2014 ENSO Mega Thread

[Dsnowx53]

Also need to remember how much the blocking was on roids that winter especially in February.

 

 

Composites of west-based and Modoki El Ninos tend to show positive 500mb height anomalies near Greenland, Iceland, and Scandinavia, though I'm not sure we can definitively say that west-based Ninos cause more blocking...though I tend to think they do. 

[JoMo]

The mid-May plume has it peaking at a moderate level late in the summer or early fall.

 

 

 

http://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/

[Quixotic1]

Since we are talking about 09-10 and blocking, the solar state may have some say about it. 09-10 was coming out of a really profound minimum. This year we'll probably be leaving Smax.

[OKpowdah]

Composites of west-based and Modoki El Ninos tend to show positive 500mb height anomalies near Greenland, Iceland, and Scandinavia, though I'm not sure we can definitively say that west-based Ninos cause more blocking...though I tend to think they do. 

 

There is a connection, via the South America hadley cell. A west-based Nino yields a zonally overturning cell rising from 180 and sinking over SA, which weakens the SA HC. A weaker HC -> weaker ST warming -> weaker eddy heat flux in the mid latitudes -> reversal in the FC circulation and meridional mass field / PV gradient ~ blocking.

[bluewave]

The tendency for the SOI to keep returning to a more positive state after the drop

we saw in March has been interrupting the WWB process out near the dateline.

The brief drop earlier this month was answered by another rise and stronger 

trades. That strong warm pool of SST's east of Australia is generally associated 

with a more +SOI.

 

-SOI

 

 

+SOI

 

 

Warmer SST's east of Australia

 

 

+SOI with warmer SST's

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Wannabehippie]

Generally, west-based Ninos do not strengthen the subtropical jet over the southern U.S. or the Caribbean as much as an east-based Nino.  This typically translates to lower wind shear and less of an impact on TCs, although numbers are still generally lower in west-based Ninos than most neutral or Nina seasons. 

 

For the second question, that depends both upon the strength of the El Nino as well as location.  Generally, the stronger the Nino and the more east-based it is, the greater the precipitation anomalies for CA and TX.  I think most would agree it's still too early at this time to determine peak strength and location.  Many El Ninos can be real drought busters.  1965-66 is an obvious counter example, which was a bad drought year for CA and about average for TX.  Note that it was a strong but not super El Nino and west based.  Odds are good for a wet winter, but far from guaranteed. 

 

SST anomalies Dec-Mar 1965-1966:

sst_1965_66.png

 

Precipitation anomalies Dec-Mar 1965-1966:

cd192_138_87_104_135_10_59_6_prcp.png

Well then I wish we get an east based El Nino, especially to help California out of its drought.

[Isotherm]

 I think we're falling behind in the progression of this ENSO event when we compare 2014 to 97-98 and other super nino seasons like 72-73, and 82-83.

 

Daily SOI is now up to +17, and the past month is averaging +2.4. Depending upon the progression of the final days of May, this month could very well finish w/ a +SOI average.

 

Let's suppose we finish May with a +SOI (> 0). If a strong El Nino develops, it would be the only such strong el nino since 1950 with a May monthly SOI averaging positive. The closest year to a +SOI was 1965, where we finished with a -0.3 monthly value. April of 1965 was strongly negative though, at -13.

 

Since 1950, we have never seen a developing strong el nino with both April and May featuring a +SOI. April 2014's value was +8.6. The current 30-day running SOI is +2.4, with some massive positive dailies that will be averaged in over this week. So we're really going to need a plummet in the last week of May. If May ends up being +SOI, I'd probably lower my expected region 3.4 peak from the +1.6c -> +1.9c range, down to the +1.3c --> +1.7c range.

 

I think it's going to be a close call, as I anticipate a bout a strong -SOI dailies will resume in the last part of May (probably). Right now I still believe we're looking at an event comparable to 1957-58 or 1965-66, with a possible region 3.4 peak of +1.6c to as high as +1.9c. But depending upon the progression of the next couple weeks, the door remains open for a lower peak. In my mind, the door for a super nino is closing very quickly, with only slim chances at this point.

 

 

Another differentiating factor in terms of 2014 vs. 1997-98 is the tropical Pacific SSTA profile, particularly near Australia.

 

May of 1997 had cold water already developing near Australia, which is a classic signal for high pressure build-up and consequently stronger westerly-wind bursts. Currently, the water is still warm near Australia, suggestive of much lower pressures in that region than we saw at this time frame in 1997. In other words, by my examination of the SSTA and pressure pattern w/ this spring's SOI tendencies, we are behind 1997, quite a bit. The subsurface is impressive but we'll see.

 

 

 

[The_Global_Warmer]

It is warmer over the West Pacific then 1997.  But the configuration looks like a classic incoming nino everywhere else.

 

 

SSTA in the Indian ocean and West Pacific have warmed substantially versus what they were before the 1997-98 event.

 

 

I don't know how much warmer they are on a regional level.  But it's much warmer almost everywhere than it was then.

 

Of course you are right.  The NINO progression is not as strong as 1997 for sure so far. 

 

 

But global ssta are currently only slightly below the peak levels of the 97/98 nino.

 

 

 

[phil882]

 I think we're falling behind in the progression of this ENSO event when we compare 2014 to 97-98 and other super nino seasons like 72-73, and 82-83.

 

Daily SOI is now up to +17, and the past month is averaging +2.4. Depending upon the progression of the final days of May, this month could very well finish w/ a +SOI average.

 

Let's suppose we finish May with a +SOI (> 0). If a strong El Nino develops, it would be the only such strong el nino since 1950 with a May monthly SOI averaging positive. The closest year to a +SOI was 1965, where we finished with a -0.3 monthly value. April of 1965 was strongly negative though, at -13.

 

Since 1950, we have never seen a developing strong el nino with both April and May featuring a +SOI. April 2014's value was +8.6. The current 30-day running SOI is +2.4, with some massive positive dailies that will be averaged in over this week. So we're really going to need a plummet in the last week of May. If May ends up being +SOI, I'd probably lower my expected region 3.4 peak from the +1.6c -> +1.9c range, down to the +1.3c --> +1.7c range.

 

I think it's going to be a close call, as I anticipate a bout a strong -SOI dailies will resume in the last part of May (probably). Right now I still believe we're looking at an event comparable to 1957-58 or 1965-66, with a possible region 3.4 peak of +1.6c to as high as +1.9c. But depending upon the progression of the next couple weeks, the door remains open for a lower peak. In my mind, the door for a super nino is closing very quickly, with only slim chances at this point.

 

 

Another differentiating factor in terms of 2014 vs. 1997-98 is the tropical Pacific SSTA profile, particularly near Australia.

 

May of 1997 had cold water already developing near Australia, which is a classic signal for high pressure build-up and consequently stronger westerly-wind bursts. Currently, the water is still warm near Australia, suggestive of much lower pressures in that region than we saw at this time frame in 1997. In other words, by my examination of the SSTA and pressure pattern w/ this spring's SOI tendencies, we are behind 1997, quite a bit. The subsurface is impressive but we'll see.

 

 

A direct comparison of the SSTs in May 1997 vs. current shows we are not far behind, with the warm pool is approximately the same location (around 170E currently). 

 

http://www.atmos.albany.edu/student/ppapin/lb13_img/special/20140518/depth.html

 

The loop above shows the evolution of both the SST surface and subsurface (with associated anomalies) from 1 Feb - 17 May. Again you see this isn't a consistent push of warmer SSTs into the EPAC, but rather "pulses" of warmer SSTs that propagate eastward by oceanic kelvin waves. Actually in the last couple of weeks, you see that the subsurface 28 degree isotherm is at approximately the same location subsurface as the May 1997 average (the last frame in the loop).

 

The current depth of the warm water between 160-100 W is pretty much unknown at this time since the buoys in these location are currently not operational. Thus, its possible the strong temperature gradient observed in this location has not been updated to account for the oceanic kelvin wave that is moving through currently. You can see 1997 in this location already has a deeper thermocline in this location, and this is the primary difference between 2014 and currently. Despite this, 2014 still shows the warm pool obviously moving eastward, as oceanic currents are still westerly, despite the +SOI.

 

 

Bottom line... 1997 had a deeper thermocline at this time in the EPAC, but the location of the warm pool max depth was in approximately the same location. The major shifting of the warm pool didn't occur until the July/August 1997 period. Plenty of time to keep watching. Things are still on track for a moderate-strong El Nino. 

[Mike.Ventrice]

Hi guys, saw some questions about modoki el nino events verses full basin ones. Did a quick and dirty analysis of this a month, focusing on differences during winter time: http://www.wsi.com/blog/energy/large-scale-differences-between-the-full-basin-el-nino-and-el-nino-modoki-during-u-s-winter/

[bluewave]

The SOI moving to neutral in May now isn't something that we have seen in most years

that proceeded  mod or strong El Nino development. The warmer waters east of Australia 

are indicative of a +SOI state with stronger trades out near the dateline. If we continue into

positive territory, it wouldn't match the other previous years. 65 was closest to neutral

response, but April was negative unlike this year.

 

May SOI before moderate or strong El Nino falls and winters

 

2014 .....-1.3 so far and rising.......positive April.....+8.6

2009......-5.1...........................+1.6 greatest 3.4 tri-monthly current version CPC

2006......-9.8...........................+1.0

2002.....-14.5...........................+1.3

1997.....-22.4...........................+2.4

1994.....-13.0...........................+1.2

1991.....-19.3...........................+1.5

1986......-6.6............................+1.3

1982......-8.2............................+2.2

1972......-16.1...........................+2.1

1965......-0.3.............................+1.9....negative April...-12.9

1957.....-12.2............................+1.8

[HM]

Have you accounted for localized effects (convection/precip etc.) that could bias the SOI? How about the exceptionally warm Indian Ocean? The climate is simply different now than it was for a lot of our classic strong events, and I'm not sure we can plot a correlation from ESRL and say definitively one thing over another. We need some very in-depth research over the matter, IMO.

[bluewave]

Have you accounted for localized effects (convection/precip etc.) that could bias the SOI? How about the exceptionally warm Indian Ocean? The climate is simply different now than it was for a lot of our classic strong events, and I'm not sure we can plot a correlation from ESRL and say definitively one thing over another. We need some very in-depth research over the matter, IMO.

 

I posted the research on the record breaking trade winds and positive SOI state since the 98 PDO flip

earlier in the thread.

 

 

 

http://www.nature.co...limate2106.html

 

 Here we show that a pronounced strengthening in Pacific trade winds over the past two decades—unprecedented in observations/reanalysis data and not captured by climate models—is sufficient to account for the cooling of the tropical Pacific and a substantial slowdown in surface warming through increased subsurface ocean heat uptake. The extra uptake has come about through increased subduction in the Pacific shallow overturning cells, enhancing heat convergence in the equatorial thermocline. At the same time, the accelerated trade winds have increased equatorial upwelling in the central and eastern Pacific, lowering sea surface temperature there, which drives further cooling in other regions. The net effect of these anomalous winds is a cooling in the 2012 global average surface air temperature of 0.1–0.2 °C, which can account for much of the hiatus in surface warming observed since 2001. This hiatus could persist for much of the present decade if the trade wind trends continue, however rapid warming is expected to resume once the anomalous wind trends abate.

 

 

 

[JBG]

It is warmer over the West Pacific then 1997.  But the configuration looks like a classic incoming nino everywhere else.

I think we should not look only at the super Niños for comparison. Not every one can be another 1997-8 or 1982-3. Those are both rare, and occurred in the context of a long-term +PDO phase. I suspect the strongest we'll do would be a repeat of 1957-8, 1972-3 or 2009-10. I suspect, even though I'm not a pro, that using warm-phase analogs is a mistake.

[HM]

I posted the research on the record breaking trade winds and positive SOI state since the 98 PDO flip

earlier in the thread.

 

While that's good information to have, that's not what I meant. What I meant involves the warming Indian Ocean and its ocean-air feedback across the SH, altering the scope of pressure/wind fields. So, IOW, it may be altering the canonical SOI response of this current basin-wide Nino. The PDO, long-term, is of course valuable; but, it has clearly switched to a positive state. It's arguably the SH-pattern that is putting any negative feedback onto ENSO, not the NH or PDO. Perhaps it is this battle which is keeping the intraseasonal oscillations active, regardless of the RMMs, instead of having forcing settle into ENSO-favored areas.

[icebreaker5221]

While that's good information to have, that's not what I meant. What I meant involves the warming Indian Ocean and its ocean-air feedback across the SH, altering the scope of pressure/wind fields. So, IOW, it may be altering the canonical SOI response of this current basin-wide Nino. The PDO, long-term, is of course valuable; but, it has clearly switched to a positive state. It's arguably the SH-pattern that is putting any negative feedback onto ENSO, not the NH or PDO. Perhaps it is this battle which is keeping the intraseasonal oscillations active, regardless of the RMMs, instead of having forcing settle into ENSO-favored areas.

 

Whether pressure is lower at Darwin due to a warmer West Pac or a warmer eastern Indian Ocean, the net result should be the same: stronger trade winds.  This should, amongst other things, suppress the ability of atmospheric kelvin waves to bring warmer surface waters eastward, making it more difficult for a strong El Nino to develop. 

 

However, and let me know if I'm following you correctly: you're saying that, for a given value of +SOI, some scenarios may be more detrimental to the development of Nino than others.  Maximum warming in the IO should favor strongest trade winds further west than would max warming in the W Pac.  By having the strongest trade winds further west, the negative feedback may not be as strong? 

[HM]

Here are a few metric comparisons among warm events to March-April 2014:

 

The very tight Hadley Cell near the Dateline is of most interest, along with the SH's warm SST. 2014 is likely going to end up one of the warmest SST Nino years down in the IO. Remember that these are comparison maps to other warm ENSO years.

[HM]

Whether pressure is lower at Darwin due to a warmer West Pac or a warmer eastern Indian Ocean, the net result should be the same: stronger trade winds.  This should, amongst other things, suppress the ability of atmospheric kelvin waves to bring warmer surface waters eastward, making it more difficult for a strong El Nino to develop. 

 

However, and let me know if I'm following you correctly: you're saying that, for a given value of +SOI, some scenarios may be more detrimental to the development of Nino than others.  Maximum warming in the IO should favor strongest trade winds further west than would max warming in the W Pac.  By having the strongest trade winds further west, the negative feedback may not be as strong? 

 

No. All I am saying is that background climate states, including the warming oceans (particularly the IO) and SH PV etc., are going to give a false SOI signal (see the maps I posted above and compare them to your regular [wave 1] SOI correlations). I see people are trying to argue against a strong event because the SOI is very positive for such an occurrence. My argument is that the SOI may be positive for other reasons, masking the true Nino that is on the way. IOW, I don't think the +SOI is a strong enough argument with all of these other unusual factors. All I see is the makings of a unique warm event, leading to a strong wave 2 tendency in forcing this spring and unusual convection/wind patterns for a growing Nino.

[Ground Scouring]

HM's informed and inclusive analysis, as always, in this case shows the dangers of underestimating the role of larger feedback mechanisms (i.e., climate change, among other factors) in altering the broader oceanic-atmospheric circulation. He is being a true scientist in acknowledging the changing reality and accounting for it when doing seasonal forecasting. Acknowledging the changing climate is the first step toward integrating that factor into our calculations of SOI, Atlantic TCHP / instability, etc.--factors that particularly affect the tropics. We're entering a new normal in many respects to the atmosphere and its teleconnections--not an asbolute normal (as climate change has always occurred), but a relative one. We are seeing diametrically opposed teleconnections operating against each other in regard to the background atmospheric state, some of which have never been seen with a strong Niño. Old climatology to some extent goes out the window. So to some extent what we have learned to expect with a given base state needs to be unlearned.

[phil882]

No. All I am saying is that background climate states, including the warming oceans (particularly the IO) and SH PV etc., are going to give a false SOI signal (see the maps I posted above and compare them to your regular [wave 1] SOI correlations). I see people are trying to argue against a strong event because the SOI is very positive for such an occurrence. My argument is that the SOI may be positive for other reasons, masking the true Nino that is on the way. IOW, I don't think the +SOI is a strong enough argument with all of these other unusual factors. All I see is the makings of a unique warm event, leading to a strong wave 2 tendency in forcing this spring and unusual convection/wind patterns for a growing Nino.

 

I'm with you HM... the SOI is a pretty one-dimensional way of looking at ENSO events in general, since there could be many other factors influencing the correlation (e.g. the SH vs. NH asymmetries in the pattern, the IOD, other local impacts from strong synoptic systems TCs ect... although synoptic details get smoothed out by the running mean). The key thing here is that ocean current measurements still show easterly propagating ocean currents along the equator, which should continue to move the warm pool east with time despite the SOI signal. 

 

[CoastalWx]

HM's informed and inclusive analysis, as always, in this case shows the dangers of underestimating the role of larger feedback mechanisms (i.e., climate change, among other factors) in altering the broader oceanic-atmospheric circulation. He is being a true scientist in acknowledging the changing reality and accounting for it when doing seasonal forecasting. Acknowledging the changing climate is the first step toward integrating that factor into our calculations of SOI, Atlantic TCHP / instability, etc.--factors that particularly affect the tropics. We're entering a new normal in many respects to the atmosphere and its teleconnections--not an asbolute normal (as climate change has always occurred), but a relative one. We are seeing diametrically opposed teleconnections operating against each other in regard to the background atmospheric state, some of which have never been seen with a strong Niño. Old climatology to some extent goes out the window. So to some extent what we have learned to expect with a given base state needs to be unlearned.

 

Thanks for breaking it down. Keep us posted.

[uncle W]

this weeks oni was +0.4...Down from +0.5 from the previous week...

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

a baby step backwards...

[bluewave]

Whether pressure is lower at Darwin due to a warmer West Pac or a warmer eastern Indian Ocean, the net result should be the same: stronger trade winds.  This should, amongst other things, suppress the ability of atmospheric kelvin waves to bring warmer surface waters eastward, making it more difficult for a strong El Nino to develop. 

 

However, and let me know if I'm following you correctly: you're saying that, for a given value of +SOI, some scenarios may be more detrimental to the development of Nino than others.  Maximum warming in the IO should favor strongest trade winds further west than would max warming in the W Pac.  By having the strongest trade winds further west, the negative feedback may not be as strong? 

 

Yeah,the the importance of the SOI turning more positive after late February and March was to show that the WWB's

would become progressively weaker. If you want to see a very strong El Nino develop, then  you need a more negative

SOI response so the trades can relax with a strong WWB pattern taking over. This is not currently happening now

at a time during the past it has before the stronger events.

 

 

[HM]

Yeah,the the importance of the SOI turning more positive after late February and March was to show that the WWB's

would become progressively weaker. If you want to see a very strong El Nino develop, then  you need a more negative

SOI response so the trades can relax with a strong WWB pattern taking over. This is not currently happening now

at a time during the past it has before the stronger events.

Look, I know it wasn't your intent; but, I think we all know what the SOI is and what it means. In an age of accelerated IO warming and Hadley Cell expansion, I suppose I was trying to think of other ways the SOI would not reflect an oncoming strong El Nino. The equatorial trades ARE weak, despite what you think the pressure difference in the SH tells you. So instead of having the anticyclone over 120-130E, it's over 150-160E. The entire SH subtropics are a wave pool and the two stagnant point locations that measure the SOI are within this noisy landscape. So, isn't it possible this metric could be influenced by some other background signal, possibly hiding its potential predictability to ENSO's strength?

[bluewave]

Look, I know it wasn't your intent; but, I think we all know what the SOI is and what it means. In an age of accelerated IO warming and Hadley Cell expansion, I suppose I was trying to think of other ways the SOI would not reflect an oncoming strong El Nino. The equatorial trades ARE weak, despite what you think the pressure difference in the SH tells you. So instead of having the anticyclone over 120-130E, it's over 150-160E. The entire SH subtropics are a wave pool and the two stagnant point locations that measure the SOI are within this noisy landscape. So, isn't it possible this metric could be influenced by some other background signal, possibly hiding its potential predictability to ENSO's strength?

 

Despite the points that you bring up, the equatorial trades were not particularly weak on the strongest +SOI days this month

in the region of the Tropical Pacific that I like to look at. But we'll just have to wait and see how significant

this pattern ultimately turns out be since it's still early in the game. It's not my intention to suggest that 

anyone didn't understand what the SOI is. But I do believe the SOI is a valuable tool to use.

 

[HM]

Daily SOI maximums should show a clearer, canonical relationship. You are also not supposed to use it for ENSO prediction and climate timescales (30 day min). So your plot there is irrelevant.

[HM]

Here is the zonal surface wind anomaly through 5/25. I'm not saying these are impressively weak, but there are some issues in SH. Perhaps it ultimately prevents a strong event, but I'm not sold.

[Isotherm]

The SOI trends over the past couple months confirm to me that attaining "super nino" status of +2.0c or greater in region 3.4, is very unlikely to occur. I still believe that there's a very good chance for a strong nino in general (+1.5c to +1.9c). With that being said, based upon solely the SOI, you would be going out on a limb in forecasting a strong el nino as we haven't seen one since (at least 1950) with both April and May +SOI months. All of the strong El Nino's since 1950 had either April or May -SOI. However, I think the PDO spike has been very impressive, and quite similar to the 1957 oncoming El Nino, which ended up peaking at +1.8c for the trimonthly region 3.4 value. Very warm SST's from AK southward into the tropics. In the decadal sense, we're not too dissimilar from the mid/late 50s era in that the PDO flipped cold approximately 7 years ago and we're in the midst of the +AMO phase (though a temporary downturn this summer).

 

We still have to keep in mind that the SOI plummet that occurred late winter, with a March value of -13.3, was very impressive and certainly reflective of an oncoming moderate to strong el nino. It just so happens that this particular event is timed differently than many of the others, and so the "relaxation period" of minimal WWB's is occurring during April/May. Thus, while statistically it may be unlikely to reach a strong nino based on the April/May SOI tendencies, I think it's more likely that the evolution of the ENSO event is timed differently than most of the other strong el ninos. The SOI looks to turn negative once into the second week of June as pressures lower substantially in the central tropical pacific, and the SOI should be looking like a robust nino is coming in another couple weeks.

[bluewave]

Daily SOI maximums should show a clearer, canonical relationship. You are also not supposed to use it for ENSO prediction and climate timescales (30 day min). So your plot there is irrelevant.

 

 

I am not sure how much a clearer relationship you are looking for with the SOI and trade wind regime. You can 

see how the WWB pattern weakened  as the -SOI in March became positive in April and May. But it will

be interesting to see how things turn out the next few months. This was the first time that a pre-Nino March

strong WWB pattern weakened in such a dramatic manner during April and May. So this will be a learning

process for everyone involved.

 

-SOI

 

 

+SOI

 

 

+SOI

 

[HM]

I am not sure how much a clearer relationship you are looking for with the SOI and trade wind regime. You can

see how the WWB pattern weakened as the -SOI in March became positive in April and May. But it will

be interesting to see how things turn out the next few months. This was the first time that a pre-Nino March

strong WWB pattern weakened in such a dramatic manner during April and May. So this will be a learning

process for everyone involved.

-SOI

MAR.gif

+SOI

APR.gif

+SOI

MAY.gif

You're not understanding because you're not understanding what I'm saying. I didn't say the SOI was flawed in what it does....the negative and positive fluctuations should show the zonal wind anomalies. The point is that it's only localized, into SH between Darwin and Tahiti, influenced by wave activity. The large scale E-C Pac is similar post WWB. So I was speculating why, in a climate sense this could be happening.