ENSO Discussion

[Phil]

To be fair, it still looks like 2018-19 will qualify as a Nino.

Eh, those SSTAs have to average above 0.5C for another several months, which seems unlikely since that’s in the middle of a KW return cycle (before the developing downwelling wave can re-condition the thermocline, which would probably occur in the M/A/M period, assuming I’m extrapolating correctly).

 

Though in the end, it might come down to one’s choice of dataset. It will almost certainly fail to meet niño criteria on CDAS and possibly HADISST, but that’s less certain on OISSTv2. Splitting hairs if the trimonly troughs down to 0.5C since the physical implications are essentially the same.

[Phil]

Despite a (likely) niño fail for the 2018/19 winter, this should help prime the thermocline/WP and get the niño train rolling for 2019/30, starting sometime in M/A/M, despite the ongoing OKW return cycle (which should last until the equinox).

 

Perhaps the strongest WWB on record, following another near record-breaker back in early January.

 

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

[Phil]

To be fair, it still looks like 2018-19 will qualify as a Nino.

Will need a short term miracle to qualify at this point. The weekly ONI will probably fall below 0.3C this week.

 

IMO, the problem was the OKW cycle was never timed well with seasonality under the current QBO/IPWP structure to hold a low pass signal under intraseasonal interference, especially this early in solar minimum/with so much residual off-equator forcing.

 

[Phil]

If the February ONI averages below 0.4C (which it very well might) it won’t qualify as a niño. And March will probably need to average +0.8C. That seems exceedingly unlikely, although I suppose it’s theoretically possible.

[Kayla]

If the February ONI averages below 0.4C (which it very well might) it won’t qualify as a niño. And March will probably need to average +0.8C. That seems exceedingly unlikely, although I suppose it’s theoretically possible.

 

Looks like it is official.

 

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml

[Webberweather53]

Looks like it is official.

 

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml

 

Simply shocking, this winter ended up being an El Nino & is undoubtedly one even though the SSTAs are marginal  . 

 

For one thing, you don't get 3 successive WWBs in a period of a month near the dateline unless the base state was already advanced enough to supplant forcing that reinforces the pre-existing anomaly, being in warm neutral won't do you any good.

 

It walks, talks, & feels like an El Nino, it's an El Nino...

[Webberweather53]

I really think they’re underestimating the niño potential during the second half of the year. I get there’s the so called “spring predictability barrier” w/ the ENSO models, but there are a number of reasons (IMO) to predict a healthy niño for 2019/20.

 

This in stark contrast to 2018/19, where I thought they were clearly over-estimating the niño likelihood. I was also attacked pretty ruthlessly here for my bearishness on the niño this winter, lol.

 

Maybe because this winter actually was an El Nino?

[Webberweather53]

AAM is literally going off the charts positive and most of the westerly momentum is right in the tropics (where it's supposed to be in an El Nino), that definitely wouldn't happen if we were in neutral ENSO.

[Webberweather53]

This +AAM anomaly we have right now is almost exclusively driven by NINO forcing from the tropics and has surpassed +3.0 sigma

[Phil]

To meet the definition of El Niño requires 5 consecutive trimonthly ONIs AOA 0.5C, however this will probably only reach 4, which is one short. The NDJ average was +0.8C, but the DJF average will probably be ~ 0.5C, and the JFM average will probably be a bit under that.

[Webberweather53]

To meet the definition of El Niño requires 5 consecutive trimonthly ONIs AOA 0.5C, however this will probably only reach 4, which is one short. The NDJ average was +0.8C, but the DJF average will probably be ~ 0.5C, and the JFM average will probably be a bit under that.

 

You of all people should know better than to make a white & black call on ENSO based on one parameter. If you want to play this game, that's fine... We'll meet the Trenberth & Hoar (1997) definition w/o a problem and we're only 0.02C, yes just 0.02C shy of the CPC's definition thanks to ASO when you use a ton of datasets. It's still an El Nino 

[Phil]

You of all people should know better than to make a white & black call on ENSO based on one parameter. If you want to play that game, that's fine, we'll meet the Trenberth & Hoar (1997) definition w/o a problem and we're only 0.02C, yes just 0.02C shy of the CPC's definition thanks to ASO when you use a ton of datasets. It's still an El Nino

I’ve made this point repeatedly in the past (which is why I’d predicted last summer that we’d be splitting hairs over whether this ends up qualifying as a warm neutral or weak niño based on our silly, threshold-based definitions for such phenomena).

 

However, the point remains the same..2018/19 will be remembered as (mostly) a false start prelude to the real deal in 2019/20, probably a moderate or strong niño next winter.

 

No “El Niño” in recorded history has displayed such a level of intraseasonal instability and near absence of a low pass signal like this year. Of course there are substantial +ENSO elements to the AAM budget, but the intrahemispheric disconnect + intraseasonal dominance west of the dateline after the equinox is as anti-niño as it can possibly get.

[Webberweather53]

It's pretty obvious this winter wasn't a neutral one, convection rarely gets consistently past the 160E longitude in the Pacific unless we've already made a significant advancement away from neutral ENSO conditions, this was already happening before this massive bout of NINO forcing this month.

[Phil]

You’ve gotta read my posts before responding.

 

The RMMs looping over the IPWP/ERW feedback is a distinctly *pre niño* forcing structure. And there is no true “neutral” ENSO, but if there was such a thing, at least in terms of the low pass/convective state, this winter is exactly that.

[Webberweather53]

I’ve made this point repeatedly in the past (which is why I’d predicted last summer that we’d be splitting hairs over whether this ends up qualifying as a warm neutral or weak niño based on our silly, threshold-based definitions for such phenomena).

 

However, the point remains the same..2018/19 will be remembered as (mostly) a false start prelude to the real deal in 2019/20, probably a moderate or strong niño next winter.

 

No “El Niño” in recorded history has displayed such a level of intraseasonal instability and near absence of a low pass signal like this year. Of course there are substantial +ENSO elements to the AAM budget, but the intrahemispheric disconnect + intraseasonal dominance west of the dateline after the equinox is as anti-niño as it can possibly get.

 

The glaring issue with this is that this so-called intrahemispheric disconnect is not ENSO neither is the prominent intraseasonal forcing this season directly related to ENSO. ENSO only provides some of the input forcing to these, the rest is dominated by the QBO & mid-latitude internal variability including SSSWEs which both aren't actually ENSO itself but signals that have already been modified by other prominent sources of external variability. It's the equivalent of saying because we have a -PNA right now that must mean we have an ongoing La Nina or vis versa, they're only extracirricular expressions of ENSO and don't directly reflect what happens in the tropical Pacific which is in fact ENSO.

 

As for a lowpass signal, it would be very unusual to see convection consistently near 160E to the dateline in neutral ENSO, the same anomaly structure existed before this month too.

 

[Webberweather53]

You’ve gotta read my posts before responding.

 

The RMMs looping over the IPWP/ERW feedback is a distinctly *pre niño* forcing structure. And there is no true “neutral” ENSO, but if there was such a thing, at least in terms of the low pass/convective state, this winter is exactly that.

 

The subseasonal signal has regularly passed thru and past the dateline unimpeded like it is now & has been for the past month or two, that only happens when the base state has significantly shifted towards El Nino.

 

You should also be reminded &/or be aware that RMM actually does a poor job at reconciling the advancement towards El Nino conditions, the 3rd EOF that's not included in the leading pair actually describes exactly that and is an important component that's missing in the popularly cited index. There's some nice literature out on this from Roundy & others that discuss what happens to the MJO-ENSO relationships if the 3rd EOF was included.

[weatherfan2012]

I’ve made this point repeatedly in the past (which is why I’d predicted last summer that we’d be splitting hairs over whether this ends up qualifying as a warm neutral or weak niño based on our silly, threshold-based definitions for such phenomena).

However, the point remains the same..2018/19 will be remembered as (mostly) a false start prelude to the real deal in 2019/20, probably a moderate or strong niño next winter.

No “El Niño” in recorded history has displayed such a level of intraseasonal instability and near absence of a low pass signal like this year. Of course there are substantial +ENSO elements to the AAM budget, but the intrahemispheric disconnect + intraseasonal dominance west of the dateline after the equinox is as anti-niño as it can possibly get.

this winter in truth has had that neutral after la nina feel to it then one that is truely nino one.alot of the neuturl following la nina winters have trended to suck in our reagion .but what interesting is the following winters ended up being all out block busters so have to wonder if 2019-2020 follows that trend.

[Phil]

The glaring issue with this is that this so-called intrahemispheric disconnect is not ENSO neither is the prominent intraseasonal forcing this season directly related to ENSO.

Of course it’s not “related” to ENSO in causation. It’s masked by ENSO, and its prominence will always destructively interfere with the establishment of the low pass structure associated with any ENSO state so long as it continues forward in time.

 

The ENSO/standing wave/seasonal mode is not compatible with the intraseasonal/propagatory/sub-seasonal mode(s) because because of their dissonant frequencies relative to what is a (relatively) unchanging series of resonance periods integral to the thermocline/OKW process..so the coupling only occurs at lower frequencies.

 

ENSO only provides some of the input forcing to these, the rest is dominated by the QBO & mid-latitude internal variability including SSSWEs which both aren't actually ENSO itself but signals that have already been modified by other prominent sources of external variability.

Exactly, which is why these peripheral forcings can be so important in determining the ENSO outcome. This is why the ONI/low pass signal has collapsed, and it’s why I was/am so bearish on this ENSO signal in general until after the equinox. The SSW/annular modes, QBO/mass circulation, solar/photochemical/TW forcings, IPWP resonance, etc, can all determine whether or not a low pass signal can be established. They have been working AGAINST the establishment of a low pass signal all winter, and that is only just now beginning to change.

 

It's the equivalent of saying because we have a -PNA right now that must mean we have an ongoing La Nina or vis versa,

I think you’ve confused what I’m arguing. I’m not saying the intraseasonal signal is caused by ENSO or whatever, I’m saying its prominence is a reflection of the fact the low pass signal is weak to non existent in the tropics (where coupling would initiate/reflect under boundary conditions set by ENSO/hydrostatics).

 

The high AAM integral in the *subtropics* and developing low pass signal over the IPWP via convection associated with the ERW train is something I’d expect to see in the early, preconditioning stages (IE: this is the dynamic forcing that produces the El Niño event..the El Niño itself is not present).

 

As for a lowpass signal, it would be very unusual to see convection consistently near 160E to the dateline in neutral ENSO, the same anomaly structure existed before this month too.

I disagree..160E is significantly west of the longitude of the EOF for VP200 and OLR in El Niño, especially at this point in the seasonal cycle. However, it does indeed fit the pre-niño structure very well.

[Phil]

The subseasonal signal has regularly passed thru and past the dateline unimpeded like it is now & has been for the past month or two, that only happens when the base state has significantly shifted towards El Nino.

Huh? It’s also regularly crossed into the EHEM (in fact the non-filtered RMMs have centered in the EHEM on 40% of all days over the last 8 weeks, with two full loops into the E-IO (ERW trains and MJO loops contributed to this). You don’t see stuff like this in niño winters. Like, ever. There are no cases of it (to this extent) at any time in the satellite era.

 

You should also be reminded &/or be aware that RMM actually does a poor job at reconciling the advancement towards El Nino conditions, the 3rd EOF that's not included in the leading pair actually describes exactly that and is an important component that's missing in the popularly cited index.

First, the multiple rounds of EHEM forcing are clear even in the absence of any filtering whatsoever.

 

As for the RMMs, I assume you’re referring to that WPAC-dominant mode that doesn’t fit the structure of the conventional W-1/MJO at that evolutionary stage? I’d say there are a lot of cases where even the MJO structure fails to match the EOFs (for example, when you have ERWs and a bifurcating MJO wave, or a collapsing ENSO regime).

 

It’s never perfect, but you should be able to spot these inconsistencies without too much trouble since there are multiple pathways to view them.

[Brian_in_Leavenworth]

this winter in truth has had that neutral after la nina feel to it then one that is truely nino one.alot of the neuturl following la nina winters have trended to suck in our reagion .but what interesting is the following winters ended up being all out block busters so have to wonder if 2019-2020 follows that trend.

At least in the PNW, before this month, it was acting like a classic El Nino.  Split flow, warmer than normal temps, storms coming at us from the SW instead of the NW, (sometimes El Nino early winters are wet, sometimes dry), many storms going into California, etc., then a huge ridge in mid to late January over us giving other parts of the country cold weather and shutting down our winter. Absolute classic for the West.  Then February happened.  Whether humans define this as an official El Nino or not, the weather until then was acting like one in our part of the world.

[Phil]

This is a fantastic case of interhemispheric disconnect especially at this point in the seasonal cycle.

 

The last three months (VP200 anoms). The Southern Hemisphere cell structure has elements of La Niña, while the Northern Hemisphere resembles El Niño.

 

 

Compare this to the 1979-present correlation between the niño 3.4 SST anomaly and the VP200 anomalies, and you can clearly see the northward displacement of the ENSO teleconnection this winter relative to climatology (which is probably a reflection of the fact this event is poorly established/yielding to the intraseasonal cycle).

 

[Phil]

This +AAM anomaly we have right now is almost exclusively driven by NINO forcing from the tropics and has surpassed +3.0 sigma

Can you elaborate on this? The AAM structure *is* the forcing, and of course the boundary conditions for its evolution are set dynamically, well in advance.

 

Also, how high does your vertical profile run? Be careful to avoid including the QBO (the tropopause is lowering).

[weatherfan2012]

This is a fantastic case of interhemispheric disconnect especially at this point in the seasonal cycle.

The last three months (VP200 anoms). The Southern Hemisphere cell structure has elements of La Niña, while the Northern Hemisphere resembles El Niño.

Compare this to the 1979-present correlation between the niño 3.4 SST anomaly and the VP200 anomalies, and you can clearly see the northward displacement of the ENSO teleconnection this winter relative to climatology (which is probably a reflection of the fact this event is poorly established/yielding to the intraseasonal cycle).

no wonder that this winter has been such a differcult one to forecasts giving the complicated signals.makes all of those outlooks back in November very when you look at it now.

[weatherfan2012]

At least in the PNW, before this month, it was acting like a classic El Nino. Split flow, warmer than normal temps, storms coming at us from the SW instead of the NW, (sometimes El Nino early winters are wet, sometimes dry), many storms going into California, etc., then a huge ridge in mid to late January over us giving other parts of the country cold weather and shutting down our winter. Absolute classic for the West. Then February happened. Whether humans define this as an official El Nino or not, the weather until then was acting like one in our part of the world.

this is very true if anything February has been the month that has what baffard many of the mets this winter if you were to tell half of them the west coast would have gotten slammed with winter many would have thought one would be crazy back in november when the winter outlooks went out most if not all the outlooks had the epic pattern in the East :lol:

[Webberweather53]

Huh? It’s also regularly crossed into the EHEM (in fact the non-filtered RMMs have centered in the EHEM on 40% of all days over the last 8 weeks, with two full loops into the E-IO (ERW trains and MJO loops contributed to this). You don’t see stuff like this in niño winters. Like, ever. There are no cases of it (to this extent) at any time in the satellite era.

 

 

First, the multiple rounds of EHEM forcing are clear even in the absence of any filtering whatsoever.

 

As for the RMMs, I assume you’re referring to that WPAC-dominant mode that doesn’t fit the structure of the conventional W-1/MJO at that evolutionary stage? I’d say there are a lot of cases where even the MJO structure fails to match the EOFs (for example, when you have ERWs and a bifurcating MJO wave, or a collapsing ENSO regime).

 

It’s never perfect, but you should be able to spot these inconsistencies without too much trouble since there are multiple pathways to view them.

 

 

There are also none, absolutely zero cases of an oncoming El Nino being coupled to a low-level descending easterly QBO regimes, so this to some extent is a mute point because the forcing here is considerably different than any other event in the satellite era! It's an apples-oranges comparison you're trying to make plus 1978 is a good example of fairly considerable E hem propagation in light of a weak NINO w/ multiple, strong-very strong passes into the E Hem

 

I'm not referring to the WPac dominant mode, (EOF 1), I specifically said EOF THREE which is NOT in the RMM... Ugh.

[Webberweather53]

Can you elaborate on this? The AAM structure *is* the forcing, and of course the boundary conditions for its evolution are set dynamically, well in advance.

 

Also, how high does your vertical profile run? Be careful to avoid including the QBO (the tropopause is lowering).

 

No, the AAM is actually indicative of the forcing of the waves that and background flow whose momentum fluxes are reflected onto this diagram. This is globally & vertically integrated AAM in the troposphere, I thought you knew that already lol perhaps you should read up on the classical papers by Weickmann et al?

[Webberweather53]

Of course it’s not “related” to ENSO in causation. It’s masked by ENSO, and its prominence will always destructively interfere with the establishment of the low pass structure associated with any ENSO state so long as it continues forward in time.

 

The ENSO/standing wave/seasonal mode is not compatible with the intraseasonal/propagatory/sub-seasonal mode(s) because because of their dissonant frequencies relative to what is a (relatively) unchanging series of resonance periods integral to the thermocline/OKW process..so the coupling only occurs at lower frequencies.

 

 

Exactly, which is why these peripheral forcings can be so important in determining the ENSO outcome. This is why the ONI/low pass signal has collapsed, and it’s why I was/am so bearish on this ENSO signal in general until after the equinox. The SSW/annular modes, QBO/mass circulation, solar/photochemical/TW forcings, IPWP resonance, etc, can all determine whether or not a low pass signal can be established. They have been working AGAINST the establishment of a low pass signal all winter, and that is only just now beginning to change.

 

 

I think you’ve confused what I’m arguing. I’m not saying the intraseasonal signal is caused by ENSO or whatever, I’m saying its prominence is a reflection of the fact the low pass signal is weak to non existent in the tropics (where coupling would initiate/reflect under boundary conditions set by ENSO/hydrostatics).

 

The high AAM integral in the *subtropics* and developing low pass signal over the IPWP via convection associated with the ERW train is something I’d expect to see in the early, preconditioning stages (IE: this is the dynamic forcing that produces the El Niño event..the El Niño itself is not present).

 

 

I disagree..160E is significantly west of the longitude of the EOF for VP200 and OLR in El Niño, especially at this point in the seasonal cycle. However, it does indeed fit the pre-niño structure very well.

 

It's not at 160E, it's really more like 170E because if you actually looked at the posted composite the anomalous convection is centered between 160-180E, which is virtually right at the dateline, that's not in fact normal/ ENSO neutral by any means, the base state has clearly already moved towards El Nino and it's nice to see the CPC actually acknowledge that.

[Phil]

There are also none, absolutely zero cases of an oncoming El Nino being coupled to a low-level descending easterly QBO regimes, so this to some extent is a mute point because the forcing here is considerably different than any other event in the satellite era! It's an apples-oranges comparison you're trying to make plus 1978 is a good example of fairly considerable E hem propagation in light of a weak NINO

Definitely a point to be made here. I’d argue 1997 was initially, and the well-timed inception of +QBO/boreal spring +NAM (which is how this year will trend) aided the coupling/low pass establishment, as the intraseasonal cycle terminated early.

 

As for 1977/78, IIRC it was a late-season EHEM MJO passage? Recall niño 3.4 was already below 0.5C by JFM, and there wasn’t any WPAC ERW cycle..so given the westerly QBO it definitely was not a niño-precursor type regime in 1978/79 (I’m sure you’d agree).

 

I'm not referring to the WPac dominant mode, (EOF 1), I specifically said EOF 3 which is NOT in the RMM... Ugh.

You said you were referring to the EOF for a pre-niño convective structure? It’s the only one I know of that diagnoses the ongoing situation accurately.

[Phil]

It's not at 160E, it's really more like 170E because if you actually looked at the posted composite the anomalous convection is centered between 160-180E, which is virtually right at the dateline, that's not in fact normal/ ENSO neutral by any means, the base state has clearly already moved towards El Nino and it's nice to see the CPC actually acknowledge that.

FWIW, you posted surface OLR (and for a single month). I’m not sure how that is useful?

 

And CPC acknowledged El Niño *conditions* (probably due to the recent inception of the standing wave/WWB as the real move to El Niño begins for 2019/20, and to save face to some extent). However, it’s less likely that the 2018/19 winter will meet El Niño criteria since the OKW return has another 4-5 weeks to run. It will be hard to pull off SSTA warming until sometime around the equinox.

[Webberweather53]

Definitely a point to be made here. I’d argue 1997 was initially, and the well-timed inception of +QBO/boreal spring +NAM (which is how this year will trend) aided the coupling/low pass establishment, as the intraseasonal cycle terminated early.

 

As for 1977/78, IIRC it was a late-season EHEM MJO passage? Recall niño 3.4 was already below 0.5C by JFM, and there wasn’t any WPAC ERW cycle..so given the westerly QBO it definitely was not a niño-precursor type regime in 1978/79 (I’m sure you’d agree).

 

 

You said you were referring to the EOF for a pre-niño convective structure? It’s the only one I know of that diagnoses the ongoing situation accurately.

 

Yes and this EOF is not included in the RMM, it explains ~20-25% of the MJO's variance largely near the eastern edge of the warmpool in the CP. The RMM index would look considerably different w/ the inclusion of EOF 3 & I'm honestly not sure how you'd be able to produce easy-to-understand 2-D graphics of said index in real-time which is one reason aside from the fact that EOFs tend to come in pairs (although this is a special case of a triplet), why they haven't used it already.

[Webberweather53]

FWIW, you posted surface OLR (and for a single month). I’m not sure how that is useful?

 

And CPC acknowledged El Niño *conditions* (probably due to the recent inception of the standing wave/WWB as the real move to El Niño begins for 2019/20, and to save face to some extent). However, it’s less likely that the 2018/19 winter will meet El Niño criteria since the OKW return has another 4-5 weeks to run. It will be hard to pull off SSTA warming until sometime around the equinox.

 

Lol what? The graphic I posted showed surface OLR for Nov-Dec-Jan-Feb of this year. I could have also shown the past month or even removed it but the OLR spatial distribution would be roughly the same w/ -OLR just barely west of the dateline.

[Phil]

On 2/14/2019 at 7:49 PM, Webberweather53 said:

No, the AAM is actually indicative of the forcing of the waves that and background flow whose momentum fluxes are reflected onto this diagram. This is globally & vertically integrated AAM in the troposphere, I thought you knew that already lol perhaps you should read up on the classical papers by Weickmann et al?

The westerly momentum was first deposited into the subtropics via wave activity *not* associated with ENSO last year, and it culminated in a brief low pass signal in the deep tropics later on in A/S/O with the STJ/z-cell contraction timed perfectly with the inception of westerly shear (ironically this was too much given the weak antecedent SSTA hold) and ended up terminating the low pass signal altogether thereafter, and ignited the intraseasonal cycle in its place).

[Phil]

Lol what? The graphic I posted showed surface OLR for Nov-Dec-Jan-Feb of this year. I could have also shown the past month or even removed it but the OLR spatial distribution would be roughly the same w/ -OLR just barely west of the dateline.

I apologize, I read that incorrectly (using a phone with a broken screen, only saw Jan).

 

However, keep in mind there are also -OLR anomalies over the maritime continent, so it’s not a coherent regime of dateline forcing, to say the least. The destructive interference is clearly evident in the spatial distribution of the anomalies. It’s even more evident in upper levels/VP anomalies, however.

 

[Jesse]

Good lord...

[Phil]

Good lord...

You rang?

[Phil]

Moving this discussing onwards from the silly anticipation over +/- 0.1C, this will (probably) be another multiyear period with +ENSO lean. There is some circumstantial evidence that this type of behavior was more common in the past, and the ongoing weakening of the EASM/ISM and quiet Sun both fit with this type of ENSO behavior.

 

This is one heck of a WWB..hard to see how this wouldn’t pump the metaphorical primer bulb for the next downwelling cycle.

 

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

[Webberweather53]

The westerly momentum was first deposited into the subtropics via wave activity *not* associated with ENSO last year, and it culminated in a brief low pass signal in the deep tropics later on in A/S/O with the STJ/z-cell contraction timed perfectly with the inception of westerly shear (ironically this was too much given the weak antecedent SSTA hold) and ended up terminating the low pass signal altogether thereafter, and ignited the intraseasonal cycle in its place).

 

You’re getting into a different chicken-egg debate above

regarding AAM/wave activity, since the wave-structure/trains are also dependent on the evolution of the angular momentum budget (for reasons you obviously know).

 

This I can definitely agree with, the subtropical wave activity last spring was the first big clue of a NINO attempt at least in 2018-19 w/ 2019-20 dependent in large part on the intensity of the former and clearly kickstarted the evolution to this year's weak dateline NINO with major hiccups along the way in the general form of the E Asia Monsoon circulation last summer and SSWE + simultaneous S Hem final warming earlier this winter setting off the IO-MC.   

[Phil]

[Webberweather53]

I apologize, I read that incorrectly (using a phone with a broken screen, only saw Jan).

 

However, keep in mind there are also -OLR anomalies over the maritime continent, so it’s not a coherent regime of dateline forcing, to say the least. The destructive interference is clearly evident in the spatial distribution of the anomalies. It’s even more evident in upper levels/VP anomalies, however.

 

 

We often see even stronger IO forcing signals in bonafide weak-moderate NINOs but that clearly doesn't make them any less NINO so this point is pretty mute in the context of modern events if you're going to play the E hem interference card.

 

What's very obvious here which is the point of what I've been saying this entire time is we've already significantly deviated from the "normal"/average state in the Pacific.

 

You will not see a predominant, anomalous, persistent convective anomaly near the dateline during "normal" or near-normal ENSO, that's pretty elementary knowledge. 

[Webberweather53]

If the argument now is going to be that this isn't a NINO event based on some highly subjective analysis of the distribution of OLR in the Pacific & Maritime Continent that's obviously fraught w/ personal biases, the OLR/precipitation indices are both in NINO territory (above 0.5 sigma which roughly corresponds to the CPC ONI threshold in terms of sigma) in January & going to be even higher for February.