2024-2025 La Nina

[Stormchaserchuck1]

5 hours ago, bluewave said:

The -PDO composite was a great match for this summer. The composites below are for a +PDO pattern in summer and winter. So they have to be reversed. The classic -PDO is a ridge south of the Aleutians and east of New England during the summer. We got one of the strongest ridges on record south of the Aleutians and east of New England. So if this -PDO state continues through the winter then it would feature a strong Aleutian Ridge and Southeast Ridge. Pretty much identical to a robust La Niña 500 mb atmospheric response. We would need to get some type of mismatch like we saw in 21-22 when the MJO 8 shifted us away from the La Niña and -PDO background for January and gave us at least one good winter month even if the winter was still warmer overall the Northeast. Otherwise, the inverse of the below composite would prevail. We probably need to see how things go in October to get some better hints. 
 

+PDO summer 500 mb pattern needs to be reversed for -PDO

Summer 2024 strong -PDO

+PDO winter composite needs to be reversed  like summer was

And May was even the most -PNA on record for May. The -PDO correlation has been carrying for a long time, even when it correlated more with the N. Pacific pattern than a +1.8c El Nino last Winter. 

[Stormchaserchuck1]

On 8/24/2024 at 11:09 AM, 40/70 Benchmark said:

I don't think it's going to be an extremely positive NAO season, which is backed up by @Stormchaserchuck1's subsurface formula. 

We're getting it up there though.. I think it will probably finish in the top 25th percentile. I do get a little nervous though when it is a H5 pattern carrying the thing.. so you could basically say +NAO leads +NAO, but if there was relative strength in the Atlantic subsurface/SSTs, it would have higher value I think. +NAO Winter looks probable, but I would probably forecast a bit lower than the index comes out (even though the CPC has been really weighing +nao events high since 2013, 16/16 of Winter months >1.11 have all been +NAO!). It's likely the CPC again has a higher nao number than the H5 pattern this Winter. 

[so_whats_happening]

8 hours ago, GaWx said:

1. Agreed it will very likely be closer to avg on Sept 1. However, the 3 main 0Z ensembles as well as 6Z GEFS agree that the highest concentration of members with a TCG is in the MDR 45-60W between 8/31 and 9/3. Overall concentration looks a bit higher vs most earlier runs. This is pretty close to when/where 23 AI-Euro runs in a row had TCG as well as TCGs on recent ICON runs. Chances seem pretty good for the next TCG during the first few days of Sept. even though the AI-Euro ironically abandoned its near Leeward Island TCG two days ago. So, we’ll see. If there is a TCG then when considering the near record warmth in many parts of the W basin, that would have the potential to be a big ACE producer. Unfortunately, it could threaten the CONUS. I’ve been enjoying the lowered stress resulting from this recent quiet. The party may be over. We’ll see.

2. I believe that this season will end up backloaded as well as concentrated in the W part of the basin due to less favorable conditions in the E basin due to a variety of reasons, some unknown.

 

Yea there seems to be a sneaky wave showing up on models that gets into the east/central Caribbean by the end of the weekend into early next week. Seems to be out of that clustering around 30W that models want to try and latch onto. Forward progression seems to be finally slowing down a bit across the MDR instead of things flying by.

I feel like many call things far too early with tropical season anymore, not saying it will but this season could easily last into November and December. Meanwhile the WPAC continues the typhoon train. I would not be surprised if we start to see two distinct warm pools one just S and SW of the Aleutians (slowly moving east) and one back toward mainland China and the Koreas. Some of the Sea of Japan (at least eastern portions) may contend with some cooling coming up.

[raindancewx]

ACE so far has been (rounded) 7 / 29 / 18 for June / July / Aug in the Atlantic.

2008:  0  / 38 / 26

2008:  0 / 38 / 26

1966: 14 / 19 / 21

1966: 14 / 19 / 21

2022:  2 / 0 / 0

-----------------

Blend: 6 / 23 / 19 

2024: 7 / 29 / 18

 

1966: 145.2 (x2)

2008: 145.7 (x2)

2022: 95.1

-----------------

Blend: 135.4

 

Sept in blend: 

1966: 39 (x2)

2008: 61 (x2)

2022: 76

---------------

Blend: 55

If we're below this, I can't see the rest of the season perking up too much.

 

Oct in blend:

1966: 30 (x2)

2008: 11 (x2)

2022: 5

---------------

Blend: 17

Pretty quick slowdown from a pretty active September.

 

Nov in blend:

1966: 15 (x2)

2008: 9 (x2)

2022: 10

--------------

Blend: 12

 

Data implies a fairly average September - we'll see.

 

[raindancewx]

August looks like the blend of the five years for most of the US, minus the unusual shot of cold air into the mountains of CA recently. This is fairly similar to what I get whenever I test features that are consistently showing up. Cold Plains, average / warm elsewhere. Actually a pretty cold December nationally.

[40/70 Benchmark]

10 minutes ago, raindancewx said:

August looks like the blend of the five years for most of the US, minus the unusual shot of cold air into the mountains of CA recently. This is fairly similar to what I get whenever I test features that are consistently showing up. Cold Plains, average / warm elsewhere. Actually a pretty cold December nationally.

That looks like the CANSIPS. I would take that and run.

[raindancewx]

That composite should hold if we see 'average' hurricane activity the rest of the way. With very little activity, I think 2022 takes over. With much stronger activity, you have to start to look at the warmer high solar active years and blend them with the stormier years for the east, so 1995, 1998, 1999, 2000, 2010, 2016, 2017 as a blend. I don't think you'd go cold/stormy with the way the background signals are, but stormy + mostly warm / some cold would be possible with much higher ACE activity (say 180+ by 11/1).

[bluewave]

10 hours ago, Stormchaserchuck1 said:

And May was even the most -PNA on record for May. The -PDO correlation has been carrying for a long time, even when it correlated more with the N. Pacific pattern than a +1.8c El Nino last Winter. 

We would need a Jan 22 style mismatch pattern in order to avoid the Euro DJF La Nada strong -PDO composite. 

 

[40/70 Benchmark]

12 hours ago, Stormchaserchuck1 said:

We're getting it up there though.. I think it will probably finish in the top 25th percentile. I do get a little nervous though when it is a H5 pattern carrying the thing.. so you could basically say +NAO leads +NAO, but if there was relative strength in the Atlantic subsurface/SSTs, it would have higher value I think. +NAO Winter looks probable, but I would probably forecast a bit lower than the index comes out (even though the CPC has been really weighing +nao events high since 2013, 16/16 of Winter months >1.11 have all been +NAO!). It's likely the CPC again has a higher nao number than the H5 pattern this Winter. 

Yea, I mentioned that your index calculating was trending upward. Obviously its going to average positive for the winter....just a matter of whether or not we still a negative month.

[40/70 Benchmark]

1 hour ago, bluewave said:

We would need a Jan 22 style mismatch pattern in order to avoid the Euro DJF La Nada strong -PDO composite. 

 

What do you think of the CANSIP? Probably would need a mismatich month to score this...

[40/70 Benchmark]

1966-1967 was an interesting cool ENSO year in that snowfall behaved more like an El Nino locally....very, very backloaded with a big Feb-March. December has seasonable snowfall and January had hardly anything...one of the worst on record.

The Farmer's Alamanac sounds alot like raindance described with the warmer and very active storm track description.

[snowman19]

Tried to tell you a month ago there was a lot of evidence pointing against a slam-dunk Niña. Yet, it can still change. Early call accurate forecasts on any weather phenomina rely solely on luck imho.

Weather is always humbling. If this does in fact turn into a cold-neutral/La Nada, it definitely humbled me as I thought a weak La Niña was the very likely outcome just a few weeks ago. Is it AGW related? Quite possibly. The other humbling phenomenon may well be the Atlantic tropical season…..

[PhiEaglesfan712]

18 minutes ago, 40/70 Benchmark said:

1966-1967 was an interesting cool ENSO year in that snowfall behaved more like an El Nino locally....very, very backloaded with a big Feb-March. December has seasonable snowfall and January had hardly anything...one of the worst on record.

The Farmer's Alamanac sounds alot like raindance described with the warmer and very active storm track description.

Yeah, it looks like January was the outlier month. At PHL, December and February had 18 in of snow, with March 6 in. Also, the cold continued into the spring, as May 1967 was the coldest May on record by a full degree F.

 

[40/70 Benchmark]

5 minutes ago, PhiEaglesfan712 said:

Yeah, it looks like January was the outlier month. At PHL, December and February had 18 in of snow, with March 6 in. Also, the cold continued into the spring, as May 1967 was the coldest May on record by a full degree F.

 

I am not opposed to late season blocking, a la 2023.

[PhiEaglesfan712]

4 minutes ago, 40/70 Benchmark said:

I am not opposed to late season blocking, a la 2023.

I guess you like a warmer winter and cooler May/summer. That doesn't really help me being near PHL, except for the unseasonably cold rainstorm that will happen near the summer solstice, which I really don't want.

I prefer the blocking to happen in November to maximize the season snow potential.

[40/70 Benchmark]

29 minutes ago, PhiEaglesfan712 said:

I guess you like a warmer winter and cooler May/summer. That doesn't really help me being near PHL, except for the unseasonably cold rainstorm that will happen near the summer solstice, which I really don't want.

I prefer the blocking to happen in November to maximize the season snow potential.

I think its exceedingingly likely to be a mild winter....just a matter of how active it is and whether or not its prohibitively warm.

[40/70 Benchmark]

We could have a coolish month...my guess would be December or maybe even March.

[PhiEaglesfan712]

If we're going to get a warm winter, I hope it's something like 2007-08, where we got the cool November and December. Yeah, the cool May reared its ugly head, but at least June and July 2008 were warm, so all wasn't lost. Also, January-April, while warm, weren't anything out of the ordinary.

 

[40/70 Benchmark]

Just now, PhiEaglesfan712 said:

If we're going to get a warm winter, I hope it's something like 2007-08, where we got the cool November and December. Yeah, the cool May reared its ugly head, but at least June and July 2008 were warm, so all wasn't lost. Also, January-April, while warm, weren't anything out of the ordinary.

 

I think that is a decent analog.

[mitchnick]

1 hour ago, snowman19 said:

Weather is always humbling. If this does in fact turn into a cold-neutral/La Nada, it definitely humbled me as I thought a weak La Niña was the very likely outcome just a few weeks ago. Is it AGW related? Quite possibly. The other humbling phenomenon may well be the Atlantic tropical season…..

 

 

 

 

 

 

 

 

Honestly, this year's hurricane forecasts were forefront in my mind when I made that post, but I believe it's true for other forecasts as well. There are just too many smaller scale features that can really screw things up.

[snowman19]

20 minutes ago, 40/70 Benchmark said:

I think that is a decent analog.

The ridiculous New Foundland warm pool is definitely a match for 07-08

[40/70 Benchmark]

7 minutes ago, snowman19 said:

The ridiculous New Foundland warm pool is definitely a match for 07-08

That year is a great example of how to still get it done in NE in an ostensibly brutal pattern....huge PV that is elongated to the SE.

[bluewave]

2 hours ago, 40/70 Benchmark said:

What do you think of the CANSIP? Probably would need a mismatich month to score this...

While I don’t know whether it will be correct or not with the more poleward extension of the Aleutian Ridge into Alaska than the Euro, we did have a pattern like this in 16-17. Very weak La Niña following the super El Niño in 15-16. Not sure if the CANSIPS may be underestimating the trough out West compared to 16-17 if that poleward extension verified.  While it was a mild winter in the East, that poleward extension got us in the game for a better snowfall outcome than the last few seasons. But we have a much stronger -PDO pattern now so not sure if we could do as well in the snowfall department as we did that season. Any improvement in snowfall over the last two seasons would be nice to see. 
 

[40/70 Benchmark]

3 minutes ago, bluewave said:

While I don’t know whether it will be correct or not with the more poleward extension of the Aleutian Ridge into Alaska than the Euro, we did have a pattern like this in 16-17. Very weak La Niña following the super El Niño in 15-16. Not sure if the CANSIPS may be underestimating the trough out West compared to 16-17 if that poleward extension verified.  While it was a mild winter in the East, that poleward extension got us in the game for a better snowfall outcome than the last few seasons. But we have a much stronger -PDO pattern now so not sure if we could do as well in the snowfall department as we did that season. Any improvement in snowfall over the last two seasons would be nice to see. 
 

Yea, that was a hair below normal snowfall here. I would take that and run this year.  Funny, a decade ago I would cringe at that season.

[michsnowfreak]

2 hours ago, PhiEaglesfan712 said:

Yeah, it looks like January was the outlier month. At PHL, December and February had 18 in of snow, with March 6 in. Also, the cold continued into the spring, as May 1967 was the coldest May on record by a full degree F.

 

1966-67 was the best winter of the 1960s in the midwest/Great Lakes. From a record snowy November, to the infamous Chicago blizzard Jan 26-27, then a cold/snowy Feb/Mar and a late April snowfall. Jan 1967 was indeed mild, but the record or near record warmth Jan 22-25 likely helped set the stage for the record winter storm Jan 26-27.

[PhiEaglesfan712]

4 minutes ago, bluewave said:

While I don’t know whether it will be correct or not with the more poleward extension of the Aleutian Ridge than the Euro, we did have a pattern like this in 16-17. Very weak La Niña following the super El Niño in 15-16. Not sure if the CANSIPS may be underestimating the trough out West compared to 16-17 if that poleward extension verified.  While it was a mild winter in the East, that poleward extension got us in the game for a better snowfall outcome than the last few seasons. But we have a much stronger -PDO pattern now so not sure if we could do as well in the snowfall department as we did that season. Any improvement in snowfall over the last two seasons would be nice to see. 
 

Assuming a central based la nina, I have 2016-17 as the 3rd analog, after 2007-08 and 1998-99. Here at PHL, it was a blend of both. The winter of 2016-17 was closer to 1998-99, in that it featured a very warm and non-snowy February and a cooler and snowy March, with some snow during the first half of January. Late spring and summer 2017 was closer to 2008, featuring a cool May, warm June and July, and cool August.

[michsnowfreak]

57 minutes ago, 40/70 Benchmark said:

I think that is a decent analog.

2007-08 was a fantastic winter snow-wise. Extremely, extremely active in the Great Lakes region from Dec-Mar.

[snowman19]

21 minutes ago, PhiEaglesfan712 said:

Assuming a central based la nina, I have 2016-17 as the 3rd analog, after 2007-08 and 1998-99. Here at PHL, it was a blend of both. The winter of 2016-17 was closer to 1998-99, in that it featured a very warm and non-snowy February and a cooler and snowy March, with some snow during the first half of January. Late spring and summer 2017 was closer to 2008, featuring a cool May, warm June and July, and cool August.

Those analogs are way better than some of the ones getting hyped on Twitter right now (83-84, 95-96, 10-11, 13-14, 17-18 and 20-21). All one has to do is check the ENSO state and you know the exact analogs certain people are going to pick before it even happens. Just like when there’s an El Niño, you know 57-58, 65-66, 76-77, 77-78, 02-03, 09-10 and 14-15 are coming. Literally every time without fail….

[PhiEaglesfan712]

1 minute ago, snowman19 said:

Those analogs are way better than some of the ones getting hyped on Twitter right now (83-84, 95-96, 10-11, 13-14, 17-18 and 20-21). All one has to do is check the ENSO state and you know the exact analogs certain people are going to pick before it even happens. Just like when there’s an El Niño, you know 57-58, 65-66, 76-77, 77-78, 02-03, 09-10 and 14-15 are coming. Literally every time without fail….

Off the bat, we can remove 83-84 and 95-96 (we don't have a +PDO) and 13-14 (that was a multi-year ENSO neutral state, and we're coming off a strong el nino). I'll keep 10-11 and 20-21 as outside chances, and only if this remains a central based la nina. Both are first year la ninas, and 10-11 is coming off a similar ENSO state as this year (strong el nino). If this year is an east-based la nina, then 10-11 and 20-21 can be thrown in the trash.

Of course, if this becomes an east based la nina, then 17-18 becomes a good analog, as does 21-22.

[GaWx]

1 hour ago, bluewave said:

While I don’t know whether it will be correct or not with the more poleward extension of the Aleutian Ridge into Alaska than the Euro, we did have a pattern like this in 16-17. Very weak La Niña following the super El Niño in 15-16. Not sure if the CANSIPS may be underestimating the trough out West compared to 16-17 if that poleward extension verified.  While it was a mild winter in the East, that poleward extension got us in the game for a better snowfall outcome than the last few seasons. But we have a much stronger -PDO pattern now so not sure if we could do as well in the snowfall department as we did that season. Any improvement in snowfall over the last two seasons would be nice to see. 
 

Aleutian ridge is as you know the opposite of what correlates best to a cold winter in SE US, an Aleutian low. Last year many of us E US folks in the El Niño thread were so excited about all of the forecasts for a mean of a solid Aleutian low. A significantly warmer and drier winter is most likely on the way down here vs last winter’s NN to slightly AN. But winter is still my favorite season! And regardless, there are almost always a few cold snaps.