2024-2025 La Nina

[mitchnick]

3 hours ago, brooklynwx99 said:

still thinking we're getting a weak to perhaps moderate Nina, but the higher-end moderate to strong event per ONI looks quite unlikely at this point

however, even if we get something along the lines of a -0.5 trimonthly ONI, we could still get a RONI reading that's in the -0.9 to -1.1 range

As crazy cold as the Cansips was, it's hard to have any confidence in it. That said, the updated forecast is reasonably close to what other modeling is now showing. Agree on the RONI, with a greater chance of going lower than higher imho.

[so_whats_happening]

Looks like we may have a rather significant pullback of VP anomalies from the Maritime Continent coming up here.

[raindancewx]

Canadian has a lot of the US by the Mississippi river cold for the next three months. Nice end to the Summer for a lot of that part of the country. Canada is shown pretty cold for the winter too. La Nina depicted much weaker than before. Just about dead in February, which is how 2016-17 went. WPO looks fairly negative at times which would prevent Central/Western Canada from getting flooded with 50 degree Pacific air in the winter.

 

[Stormchaserchuck1]

It's interesting that the roll-forwards for warm CONUS Dec - June, and Dec - July, had August as a break month along with December.. This beats even CPC, who was very bullish on much above average temperatures a short time ago. Something to consider.. the roll forwards were very warm every month through March 2025, with Dec and August being only neutral. August looks like it will fit that pattern with a -EPO developing for some of the time. Doesn't mean Sept-Oct will be cool. 

[snowman19]

15 hours ago, brooklynwx99 said:

still thinking we're getting a weak to perhaps moderate Nina, but the higher-end moderate to strong event per ONI looks quite unlikely at this point

however, even if we get something along the lines of a -0.5 trimonthly ONI, we could still get a RONI reading that's in the -0.9 to -1.1 range

@brooklynwx99  I think the best case is a La Niña does develop. If we go cold-neutral, then we are at the mercy of all the other antecedent and background conditions in the absence of a signal from ENSO. And the best match for that is 2001-02 with this record breaking solar max. The strong Niña background state won’t be denied, the west PAC warm pool/MJO 4-6 won’t be denied, the -PDO won’t be denied and neither will the high solar flux. People made that mistake (ignoring solar flux) back in 2001

[snowman19]

Shades of 2001: Final sunspot number for July….over 250. Even more activity coming. Also, very high geomag

 

[40/70 Benchmark]

16 hours ago, brooklynwx99 said:

still thinking we're getting a weak to perhaps moderate Nina, but the higher-end moderate to strong event per ONI looks quite unlikely at this point

however, even if we get something along the lines of a -0.5 trimonthly ONI, we could still get a RONI reading that's in the -0.9 to -1.1 range

I like that range for the ONI.

[snowman19]

1 hour ago, 40/70 Benchmark said:

I like that range for the ONI.

I think at this point our ONI options are either cold-neutral or weak Niña. The RONI may get to low-end moderate/high-end weak

[40/70 Benchmark]

Just now, snowman19 said:

I think at this point our ONI options are either cold-neutral or weak Niña. The RONI may get to low-end moderate/high-end weak

I don't agree for now.

[mitchnick]

11 hours ago, raindancewx said:

Canadian has a lot of the US by the Mississippi river cold for the next three months. Nice end to the Summer for a lot of that part of the country. Canada is shown pretty cold for the winter too. La Nina depicted much weaker than before. Just about dead in February, which is how 2016-17 went. WPO looks fairly negative at times which would prevent Central/Western Canada from getting flooded with 50 degree Pacific air in the winter.

 

It's pretty dry over much of the Conus thru the entire winter unfortunately.

[snowman19]

6 hours ago, mitchnick said:

It's pretty dry over much of the Conus thru the entire winter unfortunately.

@GaWx Mentioned that possibility (dry winter) awhile back. The last legit dry winter for the east coast was 22 years ago

[bluewave]

The CANSIPS has had a significant cold bias last 2 winters in the East. But so have many other seasonal models. This is why we would need a mismatch like Jan 22 that went against the La Niña and -PDO background state. That wasn’t something seen by the seasonal models either. It was a short term forecast that didn’t really happen till the models figured out Jan would go MJO 8 near the end of December. 



 

 

 

[40/70 Benchmark]

40 minutes ago, bluewave said:

The CANSIPS has had a significant cold bias last 2 winters in the East. But so have many other seasonal models. This is why we would need a mismatch like Jan 22 that went against the La Niña and -PDO background state. That wasn’t something seen by the seasonal models either. It was a short term forecast that didn’t really happen till the models figured out Jan would go MJO 8 near the end of December. 



 

 

 

Totally agree. I continue to feel as though the winter will be fairly mild overall for the east, but not as exotically so as last season.

[40/70 Benchmark]

12 hours ago, Stormchaserchuck1 said:

It's interesting that the roll-forwards for warm CONUS Dec - June, and Dec - July, had August as a break month along with December.. This beats even CPC, who was very bullish on much above average temperatures a short time ago. Something to consider.. the roll forwards were very warm every month through March 2025, with Dec and August being only neutral. August looks like it will fit that pattern with a -EPO developing for some of the time. Doesn't mean Sept-Oct will be cool. 

I would take a neutral December and mild rest of the winter.

[brooklynwx99]

13 hours ago, snowman19 said:

@brooklynwx99  I think the best case is a La Niña does develop. If we go cold-neutral, then we are at the mercy of all the other antecedent and background conditions in the absence of a signal from ENSO. And the best match for that is 2001-02 with this record breaking solar max. The strong Niña background state won’t be denied, the west PAC warm pool/MJO 4-6 won’t be denied, the -PDO won’t be denied and neither will the high solar flux. People made that mistake (ignoring solar flux) back in 2001

if we are indeed using RONI over ONI, wouldn't a cold neutral ONI reading act like a weak La Nina? for example, if we bottom out at -0.3, the RONI could very well be around -0.7. the RONI was -0.25 at the lowest in DJF 2002, so I'm not sure that this logic works if the cold neutral ONI forecasts indeed verify

if we really want to use cold neutral analogs like 2001-02, we would probably actually have a warm neutral ONI around +0.2 that "acts" like a -0.3 winter given RONI cooling things down

not to say that 2001-02 is a bad analog by the way, it's not

[snowman19]

58 minutes ago, 40/70 Benchmark said:

I would take a neutral December and mild rest of the winter.

A “neutral” December based on what averages though? The new AGW ones? Or the old ones? And I went back and looked at it for myself, Chuck wasn’t kidding, it’s extremely ugly for Nov-Mar, every month (minus December) isn’t just above average, they are way above average 

[40/70 Benchmark]

3 minutes ago, snowman19 said:

A “neutral” December based on what averages though? The new AGW ones? Or the old ones? And I went back and looked at it for myself, Chuck wasn’t kidding, it’s extremely ugly for Nov-Mar, every month (minus December) isn’t just above average, they are way above average 

Either is fine by me considering what the last two winters have looked like. I will take a holiday season that isn't prohibitive to snowfall and feels festive.

[mitchnick]

5 hours ago, snowman19 said:

@GaWx Mentioned that possibly (dry winter) awhile back. The last legit dry winter for the east coast was 22 years ago

Niñas are notoriously dry in the Mid Atlantic, so that's no surprise to me. But the Cansips has yellow of varying degrees all over the Conus, which is surprising to me. Usually, the Ohio Valley is AN during Niñas.  That said, I  think the 5H anomaly maps have the most value at this point, so for me the Cansips is more for discussion sake than a verbatim temp/precip forecast, though equatorial Pacific precip maps can have some value.

[George001]

10 hours ago, 40/70 Benchmark said:

I like that range for the ONI.

Agree, im not buying the cold neutral thing at all. The subsurface is already nearly -1C and is strengthening, how often do you see a subsurface like this lead to cold neutral in winter? We also have the strongly -PDO which is consistent with La Niña. The more aggressive Nina forecasts make sense.

[George001]

6 hours ago, snowman19 said:

@GaWx Mentioned that possibility (dry winter) awhile back. The last legit dry winter for the east coast was 22 years ago

I’m skeptical of that given the raging positive AMO (should enhance storms). If winter fails in the east, I suspect it will be due to +AN temps more so than lack of precip. AGW factor plays a big role of course, the warming oceans leads to a more favorable environment for severe storms. 

[bluewave]

The persistent record marine heatwave near Japan continues to set all-time records.

 

 

[snowman19]

2 hours ago, George001 said:

I’m skeptical of that given the raging positive AMO (should enhance storms). If winter fails in the east, I suspect it will be due to +AN temps more so than lack of precip. AGW factor plays a big role of course, the warming oceans leads to a more favorable environment for severe storms. 

I mean the AMO was positive back in 01-02 and that was our last dry winter. Yes, I know that it wasn’t as ridiculously positive as it is now, but still positive nonetheless 

[snowman19]

6 hours ago, bluewave said:

The persistent record marine heatwave near Japan continues to set all-time records.

 

 

-PDO on roids, as relentless as the MJO 4-6 forcing 

[bluewave]

7 hours ago, snowman19 said:

-PDO on roids, as relentless as the MJO 4-6 forcing 

My guess is the only way we can avoid a repeat of the last 2 winters is for some type of mismatch between the La Niña background state in at least one of the winter months and like we got in January 2022 when the MJO went into phase 8. But short term shifts in the forcing like that probably won’t be known until the period in question gets much closer. So something that can’t really be known months out in a seasonal forecast. The only other clue would be the early MJO indicator in October. But years with a weaker La Niña SST ONI response like 16-17 had a weaker MJO 5 response in October and a very warm winter. Unfortunately we don’t have that more +PDO to work with this time. 

[40/70 Benchmark]

12 hours ago, snowman19 said:

I mean the AMO was positive back in 01-02 and that was our last dry winter. Yes, I know that it wasn’t as ridiculously positive as it is now, but still positive nonetheless 

As you so often point out, CC was in its relative infancy back then.

[40/70 Benchmark]

1 hour ago, bluewave said:

My guess is the only way we can avoid a repeat of the last 2 winters is for some type of mismatch between the La Niña background state in at least one of the winter months and like we got in January 2022 when the MJO went into phase 8. But short term shifts in the forcing like that probably won’t be known until the period in question gets much closer. So something that can’t really be known months out in a seasonal forecast. The only other clue would be the early MJO indicator in October. But years with a weaker La Niña SST ONI response like 16-17 had a weaker MJO 5 response in October and a very warm winter. Unfortunately we don’t have that more +PDO to work with this time. 

I think its a given that Canada will be colder than last year, so at least New England can pull off a serivcable snowfall season if we can have some better fortune with respect to the timing of +PPs. For instace, while the jet mechanics may trigger amplification well to the west, there can still be some appreciable front end snowfalls with better timing. We haven't even had much of that the past couple of years.

That is often what distinguishes a "meh" season from a truly horrendous one.

[snowman19]

1 hour ago, 40/70 Benchmark said:

As you so often point out, CC was in its relative infancy back then.

True. And as far as the AMO going off the charts positive the last few years, it has only served to magnify and feedback into the SE ridge/WAR and result in south-based -NAO blocks when one actually does show up. @bluewave has been all over it

[snowman19]

This is troubling, this is the same effect we saw back in 2001 from that high solar onslaught. The high incoming UV from this major solar flux/record number of sunspots is heating the upper atmosphere. This mid-latitude upper atmospheric heating from UV is what caused the SPV to shrink and strengthen and in turn lead to ++AO back in ‘01. Then we saw the raging westerly zonal flow take over for months
 

[40/70 Benchmark]

10 minutes ago, snowman19 said:

This is troubling, this is the same effect we saw back in 2001 from that high solar onslaught. The high incoming UV from this major solar flux/record number of sunspots is heating the upper atmosphere. This mid-latitude upper atmospheric heating from UV is what caused the SPV to shrink and strengthen and in turn lead to ++AO back in ‘01. Then we saw the raging westerly zonal flow take over for months
 

I'm sure you have been up all night worried-sick!

[roardog]

42 minutes ago, snowman19 said:

This is troubling, this is the same effect we saw back in 2001 from that high solar onslaught. The high incoming UV from this major solar flux/record number of sunspots is heating the upper atmosphere. This mid-latitude upper atmospheric heating from UV is what caused the SPV to shrink and strengthen and in turn lead to ++AO back in ‘01. Then we saw the raging westerly zonal flow take over for months
 

I believe the upper atmosphere has longer lag when it comes to warming and cooling. Also, looking at that graph, I don’t know how anyone can think that sudden warming could have been caused entirely by the strong Nino or greenhouse gases. I mean the graph shoots straight up.