ENSO Discussion

[Geos]

Alright enough of the squabbling in here. Left some more of the legit posts, but some of the later ones weren't necessary. 

 

ENSO index continues to hang around +0.5.

 

 

Looking like a weak one at best.

 

[Front Ranger]

Pretty wack how much cooler the Atlantic is than the Pacific right now.

[stuffradio]

Here's a comparison between last week and this week.

 

[MossMan]

Here's a comparison between last week and this week.

 

Screen Shot 2018-11-19 at 9.38.55 AM.png

Less red! Less red is good!

[Phil]

Pretty wack how much cooler the Atlantic is than the Pacific right now.

It really looks like the early stages of a NATL cold event. The structure of the cooling (down to the subsurface) is truly classic.

 

The Holocene paleo records are indicative of a relationship between the NATL, IO/Asian monsoons, and the tropical/subtropical Pacific. The progressive weakening of the EASM/ISM in recent decades and eastward shift of the IPWP (along with meridional broadening) has been a precursor to each of the last 5 NATL cold cycles (the most recent being the one that started in the 1300s at the end of the MWP). They do tend to begin during warm climate regimes, which is interesting but also fits with what we have now (climate in the warm phase).

[Phil]

Alright enough of the squabbling in here. Left some more of the legit posts, but some of the later ones weren't necessary.

 

ENSO index continues to hang around +0.5.

 

Looking like a weak one at best.

Maybe delete/edit out all of the personal attacks?

 

Unbecoming of this thread.

[Bryant]

Maybe delete/edit out all of the personal attacks?

 

Unbecoming of this thread.

They definitely weren't necessary

[MossMan]

Alright enough of the squabbling in here. Left some more of the legit posts, but some of the later ones weren't necessary.

 

ENSO index continues to hang around +0.5.

 

 

Looking like a weak one at best.

 

Does this come out daily?

[Webberweather53]

The WWB on the EPS is even stronger than a few days ago.

 

I'm still wondering when this supposed EPS westerly wind bias west of the dateline is going to show up because the westerly wind anomalies even west of the dateline are getting even stronger in the model as verification nears just like the background Kim climatology shows & what I've been arguing.

 

Phil made the far flung assumption that the easterly wind bias in the EPS west of the Maritime Continent is purely derived from the convection itself, so when the convection moves eastward in the central Pacific so does the bias.

 

This assumption which has yet to be supported by any actual data from the EPS or Phil makes no consideration for the fact that much of the Maritime Continent bias in the EPS is derived from the highly variant topography and the strong diurnal cycle both of which aren't mutually exclusive and interfere w/ the MJO's own circulation and have been noted to explain much of the "barrier effect" phenomena that's prevalent in the EPS but not the CFSv2 (which may be right for the wrong reasons because its convection is too strong in the Maritime Continent). This also means the bias is somewhat quasi-stationary in space & time, and a function of the geography of the Maritime Continent itself, and doesn't effectively propagate eastward with the anomalous central Pacific convection during El Nino

 

http://blog.southernwx.com/wp-content/uploads/2018/11/NqnpRJE4-1024x768.jpg

[Geos]

Does this come out daily?

Yep

[Esquimalt]

Alright enough of the squabbling in here. Left some more of the legit posts, but some of the later ones weren't necessary.

 

ENSO index continues to hang around +0.5.

 

 

Looking like a weak one at best.

 

Where do you get the graph?

[ShawniganLake]

Where do you get the graph?

https://www.tropicaltidbits.com/analysis/ocean/nino34.png

[Webberweather53]

The weekly OISSTv2 SST anomalies were down slightly from last week, and are significantly below their recent highs but are still at +0.7C in the NINO 3.4 region. I'm going to stick with my original idea back in July" A weak-moderate modoki El Nino seems far more likely in 2018-19 w/ another NINO attempt potentially looming in 2019-20." and am interested to see if we'll get a moderate El Nino out of this but it certainly seems w/ this upcoming WWB at the end of November into December likely revamping the SSTAs over the CP (note that the NINO 3.4 anomalies are lower vs normal than all other regions) we'll have crossed the official ONI threshold no later than SON, although the modified Trenberth (1997) definition I use on my site argues it occurred in ASO which seems to agree a little bit more w/ the atmospheric response following the termination of the summer monsoons. It's trivial at this juncture because in a holistic sense considering both the ocean & atmosphere, we're virtually in a weak El Nino already if we didn't get there a month or two ago.

[Phil]

The WWB on the EPS is even stronger than a few days ago.

 

I'm still wondering when this supposed EPS westerly wind bias west of the dateline is going to show up because the westerly wind anomalies even west of the dateline are getting even stronger in the model as verification nears just like the background Kim climatology shows & what I've been arguing.

 

Phil made the far flung assumption that the easterly wind bias in the EPS west of the Maritime Continent is purely derived from the convection itself, so when the convection moves eastward in the central Pacific so does the bias.

 

This assumption which has yet to be supported by any actual data from the EPS or Phil makes no consideration for the fact that much of the Maritime Continent bias in the EPS is derived from the highly variant topography and the strong diurnal cycle both of which aren't mutually exclusive and interfere w/ the MJO's own circulation and have been noted to explain much of the "barrier effect" phenomena that's prevalent in the EPS but not the CFSv2 (which may be right for the wrong reasons because its convection is too strong in the Maritime Continent). This also means the bias is somewhat quasi-stationary in space & time, and a function of the geography of the Maritime Continent itself, and doesn't effectively propagate eastward with the anomalous central Pacific convection during El Niño

 

 

The easterly wind bias you speak of is only statistically evident when the MJO is in the IO, before it gets to the Maritime domain. Even then it’s sometimes negligible depending on factors like its own amplitude and peripheral influences. (I’m taking this right from the Kim paper you posted).

 

But this makes sense, given it’s clearly a bias that arises diabatically/hydrostatically. And of course, when the warm pool structure changes, so will convective model biases. To argue otherwise is the height of absurdity.

[Front Ranger]

The weekly OISSTv2 SST anomalies were down slightly from last week, and are significantly below their recent highs but are still at +0.7C in the NINO 3.4 region. I'm going to stick with my original idea back in July" A weak-moderate modoki El Nino seems far more likely in 2018-19 w/ another NINO attempt potentially looming in 2019-20." and am interested to see if we'll get a moderate El Nino out of this but it certainly seems w/ this upcoming WWB at the end of November into December likely revamping the SSTAs over the CP (note that the NINO 3.4 anomalies are lower vs normal than all other regions) we'll have crossed the official ONI threshold no later than SON, although the modified Trenberth (1997) definition I use on my site argues it occurred in ASO which seems to agree a little bit more w/ the atmospheric response following the termination of the summer monsoons. It's trivial at this juncture because in a holistic sense considering both the ocean & atmosphere, we're virtually in a weak El Nino already if we didn't get there a month or two ago.

 

Yeah, the MEI entered weak Nino levels in Aug/Sep with a +.51, though it dropped a bit in Sep/Oct down to +.47.

 

If we look at it for the past 6 months, 2018 has seen easily lower MEI than 2014, 2006, and even 2004. It's closer to years like 2003, 1990, and 1979. So a very weak +ENSO event from an atmospheric perspective to this point.

[Black Hole]

Yeah, the MEI entered weak Nino levels in Aug/Sep with a +.51, though it dropped a bit in Sep/Oct down to +.47.

 

If we look at it for the past 6 months, 2018 has seen easily lower MEI than 2014, 2006, and even 2004. It's closer to years like 2003, 1990, and 1979. So a very weak +ENSO event from an atmospheric perspective to this point.

 

Any indications that this (MEI) might change the next 1-2 months or are we "peaking"? SSTA's are well into nino territory at this point. 

[Front Ranger]

Any indications that this (MEI) might change the next 1-2 months or are we "peaking"? SSTA's are well into nino territory at this point. 

 

Well, I believe SOI trends correlate inversely pretty well to MEI and there is no sign of the SOI going strongly negative. Which means the atmosphere still isn't committing to much in the way of +ENSO tendencies.

[Webberweather53]

Yeah, the MEI entered weak Nino levels in Aug/Sep with a +.51, though it dropped a bit in Sep/Oct down to +.47.

 

If we look at it for the past 6 months, 2018 has seen easily lower MEI than 2014, 2006, and even 2004. It's closer to years like 2003, 1990, and 1979. So a very weak +ENSO event from an atmospheric perspective to this point.

 

I have a multitude of qualms with the original MEI a lot of which stem from the fact that the dataset uses an old, defunct loading period for its EOF (1950-1993), excluding several strongest ENSO events since 1950 after this period (1997-98, 2010-11, & 2015-16), it doesn't account for both changing observational and climate base states (no detrending or removal of AGW), plus it uses unadjusted real-time COADS data in its analysis which is often highly suspect & missing many observations that other datasets & reanalyses capture. The MEI needs a serious face lift to put it lightly & this was also the opinion of its creator (Klaus Wolter) when I talked to him a couple years ago at an American Meteorological Society conference. Unfortunately, few in the field (even distinguished climate scientists) are actually aware of these very profound weaknesses in the index but I'm hoping my masters thesis will fix that. Not to mention part of the EOF loading region intersects with mid-latitude phenomena like the PDO, and all MEI components, even those with less explained variance and more noise are given equivalent weighting in the original MEI. 

 

Lengthening the training period of the EOF from 1950 to present or even going from the 1870s to present captures a lot more variance w/ ENSO, stabilizing the EOF, and changing the EOF region like I'm currently doing which slightly asymmetrizes fields like SLP, & SST into the southern hemisphere (given that hemisphere ever so slightly more weight) & allowing the EOF region to change slightly over the course of the seasonal cycle provides a more accurate depiction of the structural evolution of ENSO over the course of the season than the MEI currently does. Variations in SST & SLP in tropical southern hemisphere correlate slightly more w/ ENSO than the N hem does, the slight asymmetry in the EOF region I've implemented, particularly w/ SLP also captures this intriguing observation.

[Front Ranger]

I hear you. But it seems like MEI to MEI comparisons by year would still be valid, especially in more recent years like 2014, 2006, etc? As in, it can still demonstrate ENSO tendencies between different years, even if the numbers might be somewhat off from a historical perspective.

[snow_wizard]

Well, I believe SOI trends correlate inversely pretty well to MEI and there is no sign of the SOI going strongly negative. Which means the atmosphere still isn't committing to much in the way of +ENSO tendencies.

 

The OLR anomalies 5N to 5S - 160W to 160E are the surest sign this potential El Nino is anything but business as usual.  The anomaly for October was +6.8 which is WAY higher than any El Nino that actually materialized in the period of reliable records.

 

http://www.cpc.ncep.noaa.gov/data/indices/olr

[Phil]

For the time being, this is an episode of destructive interference. If the current frequency holds, this will dissociate in a few weeks, and we’ll move into a regime of constructive interference towards Thanksgiving.

Here comes round 2.

 

http://www.atmos.albany.edu/student/ventrice/real_time/timeLon/u.anom.30.5S-5N.gif

[TT-SEA]

Here comes round 2.

 

http://www.atmos.albany.edu/student/ventrice/real_time/timeLon/u.anom.30.5S-5N.gif

What does that mean?

[Webberweather53]

The 9-10 m/s U850 anomalies were virtually spot on forecasts by the EPS that I posted last week. An equatorial Rossby Wave will help retrograde the +u anomalies back across the dateline a little as we close out November.

[TT-SEA]

The 9-10 m/s U850 anomalies were virtually spot on forecasts by the EPS that I posted last week. An equatorial Rossby Wave will help retrograde the +u anomalies back across the dateline a little as we close out November.

What does that mean?

[Guest daniel1]

What does that mean?

It means a crap winter for the PNW.

[MossMan]

It means a crap winter for the PNW.

Nah we will be fine.

[snow_wizard]

Yeah, the MEI entered weak Nino levels in Aug/Sep with a +.51, though it dropped a bit in Sep/Oct down to +.47.

 

If we look at it for the past 6 months, 2018 has seen easily lower MEI than 2014, 2006, and even 2004. It's closer to years like 2003, 1990, and 1979. So a very weak +ENSO event from an atmospheric perspective to this point.

 

Kind of interesting your three examples all featured nice events for the Western lowlands.

[snow_wizard]

It means a crap winter for the PNW.

 

Yup...just ignore all of the mitigating factors this year.

[Webberweather53]

Weekly OISSTv2 just spiked to its highest values yet during this El Nino event, with NINO 3.4 region SSTAs at +1.3C this week. Don't be shocked if tropical tidbits catches up within a few days.

 

Certainly doesn't look like this NINO peaked 4 weeks ago as a certain someone on this forum was vehemently promising. 

 

 

http://blog.southernwx.com/wp-content/uploads/2018/11/Screen-Shot-2018-11-26-at-12.54.13-PM-1024x661.png

[Phil]

I’m sure there will be another round of SST warming with this intraseasonal pass (shifted eastward this time compared to the last one). But yes, for all intents and purposes this event has peaked in amplitude. At least until the completion of the KW return in spring of 2019.

 

If anything, the low frequency state has weakened since autumn while intraseasonal resonance has dominated. To call this anything other than what it is (a borderline event) is just silly.

 

[Webberweather53]

But it obviously did not peak 4 weeks ago because we’ve already matched the highest previous SSTA peak of a month ago only a few days into this big WWB event. This actually will be closer to being a moderate Nino than warm neutral

[Phil]

Depends on which dataset you cherry pick. But SSTAs are a poor diagnosis on short timescales.

 

Not only do we have a weakening low pass signal, but the dateline VP200 anomalies thru A/S/O were the higher than any niño year in the satellite era. Closest match to the progression here is 1987/88, which makes sense w/ the QBO bottoming out @ 50mb.

 

The OKW cycle doesn’t line up at all, however, hence my suspicion for a niño next year (since we won’t have a clean break in time), but to argue that this +ENSO regime is strengthening, given the above, strains credulity.

[Black Hole]

But it obviously did not peak 4 weeks ago because we’ve already matched the highest previous SSTA peak of a month ago only a few days into this big WWB event. This actually will be closer to being a moderate Nino than warm neutral

Thanks for the update! I agree with you fwiw.

[Black Hole]

MJO looking pretty healthy right now. Pattern coming up matches what you would expect with it cycling into 7-8-1-2 the next few weeks. 

[Webberweather53]

It’s not unheard of for low end moderate events to have pronounced subseasonal variability but to claim we already peaked yet also state warming will continue seems contradictory considering we’ve already matched the previous peak a month ago when it was supposed to have already done so

[Phil]

It’s not unheard of for low end moderate events to have pronounced subseasonal variability but to claim we already peaked yet also state warming will continue seems contradictory considering we’ve already matched the previous peak a month ago when it was supposed to have already done so

It’s definitely *not* common to lose your low pass signal in a moderate event unless it’s beyond peak amplitude. Actually, this has never happened in a strengthening satellite-era niño.

 

It the cases where it did happen, like 1987, it always either marked the decline of the ENSO state, or a temporary degradation in structural coherence (the latter is probably the case with this one since the KW cycle has a ways to go still).

 

Right now, there is very little in the way of low frequency constraint within the tropical boundary state(s). That is not indicative of a healthy ENSO event.

[Webberweather53]

It’s definitely *not* common to lose your low pass signal in a moderate event unless it’s beyond peak amplitude. Actually, this has never happened in a strengthening satellite-era niño.

 

It the cases where it did happen, like 1987, it always either marked the decline of the ENSO state, or a temporary degradation in structural coherence (the latter is probably the case with this one since the KW cycle has a ways to go still).

 

Right now, there is very little in the way of low frequency constraint within the tropical boundary state(s). That is not indicative of a healthy ENSO event.

 

But it's pretty apparent we didn't peak a month ago as you claimed, maybe we peak in December once this wwb is finished but that's not unusual for ENSO. "Healthy" is pretty subjective however because there are numerous low-end moderate events that were anything but at this stage in the game. This is the only weak-moderate ENSO event in the satellite era that was accompanied by a low-level eQBO so it's not surprising there's high subseasonal variability.

[Phil]

But it's pretty apparent we didn't peak a month ago as you claimed, maybe we peak in December once this wwb is finished but that's not unusual for ENSO. "Healthy" is pretty subjective however because there are numerous low-end moderate events that were anything but at this stage in the game. This is the only weak-moderate ENSO event in the satellite era that was accompanied by a low-level eQBO so it's not surprising there's high subseasonal variability.

It sounds like you’re referring to SSTAs, in which case it depends on your dataset choice. On CDAS the SSTAs were much higher 3 weeks ago.

 

We should reach 1*C+ again with the oncoming intraseasonal wave, but whether or not that happens is mostly irrelevant in the grand scheme of things, in my opinion.

 

[Webberweather53]

It sounds like you’re referring to SSTAs, in which case it depends on your dataset choice. On CDAS the SSTAs were much higher 3 weeks ago.

 

We should reach 1*C+ again with the oncoming intraseasonal wave, but whether or not that happens is mostly irrelevant in the grand scheme of things, in my opinion.

 

 

 

CDAS lagged changes in OISSTv2 by a few days during the last spike near the beginning of November, and it will probably catch up shortly. We'll probably exceed +1C without much issue given what happened last time.

[Phil]

CDAS lagged changes in OISSTv2 by a few days during the last spike near the beginning of November, and it will probably catch up shortly. We'll probably exceed +1C without much issue given what happened last time.

I could definitely see this happening.

 

However, much like the last time, it will probably be a temporary spike, since another round of destructive interference will begin during the third week of December.