2024-2025 La Nina

[snowman19]

[PhiEaglesfan712]

1 hour ago, bluewave said:

My guess is the reason that the 2022 hurricane season wasn’t as active as forecast was due to the stronger Maritime Continent forcing leading to more subsidence over the Western Atlantic in August and September. 2017 didn’t have this issue so it was much more active. This is probably why the Atlantic has been so quiet in recent weeks. So we’ll probably need to see a decrease in Maritime Continent forcing next few weeks for the Atlantic to become active. The developing La Niña and record SSTs would suggest a much above average Atlantic hurricane season. But the final piece of the equation would be more favorable forcing. Plenty of time for things to shift allowing the more active forecasts to verify since it’s still very early.

 

What about 2007? Did we also have the strong Maritime Continent that year? That year was less active in the Atlantic outside of Dean and Felix, and the Pacific had a very quiet year. Pretty similar to what we have so far this year.

[snowman19]

10 hours ago, mitchnick said:

At least we know why the Snowman19/Roundy love affair ended. 

(Just bustin' on ya' Snowman)

I’m still confident that we see a La Niña. If we end up cool-neutral however, it may be a case of “be careful what you wish for”. We are and have been in a default extratropical strong La Niña state for years, even last year with the Nino, we were in a La Niña extratropical state with La Niña MJO forcing (4-6). So, that said, if there is in fact a cool-neutral ENSO, then 2001-2002 becomes an analog IMO….cool-neutral/lack of a distinct ENSO signal, -PDO, -PMM, QBO turning positive, -IOD, +AMO (although not nearly as strong) and record high solar flux 

[mitchnick]

1 hour ago, snowman19 said:

I’m still confident that we see a La Niña. If we end up cool-neutral however, it may be a case of “be careful what you wish for”. We are and have been in a default extratropical strong La Niña state for years, even last year with the Nino, we were in a La Niña extratropical state with La Niña MJO forcing (4-6). So, that said, if there is in fact a cool-neutral ENSO, then 2001-2002 becomes an analog IMO….cool-neutral/lack of a distinct ENSO signal, -PDO, -PMM, QBO turning positive, -IOD, +AMO (although not nearly as strong) and record high solar flux 

I was all for a super Niña this year originally advertised by the Cansips with the hope of breaking the warmth in the western Pacific, but it's not to be and the writing is on the wall for a big fail on any modeling that suggested a moderate or strong Niña. 

That said, I have noticed that there have been a good deal of easterly wind anomalies over the past week or 2 and currently progged along and WEST of the Dateline. I wonder if that might cause a dent in the warmth out there. Don't know, but if the progs are right, I'm interested in seeing what happens. It wouldn't do anything for any areas except for "maybe" Enso 4.

[snowman19]

1 hour ago, mitchnick said:

I was all for a super Niña this year originally advertised by the Cansips with the hope of breaking the warmth in the western Pacific, but it's not to be and the writing is on the wall for a big fail on any modeling that suggested a moderate or strong Niña. 

That said, I have noticed that there have been a good deal of easterly wind anomalies over the past week or 2 and currently progged along and WEST of the Dateline. I wonder if that might cause a dent in the warmth out there. Don't know, but if the progs are right, I'm interested in seeing what happens. It wouldn't do anything for any areas except for "maybe" Enso 4.

A full-scale, sustained change of the blazing SSTs out that way looks extremely unlikely at the moment. My point is this….if we don’t have a La Niña and instead are La Nada/cold-neutral, then we are at the mercy of all the other factors I just mentioned, which actually closely mirror 2001-02. And 01-02 was a very active Atlantic hurricane season, 17 tropical depressions, of which 15 became named storms and 4 major hurricanes, 9 hurricanes all together. ACE was over 110

[40/70 Benchmark]

14 minutes ago, snowman19 said:

A full-scale, sustained change of the blazing SSTs out that way looks extremely unlikely at the moment. My point is this….if we don’t have a La Niña and instead are La Nada/cold-neutral, then we are at the mercy of all the other factors I just mentioned, which actually closely mirror 2001-02. And 01-02 was a very active Atlantic hurricane season, 17 tropical depressions, of which 15 became named storms and 4 major hurricanes, 9 hurricanes all together. ACE was over 110

We are getting La Niña.

[PhiEaglesfan712]

41 minutes ago, 40/70 Benchmark said:

We are getting La Niña.

Yeah, which is why 2007-08 is the best analog. If we were getting an ENSO neutral, I'd probably use 1993-94 over 2001-02. That 01-02 is coming off a triple la nina (with no el nino buffer) and has a warm subsurface. 93-94 is a much better subsurface match.

1993:

 

2001: 

[snowman19]

46 minutes ago, 40/70 Benchmark said:

We are getting La Niña.

People had better hope you’re right about definitely seeing a Niña because the neutral option looks real ugly. Even high Atlantic ACE didn’t help that cluster f***

[bluewave]

1 hour ago, snowman19 said:

A full-scale, sustained change of the blazing SSTs out that way looks extremely unlikely at the moment. My point is this….if we don’t have a La Niña and instead are La Nada/cold-neutral, then we are at the mercy of all the other factors I just mentioned, which actually closely mirror 2001-02. And 01-02 was a very active Atlantic hurricane season, 17 tropical depressions, of which 15 became named storms and 4 major hurricanes, 9 hurricanes all together. ACE was over 110

Yeah, this is why La Nada winters like 01-02 and 13-14 are so dependent on other factors like the state of the PDO. The 01-02 La Nada had the very strong -PDO pattern. So the 500 mb pattern was a La Niña on steroids. Conversely, the 13-14 La Nada was all about the strong +PDO signature east of Japan and the record TNH off the West Coast. So those two factors dominated and lead to the amazing winter. 
 

[snowman19]

57 minutes ago, PhiEaglesfan712 said:

Yeah, which is why 2007-08 is the best analog. If we were getting an ENSO neutral, I'd probably use 1993-94 over 2001-02. That 01-02 is coming off a triple la nina (with no el nino buffer) and has a warm subsurface. 93-94 is a much better subsurface match.

1993:

 

2001: 

93-94 is not a good option if we go ENSO neutral IMO. Nothing matches other than neutral. And the fact that we had a strong Niña extratropical background with Niña MJO forcing last year, to me is the equivalent of having had a Niña. The other factors…cool-neutral, -PDO, -PMM, QBO going positive, -IOD, solar, +AMO, match 2001 exactly. The big elephant in the room (assuming we go neutral) is the record high solar flux we have. It was the elephant in the room back in 01-02 that was completely overlooked and ignored. Remember “Vodka cold is coming!!”? 
 

@bluewave

[Yanksfan]

3 hours ago, snowman19 said:

I’m still confident that we see a La Niña. If we end up cool-neutral however, it may be a case of “be careful what you wish for”. We are and have been in a default extratropical strong La Niña state for years, even last year with the Nino, we were in a La Niña extratropical state with La Niña MJO forcing (4-6). So, that said, if there is in fact a cool-neutral ENSO, then 2001-2002 becomes an analog IMO….cool-neutral/lack of a distinct ENSO signal, -PDO, -PMM, QBO turning positive, -IOD, +AMO (although not nearly as strong) and record high solar flux 

Basically snow  lovers in the east are screwed with any ENSO state as long as that pool of boiling water in the western pacific remains. We need it to either migrate east or hope for a big cooldown neither of which appears to be happening anytime soon.

[George001]

The latest CFS ensemble mean has a solidly moderate Nina

[so_whats_happening]

5 hours ago, bluewave said:

My guess is the reason that the 2022 hurricane season wasn’t as active as forecast was due to the stronger Maritime Continent forcing leading to more subsidence over the Western Atlantic in August and September. 2017 didn’t have this issue so it was much more active. This is probably why the Atlantic has been so quiet in recent weeks. So we’ll probably need to see a decrease in Maritime Continent forcing next few weeks for the Atlantic to become active. The developing La Niña and record SSTs would suggest a much above average Atlantic hurricane season. But the final piece of the equation would be more favorable forcing. Plenty of time for things to shift allowing the more active forecasts to verify since it’s still very early.

 

My point was not about the hurricane season it was more along the lines that we have seen this type of VP pattern before without necessarily having an over abundance of equatorial warmth near the Maritime Continent and the blazing warmth around Japan. So there must be something else to it than just those two features. Maybe it is possible those two features help to amplify the pattern a bit more over the recent years but 1999 just did not have the Maritime warmth we are currently seeing yet had a very similar setup, 1998 was fairly similar but more toward Sumatra region than New Guinea. 

I do get your point though on the hurricane season and this for sure interrupts that process even with indicators through the roof.

[bluewave]

1 hour ago, so_whats_happening said:

My point was not about the hurricane season it was more along the lines that we have seen this type of VP pattern before without necessarily having an over abundance of equatorial warmth near the Maritime Continent and the blazing warmth around Japan. So there must be something else to it than just those two features. Maybe it is possible those two features help to amplify the pattern a bit more over the recent years but 1999 just did not have the Maritime warmth we are currently seeing yet had a very similar setup, 1998 was fairly similar but more toward Sumatra region than New Guinea. 

I do get your point though on the hurricane season and this for sure interrupts that process even with indicators through the roof.

I think the process by which we got to that forcing state in July 1999 differed from what we are seeing this year. July 1999 was already the 2nd summer of a very strong La Niña with very cold SSTs in the EPAC leading to subsidence there. The Maritime Cintinent forcing was strong since it was still warmer relative to the EPAC. This year the EPAC is still warmer than average due to the lingering warmth from the El Niño. The WPAC record warmth is currently the warmest SSTs in the Pacific. So the strongest forcing is located in that region. Past La Niña events before the warming of the WPAC were more defined by the magnitude of the cooling in the ONI areas. These days it’s the magnitude of the warmth across the WPAC which seems to define the La Niña background state. This is how the weaker La Ninas in 16-17 and 22-23 managed to create such a strong La Niña background pattern even if the ONI SST’s didnt suggest such warm La Niña winters.

As for the tropics, the record Atlantic SSTs and La Niña background favor a very active season. So if the forcing comes closer to the Atlantic and Africa in the coming weeks, then it will be off to the races for Atlantic tropical activity. So 2 out of the 3 factors are lined up for a big hurricane season. We just need the forcing to shift leading to more rising air and less dust over the Atlantic for things to really take off. It’s still very early in the season with plenty of time to see how things verify. 

[so_whats_happening]

1 hour ago, bluewave said:

I think the process by which we got to that forcing state in July 1999 differed from what we are seeing this year. July 1999 was already the 2nd summer of a very strong La Niña with very cold SSTs in the EPAC leading to subsidence there. The Maritime Cintinent forcing was strong since it was still warmer relative to the EPAC. This year the EPAC is still warmer than average due to the lingering warmth from the El Niño. The WPAC record warmth is currently the warmest SSTs in the Pacific. So the strongest forcing is located in that region. Past La Niña events before the warming of the WPAC were more defined by the magnitude of the cooling in the ONI areas. These days it’s the magnitude of the warmth across the WPAC which seems to define the La Niña background state. This is how the weaker La Ninas in 16-17 and 22-23 managed to create such a strong La Niña background pattern even if the ONI SST’s didnt suggest such warm La Niña winters.

I dont remember stating 22-23, I did post about 2020 (since this was a first year Nina situation) though maybe that is why you keep mentioning 22-23 year? To use 2020 as an example this was the pattern that looked almost identical to placement for your July picture. By the looks of it forcing should have been much further east due to those rather anomalous waters around New Guinea, but that wasn't the case. Was 2020 just an anomaly to the situation?

1998 (since this was also a first year La Nina) seemed like reasonable placement due to the waters around Sumatra actually showing a more positive value than most in the pacific, besides the lasting affects of the super Nino into almost mid summer across 1+2 region.

2005 had a funky look as well a westward displaced forcing compared to where greatest warm values were.

Honestly this year should look fairly similar to 1998 VP with the warmest warmest waters overall near Sumatra or a less intense version of 1998 and broader -VP but as shown that is not the case. Is the atmosphere essentially trying to split the difference because both areas are almost equally warm?

I do have to go though so ill try to get a response in tomorrow when Im at work all day.

[GaWx]

The 7/26 OISSTa drop of 0.17 is the largest since at least early May. RONI is likely now finally back into Niña

[Stormchaserchuck1]

6 hours ago, bluewave said:

Yeah, this is why La Nada winters like 01-02 and 13-14 are so dependent on other factors like the state of the PDO. The 01-02 La Nada had the very strong -PDO pattern. So the 500 mb pattern was a La Niña on steroids. Conversely, the 13-14 La Nada was all about the strong +PDO signature east of Japan and the record TNH off the West Coast. So those two factors dominated and lead to the amazing winter. 

13-14 PDO was because of the pattern, though. It's like pointing out that the ground is cold after 4 months of 20 degree days. 

[bluewave]

3 minutes ago, Stormchaserchuck1 said:

13-14 PDO was because of the pattern, though. It's like pointing out that the ground is cold after 4 months of 20 degree days. 

The 500 mb pattern generally leads the SST response. The +PDO and TNH SST pattern for the 13-14 winter had its origins with the very strong NE PAC block during the summer of 2013. The block just kept stronger right into 2015. Then we had the strong reversal during the winters which has lasted 9 years so far. The best NE PAC blocking since then has mostly been during the warm season leading to all the record heat, drought, and wild fires over Western North America. We did get a few decent intervals of NE PAC cold season blocking in December 2017, 2020, and Jan 2022. But the duration was too short to tilt the balance if the winter colder than average. The wall to wall blocking out there during the 13-14 and 14-15 winters were really memorable even if it was short lived during the winters which have followed.

[PhiEaglesfan712]

40 minutes ago, bluewave said:

The 500 mb pattern generally leads the SST response. The +PDO and TNH SST pattern for the 13-14 winter had its origins with the very strong NE PAC block during the summer of 2013. The block just kept stronger right into 2015. Then we had the strong reversal during the winters which has lasted 9 years so far. The best NE PAC blocking since then has mostly been during the warm season leading to all the record heat, drought, and wild fires over Western North America. We did get a few decent intervals of NE PAC cold season blocking in December 2017, 2020, and Jan 2022. But the duration was too short to tilt the balance if the winter colder than average. The wall to wall blocking out there during the 13-14 and 14-15 winters were really memorable even if it was short lived during the winters which have followed.

The blocking in 2020 didn't come until after the winter was over. We did get a cold spell in April and early May, but that was way too late for any snow.

[bluewave]

2 minutes ago, PhiEaglesfan712 said:

The blocking in 2020 didn't come until after the winter was over. We did get a cold spell in April and early May, but that was way too late for any snow.

The +PNA NE PAC block in December 2020 was one for the record books. It was the highest December +PNA on record for a La Niña as strong as that one. There were some clues from the October MJO indicator. But that La Niña mismatch was quite impressive.  
 

[raindancewx]

I have a fairly coherent analog group that's been working pretty well. Anyone else?

[PhiEaglesfan712]

11 minutes ago, raindancewx said:

I have a fairly coherent analog group that's been working pretty well. Anyone else?

For me, 2007-08 is the best match and 1998-99 is the second best.

[Stormchaserchuck1]

1 hour ago, raindancewx said:

I have a fairly coherent analog group that's been working pretty well. Anyone else?

You're doing pretty good.  I've done roll forward stuff with various global patterns (Mexican heat wave in May, CONUS record temps over the past 8 months, +EPO since the Winter, +NAO since May), and they are showing continued above average through March 2025.. But sometimes the EPO pattern will flip like you said.. that's how we could get some colder weather in here.  Usually it would have to start in Sept-Oct.

[Stormchaserchuck1]

38 minutes ago, bluewave said:

The +PNA NE PAC block in December 2020 was one for the record books.

Just a little musing but.. I think the classic PNA position is too far north. Push it south and you have a much higher correlation to East Coast temperatures. The problem is, in the classic PNA patterns, the anomaly often spills over into Alaska, and the temperature correlation over the US becomes neutralized. 

Here's the cold season H5 correlation to classic PNA

Temps

Push that N. Pacific pattern south a bit:

And this is what you have: 

It makes sense that a Low/High in the N. Pacific at 50N would be less of a linear effect than 30/40N. For US temps, you have a hybrid between a cold and warm pattern, being called the PNA. That's why Dec 2020 wasn't so cold.

[GaWx]

1 hour ago, Stormchaserchuck1 said:

Just a little musing but.. I think the classic PNA position is too far north. Push it south and you have a much higher correlation to East Coast temperatures. The problem is, in the classic PNA patterns, the anomaly often spills over into Alaska, and the temperature correlation over the US becomes neutralized. 

Here's the cold season H5 correlation to classic PNA

Temps

Push that N. Pacific pattern south a bit:

And this is what you have: 

It makes sense that a Low/High in the N. Pacific at 50N would be less of a linear effect than 30/40N. For US temps, you have a hybrid between a cold and warm pattern, being called the PNA. That's why Dec 2020 wasn't so cold.

Chuck, 
 Your maps make sense because the correlation of a +PNA to cold in the SE is stronger than it is in the NE and also stronger in the SE to that from -EPO.

 Per your maps:

-the correlation to BN temps of a +PNA is 0.3-0.5 in the SE vs 0.0-0.25 in the NE. So, in SE, +PNA is more crucial to cold than -EPO with the combo typically being the coldest.

-the correlation to BN temps of a -EPO is only 0.1-0.3 in the SE vs 0.3-0.4 in the NE. So, in the NE and especially New England, a -EPO is much more crucial to cold than +PNA.

-the correlation to BN temps in the Midwest and Plains is 0.25-0.5 for -EPO vs a mainly negative correlation for +PNA.

-of course it gets more complex when considering what combo of PNA and EPO exists

[Stormchaserchuck1]

32 minutes ago, GaWx said:

Chuck, 
 Your maps make sense because the correlation of a +PNA to cold in the SE is stronger than it is in the NE and also stronger in the SE to that from -EPO.

 Per your maps:

-the correlation to BN temps of a +PNA is 0.3-0.5 in the SE vs 0.0-0.25 in the NE. So, in SE, +PNA is more crucial to cold than -EPO with the combo typically being the coldest.

-the correlation to BN temps of a -EPO is only 0.1-0.3 in the SE vs 0.3-0.4 in the NE. So, in the NE and especially New England, a -EPO is much more crucial to cold than +PNA.

-the correlation to BN temps in the Midwest and Plains is 0.25-0.5 for -EPO vs a mainly negative correlation for +PNA.

-of course it gets more complex when considering what combo of PNA and EPO exists

I think for a max correlation over the continental US, you want something exactly in between the PNA and PNA-associated with EPO combo. 50/50 could be the max correlation reading, as a hybrid between the two patterns so you get the Upper Midwest and the Southeast on the same page, call it a N. Pacific low at 40N. But the classic PNA does not have a high correlation over the Northeast, despite a lot of what you hear, you are right about that. If you look at precip, the classic PNA actually comes in drier than colder over the East, making all things equal, not a very high snow-correlated pattern. It does have much lower SLP correlation on the coast though.  So stronger storms with not as much moisture is +PNA.  El Nino of course is inversely related to that: So when you get a +PNA in non-El Nino, it is especially dry. And -PNA in non-La Nina is especially wet. 

[Stormchaserchuck1]

Not a bad little pattern for the warmest day of the year, on average (~July 27-28) 

[bluewave]

12 hours ago, Stormchaserchuck1 said:

Just a little musing but.. I think the classic PNA position is too far north. Push it south and you have a much higher correlation to East Coast temperatures. The problem is, in the classic PNA patterns, the anomaly often spills over into Alaska, and the temperature correlation over the US becomes neutralized. 

Here's the cold season H5 correlation to classic PNA

When the +PNA linked up with a south based block like in December 2020 the pattern was much warmer than if the the -NAO -AO block was further north. Probably a result of the much warmer SSTs off the East Coast boosting the ridge near New England. In the older days with colder SSTs this would have been a much colder December pattern in the Northeast. The greatest SST and 500 mb height variance between all the other strong +PNA -AO Decembers since 1950 is east of New England. The lower heights near Alaska were probably a function of the strong -PDO background state in the Pacific. So the very strong +PNA block was anchored a little further south than usual. It was the only such case of a greater than +1.20 +PNA  combined with a lower than -1.500 -AO in December since 1950. So December 2020 was much warmer than past strongly +PNA and -AO Decembers. It’s one of the reasons that we have had a record 9 warmer winters in a row for the Northeast. Since it’s easier to get a warm winter when past teleconnections manifest differently in a warmer climate and  don’t  produce cold patterns like they did in a colder era.

December 2020 compared to all previous Decembers with PNA greater than +1.20 and AO lower than -1.500 since 1950
 

 

[PhiEaglesfan712]

12 hours ago, Stormchaserchuck1 said:

It makes sense that a Low/High in the N. Pacific at 50N would be less of a linear effect than 30/40N. For US temps, you have a hybrid between a cold and warm pattern, being called the PNA. That's why Dec 2020 wasn't so cold.

We really only got one cold and snowy month at PHL that winter, and that was February 2021. Those closer to the coast, like ACY, escaped the snow that year for the most part. So, pretty much an inverse of 2017-18.

[mitchnick]

5 minutes ago, PhiEaglesfan712 said:

We really only got one cold and snowy month at PHL that winter, and that was February 2021. Those closer to the coast, like ACY, escaped the snow that year for the most part. So, pretty much an inverse of 2017-18.

Here on Hanover, that 12/20 storm dropped almost 6" before changing to sleet. It changed back to snow before ending and we ended up with around 8". The month of 2/21 dropped a little over 20". Yeah, I'd take that winter again.