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El Nino 2023-2024


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2 hours ago, brooklynwx99 said:

again, I don't understand the issue of the SW trough for December. most stronger Ninos feature this -PNA/+NAO pattern, so it should not be surprising. it is likely going to be a warm month

Why are El Nino's warm in December? What is the physical reason? Why aren't La Nina's cold? 

Cold Winter's start cold in December, it's the intro month to longer wavelengths season.. the Winter sets in in December at like a 0.30-40 correlation, if you base it on a 200yr period. Really, Oct and Nov should start cold too. 

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Just flipping thru some reanalysis images, it looks like the surface pressure anomaly pattern was weak in Oct - you need strong low anomalies in E Pac and strong high anomalies in W Pac for high MEI.  Accordingly, the 30-day SOI in October rose thru the whole month

Same for low level zonal winds - need strong westerly anoms across the West and Central Pac for high MEI - didn't have that in Oct.

OLR pattern for +MEI looked OK, but not robust

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1 hour ago, bluewave said:

The latest MEI actually dropped to +0.3 with the unusually strong La Niña background state for Nino 3.4 SSTs in the strong range. 

https://psl.noaa.gov/enso/mei/

7 November 2023

Current Value: 0.3

Just you wait until that next downwelling-Kelvin WWB comes along.....we only look at MEI during Modoki.

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22 minutes ago, 40/70 Benchmark said:

Just you wait until that next downwelling-Kelvin WWB comes along.....we only look at MEI during Modoki.

It makes sense that the MEI is so low when the -PDO was the lowest on record in October for a developing El Niño at -2.36. The increasing La Niña background state has been acting as a brake on El Niño development since Labor Day 2012. So the historic expansion of the WPAC pool even extending northward to Japan has proven to be a game changer for the global climate system.


https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat

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5 minutes ago, bluewave said:

It makes sense that the MEI is so low when the -PDO was the lowest on record in October for a developing El Niño at -2.36. The increasing La Niña background state has been acting as a brake on El Niño development since Labor Day 2012. So the historic expansion of the WPAC pool even extending northward to Japan has proven to be a game changer for the global climate system.


https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat

Simple climo, too....we don't get super el Nino again so soon after 2015.

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35 minutes ago, 40/70 Benchmark said:

All joking aside, this doesn't change anything IMO...its not going to be a frigid winter.

If MEI has trouble getting above 1.0, then it could be a big deal. I still expect it to but that was prob the nail in the coffin for anything above 1.5 (it was already looking dubious for that anyway before the update) 

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7 minutes ago, ORH_wxman said:

If MEI has trouble getting above 1.0, then it could be a big deal. I still expect it to but that was prob the nail in the coffin for anything above 1.5 (it was already looking dubious for that anyway before the update) 

I'm not astute with these teleconnections like yall are, but do we want the MEI real high or as low as possible for a better chance at non ratter of a winter?

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1 hour ago, ORH_wxman said:

If MEI has trouble getting above 1.0, then it could be a big deal. I still expect it to but that was prob the nail in the coffin for anything above 1.5 (it was already looking dubious for that anyway before the update) 

My research showed that we want to keep the MEI under 1.2.

If it goes over 1.2, then we go warm everywhere except a small part of the SW.

If it stays between 0.5 and 1.2, then we have a decent shot at a (relatively) colder winter and still have a decent STJ. 

If it stays under 0.5, then all bets are off. It could go either way.

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Which do you guys like now? RONI went up, MEI went down for the recent updates.

For me, the issue with the MEI is timeliness as much as anything. Takes forever to update. If you map out correlations of Nino 3.4 SSTs, v. the MEI, v. the SOI, they're all basically the same long-term for sensible US weather, at about the same correlation rate.

The RONI thing on the other hand is just overkill. CPC already normalizes Nino 3.4 against a running 30-year average in the Pacific. No need to subtract out the other oceans. The Indian is warming faster than the Pacific but not dramatically so. In any given ENSO event you can also have a temporary out of trend blip in the Atlantic or Indian v. the linear tendency in warming.

As far as the PDO, the version of it I use is still extremely negative, at -1.7 in October. Link is down at the moment.

https://oceanview.pfeg.noaa.gov/erddap/tabledap/cciea_OC_PDO.htmlTable?time,PDO

In general, you have a fairly strong winter negative correlation between the +AMO/-PDO. -PDO and warm Atlantic conditions are associated with La Nina. This year we had an active and very warm Atlantic, so it's not really surprising to see the PDO hanging on.

https://psl.noaa.gov/data/correlation/table/corr.table_dec.txt

Screenshot-2023-11-07-6-21-49-PM

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1 hour ago, ORH_wxman said:

If MEI has trouble getting above 1.0, then it could be a big deal. I still expect it to but that was prob the nail in the coffin for anything above 1.5 (it was already looking dubious for that anyway before the update) 

I was just about to post that strong is off of the table....I had the ceiling at 1.6, but that will be rewritten.

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6 minutes ago, Terpeast said:

My research showed that we want to keep the MEI under 1.2.

If it goes over 1.2, then we go warm everywhere except a small part of the SW.

If it stays between 0.5 and 1.2, then we have a decent shot at a (relatively) colder winter and still have a decent STJ. 

If it stays under 0.5, then all bets are off. It could go either way.

Do you or does anyone else have a link to MEI before 1979? I’d like to see the MEI for more El Niños.

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14 minutes ago, brooklynwx99 said:

Raindance is above such silly indices as the RONI and MEI. we are just plebeians compared to his vast sea of atmospheric knowledge

Life is one big correlation table...from solving world hunger, to alleviating acute personality disorders and getting laid....check the table-

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11 minutes ago, Terpeast said:

My research showed that we want to keep the MEI under 1.2.

If it goes over 1.2, then we go warm everywhere except a small part of the SW.

If it stays between 0.5 and 1.2, then we have a decent shot at a (relatively) colder winter and still have a decent STJ. 

If it stays under 0.5, then all bets are off. It could go either way.

 

3 minutes ago, GaWx said:

Do you or does anyone else have a link to MEI before 1979? I’d like to see the MEI for more El Niños.

Was just looking at this.  Eric Webb has a page with an MEI that he did work to produce back to 1948 - https://www.webberweather.com/multivariate-enso-index.html  

Negative thing is that it is not updated in real-time

..."Here, the same original definition of the MEI is generally utilized, however several adjustments were made to increase the quality and reliability of the data.  The detrended PCs in this MEI Index are based on more and newer data (1948-2018) as compared with Wolters MEI (1950-1993) and the detrending step along w/ the utilization of 30-year sliding base periods reduces the AGW signal in the data that is still present in the original MEI. Also, this version of the MEI is 2 years longer (1948-Present) compared to the original MEI (1950-present)"

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2 minutes ago, griteater said:

 

Was just looking at this.  Eric Webb has a page with an MEI that he did work to produce back to 1948 - https://www.webberweather.com/multivariate-enso-index.html  

Negative thing is that it is not updated in real-time

..."Here, the same original definition of the MEI is generally utilized, however several adjustments were made to increase the quality and reliability of the data.  The detrended PCs in this MEI Index are based on more and newer data (1948-2018) as compared with Wolters MEI (1950-1993) and the detrending step along w/ the utilization of 30-year sliding base periods reduces the AGW signal in the data that is still present in the original MEI. Also, this version of the MEI is 2 years longer (1948-Present) compared to the original MEI (1950-present)"

That is the one I use for pre 1979.

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5 minutes ago, griteater said:

 

Was just looking at this.  Eric Webb has a page with an MEI that he did work to produce back to 1948 - https://www.webberweather.com/multivariate-enso-index.html  

Negative thing is that it is not updated in real-time

..."Here, the same original definition of the MEI is generally utilized, however several adjustments were made to increase the quality and reliability of the data.  The detrended PCs in this MEI Index are based on more and newer data (1948-2018) as compared with Wolters MEI (1950-1993) and the detrending step along w/ the utilization of 30-year sliding base periods reduces the AGW signal in the data that is still present in the original MEI. Also, this version of the MEI is 2 years longer (1948-Present) compared to the original MEI (1950-present)"

Sorry @GaWx This is what I used, not the other link.

It was a pain to copy the color coded table into my own excel, though.

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