ENSO Updates (2007 thru 2023)

[LarryWx]

Today's weekly ENSO report has the OHC up to +1.01 C vs last week's report's +0.94 C. That 0.07 C warming is pretty decent warming for just one week, especially with it up at these levels.

Hey Larry, can you post your SOI monthly averages for June and July for both Tahiti and Darwin in previous El Nino/La Nina years? I thought they were a great barometer to gauge El Nino chances.

Hey King, Here's what I posted last year (exactly one year ago actually!):

Strictly out of curiosity to come up with some additional guidelines to be used as we see how ENSO progresses this summer, I just did some calcs based on 1981-2016 Darwin/Tahiti monthly SLP's in mb that some may find interesting:

Avg June/July/Aug Darwin SLP minus 1000: 13.0/13.5/13.5
Avg June/July/Aug Tahiti SLP minus 1000: 13.7/14.3/14.6

Avg June/July/Aug Darwin SLP minus 1000 strong Nino: 13.5/14.4/14.6
Avg June/July/Aug Darwin SLP minus 1000 wk-mod Nino: 13.0/13.8/13.7
Avg June/July/Aug Darwin SLP minus 1000 weak Nina: 13.0/13.0/12.8
Avg June/July/Aug Darwin SLP minus 1000 mod-str Nina: 12.8/13.1/12.9

Avg June/July/Aug Tahiti SLP minus 1000 strong Nino: 12.8/13.4/13.6
Avg June/July/Aug Tahiti SLP minus 1000 wk-mod Nino: 13.5/13.9/13.7
Avg June/July/Aug Tahiti SLP minus 1000 weak Nina: 14.2/14.3/15.1
Avg June/July/Aug Tahiti SLP minus 1000 mod-str Nina: 14.1/15.2/15.2

Some analysis of these #'s:

- At Darwin, SLP differences from one ENSO cat. to another are greater in July than June and even greater in Aug. Perhaps this means that in Nino's that avg. Australian sfc highs are stronger and/or extend further north in July/Aug vs June whereas in Nina's they stay about the same through that period?

- At Tahiti, SLP differences from one ENSO cat. to another are much greater in June than the rather narrow range for Darwin. So, perhaps this means that Tahiti is more crucial than Darwin in June. These diffs from one ENSO cat to another rise more in July from June.

- SLP averages higher in Darwin than Tahiti in strong Ninos, they average ~same in weak to mod Ninos, and are clearly higher at Tahiti than Darwin in Ninas. ALL years combined incl neutral ENSO average nearly 1 mb higher at Tahiti than Darwin. This is probably near where neutral years, alone, fall. That is why the SOI is near 0 when Tahiti is ~1 mb higher than Darwin.

- When I refer to ENSO cat., I mean the upcoming fall/winter peak as opposed to where it is during JJA.
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Monthly SLP data sources:

Darwin monthly SLP (I started with 1981): http://www.cpc.ncep.noaa.gov/data/indices/darwin

Tahiti monthly SLP (I started with 1981): http://www.cpc.ncep.noaa.gov/data/indices/tahiti

[LarryWx]

I just noticed something quite interesting about the May, 2018, pressures at Tahiti and Darwin:

Darwin monthly SLP: http://www.cpc.ncep.noaa.gov/data/indices/darwin

Tahiti monthly SLP: http://www.cpc.ncep.noaa.gov/data/indices/tahiti

- Tahiti's May, 2018, SLP, which was 1014.1, was the highest on record back to 1951! The normal is only 1012.7. The four highest on record preceding El Nino were 1013.9 (2014 and 1976) followed by 13.7 (2004) and 13.3 (1979), all 4 weak Ninos.
- However, Darwin's was also above normal with its 1012.2. Only 9 of the prior 67 years had higher and 3 were the same. The four cited weak Nino years all had lower Darwin pressures ranging from 10.6 to 12.0. That's why all 4 of those years had a +SOI in May.
- All of the above along with the latest Eurosip for ASO being only warm neutral tells me that any 2018-9 El Nino, which is strongly hinted at by the current +1.01 OHC, would likely be weak to low end moderate.

[NDG]

Experts starting to back up the information the ENSO enthusiasts here on Storm2k put out.

M Ventrice has been has been on the El Niño wagon for a while now

Compared to his El Nino tweets in 2014 and 2015, he's only seldomly spoke about the atmosphere coming out of a La Nina state and into Neutral. Think he tweeted once in April about the warm subsurface pool.

In the other hand Michael Clark just made a 180 deg turn.

@Met_mdclark
I wouldn't be shocked if there is some kind of #ElNino watch issued here at some point in the month of June for Fall into Winter development at this rate. Ill start talking about this more in the days ahead on http://Bamwx.com #AGwx #OAtt #Energy
 https://twitter.com/Met_mdclark/status/1003646716116111362

[Ntxw]

We all knew to some extent a late bloomer type +ENSO event might occur like 2009. That was a possible path (though I don't think we end up that high an event and possibly later start). June is probably the latest these indicators needs to flip from the Nina state to be viable and its slowly working that way. Just got to hold up the subsurface long enough for when trades relax.

[CyclonicFury]

I originally did not think El Niño was that likely with an extended +SOI setup, but it appears as if we are headed for a weak event at least now. The subsurface warm pool has begun to restrengthen with no subsurface cold pool at all, and with a slowing of the trades expected this month, I think we will be well into warm neutral territory by mid-June. We may not see an event officially declared until sometime in the fall. Not expecting a strong event - a weak-moderate central based El Niño similar to 2006 in intensity seems the most reasonable for now.

[NotSparta]

Experts starting to back up the information the ENSO enthusiasts here on Storm2k put out.

M Ventrice has been has been on the El Niño wagon for a while now

Compared to his El Nino tweets in 2014 and 2015, he's only seldomly spoke about the atmosphere coming out of a La Nina state and into Neutral. Think he tweeted once in April about the warm subsurface pool.

to be fair this time in 2015 the atmosphere was already in a nino state

[Kingarabian]

M Ventrice has been has been on the El Niño wagon for a while now

Compared to his El Nino tweets in 2014 and 2015, he's only seldomly spoke about the atmosphere coming out of a La Nina state and into Neutral. Think he tweeted once in April about the warm subsurface pool.

In the other hand Michael Clark just made a 180 deg turn.

@Met_mdclark
I wouldn't be shocked if there is some kind of #ElNino watch issued here at some point in the month of June for Fall into Winter development at this rate. Ill start talking about this more in the days ahead on http://Bamwx.com #AGwx #OAtt #Energy
[tweet]https://twitter.com/Met_mdclark/status/1003646716116111362[tweet]

Yeah, just seen it

[weathaguyry]

I would appreciate it if someone could tell me about how much of a role the MJO plays in determining ENSO, and which phases mean what, I would guess that phases 4/5 would support stronger trades and that phases 8/1 would support WWBs, but I'm not exactly sure.

[NotSparta]

I would appreciate it if someone could tell me about how much of a role the MJO plays in determining ENSO, and which phases mean what, I would guess that phases 4/5 would support stronger trades and that phases 8/1 would support WWBs, but I'm not exactly sure.

[img]http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/ensplume_small.gif[img]

Seems to me that the Western Pacific sectors help WWBs, and mjo in the Indian Ocean hurts them.

[Haris]

Do you know where is a good site to study each MJO phase in great depth?

[StruThiO]

http://www.bom.gov.au/climate/enso/?hoo ... 7684fd903a

BoM ENSO wrap up

[NDG]

@BenNollWeather
Westerly wind burst (WWB) incoming!

The ECMWF has trended stronger with a trade wind relaxation/reversal across the central Pacific over the next 2 weeks. This is expected to result in notable SST warming.

Interestingly, 1997 had a strong WWB around the same time.

 https://twitter.com/BenNollWeather/status/1003955179400523777

[Kingarabian]

I would appreciate it if someone could tell me about how much of a role the MJO plays in determining ENSO, and which phases mean what, I would guess that phases 4/5 would support stronger trades and that phases 8/1 would support WWBs, but I'm not exactly sure.

[img]http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/ensplume_small.gif[/mg]

The MJO plays a large role in triggering El Nino's or La Nina's.

It's going to be a long post if I go in depth, but here's a brief summary:

During the beginning stages of an El Nino, the MJO is pretty active. It's the strongest and spends a lot of time in the WPAC and the EPAC, particularly phases 7/8/1. By being in these phases, trade winds across the equatorial Pacific are slower than average or shift into westerlies (WWB triggered) due to what I believe is increased convergence. With the winds moving west to east, warm water in the WPAC is then pushed east towards the CPAC/EPAC and basically that's how a downwelling Kelvin wave is triggered. If the ocean response is there, you would then see a large and strong warm subsurface pool form (as we have currently). Further MJO activity in phases 7/8/1 allows more WWB's to take place and with a warm sub surface pool in place, the warm anomalies to reach the surface and proceeds into warming the Nino regions.

When an El Nino is in place, the MJO signal is usually incoherent and spends most of its time in the circle.

In a La Nina, the favored phases are generally 3/4/5. The MJO spends most of its time over the IO or the MC and offers no resistance to the trades, thus they remain strong across the equatorial Pacific.

[Kingarabian]

 https://twitter.com/webberweather/status/1004025311481212928




Sums up the reason why RMM can't catch the MJO moving into the CPAC and EPAC.

Eric Blake also pointed out how it's interesting that majority of the rising VP200 anomalies skipped the WPAC and are moving into the CPAC/EPAC.

[NDG]

Maybe a reason why C.A. has not gotten into the usual dryer wx pattern that they usually experience by this time of the year during an El Nino on the horizon.

[Ntxw]

NCDC PDO rose a little bit to -0.61 which is close to what March was. This means JISAO will likely rise a little bit back positive. March JISAO PDO was +0.37

[NDG]

NCDC PDO rose a little bit to -0.61 which is close to what March was. This means JISAO will likely rise a little bit back positive. March JISAO PDO was +0.37

Feb was +0.37, March was at -0.05
For some reason they haven't updated April yet which was probably lower than March. May is probably back up to near -0.05, 3rd month in a row negative, IMO.

http://research.jisao.washington.edu/pdo/PDO.latest.txt

[Ntxw]

NCDC PDO rose a little bit to -0.61 which is close to what March was. This means JISAO will likely rise a little bit back positive. March JISAO PDO was +0.37

Feb was +0.37, March was at -0.05
For some reason they haven't updated April yet.

http://research.jisao.washington.edu/pdo/PDO.latest.txt

You are right! For some reason I assumed they updated April already...

So post correction is same except replace March for Feb. April then was likely lower than March.

[cycloneye]

Ntxw,Kingarabian ,will the two cyclones in EPAC with their westerly flow affect or not the Equatorial waters?

[Ntxw]

Ntxw,Kingarabian ,will the two cyclones in EPAC with their westerly flow affect or not the Equatorial waters?

The WWB likely has created a favorable environment for formation and intensification, likewise the the cyclones will also feedback and solidify the active WWB and perhaps prolong such an event.