:

 

Will the westerly winds be enough to stop the negative anomalies that are now showing up below 100 metres from progressing towards the surface? Or just cause a delay?

According to the CFSv2, the el nino event is expected to peak by July with a slow weakening after that. Even at its peak it looks like a relatively weak event so it may not suppress hurricane activity that much. The tropical Atlantic is more lively late summer and early autumn anyway. 

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

[cheeky_monkey]

On 02/05/2019 at 12:44, knocker said:

 

kiss good bye to a cold winter 2019-20 if this happens

[Don]

On 06/05/2019 at 00:21, cheeky_monkey said:

kiss good bye to a cold winter 2019-20 if this happens

We are used to doing that these days, sadly!

[feb1991blizzard]

On 06/05/2019 at 00:21, cheeky_monkey said:

kiss good bye to a cold winter 2019-20 if this happens

In May 2019????

EDIT : would be more interested in the Atlantic SST profile in May wrt next winter than the ENSO state.

Edited May 7, 2019 by feb1991blizzard