ENSO Discussion

[Phil]

One heck of a trade wind burst along/west of the dateline upcoming over the next few weeks. If this can continue for another ~ 5 weeks, we can probably rule out a moderate Niño for next winter.

[TT-SEA]

One heck of a trade wind burst along/west of the dateline upcoming over the next few weeks. If this can continue for another ~ 5 weeks, we can probably rule out a moderate Niño for next winter.

 

Good news.    

[Phil]

The SSTA distribution is starting to take on more of a 2010-2012 look, following the big -NAM (-AO/-NAO) event that appears to have reorganized the tropical teleconnections a bit.

 

http://www.tropicaltidbits.com/analysis/ocean/cdas-sflux_ssta_relative_global_1.png

[Phil]

Some EPAC warming upcoming

Bustola.

 

Looks like too much inertia in the WPAC thermocline with the trade burst.

[Phil]

Moderate Nino (ONI peak trimonthlies +1.0 to +1.4) looks like most likely outcome to me.

You might want to reconsider. This trade wind burst isn't going anywhere anytime soon.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/49AFF326-F983-4ABF-AAA1-A6BA97CCFEEA_zps8uisqek3.jpg

[SilverFallsAndrew]

Kinda looks like a Nina may be back on the table.

[Front Ranger]

You might want to reconsider. This trade wind burst isn't going anywhere anytime soon.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/49AFF326-F983-4ABF-AAA1-A6BA97CCFEEA_zps8uisqek3.jpg

 

We'll see. Like I said, that was based purely on historical ENSO progression. The ebbs and flows of trade wind bursts don't necessarily mean much at this point. Long way to go.

[Phil]

We'll see. Like I said, that was based purely on historical ENSO progression. The ebbs and flows of trade wind bursts don't necessarily mean much at this point. Long way to go.

 

What? Wind stresses drive the ENSO, most efficiently within the ideal fluid inertial resonance period of the equatorial Pacific thermocline. These "ebbs and flows" in circulation occur on numerous frequencies, which are determined by globally-integrated boundary conditions. You have higher frequency "ebbs and flows" (MJO waves, convectively-coupled Kelvin waves, etc), and lower frequency "ebbs and flows" that can last anywhere from months to centuries.

[Phil]

Also, what "historical ENSO progression" are you referring to?

 

I can't find a single example of a moderate niño developing just two years after a super-niño. There's a reason for that.

[Front Ranger]

Also, what "historical ENSO progression" are you referring to?

 

I can't find a single example of a moderate niño developing just two years after a super-niño. There's a reason for that.

 

Years where ENSO has rebounded from a weak Nina/negative neutral to weakly positive/neutral in the spring.

 

Examples would be: 2009, 2002, 1997, 1986, 1972, 1965, 1963, and 1951. The bolded all went on to become moderate Ninos, and 1951 almost did. Not a single -ENSO winter followed.

[Jesse]

Kinda looks like a Nina may be back on the table.

Mircavkles never seise.

[Phil]

Years where ENSO has rebounded from a weak Nina/negative neutral to weakly positive/neutral in the spring.

 

Examples would be: 2009, 2002, 1997, 1986, 1972, 1965, 1963, and 1951. The bolded all went on to become moderate Ninos, and 1951 almost did. Not a single -ENSO winter followed.

This doesn't address the point. What leads you to predict a moderate niño?

 

It's one thing to see a +ENSO, but it's another thing to see a moderate niño less than two years after a super niño. That has never occurred in recorded history, and there are many reasons for that. As a forecaster, you'd better have a very good reason to go that route.

[Front Ranger]

This doesn't address the point. What leads you to predict a moderate niño?

 

It's one thing to see a +ENSO, but it's another thing to see a moderate niño less than two years after a super niño. That has never occurred in recorded history, and there are many reasons for that. As a forecaster, you'd better have a very good reason to go that route.

 

Hey, that could be a factor. Of course, we only have 4 previous examples (in the modern era of measuring ENSO) to go off of, so that's a pretty small sample size.

 

We've also had not previously seen a super Nino follow a weak Nino, and that's what happened in 2016. So I'm not sure there's hard and fast rules to these things.

[Phil]

Hey, that could be a factor. Of course, we only have 4 previous examples (in the modern era of measuring ENSO) to go off of, so that's a pretty small sample size.

 

We've also had not previously seen a super Nino follow a weak Nino, and that's what happened in 2016. So I'm not sure there's hard and fast rules to these things.

Well, we have adequate ENSO reconstructions which run back to the 1860s, and even then, never has a moderate niño occurred within two years following a super niño.

 

Also, 2014/15 was (theoretically) a low-solar abomination of the IPWP cycle, given the super niño cycle is driven by the interdecadal-longitudinal fluctuation(s) of the IPWP relative to the response-preference to external forcings and resonances. The IPWO cycle is driven, on a fluid-inertial lag, by solar/external forcings on the peripheral boundary conditions for tropical convection (QBO/tropical static stability, annular modes). The larger the systematic disequilibrium to the response-preference to external forcing, the closer the super niño response will occur to the west shifted IPWP regime. The weaker solar forcing has dampened this IPWP cycle in recent years, so the super niño attempt in 2014/15, which was right at the peak in the eastward IPWP regime, failed, hence restarting in 2015/16:

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/AECFD5C7-1C51-4FD0-978B-991F95341177_zpsebb3dkw4.jpg

[Phil]

This is why you typically see a moderate/strong El Niño develop near/just after solar minimum. At first it sounds counterintuitive given the broad IPWP is a response to solar maximum, but the niño response during solar minimum actually occurs because of the westward retraction of the IPWP. It steepens the longitudinal thermo-convective gradient across the tropical Pacific and steepens the thermocline, which preconditions the system for a downwelling oceanic KW, which is then set off by a reduction in tropical static stability by the winter -NAM (-AO) response to the strengthened BDC/poleward O^3 flux, a hallmark of low solar.

 

This allows the MJO/intraseasonal convection to leave the confines of the IPWP, and propagate eastward across the Pacific, forcing a WWB regime that can then easily initiate a downwelling oceanic KW.

 

By this logic, we can expect an overall westward retraction of the IPWP over the next few years, which should force an El Niño response during 2019/20, followed by a multi-year moderate or strong La Niña state in the early 2020s.

[Phil]

Back to IO/dateline cooling, maritime warming.

 

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

[SilverFallsAndrew]

Pretty clear there will not be an El Nino this winter. 

[Phil]

Moderate Nino (ONI peak trimonthlies +1.0 to +1.4) looks like most likely outcome to me.

Another Flatiron bust.

[Front Ranger]

Another Flatiron bust.

Yeah, not looking likely but July is probably a little too early to say where we end up this winter.

 

Calling out a bust 6 months in advance doesn't come across as desperate at all.

[Phil]

Yeah, not looking likely but July is probably a little too early to say where we end up this winter.

 

Calling out a bust 6 months in advance doesn't come across as desperate at all.

What goes around comes around, my friend.

[Front Ranger]

I told you that I'd start highlighting your busts, since you spent months critiquing my forecasts, then refused to participate in the forecast contest.

 

What goes around comes around, my friend.

 

Not true. I called you out for insisting that June (and then early summer) was going to end up "cool/troughy" when it obviously wasn't.

 

Not the same as hunting busts 6 months before verification. 

[Geos]

ENSO index region 3.4 sure crashed...

 

[Black Hole]

Well, so much for el nino watch. Subsurface is cooling and most areas are near 0 anomaly right now, but trending downwards.

Looks like a negative neutral is most likely, with a small chance of weak la nina developing. 

[Phil]

Well, so much for el nino watch. Subsurface is cooling and most areas are near 0 anomaly right now, but trending downwards.

 

Looks like a negative neutral is most likely, with a small chance of weak la nina developing.

I'd argue the circulation is mostly analogous to an east based niña already, despite the lack of cooler SSTAs? The WPAC warm pool is enhanced relative to the EPAC, which is increasingly focusing convection there.

 

The WPAC warm pool is also expanded significantly poleward relative to average, which I think driven the off-equator WPAC convection that's reinforcing the rossby wave train driving the warmth over the PNW. When the MJO destructively interferes with this background state upon leaving the Pacific/IPWP area (as it will over the next two weeks) the heat pattern seems to break down. At least that's what I'm thinking.

 

So if this continues, I think there should be another push towards western heat/ridging in early September, assuming we're following the same MJO/intraseasonal periodicity observed since May?

[Phil]

Looks more east-based to me this year, though. The entire IPWP convective engine is shifted N/W, out of the E-IO/W-Indo and into the WPAC/E-Indo area, and even the off-equator WPAC. This versus last year's 120E exhaust pipe and -IOD cell.

[Jesse]

Looks more east-based to me this year, though. The entire IPWP convective engine is shifted N/W, out of the E-IO/W-Indo and into the WPAC/E-Indo area, and even the off-equator WPAC. This versus last year's 120E exhaust pipe and -IOD cell.

So blowtorch fall/winter for the west?

[stuffradio]

ENSO index region 3.4 sure crashed...

 

It fears the nukes.

[Phil]

So blowtorch fall/winter for the west?

Well, I think A/S/O will blowtorch overall, but IMO it's unlikely to continue into winter. At least in the PNW. Since the warmth is likely being driven by an enhanced/poleward WPAC warm pool, the circulation should change once we make the seasonal transition out of the Asian monsoonal circulation and develop the Siberian high in mid/late autumn. This will play differently on the tropical convection and rossby wave train.

 

That said, I'll need another 4-5 weeks to make any preliminary winter forecasts. Biggest wildcards are solar wind/geomag and the seasonal transition of the Eurasian circulation/how it plays on the IPWP convection.

[Jesse]

Well, I think A/S/O will blowtorch overall, but IMO it's unlikely to continue into winter. At least in the PNW. Since the warmth is likely being driven by an enhanced/poleward WPAC warm pool, the circulation should change once we make the seasonal transition out of the Asian monsoonal circulation and develop the Siberian high in mid/late autumn. This will play differently on the tropical convection and rossby wave train.

 

That said, I'll need another 4-5 weeks to make any preliminary winter forecasts. Biggest wildcards are solar wind/geomag and the seasonal transition of the Eurasian circulation/how it plays on the IPWP convection.

I just figured. Whenever I hear the term "WPAC forcing" it means we are either torching or are going to torch. I understand very little else from your posts, but I've at least learned that much.

 

For the record, it's been since 2013 since we have failed to see a record warm month in the August-November period, so for whatever reason we have been torching in this time frame every year despite what have likely been a multitude of factors playing into it each year.

[Phil]

I just figured. Whenever I hear the term "WPAC forcing" it means we are either torching or are going to torch. I understand very little else from your posts, but I've at least learned that much.

Haha, yeah WPAC/dateline convective forcing is almost always going to torch you guys during the warm season, especially in the modern climata era, since it's shifted poleward with the more expanded and slower Hadley Cell.

 

The cold season is more complicated, though.

 

For the record, it's been since 2013 since we have failed to see a record warm month in the August-November period, so for whatever reason we have been torching in this time frame every year despite what have likely been a multitude of factors playing into it each year.

This is because the WPAC warm pool (also referred to as the IPWP, or Indo-Pacific Warm Pool) has been notably enhanced and shifted poleward during boreal autumn since the climate system shakeup that occurred in January of 2013. It slows the seasonal retraction of the Hadley Cell and monsoonal circulation.

[Jesse]

This is because the WPAC warm pool (also referred to as the IPWP, or Indo-Pacific Warm Pool) has been notably enhanced and shifted poleward during boreal autumn since the climate system shakeup that occurred in January of 2013.

Any idea when this could change again?

[Phil]

FWIW, this is the domain I'm referring to. It might not look impressive on the SSTA maps, but these are by far the warmest waters on Earth during A/S/O and they're the primary exhaust source during this time period. The last time the IPWP was this enhanced/poleward shifted was during the Medieval Warm Period, over 900 years ago.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/24FD58D7-535B-43A4-9BD2-4328AEA35DCD_zpskwrd4wis.jpg

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/DA940694-189B-4DB5-8407-99CEB5F78D39_zpsokkzcbcg.jpg

[Phil]

FWIW, the circles I drew only highlight the northern periphery of the warm pool. The entire thing is just a massive thermodynamic engine. When it's enhanced (relative to the surrounding waters) it's a much more efficient heat pump and ventilation system.

[Jesse]

FWIW, the circles I drew only highlight the northern periphery of the warm pool. The entire thing is just a massive thermodynamic engine. When it's enhanced (relative to the surrounding waters) it's a much more efficient heat pump and ventilation system.

Thank you for answering my question.

[Phil]

Any idea when this could change again?

Solar minimum will retract the IPWP westward (on a modest lag) as it always does (see 2007-2012), so 2018-2021 will see this typical longitudinal retraction, but we're near the peak of the longer term IPWP inflation cycle, so it will take several decades to retract it back *equatorward*, into a less steroidal state.

 

It took some time for the Pacific to transition out of its low frequency cold climate/LIA state (equatorward contracted warm pool, +ENSO) into its warm climate state (poleward expanded warm pool, -ENSO), so perhaps it's reasonable to expect a similar retraction time, with similar fits and starts.

[Jesse]

Solar minimum will retract the IPWP westward (on a modest lag) as it always does (see 2007-2012), so 2018-2021 will see this typical longitudinal retraction, but we're near the peak of the longer term IPWP inflation cycle, so it will take several decades to retract it back equatorward, into a less "steroidal" state.

 

It took some time for the Pacific to transition out of its low frequency cold climate/LIA state (equatorward-contracted warm pool/+ENSO) into its warm climate state (poleward-expanded warm pool/-ENSO), so perhaps it's reasonable to expect a similar retraction time, with similar fits and starts.

I read this as: torchy falls for the rest of my life.

[Phil]

I read this as: torchy falls for the rest of my life.

Lol, well maybe from a decadal averaging standpoint they'll run warmer, but colder western autumns can happen in spite of the expanded IPWP. The dice are just loaded in favor of warmer autumns (and cooler springs).

[Jesse]

Lol, well maybe from a decadal averaging standpoint they'll run warmer, but colder western autumns can happen in spite of the expanded IPWP. The dice are just loaded in favor of warmer autumns (and cooler springs).

Got it. That has certainly been the overwhelming tendency here the last few decades.

[Front Ranger]

Got it. That has certainly been the overwhelming tendency here the last few decades.

 

Warmer falls, cooler springs has been the tendency for most of the NH as well. 

[Jesse]

Lol, well maybe from a decadal averaging standpoint they'll run warmer, but colder western autumns can happen in spite of the expanded IPWP. The dice are just loaded in favor of warmer autumns (and cooler springs).

 

What sort of indices favor this?