E.N.S.O. Discussion

[summer blizzard]

 

[Kirkcaldy Weather]

 

[Kirkcaldy Weather]

 

[karyo]

The significant cooling has continued and the latest update gives a value of -0.3 for Nino 3.4. The value was +0.7 just a month ago.

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

[summer blizzard]

Likely to continue for a while yet it seems. 

[Kirkcaldy Weather]

 

[Kirkcaldy Weather]

 

[Singularity]

For those who suspect / believe La Nina equates to a poor UK summer, check out these maps for the 9 hottest UK summers (La Nina present in three of those) and the attending conversation (comments).

A great point is made by Simon Lee about well-established and emerging La Ninas being different entities. I've seen this in my own research - it takes many months for the atmospheric circulation to start exhibiting a clear, persistent response as far afield as the North Atlantic.

Before then, there's an increased risk of negative summer NAO interludes, but they don't always bring cool or even unsettled weather to the UK. Much like in winter, the focal point of high pressure can vary between an eastward skew (near to the UK, cool, sometimes unsettled but sometimes very dry) and a westward skew (no direct influence on UK, either very unsettled but mild or warm, or dry and very warm or hot, depending on whether the polar jet is powering across the N. Atlantic or in a weak, looping state with cut-off lows... something we saw a fair bit of June-July 2019).

[summer blizzard]

1.2 and 3.4 are now both negative for the first time since May 23rd 2018.

Ironically though there's a tropical gyre forming in the east Pacific which will likely produce westerlies in the 1.2 region and rewarm it a bit (or delay further falls). 

[Kirkcaldy Weather]

 

[Kirkcaldy Weather]

 

[summer blizzard]

Just looking at the data and I think the ONI for MAM will drop to 0.3. Both March and April averaged about 0.45 and May has averaged about -0.1. Since it looks like June will probably record at least -0.6 though I would expect AMJ to drop to about -0.1 (more if June goes deeper but there's a WWB forecast) before we finally average around the weak Nina mark for MJJ.

[summer blizzard]

As postulated the WWB did knock back the development of our La Nina event however the sub-surface was largely untouched with upper ocean heat content still low. With that passing more or less now it looks like trades will increase so 3.4 is likely to start dropping again. 

[Daniel*]

 

[karyo]

On 15/06/2020 at 02:42, Daniel* said:

 

It will be interesting to see if this forecast materialises. Regardless of that, the latest update shows a continuous drop of temperatures across the region. Region 3.4 now has a value of -0.6

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

 

[Kirkcaldy Weather]

 

[mountain shadow]

6 minutes ago, Kirkcaldy Weather said:

 

Any idea what a La Nina brings to these islands my linoleum loving weather dude?

[Kirkcaldy Weather]

5 minutes ago, mountain shadow said:

Any idea what a La Nina brings to these islands my linoleum loving weather dude?

I'm not the most knowledgeable when it comes to possible effects for UK due to La Nina / El Nino etc hopefully someone will be able to give u an idea of the possible effects

[damianslaw]

In summer I think it increases likelihood of mid Atlantic high ridge development, with the UK prone to cool showery north westerly airstreams, often on the cold side of the jet.

Edited June 29, 2020 by damianslaw

[Radiating Dendrite]

In winter it tends to lead to colder starts. Given this and solar minimum I'd already feel confident in saying that winter should be much better than the last few, especially if the easterly QBO actually grows a pair and does its thing. 

[karyo]

All this talk about La Nina and yet in the last two weeks temperatures have increased in most parts of tropical Pacific. Region 3.4 went from -0.6 to +0.1 in just a couple of weeks. 

Even the subsurface temperature anomalies are now positive in the western half of the Pacific.

[Metwatch]

On 30/06/2020 at 06:31, Radiating Dendrite said:

In winter it tends to lead to colder starts. Given this and solar minimum I'd already feel confident in saying that winter should be much better than the last few, especially if the easterly QBO actually grows a pair and does its thing. 

And plus we have had too much warm wx this year like it just has to be colder later this year otherwise we may have warmest Uk year on record.

QBO definintly needs to do its job too. Hopefully we get an early SSW and in its right scenario for cold wx. Also the strong sea ice loss may help too, and hoping that snow cover gets quick to recover. Tripole in the SSTA is another good sign.

[summer blizzard]

4 hours ago, karyo said:

All this talk about La Nina and yet in the last two weeks temperatures have increased in most parts of tropical Pacific. Region 3.4 went from -0.6 to +0.1 in just a couple of weeks. 

Even the subsurface temperature anomalies are now positive in the western half of the Pacific.

Yes, we've got a strange situation where all the cold has concentrated east of 160E. The daily values in 1.2 are below 1.

The outlook in the Pacific does look like producing persistent trades over and west of the dateline though so we may see 3.4 cool back down.

Never underestimate the ability of the weather to try screw you is the lesson.

[Don]

5 hours ago, summer blizzard said:

Yes, we've got a strange situation where all the cold has concentrated east of 160E. The daily values in 1.2 are below 1.

The outlook in the Pacific does look like producing persistent trades over and west of the dateline though so we may see 3.4 cool back down.

Never underestimate the ability of the weather to try screw you is the lesson.

Strange situation with ENSO, strange situation with the QBO.  What's going on?!  I don't think long range forecasting is going to get any easier!

Edited July 2, 2020 by Don

[summer blizzard]

20 minutes ago, Don said:

Strange situation with ENSO, strange situation with the QBO.  What's going on?!  I don't think long range forecasting is going to get any easier!

It's not that abnormal to be fair. Although the assumption was a quick flip (some events literally drop by 1 on the Oni scale in 3 months) there are plenty (95, 05, 07) which slow burn the transition. Strictly speaking a weak Nina is also much better than a proper event for winter anyway.