El Nino 2023-2024

[bluewave]

53 minutes ago, snowman19 said:

Very likely we see more big warming in December, here’s why:

Officially strong or super as per ONI probably won’t make that much of a difference on our sensible weather when we have a solid block of +30C SSTs from Maritime Continent to just east of the Dateline. December forcing in the MJO 4-7 regions is a warmer than average pattern for us. The current Nino 4s around the MJO 7 region are close to the warmest on record set during the 15-16 super El Niño.

 

 

 

[griteater]

From NOAA's weekly MJO update:

 

[griteater]

Here is an MJO product that combines the standard MJO with the current 120-day signal (i.e. the background base tropical forcing pattern).  This product has the MJO running thru 8-1-2 from Dec 15 to Jan 10.  Euro Weeklies look similar.

Source: https://ncics.org/portfolio/monitor/mjo/RMM/

 

[mitchnick]

2 hours ago, snowman19 said:

@Bluewave @Gawx Very likely we see more big warming in December, here’s why:
 

That's not new. Both of us have posts referencing it and yesterday I posted how the Cfs had weakened it over the past 3 days.

[NEPASnow]

WWB will cause a temporary but not permanent warming and will eventually revert back to where it was before.  With 3.4 becoming the warmest and is goes to basin wide with best forcing around the equator still.  I linked the time where this is mentioned.  Good Video

 

[GaWx]

 This is easily the strongest cold signal for the first week of January in the E US of any Euro Weekly run that I’ve seen and as strong a cold signal as for any land area on the globe for then. Keep in mind this is way out in week 6, when it is hard to have a strong signal away from normal in an ensemble mean. This timeframe is consistent with an MJO prog favoring cold in the E US. Per @griteaterposted MJO chart the prog is for a slow moving fairly weak (just outside the COD) phase one then, which tends to favor cold in the E US, especially during El Niños:

 

 
 Looking further out on griteater’s MJO prog, the week after this is progged to continue to move slowly in weak phase 1 and then entering weak phase 2, which would favor another cold week Jan 8-15.

 The last time the first half of Jan was cold dominated in the E US was in 2018. Though not El Niño, it was mainly in a moderate MJO phase 2:

[Itryatgolf70]

2 hours ago, GaWx said:

 This is easily the strongest cold signal for the first week of January in the E US of any Euro Weekly run that I’ve seen and as strong a cold signal as for any land area on the globe for then. Keep in mind this is way out in week 6, when it is hard to have a strong signal away from normal in an ensemble mean. This timeframe is consistent with an MJO prog favoring cold in the E US. Per @griteaterposted MJO chart the prog is for a slow moving fairly weak (just outside the COD) phase one then, which tends to favor cold in the E US, especially during El Niños:

 

 
 Looking further out on griteater’s MJO prog, the week after this is progged to continue to move slowly in weak phase 1 and then entering weak phase 2, which would favor another cold week Jan 8-15.

 The last time the first half of Jan was cold dominated in the E US was in 2018. Though not El Niño, it was mainly in a moderate MJO phase 2:

Larry, like I mentioned a few days ago, the tropicaltidbits sst anomalies chart for the regions give the best interpretation of the current sst based every six hours. If I was the CPC, I would seriously give those some consideration. Those are not even remotely close to 2.0 in any region.

[Daniel Boone]

4 hours ago, griteater said:

Here is an MJO product that combines the standard MJO with the current 120-day signal (i.e. the background base tropical forcing pattern).  This product has the MJO running thru 8-1-2 from Dec 15 to Jan 10.  Euro Weeklies look similar.

Source: https://ncics.org/portfolio/monitor/mjo/RMM/

 

If that turns out to be realized, good odds of a cold probably snowy Holiday period, providing that warm pool off Japan doesn't throw a monkey wrench and alter the typical downstream pattern. Could that be at least partially responsible for an eastward displaced Aleutian/Goa Lp.?. 

[griteater]

20 minutes ago, Daniel Boone said:

If that turns out to be realized, good odds of a cold probably snowy Holiday period, providing that warm pool off Japan doesn't throw a monkey wrench and alter the typical downstream pattern. Could that be at least partially responsible for an eastward displaced Aleutian/Goa Lp.?. 

If the PDO is winning, we may see a central Pac ridge and east Pac / west coast trough.  If east-based, super nino idea is winning, we may see a big east-based Aleutian Low.  If west-based forcing, strong nino idea is winning, we may see a climo Aleutian Low with -EPO / +PNA.  My chips are on the last one for Dec 20 - Jan 10, but we'll see.  Should see an undercutting subtropical jet stream at times in all cases...and increased potential for high-latitude blocking.

[GaWx]

1 hour ago, Itryatgolf70 said:

Larry, like I mentioned a few days ago, the tropicaltidbits sst anomalies chart for the regions give the best interpretation of the current sst based every six hours. If I was the CPC, I would seriously give those some consideration. Those are not even remotely close to 2.0 in any region.

I like the every six hours frequency. However, that’s CDAS based, which is quite cold biased.

[GaWx]

In addition to what the EPS has been showing, possibilities are there for SSW late Dec-early Jan per 11/27 extended GEFS, too:

[GaWx]

20 hours ago, GaWx said:

 The OHC is still being adjusted upward for the same timeframe and is now showing a new high on this graph for this event of ~+1.40 with further ongoing sharp rises being suggested. Keeping in mind reporting lag as this particular graph is updated only through ~10 days ago (midmonth instead of late month), Nov has a good shot to exceed June as the warmest month of this Nino so far in the monthly table. This is for 5N to 5S down to 300m and uses a 1991-2020 base:

 OHC has again been readjusted warmer but also was just extended out 5 more days: the result is by far the warmest this Nino with ~+1.6 as of Nov 22 and is still suggesting more sharp rises! Those very warm TAO maps are finally being reflected here. It looks like Nov will easily end up the new warmest month for this event so far barring something unforeseen:

[bluewave]

12 hours ago, griteater said:

Here is an MJO product that combines the standard MJO with the current 120-day signal (i.e. the background base tropical forcing pattern).  This product has the MJO running thru 8-1-2 from Dec 15 to Jan 10.  Euro Weeklies look similar.

The latest EPS weeklies don’t  move the forcing past MJO 7 in December as the warm pool is too strong near the Dateline. So it never achieves the classic MJO 8 look with the VP anomalies shifting well east in December. The last time Nino 4 was this warm in 15-16 it took until January for the MJO to shift over to 8-1-2. But while it was colder than when in the MJO 4-7 phases, it never got colder than average due to the overpowering jet stream off the Pacific. But we did see an eventual snowfall improvement due to blocking later in the season. The one caveat now is that the WPAC warm pool is stronger this year. So we may still get further competition from the warmer MJO phases. The RMM charts have been too fast in recent years to move the MJO out of the warmer phases. While the VP anomaly charts have been more reliable. But even they have been to fast to move the MJO to 8-1-2.
 

[griteater]

1 hour ago, bluewave said:

The latest EPS weeklies don’t  move the forcing past MJO 7 in December as the warm pool is too strong near the Dateline. So it never achieves the classic MJO 8 look with the VP anomalies shifting well east in December. The last time Nino 4 was this warm in 15-16 it took until January for the MJO to shift over to 8-1-2. But while it was colder than when in the MJO 4-7 phases, it never got colder than average due to the overpowering jet stream off the Pacific. But we did see an eventual snowfall improvement due to blocking later in the season. The one caveat now is that the WPAC warm pool is stronger this year. So we may still get further competition from the warmer MJO phases. The RMM charts have been too fast in recent years to move the MJO out of the warmer phases. While the VP anomaly charts have been more reliable. But even they have been to fast to move the MJO to 8-1-2.
 

Euro Ext here Dec 4-9 has -VP from W IO to Dateline 

 

Dec 9-14 it's centered over the Dateline

 

Dec 20-25 it's weakened some over the Dateline, but it's hanging there as part of the ongoing, west-based low frequency Nino signal this summer/fall.  More -VP has moved east into Americas / Atl Ocean / Africa / W IO (MJO 8-1-2)

 

It holds that look to the end at Jan 7-12

 

Could be some slight timing differences in the end, but IMO, the general idea is on point here

[bluewave]

2 minutes ago, griteater said:

Euro Ext here Dec 4-9 has -VP from W IO to Dateline 

 

Dec 9-14 it's centered over the Dateline

 

Dec 20-25 it's weakened some over the Dateline, but it's hanging there as part of the ongoing, west-based low frequency Nino signal this summer/fall.  More -VP has moved east into Americas / Atl Ocean / Africa / W IO (MJO 8-1-2)

 

It holds that look to the end at Jan 7-12

 

Could be some slight timing differences in the end, but IMO, the general idea is on point here

Those VP charts are showing the MJO lingering in 7. The ultra long range guidance was trying to dampen the convection too much near the Dateline around the holidays. My guess is this is just the models losing the signal in the increased long range noise. As models get closer it’s easier for them to see the signal.

 

New run

 

Old run

 

 

[40/70 Benchmark]

3 hours ago, bluewave said:

The latest EPS weeklies don’t  move the forcing past MJO 7 in December as the warm pool is too strong near the Dateline. So it never achieves the classic MJO 8 look with the VP anomalies shifting well east in December. The last time Nino 4 was this warm in 15-16 it took until January for the MJO to shift over to 8-1-2. But while it was colder than when in the MJO 4-7 phases, it never got colder than average due to the overpowering jet stream off the Pacific. But we did see an eventual snowfall improvement due to blocking later in the season. The one caveat now is that the WPAC warm pool is stronger this year. So we may still get further competition from the warmer MJO phases. The RMM charts have been too fast in recent years to move the MJO out of the warmer phases. While the VP anomaly charts have been more reliable. But even they have been to fast to move the MJO to 8-1-2.
 

The other caveat being that this el Nino isn't half as coupled with the atmosphere as that one was. People need to stop comparing this to the most intense el Nino events in history because this is orders of magnitude less expressed in the hemisphere, regardless of the SST anomalies.

 

[bluewave]

24 minutes ago, 40/70 Benchmark said:

The caveat being that this el Nino isn't half as coupled with the atmosphere as that one was. People need to stop comparing this to the most intense el Nino events in history because this is orders of magnitude less intense, regardless of the SST anomalies.

We needed the strength of that one to eventually shut down the warmest MJO 4-6 phases we got in December. So while the rest of the season was warmer than average, it wasn’t nearly as warm. The blocking was able to take over later on and produce the record snowfall. So not sure if this El Niño gets strong enough to counter any warmer MJO 4-6 phases associated with that +30C warm pool near the Maritime Continent. We can hope that the warmer Maritime Continent forcing we are seeing now fades away by January and February and allows a typical backloaded El Niño response with blocking for snow even if it doesn’t get really cold. The last thing we want is MJO 4-6 phases mucking up the late winter El Niño response. So we have plenty of time to see how things evolve since we usually don’t expect much from the front end of El Niño winters.

[CoastalWx]

Those MJO progression charts under forecast how the wave traverses the globe many times. Just keep that in mind. Look at how the previous weeks have progressed. You also get the sense of the progression on those charts past 12/19. I don't believe the wave will stop abruptly near the dateline.

I do think we may begin to see a standing low frequency wave develop near the dateline, but it's a bit early to tell. 

[Maestrobjwa]

41 minutes ago, 40/70 Benchmark said:

The other caveat being that this el Nino isn't half as coupled with the atmosphere as that one was. People need to stop comparing this to the most intense el Nino events in history because this is orders of magnitude less expressed in the hemisphere, regardless of the SST anomalies.

 

Layman question: How is "coupling" measured? (It's always been a bit of a nebulous concept to me, lol)

[40/70 Benchmark]

29 minutes ago, bluewave said:

We needed the strength of that one to eventually shut down the warmest MJO 4-6 phases we got in December. So while the rest of the season was warmer than average, it wasn’t nearly as warm. The blocking was able to take over later on and produce the record snowfall. So not sure if this El Niño gets strong enough to counter any warmer MJO 4-6 phases associated with that +30C warm pool near the Maritime Continent. We can hope that the warmer Maritime Continent forcing we are seeing now fades away by January and February and allows a typical backloaded El Niño response with blocking for snow even if it doesn’t get really cold. The last thing we want is MJO 4-6 phases mucking up the late winter El Niño response. So we have plenty of time to see how things evolve since we usually don’t expect much from the front end of El Niño winters.

We didn't need the overwhelming canonical response that produced the powerful Pac jet that eviscerated the entire month of December. I'm sorry, I just do not agree with you. 

We'll see how it plays out...I am not concerned about the winter being dominated by Maritime forcing.....during thaw periods, I can see some phase 6...sure.

[40/70 Benchmark]

15 minutes ago, Maestrobjwa said:

Layman question: How is "coupling" measured? (It's always been a bit of a nebulous concept to me, lol)

The bi-monthly Multivariate El Niño/Southern Oscillation (ENSO) index (MEI.v2) is the time series of the leading combined Empirical Orthogonal Function (EOF) of five different variables (sea level pressure (SLP), sea surface temperature (SST), zonal and meridional components of the surface wind, and outgoing longwave radiation (OLR)) over the tropical Pacific basin (30°S-30°N and 100°E-70°W). The EOFs are calculated for 12 overlapping bi-monthly "seasons" (Dec-Jan, Jan-Feb, Feb-Mar,..., Nov-Dec) in order to take into account ENSO's seasonality, and reduce effects of higher frequency intraseasonal variability. During the typical height of ENSO during late Fall/early Winter, the canonical features of atmosphere and ocean anomalies are shown schematically below based on a composite of 11 historical El Niño and La Niña events. Key features of composite positive MEI events (warm, El Niño) include (1) anomalously warm SSTs across the east-central equatorial Pacific, (2) anomalously high SLP over Indonesia and the western tropical Pacific and low SLP over the eastern tropical Pacific, (3) reduction or reversal of tropical Pacific easterly winds (trade winds), (4) suppressed tropical convection (positive OLR) over Indonesia and Western Pacific and enhanced convection (negative OLR) over the central Pacific (Fig. 1a). Key features of composite negative MEI events (cold, La Niña, Fig. 1b) are of mostly opposite phase. For any single El Niño or La Niña situation, the atmospheric articulations may depart from this canonical view.

 

 

Fig. 1: Schematic diagram showing the physical mechanisms by which the SST (shaded), OLR (contours), surface zonal and meridional winds (vectors), and sea level pressure (represented by "H" and "L" which indicate the high and low pressure center, respectively) determine the wintertime Multivariate ENSO Index (MEI) during (a) El Niño and (b) La Niña events. The schematic is based on the composite anomalies for November-December (ND) drawn from 11 warm events and 11 cold events during 1980-2016.

 

[40/70 Benchmark]

1 minute ago, 40/70 Benchmark said:

The bi-monthly Multivariate El Niño/Southern Oscillation (ENSO) index (MEI.v2) is the time series of the leading combined Empirical Orthogonal Function (EOF) of five different variables (sea level pressure (SLP), sea surface temperature (SST), zonal and meridional components of the surface wind, and outgoing longwave radiation (OLR)) over the tropical Pacific basin (30°S-30°N and 100°E-70°W). The EOFs are calculated for 12 overlapping bi-monthly "seasons" (Dec-Jan, Jan-Feb, Feb-Mar,..., Nov-Dec) in order to take into account ENSO's seasonality, and reduce effects of higher frequency intraseasonal variability. During the typical height of ENSO during late Fall/early Winter, the canonical features of atmosphere and ocean anomalies are shown schematically below based on a composite of 11 historical El Niño and La Niña events. Key features of composite positive MEI events (warm, El Niño) include (1) anomalously warm SSTs across the east-central equatorial Pacific, (2) anomalously high SLP over Indonesia and the western tropical Pacific and low SLP over the eastern tropical Pacific, (3) reduction or reversal of tropical Pacific easterly winds (trade winds), (4) suppressed tropical convection (positive OLR) over Indonesia and Western Pacific and enhanced convection (negative OLR) over the central Pacific (Fig. 1a). Key features of composite negative MEI events (cold, La Niña, Fig. 1b) are of mostly opposite phase. For any single El Niño or La Niña situation, the atmospheric articulations may depart from this canonical view.

 

 

Fig. 1: Schematic diagram showing the physical mechanisms by which the SST (shaded), OLR (contours), surface zonal and meridional winds (vectors), and sea level pressure (represented by "H" and "L" which indicate the high and low pressure center, respectively) determine the wintertime Multivariate ENSO Index (MEI) during (a) El Niño and (b) La Niña events. The schematic is based on the composite anomalies for November-December (ND) drawn from 11 warm events and 11 cold events during 1980-2016.

 

Introducing the Relative Ocean Nino Index

 Oldenborgh et al have observed that the crux of the issue is that the traditional Nino 3.4, from which the ONI is derived, "not only describes ENSO but also has a trend due to global warming, which has very different impacts from that of el Nino" (Oldenborgh et al, 2021). The piece goes onto assert that this is problematic because the "spacial pattern of the observed SST trend over the past century does not resemble the ENSO pattern" (Oldenborgh et al, 2021). The suggested solution is to use the Relative Ocean Nino Index (RONI), which is a value derived from the difference of the original index with the contemporaneous tropical mean SST anomalies. According to Oldenborgh et al, subtracting the tropical mean SST anomaly not only removes the trend, but also results in an SST anomaly (RONI) that is of more direct relevance to changes in tropical convection driven by SST anomalies. Removing the trend in order to distinguish between ENSO related warming and climate change attributed background warming is important because tropical convection is more sensitive to the warming of ENSO relative to the rest of the tropics. Thus convection will concentrate in areas that warm the most relative to the tropical mean background warming. This is why the current generally warm Pacific basin is reducing the ability of ENSO to assert itself in the hemisphere to a level commensurate with the current 1.5 ONI value, as reflected by the ASO tri-monthly RONI value of 1.05, which is weak-moderate and somewhat more in line with the current 0.3 MEI value. This explains why el Nino has thus far failed to redistribute the tropical convection denoted by the negative velocity potential away from the central Pacific to the eastern Pacific, co-located with the strongest ENSO anomalies in regions 1.2 and 3, as was the case in 1997 and 2015. In comparison, the ASO RONI values were 2.15 and 1.87, which explains why the tropical forcing was much more co-located with the greatest anomalies to the east. The ocean-atmosphere coupling was much stronger. This is reflected by the AS bi-monthly MEI values of 2.2 and 2.1 as compared to the current value of 0.3. Theoretically speaking, should the el Nino become intense enough and the warmest anomalies remain strongly biased to the east, at some point the convective forcing should realign itself with the strongest positive ENSO anomalies to the east and away from the residual warmest absolute SSTs to the west. The key is what is this critical threshold and will it be reached.

[40/70 Benchmark]

I mentioned in my work that since the forcing has been so far west, that phase 6 will be an issue during periods of thawing....2006-2007 also had this issue, but that winter was much different near the pole due to solar considerations.

[40/70 Benchmark]

9 minutes ago, 40/70 Benchmark said:

The bi-monthly Multivariate El Niño/Southern Oscillation (ENSO) index (MEI.v2) is the time series of the leading combined Empirical Orthogonal Function (EOF) of five different variables (sea level pressure (SLP), sea surface temperature (SST), zonal and meridional components of the surface wind, and outgoing longwave radiation (OLR)) over the tropical Pacific basin (30°S-30°N and 100°E-70°W). The EOFs are calculated for 12 overlapping bi-monthly "seasons" (Dec-Jan, Jan-Feb, Feb-Mar,..., Nov-Dec) in order to take into account ENSO's seasonality, and reduce effects of higher frequency intraseasonal variability. During the typical height of ENSO during late Fall/early Winter, the canonical features of atmosphere and ocean anomalies are shown schematically below based on a composite of 11 historical El Niño and La Niña events. Key features of composite positive MEI events (warm, El Niño) include (1) anomalously warm SSTs across the east-central equatorial Pacific, (2) anomalously high SLP over Indonesia and the western tropical Pacific and low SLP over the eastern tropical Pacific, (3) reduction or reversal of tropical Pacific easterly winds (trade winds), (4) suppressed tropical convection (positive OLR) over Indonesia and Western Pacific and enhanced convection (negative OLR) over the central Pacific (Fig. 1a). Key features of composite negative MEI events (cold, La Niña, Fig. 1b) are of mostly opposite phase. For any single El Niño or La Niña situation, the atmospheric articulations may depart from this canonical view.

 

 

Fig. 1: Schematic diagram showing the physical mechanisms by which the SST (shaded), OLR (contours), surface zonal and meridional winds (vectors), and sea level pressure (represented by "H" and "L" which indicate the high and low pressure center, respectively) determine the wintertime Multivariate ENSO Index (MEI) during (a) El Niño and (b) La Niña events. The schematic is based on the composite anomalies for November-December (ND) drawn from 11 warm events and 11 cold events during 1980-2016.

 

This pressure/SST dipole that you see in the MEI schematic above is what has retarded the development of this el Nino and epitomizes the disfunction of the warm ENSO paradigm to date. The weaker dipole resulted in less prominent WWB in much the same manner that an east coast storm lacking a strong pressure gradient will have less wind and meager baroclinicity...thus a weaker system. The issue has been alleviated to an extent, but its never going to catch up the the SST anomalies.

[jbenedet]

1 hour ago, 40/70 Benchmark said:

The other caveat being that this el Nino isn't half as coupled with the atmosphere as that one was. People need to stop comparing this to the most intense el Nino events in history because this is orders of magnitude less expressed in the hemisphere, regardless of the SST anomalies.

 

This uncoupling argument, saying it will stay indefinitely uncoupled is weak. It defies the physical equations.

The atmosphere *must* respond for the system to rebalance. The longer it is uncoupled the stronger the El Niño will become; and in turn the eventual atmospheric response more extreme.
 

.

[40/70 Benchmark]

5 minutes ago, jbenedet said:

This uncoupling argument, saying it will stay indefinitely uncoupled is weak. It defies the physical equations.

The atmosphere *must* respond for the system to rebalance. The longer it is uncoupled the stronger the El Niño will become; and in turn the eventual atmospheric response more extreme.
 

.

Good thing I didn't say that. 

The atmosphere will respond, sure, just not as much as did in other instances of a 1.9+ ONI....the response will be different.

[jbenedet]

Still not following the logic here. Seeing a weak El Niño atmospheric response to date has allowed El Niño conditions to intensify, and also (obviously) means it just shows up at a later winter date.

Unless we capitalized on a snowier than normal November (did not) and December (remains to be seen)—this is a better argument for those calling for warmer/less snowy winter in the CONUS. 

[GaWx]

23 hours ago, GaWx said:

 Meanwhile, WCS just reported the largest daily drop in Nino 3.4 in two months with a drop from +2.10 to +1.98! That’s the coolest on WCS since Nov 16th and certainly unexpected by me:

 

 The daily WCS PDO dropped to -0.84 from -0.77.

WCS updates:

-Nino 3.4 dropped very slightly to +1.97 from +1.98

-PDO dropped from -0.84 to -0.93.

[40/70 Benchmark]

7 minutes ago, jbenedet said:

Still not following the logic here. Seeing a weak El Niño atmospheric response to date has allowed El Niño conditions to intensify, and also (obviously) means it just shows up at a later winter date.

Unless we capitalized on a snowier than normal November (did not) and December (remains to be seen)—this is a better argument for those calling for warmer/less snowy winter in the CONUS. 

This makes zero sense.

The convective forcing pattern has been fairly similar to years such as 1965, 1986 (also developed late) and 2009, which also had less pronounced Pacific dipoles and the eastern US did just fine in the snowfall department.

[40/70 Benchmark]

5 minutes ago, GaWx said:

WCS updates:

-Nino 3.4 dropped very slightly to +1.97 from +1.98

-PDO dropped from -0.84 to -0.93.

You mean rose?