2024-2025 La Nina

[so_whats_happening]

Been awhile since I have posted one of these updates. Life has been a bit much lately...

 

[Daniel Boone]

50 minutes ago, so_whats_happening said:

The only thing I do worry about and it certainly has been something brought up several times by Bluewave is the linking of the -NAO domain with the SE Ridge pattern. It never is a guarantee but has shown that it does/ has happen quite a bit of recent. With a further south -NAO it could in fact hurt us rather than be beneficial, speculative of course at this time since we have yet to see a pattern really sustain whether warm or cold. What we have had thus far is a lot of swinging back and forth of temps.

Started to mention that, lol. Then I thought, maybe those ssts being where they are may help create a Tendency for LP to keep seperation. However,it may actually cause it to link further west and still do the damage. 

[GaWx]

6 hours ago, bluewave said:

We’ll see if the later runs can cool enough so RDU doesn’t break their latest first freeze record.

 The left side of the image below shows the cooling of the 12Z EPS (purple) vs 0Z (yellow) by 6 HDD along with the coldest days being at the end, which helped NG to close in the higher portion of its session range (its lowest of session was before the 12Z models were released thanks largely to the then 10 HDD cooler Mon 0Z EPS vs Sun’s 12Z run).
 
 Again, it will be interesting to see as said by Huffman above whether this next progged cold period gets muted like was the case with late 11/24-7 as a new SE ridge appeared seemingly out of nowhere. This underplaying of the SE ridge has been a forecast problem for years coincident with the very warm W Pac. 
 

 To reiterate: the 11/14 0Z EPS had 11/23-7 with 89 HDD. This 11/18 12Z run despite being cold at the end had only 68 HDD during 11/23-7, a whopping 4 degrees warmer per day (AN) vs the 11/14 0Z run’s BN! Will this later period eventually have the same fate? I hope not. Stay tuned!

[PhiEaglesfan712]

12 hours ago, mitchnick said:

Gefs puts us in Phase 6 by the first of December. Assuming an amplitude >1, we get this below. It's not that far off what the models are advertising. Unless I pulled up the wrong map, which is always possible. 

The last case that fits this criteria was late November/early December 2020.

  2020     11     29    -0.95333     0.77863      6   1.2308950
  2020     11     30    -1.06396     0.66050      6   1.2523063
  2020     12      1    -1.11400     0.51679      6   1.2280341
  2020     12      2    -1.10499     0.36181      6   1.1627164
  2020     12      3    -1.04231     0.21018      6   1.0632901
  2020     12      4    -0.93507     0.07536      6   0.9381018

I'll take my chances with MJO 6. This is what kicked off December 2020 and February 2021.

[GaWx]

 Through the 0Z/6Z EPS/GEFS the colder late solutions are continuing. NG is up near multi-session highs as a result.

*Edit for 12Z GFS fwiw showing hard freezes much of E/SE US early Dec.

[MJO812]

2 hours ago, GaWx said:

 Through the 0Z/6Z EPS/GEFS the colder late solutions are continuing. NG is up near multi-session highs as a result.

*Edit for 12Z GFS fwiw showing hard freezes much of E/SE US early Dec.

Euro is also on board

[mitchnick]

Just now, MJO812 said:

Euro is also on board

Love that sig pick. 

[bluewave]

2 hours ago, GaWx said:

 Through the 0Z/6Z EPS/GEFS the colder late solutions are continuing. NG is up near multi-session highs as a result.

*Edit for 12Z GFS fwiw showing hard freezes much of E/SE US early Dec.

You can see the battle unfolding from run to run between how long to linger this current more Nino-like regime and how fast to bring back a more Niña-like background pattern. 
 

[GaWx]

22 minutes ago, bluewave said:

You can see the battle unfolding from run to run between how long to linger this current more Nino-like regime and how fast to bring back a more Niña-like background pattern. 
 

1. 12Z GEFS/EE appear to my eyeballs to probably have little change in total US pop weighted HDDs vs their respective prior runs.

2. OMG, there’s finally now an OMG reaction! Wow! This was much needed.

[bluewave]

17 minutes ago, GaWx said:

1. 12Z GEFS/EE appear to my eyeballs to probably have little change in total US pop weighted HDDs vs their respective prior runs.

2. OMG, there’s finally now an OMG reaction! Wow! This was much needed.

This is probably the first time we had such an impressive November Nino temperature rise following a borderline super El Niño SSTs like last winter.

 

[PhiEaglesfan712]

2002-03 to 2009-10 was a weird stretch of 4 one-year el ninos in 8 years.

2002-03 - Moderate el nino

2003-04 - ENSO neutral

2004-05 - Weak el nino

2005-06 - Weak la nina

2006-07 - Weak el nino

2007-08 - Strong la nina

2008-09 - Weak la nina

2009-10 - Strong el nino

[snowman19]

This is probably the first time we had such an impressive November Nino temperature rise following a borderline super El Niño SSTs like last winter.


 

Region 1+2 in an El Niño….yea, looks like an east-based La Niña to me lol Anyway, as you know, because of AGW, the RONI may be a better measure of what ENSO is really doing right now and FWIW the models are still showing a strong EWB in region 3.4 coming up

RONI:

And as far as the MJO/tropical forcing, if the models are correct with a robust wave going from phases 3-7 in December, then we should expect changes in the long range pattern. Unless, there’s some total mismatch like you had alluded to possibly being the case. Here are the composites for MJO phases 3-7 in December with a -ENSO, they are all warm in the east:

[bluewave]

16 minutes ago, snowman19 said:

Region 1+2 in an El Niño….yea, looks like an east-based La Niña to me lol Anyway, as you know, because of AGW, the RONI may be a better measure of what ENSO is really doing right now and FWIW the models are still showing a strong EWB in region 3.4 coming up

RONI:

 

 

 

And as far as the MJO/tropical forcing, if the models are correct with a robust wave going from phases 3-7 in December, then we should expect changes in the long range pattern. Unless, there’s some total mismatch like you had alluded to possibly being the case. Here are the composites for MJO phases 3-7 in December with a -ENSO, they are all warm in the east:

 

 

 

 

 

 

 

 

 

 

You can see the EPS weeklies showing mixed influences between Nino-like and Nina-like elements. We will probably need at least another 10 days to know which becomes more dominant. Another possibility is that we get some type of interference pattern between the two but still too earky to know.

https://charts.ecmwf.int/products/extended-anomaly-z500?base_time=202411190000&projection=opencharts_global&valid_time=202412020000

 

[snowman19]

1 minute ago, bluewave said:

You can see the EPS weeklies showing mixed influences between Nino-like and Nina-like elements. We will probably need at least another 10 days to know which becomes more dominant. Another possibility is that we get some type of interference pattern between the two but still too earky to know.

https://charts.ecmwf.int/products/extended-anomaly-z500?base_time=202411190000&projection=opencharts_global&valid_time=202412020000

 

My guess is that the tail end of November into the start of December is “hangover” from the big WWB event we just saw. Once that wears off, the question becomes, are we then at the mercy of the MJO? Because if we do in fact see an MJO 3-7 pass with amplitude in December, we are going to go into a mild pattern on the east coast. All 5 of those phases are warm here. One of the 1st signs I would look for is the SE ridge/WAR suddenly getting stronger on modeling. But again, maybe we see some strange mismatch this year? The only way to know for sure is to wait and see like you said. And based on the RONI, we are in a La Niña despite what the old, traditional ONI may be “saying”. The warm tropics are clearly skewing the old indexes 

[George001]

The whole Nina background state this, Nina that idea might need to be tossed out the window. All guidance busted way too cool with the ENSO projections, it’s mid November and ENSO 4 and 1.2 are in WARM neutral territory while ENSO 3.4 and 3 are right at +0.0. Guidance has ENSO 3.4 cooling again, but I’m skeptical of the more aggressive solutions given what we have seen this fall.
 

[George001]

6 minutes ago, snowman19 said:

My guess is that the tail end of November into the start of December is “hangover” from the big WWB event we just saw. Once that wears off, the question becomes, are we then at the mercy of the MJO? Because if we do in fact see an MJO 3-7 pass with amplitude in December, we are going to go into a mild pattern on the east coast. All 5 of those phases are warm here. One of the 1st signs I would look for is the SE ridge/WAR suddenly getting stronger on modeling. But again, maybe we see some strange mismatch this year? The only way to know for sure is to wait and see like you said. And based on the RONI, we are in a La Niña despite what the old, traditional ONI may be “saying”. The warm tropics are clearly skewing the old indexes 

My issue is 2 of the 4 key ENSO regions are straight up in warm neutral territory. The RONI is rising too, it’s in Nina territory still but barely. I would not expect a moderate to strong Nina base state like 07-08, 10-11, 11-12, 22-23, 20-21 etc given the recent trends. Either way, I agree with you that guidance is too cold for the 1st week of December. The tendency has been for guidance to underestimate the MJO amplitude this fall, if that continues we should expect to see higher amplitude MJO in the warm phases and thus a correction warmer during the early to mid December period.

[PhiEaglesfan712]

3 minutes ago, George001 said:

My issue is 2 of the 4 key ENSO regions are straight up in warm neutral territory. The RONI is rising too, it’s in Nina territory still but barely. I would not expect a moderate to strong Nina base state like 07-08, 10-11, 11-12, 22-23, 20-21 etc given the recent trends. Either way, I agree with you that guidance is too cold for the 1st week of December. The tendency has been for guidance to underestimate the MJO amplitude this fall, if that continues we should expect to see higher amplitude MJO in the warm phases and thus a correction warmer during the early to mid December period.

As I have said all along, the first third of December will be colder than average for most of the Eastern US, while the middle third of December will be warmer than average. I think the potential is there for a snowstorm somewhere on Dec. 4 or 5.

[brooklynwx99]

25 minutes ago, snowman19 said:

My guess is that the tail end of November into the start of December is “hangover” from the big WWB event we just saw. Once that wears off, the question becomes, are we then at the mercy of the MJO? Because if we do in fact see an MJO 3-7 pass with amplitude in December, we are going to go into a mild pattern on the east coast. All 5 of those phases are warm here. One of the 1st signs I would look for is the SE ridge/WAR suddenly getting stronger on modeling. But again, maybe we see some strange mismatch this year? The only way to know for sure is to wait and see like you said. And based on the RONI, we are in a La Niña despite what the old, traditional ONI may be “saying”. The warm tropics are clearly skewing the old indexes 

agreed with 3-5, but 6 and 7 are warm. the MJO isn't a silver bullet... there could be other factors at play. I also thought that models would trend warmer in the late Nov - early Dec period, but that does not appear to be the case. CPC likely busts warm on their forecast for early Dec

[George001]

13 minutes ago, PhiEaglesfan712 said:

As I have said all along, the first third of December will be colder than average for most of the Eastern US, while the middle third of December will be warmer than average. I think the potential is there for a snowstorm somewhere on Dec. 4 or 5.

I hope so, but I am skeptical of December as a whole especially given the recent warming trends in the ENSO region as well as the tendency for guidance to underestimate MJO amplitude. I’m not expecting any flakes before Christmas week for my area.

[mitchnick]

21 minutes ago, brooklynwx99 said:

agreed with 3-5, but 6 and 7 are warm. the MJO isn't a silver bullet... there could be other factors at play. I also thought that models would trend warmer in the late Nov - early Dec period, but that does not appear to be the case. CPC likely busts warm on their forecast for early Dec

Are there temp plots for Neutral since we're likely closer to that than textbook Niña?

[mitchnick]

I pulled this off the MA forum since I don't have an X account. 

https://x.com/webberweather/status/1858974921260769366?ref_src=twsrc^tfw|twcamp^tweetembed|twterm^1858974921260769366|twgr^218a23fb7d50a5fcd5e2639788423433ba212012|twcon^s1_&ref_url=https%3A%2F%2Fwww.americanwx.com%2Fbb%2Findex.php%3Fapp%3Dcoremodule%3Dsystemcontroller%3Dembedurl%3Dhttps%3A%2F%2Ftwitter.com%2Fwebberweather%2Fstatus%2F1858974921260769366%3Fs%3D4626t%3DJYOHM881b6groqc0-RqtxA

[snowman19]

13 minutes ago, mitchnick said:

Are there temp plots for Neutral since we're likely closer to that than textbook Niña?

@mitchnick

Here’s phases 6-7, Neutral, December:

 

 

 

 

[mitchnick]

Just now, snowman19 said:

Here’s phases 6-7, Neutral, December:

https://www.twitter.compeacockreports/status/1858848162280014096?s=46&t=NChJQK9_PUjA1K7D2SMojw

Won't link.

[mitchnick]

4 minutes ago, snowman19 said:

@mitchnick

Here’s phases 6-7, Neutral, December:

 

 

 

 

Thanks. Anyone have the link to those MJO composite maps? All I have are the ones from the American wx site. Thanks.

[Wow]

3 hours ago, George001 said:

I hope so, but I am skeptical of December as a whole especially given the recent warming trends in the ENSO region as well as the tendency for guidance to underestimate MJO amplitude. I’m not expecting any flakes before Christmas week for my area.

The way things are trending with other the OP and ens runs recently I think your odds are looking better up there. 

[GaWx]

 The 11/17 daily EPO of +233 (the latest daily available), which was the highest daily since way back on June 4, will probably end up being the highest for quite awhile. Models are unanimous in dropping it very sharply to at or near the lowest daily of 2024 on 11/21 or 11/22 (~-250)! The consensus then has it remaining negative the rest of Nov fwiw. When combining the low point and duration of this upcoming -EPO, it could end up the most impressive since way back in Oct of 2023!

https://downloads.psl.noaa.gov/Public/map/teleconnections/epo.reanalysis.t10trunc.1948-present.txt

[GaWx]

 With the 0Z EPS being significantly colder in the E US vs the 12Z run overall on days 7-15, NG is up to session highs. The coldest in late in the run (early Dec), when it is much BN with a hard freeze implied in much of the E US on 1-2 mornings.

 This cold is being driven by a solid -EPO/-WPO.

[so_whats_happening]

10 hours ago, mitchnick said:

Thanks. Anyone have the link to those MJO composite maps? All I have are the ones from the American wx site. Thanks.

https://www.meteonetwork.it/models/mjo/

[PhiEaglesfan712]

Cold beginning of December is pretty much locked at this point. The question now is whether any part of the Eastern US can capitalize on this winter.

[bluewave]

3 hours ago, so_whats_happening said:

https://www.meteonetwork.it/models/mjo/

Sometimes those composites work and other times the JMA are more reliable. Many of the MeteoNetwork composites are lower sample size. I translated the site to show the color codes and the degree of reliability.
 

MJO Tables - MeteoNetwork

Medium-high reliability

Medium-low reliability

Low reliability

Plotting not available due to lack of data

I like the JMA since each composite is based on a big sample size from 60 to 100 dates. Sample size can often be an issue with MJO composites so you need to see which work better in real time and then try to extrapolate out where the MJO is going and whether it’s having a strong enough effect. This current pattern forecast for late November is more of a +AAM with blocking near the Aleutians and Baffin Island. So the MJO may still be running in the background but not dominating the pattern. We’ll have to wait until early December to determine whether the +AAM dominates or we get a warmer MJO 5-7 influence. Another possibility would be an odd combination of both almost like wave interference.

 

https://ds.data.jma.go.jp/tcc/tcc/products/clisys/mjo/composite.html

 

High AAM pattern for late November