ENSO Watch 2020

Oneiric 3

Only just seen this, but a surprisingly rapid fall in what was a prolonged period of a positively neutral ENSO phase in the last couple of weeks:



If this continues not sure how it will effect global weather systems around that region, but with SST's actually increasing over pretty much all other parts of the N. Pacific, perhaps any potential effects will be neutralised.

Here in Ireland, a negatively neutral or borderline La Nina doesn't seem to bring anything specific during the summer. 2007 and 2008 for example were wet, while the summers of 2010 and 2011 were, if my memory serves me correctly, both rather bland. Summer 2013 also was in near La Nina territory and brought some very hot weather here, but in contrast, the summer of 1985, also a borderline La Nina summer, was by all accounts, nasty.

sryanbruen

Been carefully watching this for a few months now with seasonal models increasingly bullish of La Niña developing - CFSv2 has particularly been bullish on this for a while. However, as far as I can see, the Pacific just isn’t set up at the moment to develop this La Niña much.

Haven’t had a proper La Niña event since 2011-12. The Niña events of 2016-17 and 2017-18 were weak and the former was record weak to the point it didn’t even last to the winter.

Oneiric 3

As Syran mentioned yesterday, the Pacific, although now in a slightly negative neutral ENSO phase, just can't seem to decide what to do and a good example of that is looking at the SOI index:

https://www.longpaddock.qld.gov.au/soi/

Something I have been keeping an eye on for a while, and while it is currently in slightly positive territory (which is conducive to a slightly negative ENSO) it just can't seem to get going at all, with the latest run of daily values now tending back into the negatives again.

Oneiric 3

Latest update:



Hard to know where this is all going as the NINO index looks to be bottoming out, but at the same time, it does look like the SOI is trying to get back into positive territory again (but for how long?), so will this be a case now where, after an unusually long period of positively neutral NINO conditions, that we are now entering a prolonged phase of its negative equivalent?

Also, found out just recently that while NOAA uses the 0.5c plus or minus to determine whether the NINO state is positive or negative, BOM (the Australian Met Office) actually use the 0.8c benchmark. Interesting.

Nabber

The volume of weather acronyms can be daunting. :pac:
UK Met Office have a 5 minute video on El Nino and La Nina for those interested.

For those looking for more information ENSO impact on Europe (.pdf)

Oneiric 3 wrote: »

Here in Ireland, a negatively neutral or borderline La Nina doesn't seem to bring anything specific during the summer. 2007 and 2008 for example were wet, while the summers of 2010 and 2011 were, if my memory serves me correctly, both rather bland. Summer 2013 also was in near La Nina territory and brought some very hot weather here, but in contrast, the summer of 1985, also a borderline La Nina summer, was by all accounts, nasty.

I wonder would it be possible to determine over multidecadal scale the difference between ESNO and other factors that play a larger role in our climate and distinguish between a 1% influence factor from 10%. If global temperatures are on the rise and modifying the climate how reliable is one decades out come in predicting future decades.
My own opinion is that ENSO does impact Europe, much the same way that NAO impacts Pacific regions, but I don't think we understand enough about the intricacies of our planets climate to determine level of impact or the technology to accurately measure our predictions.

Oneiric 3

Latest update. Struggling.

Oneiric 3

Must be the lamest attempt at a 'La Nina' that I have ever witnessed:



SOI, as is the norm these last few months, remains all over the place, with no strong signal becoming established either way.

Oneiric 3

Just to focus in on the near North Atlantic, looks like something cool 'blob' has developed around and to the west of Ireland: May be one reason why this summer has been so breezy so far:



Broader N. Atlantic region generally in a general cool state for the last few months:



How long more this coolish trend will last, and what effect it will have the weather in the 2nd half of Summer remains to be seen.

Oneiric 3

Weekly Nino 3.4 values (from 'BOM') since 2005 up to present. Red dotted line represents 91 day running average.



Despite longer range forecast modelling a La Nina over the last few months, it still is struggling to get going, with 'SOI' values continuing wave frequently between positive and negative and pretty much as they have done since the start of the year.

https://data.longpaddock.qld.gov.au/SeasonalClimateOutlook/SouthernOscillationIndex/SOIDataFiles/DailySOI1887-1989Base.txt

PS, apologies for the crappy date style in chart, I didn't formatted them properly.

sryanbruen

This La Nina might finally be starting to take off. Equatorial Pacific has been cooling more consistently and the PDO is negative this time around so more favourable of Nina.

SOI has been trending more positive too than negative.

sryanbruen

Jul-Aug-Sep will likely be the first tri-monthly period to have reached La Nina threshold (-0.5C or lower). Nino 3.4 has been in that threshold since the beginning of September undisturbed meaning we can safely say this Nina signature is locked in for the foreseeable future as far as we can see albeit still at a weak level (-1.1C or lower is moderate).



The SOI has been positive for a while now too.

Nabber

USA focused but this might help some with ENSO and correlation with MJO.
It avoids trying to encompass the AGW/Global warming situation. So might be an easier read for some.

https://www.climate.gov/news-features/blogs/enso/catch-wave-how-waves-mjo-and-enso-impact-us-rainfall

Oneiric 3

From NOAA.