ENSO Discussion

[Guest daniel1]

The ECMWF is pretty gung ho for an Indian Ocean MJO wave. That could destroy any chance of a Nino.

Lol there you go again. The SOI was positive for the past week which is what led to cooling in the ENSO regions. It’s now going back negative which should lead to increased warning again.

[TT-SEA]

Jim knows his ENSO stuff and he will actually report when things are not going the way he wants. Or he just stops posting about it altogether. He is not just making it up.

[Jesse]

Lol there you go again. The SOI was positive for the past week which is what led to cooling in the ENSO regions. It’s now going back negative which should lead to increased warning again.

Where is your met degree?

[Brian_in_Leavenworth]

Lol there you go again. The SOI was positive for the past week which is what led to cooling in the ENSO regions. It’s now going back negative which should lead to increased warning again.

Today's SOI is only -1.03, which will not cause much warming, and the readings for the last couple of days were also  barely in the negative range.  The Hovmollers say that the SOI will turn positive again in the next few days (and in fact today's reading was heading in that direction compared to the last few days.  Listen, we don't mind debates about the future of ENSO, or what the next storm will do, that is cool, but to make it personal like you do is not cool at all.   Do not make it personal like you have been, or you won't last here very long.  And by the way, there have been several winters where the PNW (western side) did ok during an El Nino, like 2006-2007.  Where I live we get snow either way, and the last major El Nino a couple of years ago produced a very snowy December and early January.  

 

But I do think that a weak El Nino does seem to be in the cards, but I have seen El Nino fails before.

 

[Phil]

Feels like an eventual Niño is inevitable. Avoiding one now is just kicking the can down the road and making a multi-year warm ENSO event more likely, IMO.

FWIW, cold climate periods following the mid-Holocene transition (including the LIA) tended to feature a higher frequency of weak multiyear niños and strong single year niñas. The climate system actually loses heat during niños, so in some ways they’re a blessing in disguise.

[Jesse]

FWIW, cold climate periods following the mid-Holocene transition (including the LIA) tended to feature a higher frequency of weak multiyear niños and strong single year niñas. The climate system actually loses heat during niños, so in some ways they’re a blessing in disguise.

I’ve heard that before. Haven’t you talked about the upcoming mutli-year Niña being the best thing since sliced bread for us, though?

[Geos]

Region 1+2 is still sinking hard.

 

[Black Hole]

Please stop fighting. I like not having to do anything but today you guys made me do my job. 

[snow_wizard]

Feels like an eventual Niño is inevitable. Avoiding one now is just kicking the can down the road and making a multi-year warm ENSO event more likely, IMO.

 

It will probably happen next winter.  Little chance of a multi year Nino so soon after the last one.  You are getting unreasonably dour IMO.  As for the current season...we have a 30 day SOI currently around zero and an Indian Ocean MJO wave coming up which will mean a Ninaish atmosphere and a liklihood of positive 30 day SOI values coming up.

[Phil]

It will probably happen next winter. Little chance of a multi year Nino so soon after the last one. You are getting unreasonably dour IMO. As for the current season...we have a 30 day SOI currently around zero and an Indian Ocean MJO wave coming up which will mean a Ninaish atmosphere and a liklihood of positive 30 day SOI values coming up.

It doesn’t look like a coherent MJO to me. Technically a wave-2 structure there (waves in W-IO & Pacific), with Indo-Pacific subsidence (which is more niño-esque). That said, November could be decent in the West due to the retracting jet/AAM deposition by Eurasia, with the poleward propagation via eddy transports becoming evident as well.

 

This feels like something that would end up tightening the vortex into December, though. Don’t really expect big cold anywhere in the USA until after New Years, at this point.

[Geos]

As long as it doesn't get any stronger than this. I think we'll be ok. Need some stormiest in the GOA to break up that "son of blob" though.

 

[TigerWoodsLibido]

As long as it doesn't get any stronger than this. I think we'll be ok. Need some stormiest in the GOA to break up that "son of blob" though.

 

Wasn't the blob there in 13-14?

[Front Ranger]

Wasn't the blob there in 13-14?

 

I believe the GOA was quite warm in 2013, similar to this fall, as there has been quite a bit of blocking in that area.

[Front Ranger]

It doesn’t look like a coherent MJO to me. Technically a wave-2 structure there (waves in W-IO & Pacific), with Indo-Pacific subsidence (which is more niño-esque). That said, November could be decent in the West due to the retracting jet/AAM removal by Eurasia, with the poleward propagation via eddy transports becoming evident as well.

 

This feels like something that would end up tightening the vortex into December, though. Don’t really expect big cold anywhere in the USA until after New Years, at this point.

 

I disagree. I think there's a good shot at a major cold wave into the U.S. in mid November, and another one by late December.

[Phil]

As long as it doesn't get any stronger than this. I think we'll be ok. Need some stormiest in the GOA to break up that "son of blob" though.

 

The blob is meaningless, IML. There are no physically-plausible mechanisms (that I’m aware of) through which it can force ridging.

[Phil]

I disagree. I think there's a good shot at a major cold wave into the U.S. in mid November, and another one by late December.

I guess we’ll see. I envision a run-of-the-mill cool pattern morphing into a zonal pattern by December with a strong vortex.

[Front Ranger]

I guess we’ll see. I envision a run-of-the-mill cool pattern morphing into a zonal pattern by December with a strong vortex.

I don't see any pattern locking in for long over the next couple months. More variability than usual.

[Phil]

I don't see any pattern locking in for long over the next couple months. More variability than usual.

I agree with you here, so long as we avoid a strong, baratropic-mode PV. The reason I say this is because, ironically, the strat PV/NAM essentially controls the degree of static stability in the tropics, and this has a huge effect on the ability of MJO/intraseasonal forcings to strengthen and overpower the +ENSO background cell. A strong, baratropic mode PV directly warms/lowers the tropical tropopause, which increases static stability and stunts convection, rendering the MJO impotent.

 

Therefore, since the most significant “pattern variability” in the middle latitudes arises via high frequency MJO activity and vacillations in AAM balance, when you have a strong stratospheric vortex, you will see a more stable pattern that mirrors the background ENSO/low-freq regime, because the tropics (hence the entire system structure) is more stable. Literally.

[Phil]

The research on this is fascinating.

 

https://journals.ametsoc.org/doi/abs/10.1175/2009JCLI3369.1

 

The truth is you don’t need a SSW/PV breakdown to perturb the integral of tropical static stability. You just need enhanced wave breaking activity bombarding the vortex/beefing up the mass circulation to see the results in the tropical convection.

 

We saw last February how quickly the pattern changed once that first wave attack occurred (well before the follow-up attack/actual SSW). It’s a fascinating process.

[Phil]

This paper is a classic. A must-read.

 

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005GL024510

 

The climatological response is a southward migration and intensification of the ITCZ convection and the immediate ignition of MJO activity.

 

Considering the fact that off-equator/north-displaced NPAC convection/wide Hadley Cells are almost solely responsible for the degradation of west coast climate in recent decades, the fact the SSW-tendencies directly oppose these changes can only render them beneficial.

[ShawniganLake]

I agree with you here, so long as we avoid a strong, baratropic-mode PV. The reason I say this is because, ironically, the strat PV/NAM essentially controls the degree of static stability in the tropics, and this has a huge effect on the ability of MJO/intraseasonal forcings to strengthen and overpower the +ENSO background cell. A strong, baratropic mode PV directly warms/lowers the tropical tropopause, which increases static stability and stunts convection, rendering the MJO impotent.

 

Therefore, since the most significant “pattern variability” in the middle latitudes arises via high frequency MJO activity and vacillations in AAM balance, when you have a strong stratospheric vortex, you will see a more stable pattern that mirrors the background ENSO/low-freq regime, because the tropics (hence the entire system structure) is more stable. Literally.

Looks like the CFS is picking up the possibility of a strat warming event later in November.

 

[Phil]

Looks like the CFS is picking up the possibility of a strat warming event later in November.

 

0B1B0D29-0019-4923-8510-B9A4D8BD3387.png

Ha, I was literally just about to post a picture of that tweet by Dr. Ventrice.

 

If it happens, it would greatly increase the chances for a legitimate winter event in the West. Right now the stratosphere and troposphere are relatively decoupled from one another, so it’s hard to know which way things swing.

[TigerWoodsLibido]

[AbbyJr]

Ha, I was literally just about to post a picture of that tweet by Dr. Ventrice.

 

If it happens, it would greatly increase the chances for a legitimate winter event in the West. Right now the stratosphere and troposphere are relatively decoupled from one another, so it’s hard to know which way things swing.

 

So stratospheric warming events commonly increase the chances of Arctic outbreaks in BC and the PNW? I always thought they were more linked with Arctic air in the East...? 

[Phil]

So stratospheric warming events commonly increase the chances of Arctic outbreaks in BC and the PNW? I always thought they were more linked with Arctic air in the East...?

Nope! That’s a myth perpetuated by the mass media and east coast snow weenie wishcasters.

 

Especially in +ENSO, PV breakdowns aid the West via reducing the integral of static stability in the tropics, which ignites the MJO, which can destructively interfere with the low-frequency ENSO convective tendencies.

 

A strong PV keeps the tropical upper troposphere warm, which reduces deep convection and allows the low frequency/ENSO cell to maintain itself more easily via a lack of destructive MJO interference.

 

This is a bit oversimplified, but sufficiently summarizes the situation, IMO.

[AbbyJr]

Nope! That’s a myth perpetuated by the mass media and east coast snow weenie wishcasters.

 

Especially in +ENSO, PV breakdowns aid the West via reducing the integral of static stability in the tropics, which ignites the MJO, which can destructively interfere with the low-frequency ENSO convective tendencies.

 

A strong PV keeps the tropical upper troposphere warm, which reduces deep convection and allows the low frequency/ENSO cell to maintain itself more easily via a lack of destructive MJO interference.

 

This is a bit oversimplified, but sufficiently summarizes the situation, IMO.

Thanks Phil! Do you have some links to some easy to read charts and or models for monitoring stratospheric warming?

[Phil]

Thanks Phil! Do you have some links to some easy to read charts and or models for monitoring stratospheric warming?

I like Hannah Attard’s site, personally. The top two images are plots of observed and modeled 10mb zonal winds at 65N (IE, how strong/intense the vortex is). It updates w/ the 00z GFS/GEFS.

 

http://www.atmos.albany.edu/student/hattard/realtime.php

 

Can also use Levi Cohen’s site for a visual interpretation of the modeled behavior of the PV. Updates with every GFS run:

 

https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=nhem&pkg=Tz10&runtime=2018102518&fh=-114

[AbbyJr]

I like Hannah Attard’s site, personally. The top two images are plots of observed and modeled 10mb zonal winds at 65N (IE, how strong/intense the vortex is). It updates w/ the 00z GFS/GEFS.

 

http://www.atmos.albany.edu/student/hattard/realtime.php

 

Can also use Levi Cohen’s site for a visual interpretation of the modeled behavior of the PV. Updates with every GFS run:

 

https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=nhem&pkg=Tz10&runtime=2018102518&fh=-114

 

Awesome, thanks! 

[snow_wizard]

The 30 day SOI average has been slightly positive for 5 days running now.  The oceanic temperature profile is pretty Ninoish, but the atmosphere is very reluctant.  The coming Indian Ocean MJO wave could put the 30 SOI average strongly positive over the next couple of weeks.  No matter how you slice it this is a tough call.

[Brian_in_Leavenworth]

The 30 day SOI average has been slightly positive for 5 days running now.  The oceanic temperature profile is pretty Ninoish, but the atmosphere is very reluctant.  The coming Indian Ocean MJO wave could put the 30 SOI average strongly positive over the next couple of weeks.  No matter how you slice it this is a tough call.

OTOH, this looks like it could give a boost to the Nino.

 

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

[Phil]

OTOH, this looks like it could give a boost to the Nino.

 

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

Hmmm. That looks like destructive interference to me.

 

Enhanced trades along/west of the dateline are the background state in La Niña years (or late-stage EPAC-based Niños).

 

In this case, it’s merely intraseasonal (forcing via MJO and AAM voids/transport) overriding the relatively weak +ENSO-ish background state. Will probably last a few weeks before dissociating as we approach Thanksgiving.

[Webberweather53]

Hmmm. That looks like destructive interference to me.

 

Enhanced trades along/west of the dateline are the background state in La Niña years (or late-stage EPAC-based Niños).

 

In this case, it’s merely intraseasonal (forcing via MJO and AAM voids/transport) overriding the relatively weak +ENSO-ish background state. Will probably last a few weeks then reverse as we approach Thanksgiving.

 

The net effect of an equivalent period of easterly trades following a strong WWB is to warm the tropical Pacific because the latter is associated with local & large-scale remote positive feedbacks while the other isn't.

[Webberweather53]

Against the best wishes of some here, it seems pretty clear to me we're entering an El Nino regime right now. As I thought might happen a while ago, the atmosphere finally responded following the termination of the eastern hemisphere monsoon circulations and global AAM distribution is what you'd expect in a NINO and the ocean is warming (& a lot), OISSTv2 weekly anomalies are exceeding +1C in the NINO 3.4 region.

[Phil]

The net effect of an equivalent period of easterly trades following a strong WWB is to warm the tropical Pacific because the latter is associated with local & large-scale remote positive feedbacks while the other isn't.

Of course, I agree we wouldn’t see them cancel out given the OKW/fluid inertia already present upstream.

 

Thst said, trades over the IPWP/WPAC should still be considered destructive interference, no? All it does is increase the Indonesian throughflow and reduce the WWV in the eastern half of the warm pool. I cannot figure how that could possibly teleconnect constructively with +ENSO, especially with the extratropical AAM load now in the propagatory phase.

[Webberweather53]

Of course, I agree we wouldn’t see them cancel out given the OKW/fluid inertia already present upstream.

 

Thst said, trades over the IPWP/WPAC should still be considered destructive interference, no? All it does is increase the Indonesian throughflow and reduce the WWV in the warm pool. No way to teleconnect that constructively with +ENSO, especially with the AAM load now in the propagatory phase.

 

It's interference for sure but the net impact still leads to warming because the positive feedbacks are strong w/ westerly wind anomalies both in terms of local advection from surface and upper ocean currents & modulation of deep, moist convection. It's the same reason you can still get an El Nino in 2014 even with just one strong westerly wind burst for a few weeks then a few-several months of easterlies but the net effect is still warming in the long run. Easterly trade wind bursts and WWBs aren't created equal and shouldn't be treated as such even if their magnitudes are the same.

 

It actually does teleconnect to +ENSO because we've underwent more than one phase cycle of subseasonal forcing and this subtropical westerly wind anomaly has persisted and actually intensified despite brief bouts of E Hem forcing.

[Geos]

ENSO hovering around that 0.5 mark. 

 

With the forecasted ocean temperature changes from the graphic above, it looks like more cooling than anything coming up - especially when you consider the area of cold vs. warmer.

[Webberweather53]

CDAS is running about 0.5-0.6C below OISSTv2 which shows anomalies > 1C in the NINO 3.4 & NINO 4 region.

 

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

[Phil]

It's interference for sure but the net impact still leads to warming because the positive feedbacks are strong w/ westerly wind anomalies both in terms of local advection from surface and upper ocean currents & modulation of deep, moist convection. It's the same reason you can still get an El Nino in 2014 even with just one strong westerly wind burst for a few weeks then a few-several months of easterlies but the net effect is still warming in the long run. Easterly trade wind bursts and WWBs aren't created equal and shouldn't be treated as such even if their magnitudes are the same.

 

It actually does teleconnect to +ENSO because we've underwent more than one phase cycle of subseasonal forcing and this subtropical westerly wind anomaly has persisted and actually intensified despite brief bouts of E Hem forcing.

Well, I agree that the effects on the thermocline aren’t neutral in this case, given the evolution of the loop(s) to +ENSO (albeit slowly).

 

However, I’m vehemently opposed to the idea that the higher frequency interference “teleconnects” to the ENSO/lower frequency modes beneath it, because there is a strong inverse relationship in their power spectras. An active MJO/intraseasonal cycle dynamically opposes a stronger ENSO state at this point in the seasonal cycle.

 

IMO, you can technically parameterize the high frequency vacillation(s) as a form of blue noise, through which the ENSO/lower frequency components arise on a prefferred series of resonance points integral to the system. So they certainly don’t constructively interfere in the long run.

[Webberweather53]

Well, I agree that the effects on the thermocline aren’t neutral in this case. Altogether the longer term evolution has been inching towards +ENSO.

 

However, I’m vehemently opposed to the idea that the higher frequency interference “teleconnects” to the ENSO/lower frequency modes beneath it, because there is a strong inverse relationship in their power spectras. An active MJO/intraseasonal cycle dynamically opposes a stronger ENSO state.

 

IMO, you can technically parameterize the high frequency vacillation(s) as a form of blue noise, through which the ENSO/lower frequency components arise on a prefferred series of resonance points integral to the system itself.

 

The +AAM in the subtropics has persisted in spite of more than one bout of enhanced IO convection, it should not be dismissed solely as high frequency noise because if it was mostly subseasonal variability, the anomaly would have eroded already.

[Webberweather53]

"However, I’m vehemently opposed to the idea that the higher frequency interference “teleconnects” to the ENSO/lower frequency modes beneath it, because there is a strong inverse relationship in their power spectras. An active MJO/intraseasonal cycle dynamically opposes a stronger ENSO state at this point in the seasonal cycle."
 

This relationship is true for many reasons that aren't physically related to what you're describing here but rather are artifacts. One good example is how advection by the stronger background flow and alterations in convective distribution, especially in areas that traditionally observe more during El Ninos narrows the MJO's bandwidth s.t. it shifts to higher frequency, eastward propagating Kelvin modes. When you actually boil it down, this doesn't explicitly say anything about the amplitude of the totality of subseasonal variability but rather that the shift of the MJO towards Kelvin Waves gives the illusion of "weaker" MJO activity when reality doesn't necessarily corroborate this.