2024-2025 La Nina

[GaWx]

 Here's something different and unexpected: the brand new BoM is much colder than the prior run!

New run dips to -0.8 in Oct and Nov:

 

Compare that to the run from 2 weeks earlier, that dipped only to -0.3 in Oct!

[snowman19]

We are outperforming the solar prediction made by NOAA at the beginning of this month by so much it’s not funny. Both sunspots and solar flux. Geomag is also way overperforming original predictions

[snowman19]

It will be interesting to see how things go once we reach the peak in September. With the slowdown after Ernesto the ACE should be less above average.  The average ACE by September 1st is 50. The 200+ ACE seasons since 1988 were usually around 100 by the start of September. But with hurricanes it only takes one hitting a populated area to have a big season. 
 
https://kouya.has.arizona.edu/tropics/index.html
 

[40/70 Benchmark]

28 minutes ago, bluewave said:

We may have to wait until September for our next significant tropical development as there is an unusually large amount of sinking air over the Atlantic Basin right now. It appears that the La Niña forcing is so strong near the Maritime Continent that it’s focusing all the strongest tropical convection there. But with record Atlantic SSTs in place any shift in the MJO could lead to an increase in Atlantic activity down the road. 
 

 

God, that nuclear forcing around the MC continues to just eradicate any semblance of intersting weather for east coast enthusiasts....winter or tropical.

[Typhoon Tip]

38 minutes ago, bluewave said:

We may have to wait until September for our next significant tropical development as there is an unusually large amount of sinking air over the Atlantic Basin right now. It appears that the La Niña forcing is so strong near the Maritime Continent that it’s focusing all the strongest tropical convection there. But with record Atlantic SSTs in place any shift in the MJO could lead to an increase in Atlantic activity down the road. 
 

 

We should also see an eastern continent/mid latitude ridging and warm intrusion, too. Could be the last heat wave chance of this season ...circa early next week.

models are tepid on the idea ( operational ) but some of that ( the GFS in particular ) is native bias related. 

[PhiEaglesfan712]

August 2024 IRI update: 

[snowman19]

25 minutes ago, 40/70 Benchmark said:

God, that nuclear forcing around the MC continues to just eradicate any semblance of intersting weather for east coast enthusiasts....winter or tropical.

Nothing to stop it either. Niña/-IOD favors it right there (MC)

[GaWx]

4 minutes ago, bluewave said:

We may have to wait until September for our next significant tropical development as there is an unusually large amount of sinking air over the Atlantic Basin right now. It appears that the La Niña forcing is so strong near the Maritime Continent that it’s focusing all the strongest tropical convection there. But with record Atlantic SSTs in place any shift in the MJO could lead to an increase in Atlantic activity down the road. 
 

 

 While Ernesto is still out there and is near or at its strongest yet continuing to add more ACE (it’s nearing 54 already), ensembles (Euro/GFS) are hinting at a TC in the W basin during the 9-15 day period. It appears to me that AEW(s) coming off Africa ~Aug 24-7 may be the main instigator. I’ve been especially following something coming off ~Aug 24-5, which the last three 12 hourly ICON runs have a surface low from. Also, the Euro Weeklies have been suggesting an increase in activity in early Sep continuing into mid Sept:

Euro weeklies ACE forecast vs norm last 7 days (newest far right, which is 0Z of Sunday):

8/26-9/1: 60%/60%/50%/60%/50%/50%/50%; Norm 14

9/2-8: 110%/110%/110%/110%/120%/100%/110%; norm 15

9/9-15: NA/120%/90%/80%/90%/80%/100%; norm 16

 So, the weeklies have been pretty consistently calling for ~7 for 8/26-9/1, 17 for 9/2-8, and 16 for 9/9-15. That would get ACE to ~96 after Ernesto finishes at ~56 vs the 1991-2020 avg for 9/15 of 70. That’s if these numbers aren’t underdone. I think they’re more likely underdone than overdone assuming there actually are TCs during this period due to a low ACE bias.

  In summary, the signal for the last 7 days of Euro weekly runs is for a sharp ramp up to increased activity in early to mid Sep after a somewhat quiet week or so right after Ernesto loses its tropical classification. So, I anticipate only a short quiet period. Then I could easily see something like 3 more TCs late Aug through 9/15, starting as early as with the AEW leaving Africa 8/24-5, with 2-3 of these Hs. That would bring the season to 5-6H by 9/15, well on the way to ~10H for the season. If there are 3H by 9/15, ACE could easily then be ~115 vs a 70 normal, well on the way to a hyper season.

 

[40/70 Benchmark]

49 minutes ago, snowman19 said:

Nothing to stop it either. Niña/-IOD favors it right there (MC)

It won't abate until later this decade.

[George001]

8 hours ago, GaWx said:

 Here's something different and unexpected: the brand new BoM is much colder than the prior run!

New run dips to -0.8 in Oct and Nov:

 

Compare that to the run from 2 weeks earlier, that dipped only to -0.3 in Oct!

Doesn’t BOM have a warm bias? It predicted the Nino to be a super event rivaling 2016 last year. While the Nino did end up becoming a very powerful event, it was not on par with 2016/1998. It was more in line with 57-58, 72-73, etc (high end strong/low end super). This is definitely something to watch.

[GaWx]

1 hour ago, PhiEaglesfan712 said:

August 2024 IRI update: 

 Keep in mind that BoM (AUS-Access) incorporated in this was the prior run, which dipped down only to -0.23 for SON. But as I posted about early this morning, it plunged to ~-0.8 in the brand new run in both Oct and Nov, producing SON way down at -0.73.

[GaWx]

17 minutes ago, George001 said:

Doesn’t BOM have a warm bias? It predicted the Nino to be a super event rivaling 2016 last year. While the Nino did end up becoming a very powerful event, it was not on par with 2016/1998. It was more in line with 57-58, 72-73, etc (high end strong/low end super). This is definitely something to watch.

 Actually through 2022 BoM interestingly had no discernible bias (some years too warm while others too cold…was a mix that washed out). Then 2023 itself was way too warm as it called for ONI maxes in the high +2s several times vs the actual of ~+2.0 ONI (RONI only ~+1.5).

 So, I don’t know that I can consider BoM warm biased based on just one year. This is unlike the consistent warm bias of the Euro, especially for non-El Nino years. We’ll have to see how the next few years go for BoM. With this new run down to -0.73 for SON, any warm bias it was showing for 2024 may have finally been corrected. I continue to favor the UKMET somewhat after last year’s stellar performance/steadiness and this year’s steadiness. August UKMET run dipped to -0.94 in NDJ. That may turn out slightly too low. Right now I’m guessing ~-0.75/~-1.25 low for ONI/RONI, in partial deference to the JMA’s rise to -0.56 for its ONI low on its Aug run.

[PhiEaglesfan712]

1 hour ago, George001 said:

Doesn’t BOM have a warm bias? It predicted the Nino to be a super event rivaling 2016 last year. While the Nino did end up becoming a very powerful event, it was not on par with 2016/1998. It was more in line with 57-58, 72-73, etc (high end strong/low end super). This is definitely something to watch.

The thing about the 2023-24 el nino is that the RONI peaked at about +1.5, which is in line with the 2009-10 el nino, a borderline moderate/strong el nino. Here's the crazy part, though: The MEI had 2023-24 only as a weak el nino, with a peak similar to the 2006-07 el nino.

I'd put 2023-24 in line with years like 57-58, 65-66, 91-92, and 2009-10 (as well as 86-88, but that was a summer peaking el nino). All strong el ninos, but not super el ninos. The 2009-10 and 2023-24 el ninos fall short on the MEI compared to 86-88 and 91-92 el ninos. And you won't believe this, but the ENSO neutral years following the 91-92 el ninos (92-93 and 93-94) even had a higher peak on the MEI than 2009-10 and 2023-24.

[Note: If you include the natural el nino in 94-95, then you basically have a 4-year strong el nino on the MEI.]

[GaWx]

 If the GFS/Euro end up verifying well, there could be as many as 4 straight Tahiti SLPs of 1019+ during Aug 19-22. I’d be very surprised if there isn’t at least one. Keep in mind that higher Tahiti pressure is favored during developing La Niña. There hasn’t been even a single day of 1019+ since 2010!

Tahiti SLP 1019+ since 1991:

1019.55: 1994 (Aug)

1019.1, 1019.44: 1996 (June)

1019.3: 1998 (Aug)

1019.28: 1999 (Aug)

1019.24: 2010 (July)

1019.44, 1019.61, 1019.78, 1019.59, 1019.14: 2010 (Sep)

1019.05: 2010 (Sep)

 

 -So, there have been only 13 days of Tahiti SLP of 1019+ over the last 33 years with the record high being 1019.78 (Sep of 2010).

- This shows there’s been only one time when there were more than two days in a row of that (Sep of 2010). That was during the longest streak on record, 5 days.

- This shows that all were during June-Sep with a mean date of Aug. That makes sense because that’s during their winter, when sfc cold high pressures are at their highest SLP of the year.

- There is a decent correlation between high Tahiti SLP periods and an active Atlantic tropics mainly 1-3 weeks afterward. That jibes well with the idea of an active Atlantic sometime between very late this month and mid Sep.

[mitchnick]

5 hours ago, GaWx said:

 If the GFS/Euro end up verifying well, there could be as many as 4 straight Tahiti SLPs of 1019+ during Aug 19-22. I’d be very surprised if there isn’t at least one. Keep in mind that higher Tahiti pressure is favored during developing La Niña. There hasn’t been even a single day of 1019+ since 2010!

Tahiti SLP 1019+ since 1991:

1019.55: 1994 (Aug)

1019.1, 1019.44: 1996 (June)

1019.3: 1998 (Aug)

1019.28: 1999 (Aug)

1019.24: 2010 (July)

1019.44, 1019.61, 1019.78, 1019.59, 1019.14: 2010 (Sep)

1019.05: 2010 (Sep)

 

 -So, there have been only 13 days of Tahiti SLP of 1019+ over the last 33 years with the record high being 1019.78 (Sep of 2010).

- This shows there’s been only one time when there were more than two days in a row of that (Sep of 2010). That was during the longest streak on record, 5 days.

- This shows that all were during June-Sep with a mean date of Aug. That makes sense because that’s during their winter, when sfc cold high pressures are at their highest SLP of the year.

- There is a decent correlation between high Tahiti SLP periods and an active Atlantic tropics mainly 1-3 weeks afterward. That jibes well with the idea of an active Atlantic sometime between very late this month and mid Sep.

Found this Eps weeklies September precip forecast in the MA forum.

Suggests to me that most tropical activity stays offshore. 

[kazimirkai]

I know this is off topic but I'm somewhat new to this site, don't know the best place to ask, and this blog seemed active. Where can I find maps showing the amount of rainfall in the past year? Like for some reason its unreasonably difficult to find a "national 2023 total rainfall" map anywhere.

[so_whats_happening]

Looks like Typhoon Ampil put a decent dent into the SST heat east of Japan and the smaller tropical systems over the last week or so here and there have cooled the area somewhat. It looks as though the SST warmth is now concentrated into two areas one hundreds of miles ENE of Japan and then another concentrated area around Sea of Japan,  the Koreas, and the East China sea/ Yellow sea region.

It will be interesting if this was just a quick cooldown before we cook the area again or if this may have finally started a change. Regardless the PDO will still probably hold in the -2 to -3 range for quite some time unless we continue to see more typhoon activity in the next few months. I would post animations but it seems the file is slightly corrupted halfway through, hope they can fix this in the future.

Another interesting note is the cooling showing up around Sumatra. Again another little blip or something to keep an eye on.

[GaWx]

4 minutes ago, so_whats_happening said:

Looks like Typhoon Ampil put a decent dent into the SST heat east of Japan and the smaller tropical systems over the last week or so here and there have cooled the area somewhat. It looks as though the SST warmth is now concentrated into two areas one hundreds of miles ENE of Japan and then another concentrated area around Sea of Japan,  the Koreas, and the East China sea/ Yellow sea region.

It will be interesting if this was just a quick cooldown before we cook the area again or if this may have finally started a change. Regardless the PDO will still probably hold in the -2 to -3 range for quite some time unless we continue to see more typhoon activity in the next few months. I would post animations but it seems the file is slightly corrupted halfway through. hope they can fix this in the future.

Another interesting note is the cooling showing up around Sumatra. Again another little blip or something to keep an eye on.

 I’ve found that most, if not all, of the significant cooling from strong and/or large TCs tends to reverse within a few weeks during early to mid season.

[so_whats_happening]

1 minute ago, GaWx said:

 I’ve found that most, if not all, of the significant cooling from strong and/or large TCs tends to reverse within a few weeks during early to mid season.

The nice stripe we had last year due to Franklin, fairly similar to what Ernesto produced actually managed to stick around for some time. If this had occurred in June or July I would have agreed in the reversal but as we get later into the summer and early fall these tend to have more profound impacts. This allowed for more troughing episodes to show up more in this region as we moved into fall and early winter.

If we can continue to see multiple tropical systems forming in the general region we could start to see a small cold pool form. Again not proclaiming this will collapse the -PDO state but simply dents and dings will start to add up. Instead of having a monstrous + anomaly we could start to see it show just a more above normal look if it keeps up.

Especially if we are going to see lift concentrated into the MC/ West Pacific like models are suggesting toward the end of the month. I think the area ENE of Japan will just continue to be pushed E over time.

[so_whats_happening]

1 hour ago, kazimirkai said:

I know this is off topic but I'm somewhat new to this site, don't know the best place to ask, and this blog seemed active. Where can I find maps showing the amount of rainfall in the past year? Like for some reason its unreasonably difficult to find a "national 2023 total rainfall" map anywhere.

This is probably best left for the Meteorology 101, but it really depends on how detailed of a picture or number you want.

This site does rather well in capturing the numbers, you even have the option to zoom into states to get a closer look. https://hprcc.unl.edu/maps.php?map=ACISClimateMaps

Outside of that weather.gov is your other best option and click in a region (say NYC area) then climo for very localized totals but no actual map.

[snowman19]

9 hours ago, PhiEaglesfan712 said:

August 2024 IRI update: 

I would be shocked if we don’t see a trimonthly weak La Niña (ONI). Cold-neutral is a given, that’s happening and IMO the probability of a weak La Niña is growing more and more likely by the day

[so_whats_happening]

@snowman19 there seems to have been another decent volcanic eruption this one much further north.

https://www.cnn.com/2024/08/17/world/earthquake-kamchatsky-tsunami-warning-russia-intl-latam?cid=ios_app

[PhiEaglesfan712]

1 hour ago, snowman19 said:

I would be shocked if we don’t see a trimonthly weak La Niña (ONI). Cold-neutral is a given, that’s happening and IMO the probability of a weak La Niña is growing more and more likely by the day

FWIW, the August 2024 CPC and IRI forecasts look eerily similar to August 2021: 

What ended up happening is a moderate la nina, which peaked very late into the year, and you could make the argument that it carried over to the next year. I've been hinting at a possible between season peak for this la nina. I wouldn't be surprised if 2024-25 and 2025-26 repeated the same ONI trajectory as 2021-22 and 2022-23.

[snowman19]

7 hours ago, so_whats_happening said:

@snowman19 there seems to have been another decent volcanic eruption this one much further north.

https://www.cnn.com/2024/08/17/world/earthquake-kamchatsky-tsunami-warning-russia-intl-latam?cid=ios_app

I believe to have a significant climate effect it needs to be a tropical volcano that reaches the stratosphere with a VEI of “high-end” 5 or above. I defer to @Volcanic Winter

[snowman19]

12 hours ago, GaWx said:

 I’ve found that most, if not all, of the significant cooling from strong and/or large TCs tends to reverse within a few weeks during early to mid season.

Even a very strong El Niño couldn’t flip the PDO, it actually got more strongly negative. With a La Niña developing, I very seriously doubt TC’s moving through are going to do anything but cause transient, temporary cooling then right back to the marine heatwave. We’ve seen this happen already. SSTs that anomalously warm aren’t just going away, it would take months of a constant assault. The North Pacific High just keeps rebuilding over and over, as long as that feedback cycle continues, the PDO is going to continue to be strongly negative. The PMM also failed to respond to the Nino, that was one of the reasons for the huge disconnect with the MEI last winter. We’ve also heard how many times now that the AMO is about to flip negative, when in fact it’s just gotten stronger positive. Kind of like how JB has been saying that arctic sea ice is going to increase lol It’s akin to the MJO….how many times in the last 5+ years have we seen failed attempt after failed attempt at phases 8-1-2? It just stays in phases 4-6….why? Because that’s where the warmest SSTs are. The 31C isotherm is right there. The atmosphere will always put the strongest convection/forcing where the warmest SSTs are despite what a climate model or even ENSO may say as we saw last winter. Now that the IOD is going negative along with a Niña, that just gives more support of the MJO in those phases

On an unrelated note, I know you follow it, but it looks like the sunspot number for August is going to be over 230. Also appears that the QBO is going to see a rather large rise this month

Edit: @40/70 Benchmark I don’t think a volcanic eruption that far north would have an effect on the stratosphere even if it were June. Tropical volcanoes are the ones that do it

[40/70 Benchmark]

3 hours ago, snowman19 said:

I believe to have a significant climate effect it needs to be a tropical volcano that reaches the stratosphere with a VEI of “high-end” 5 or above. I defer to @Volcanic Winter

Its too late to have an impact for the coming winter, anyway.

[40/70 Benchmark]

2 hours ago, snowman19 said:

Even a very strong El Niño couldn’t flip the PDO, it actually got more strongly negative. With a La Niña developing, I very seriously doubt TC’s moving through are going to do anything but cause transient, temporary cooling then right back to the marine heatwave. We’ve seen this happen already. SSTs that anomalously warm aren’t just going away, it would take months of a constant assault. The North Pacific High just keeps rebuilding over and over, as long as that feedback cycle continues, the PDO is going to continue to be strongly negative. The PMM also failed to respond to the Nino, that was one of the reasons for the huge disconnect with the MEI last winter. We’ve also heard how many times now that the AMO is about to flip negative, when in fact it’s just gotten stronger positive. Kind of like how JB has been saying that arctic sea ice is going to increase lol It’s akin to the MJO….how many times in the last 5+ years have we seen failed attempt after failed attempt at phases 8-1-2? It just stays in phases 4-6….why? Because that’s where the warmest SSTs are. The 31C isotherm is right there. The atmosphere will always put the strongest convection/forcing where the warmest SSTs are despite what a climate model or even ENSO may say as we saw last winter. Now that the IOD is going negative along with a Niña, that just gives more support of the MJO in those phases

On an unrelated note, I know you follow it, but it looks like the sunspot number for August is going to be over 230. Also appears that the QBO is going to see a rather large rise this month

I think we may begin to see some chinks in the armor of the PAC cold phase following this La Nina, but I agree its not happening for this cold season.

[bluewave]

So far the models are not showing any major hurricanes in the Atlantic basin from August 20th through September 1st. This isn’t a typical occurrence for heading into a La Niña winter. The only other years this happened since 1995 were in 2022 and 2000. While the sample size is very small to draw from, 2022 had a very active September with hurricanes Danielle and Earl reaching cat 1 and cat 2 status. The big stories that month were Fiona going Cat 4 and Ian Cat 5. 
 

La Niña years since 1995 major hurricanes August 20th September 1st

2022….none

2021….Ida….Cat 4…..Larry Cat 3

2020…Laura Cat 4

2017….Harvey Cat 4…Irma Cat 5

2016….Gaston Cat 3

2011….Irene Cat 3

2010…Danielle Cat 4….Earl Cat 4

2008….Gaston Cat 4

2007…..Dean….Cat 5

2005…..Katrina Cat 5

2000…..none

1999…..Brett Cat 4….Cindy Cat 4

1998…..Bonnie Cat 3

1995…..Louis Cat 4

[40/70 Benchmark]

3 hours ago, snowman19 said:

Even a very strong El Niño couldn’t flip the PDO, it actually got more strongly negative. With a La Niña developing, I very seriously doubt TC’s moving through are going to do anything but cause transient, temporary cooling then right back to the marine heatwave. We’ve seen this happen already. SSTs that anomalously warm aren’t just going away, it would take months of a constant assault. The North Pacific High just keeps rebuilding over and over, as long as that feedback cycle continues, the PDO is going to continue to be strongly negative. The PMM also failed to respond to the Nino, that was one of the reasons for the huge disconnect with the MEI last winter. We’ve also heard how many times now that the AMO is about to flip negative, when in fact it’s just gotten stronger positive. Kind of like how JB has been saying that arctic sea ice is going to increase lol It’s akin to the MJO….how many times in the last 5+ years have we seen failed attempt after failed attempt at phases 8-1-2? It just stays in phases 4-6….why? Because that’s where the warmest SSTs are. The 31C isotherm is right there. The atmosphere will always put the strongest convection/forcing where the warmest SSTs are despite what a climate model or even ENSO may say as we saw last winter. Now that the IOD is going negative along with a Niña, that just gives more support of the MJO in those phases

On an unrelated note, I know you follow it, but it looks like the sunspot number for August is going to be over 230. Also appears that the QBO is going to see a rather large rise this month

Edit: @40/70 Benchmark I don’t think a volcanic eruption that far north would have an effect on the stratosphere even if it were June. Tropical volcanoes are the ones that do it

That is in actually incorrect.....they can all have an impact, but said impact differs based upon size and location.

[40/70 Benchmark]

24 minutes ago, bluewave said:

So far the models are not showing any major hurricanes in the Atlantic basin from August 20th through September 1st. This isn’t a typical occurrence for heading into a La Niña winter. The only other years this happened since 1995 were in 2022 and 2000. While the sample size is very small to draw from, 2022 had a very active September with hurricanes Danielle and Earl reaching cat 1 and cat 2 status. The big stories that month were Fiona going Cat 4 and Ian Cat 5. 
 

La Niña years since 1995 major hurricanes August 20th September 1st

2022….none

2021….Ida….Cat 4…..Larry Cat 3

2020…Laura Cat 4

2017….Harvey Cat 4…Irma Cat 5

2016….Gaston Cat 3

2011….Irene Cat 3

2010…Danielle Cat 4….Earl Cat 4

2008….Gaston Cat 4

2007…..Dean….Cat 5

2005…..Katrina Cat 5

2000…..none

1999…..Brett Cat 4….Cindy Cat 4

1998…..Bonnie Cat 3

1995…..Louis Cat 4

2022 is high, high on my analog list.