Another La Nina Incoming for the 2024-2025 Winter

[tron777]

Hello All! I wanted to go ahead and get our annual Early Winter Thoughts thread kicked off. The things that I am watching and noticing right now are as follows:

1) ENSO: We do look to have a La Nina for the upcoming winter. Originally, it looked like a moderate to strong event was incoming, however, unless something changes, it maybe a weak event. That is a good thing should it remain weak. However, the coolest readings maybe central based which is good for an El Nino but not good for a La Nina. If I recall correctly, for a Nina, we want it to be East based with the coolest readings off the South American Coast.

2) A Westerly or +QBO: This is good when paired with a La Nina ENSO event in terms of getting some blocking going and / or a weaker then normal PV. With an El Nino it is opposite, a--QBO or Easterly QBO is better for blocking episodes. So a +QBO for this winter is a good thing.

3) -PDO: This is not good however as the very strongly -PDO looks to continue for the foreseeable future. The marine heatwave over and off the coast of Japan has been ongoing for the last several years and it is continuing to occur this year. In the winter, it has helped to provide a very strong Pacific jet. With the PDO being very negative, we may expect the same thing this winter so a -PNA (trough west, ridge east) could be the end result.

4) High solar - The sunspot count and solar activity of the sun, like last year, continues this year. What impact that has on the PV and high arctic remains to be seen, but typically you'd want low solar activity for better blocking as well as -AO and -NAO periods.

We will have much more to discuss as time goes on. I will post some images to go with this post when I get time probably during the 1st week of August. For now, I just wanted to get the discussion going and to put a bug in everyone's ear. Due to point #3 (the -PDO) I am keeping expectations low for a cold and snowy winter and I am leaning towards a milder winter with below normal snowfall. Obviously, things can and do change in weather and since it is only late July, we have many months to go to see how things evolve.

[tpweather]

Good Morning Les and what took you so long to start the winter talk lol. Mid-summer and though it has not been a scorcher it has been dry in my area. Nothing better than start talking about my favorite season in terms of weather and love the period leading up to winter as well. As we know around here to get a decent winter many things must go our way. Long term predictions have not panned out well in recent years and that is met's and forecasters.

[tron777]

Good Morning Les and what took you so long to start the winter talk lol. Mid-summer and though it has not been a scorcher it has been dry in my area. Nothing better than start talking about my favorite season in terms of weather and love the period leading up to winter as well. As we know around here to get a decent winter many things must go our way. Long term predictions have not panned out well in recent years and that is met's and forecasters.

I started the thread for last winter in early August! So I started it a tad earlier this year just to get the discussion going and to get people thinking about it. The first week of August as I mentioned, I will have much more time to take a deeper dive into the very long term.

[tpweather]

Just wanted to add a few thoughts and again we know things can change and already this summer that has happened. First the expected return of La Nina in mid-summer is know forecast by models to come probably in later September or October and this was a big bust by the models and again long term models are still a 50/50 shot in many cases. With this delay imo the Atlantic Hurricane season will be lower on number than what the models showed earlier this spring. The India monsoon season on the other hand has been very busy and with the current forecast of La Nina the monsoon may go well into September and again India with a huge population this is not bad news.

With La Nina starting later once we head into November and December we may well be in a weak La Nina and usually but not always this bodes well for us in terms of some decent winter weather. Yes other factors that we will not have any way of knowing until we get closer in time but I do like a weak La Nina to help our chances in a decent late November and December to provide some winter weather.

These are some of my early thoughts and my guess is this topics will start to get busy by October and then we will see how we stand and also was the Hurricane season busy or a bust.

[MVWxObserver]

Just wanted to add a few thoughts and again we know things can change and already this summer that has happened. First the expected return of La Nina in mid-summer is know forecast by models to come probably in later September or October and this was a big bust by the models and again long term models are still a 50/50 shot in many cases. With this delay imo the Atlantic Hurricane season will be lower on number than what the models showed earlier this spring. The India monsoon season on the other hand has been very busy and with the current forecast of La Nina the monsoon may go well into September and again India with a huge population this is not bad news.

With La Nina starting later once we head into November and December we may well be in a weak La Nina and usually but not always this bodes well for us in terms of some decent winter weather. Yes other factors that we will not have any way of knowing until we get closer in time but I do like a weak La Nina to help our chances in a decent late November and December to provide some winter weather.

These are some of my early thoughts and my guess is this topics will start to get busy by October and then we will see how we stand and also was the Hurricane season busy or a bust.

The one thing about an active monsoon season in an overall impoverished India is on the flip side, horrific flooding often.

[tpweather]

Hey Eric, hope you and your family are doing well. You are correct about the flooding and poverty is so much a part of life in India and many folks end up in the areas where it floods every year and they don't have the income to get away from that area. So yes that they are getting rain but for many folks this means flooding.

[airwolf76]

my early thoughts at this point are for a weak to moderate La Nina for most of the winter and I am thinking we will see average to below avg temps. no idea on snowfall yet. I am more concerned with the upcoming fall then I am with winter

[tron777]

As I mentioned before, I'll be able to hopefully post a little more in this thread next week but for now, the -PDO on steroids along with the record breaking heat wave in Japan (yet again) leads me to believe that we'll have a mild winter again this season. Would love to see these things change but for now, it's hard to go against the trends of the past several winters. Additionally, this does promote MJO forcing in phases 4-6 which in the winter time, are death phases for cold and snow lovers in the Eastern US.

[tpweather]

As I mentioned before, I'll be able to hopefully post a little more in this thread next week but for now, the -PDO on steroids along with the record breaking heat wave in Japan (yet again) leads me to believe that we'll have a mild winter again this season. Would love to see these things change but for now, it's hard to go against the trends of the past several winters. Additionally, this does promote MJO forcing in phases 4-6 which in the winter time, are death phases for cold and snow lovers in the Eastern US.

No doubt the underwater volcano's are heating up Japan and other places along the coasts of Asia,South and North America. We still have very little knowledge of the oceans and my guess over the next several years that will be a big part of forecasting

[tron777]

It looks like we'll have a strongly westerly QBO for winter with the July reading coming in at +12.68. The QBO just turned positive in June so this is a big increase. Also of note... there continues to be big time high pressure over the South Pole with numerous SSW events occurring over the Antarctic. I came across an article that suggests that our weather in the months to come can be effected with colder then normal Central and Eastern Us winters possible along with lower pressures over Canada and the US in winter.

Link to the article:

https://www.severe-weather.eu/long-rang ... europe-fa/

Also per Ben Noll:

Due to the ongoing minor sudden stratospheric warming event, the Antarctic Oscillation / Southern Annular Mode (SAM) has dipped to -3.4σ, the lowest July value since July 2011. Only seven Julys since 1979 featured lower values of the SAM than 2024: 2011, 2007, 2001, 1995, 1992

I would take all of this with a grain of salt since it is only August mind you, but I did find the information interesting.

[tpweather]

Great info Les and yes record high temps were recorded in that region as the cold spread northward. I have not heard of many SSW events over the years and sure I have missed some but this one no doubt was huge.

[tron777]

Great info Les and yes record high temps were recorded in that region as the cold spread northward. I have not heard of many SSW events over the years and sure I have missed some but this one no doubt was huge.

I'm still going warm for this winter due to the persistent Marine Heatwave and -PDO as well as high solar activity. However, the lack of La Nina getting its act together and the SSW events over the South Pole may help to counteract some of the warm signals I am seeing. What I mean is... it should not be a wall to wall mild winter. Maybe we can get a month in there with some good blocking periods. One thing I am gaining confidence on is that Canada will be cold. I'm also not expecting a +WPO / +EPO either that we've seen the past several winters. If we can manage a -WPO, periods of -EPO should follow. Maybe a modified version of 2013-2014.

[tron777]

Below is the Euro Seasonal avg. 500 MB pattern for DJF from the August run. It's a typical La Nina pattern and the same pattern we've been in for the last several winters, esp when we had the triple dip La Nina. When the models go cold, then we asre warm. When they go warm, maybe we turn cold?

IMG_0712.png.e9cdd724d9bb7a5f8ba25051c260ec3f.png

[tpweather]

Below is the Euro Seasonal avg. 500 MB pattern for DJF from the August run. It's a typical La Nina pattern and the same pattern we've been in for the last several winters, esp when we had the triple dip La Nina. When the models go cold, then we asre warm. When they go warm, maybe we turn cold?


IMG_0712.png.e9cdd724d9bb7a5f8ba25051c260ec3f.png

Yes the whole earth except for the south pole is warm. We know that is incorrect of course

[tron777]

Below is the Euro Seasonal avg. 500 MB pattern for DJF from the August run. It's a typical La Nina pattern and the same pattern we've been in for the last several winters, esp when we had the triple dip La Nina. When the models go cold, then we asre warm. When they go warm, maybe we turn cold?


IMG_0712.png.e9cdd724d9bb7a5f8ba25051c260ec3f.png

Yes the whole earth except for the south pole is warm. We know that is incorrect of course

True Tim, but the Aleutian Ridge is classic La Nina and it does fit with the very warm SST's out that way.

ssta.daily.current.png

None of this really matters since it is early August but the weather locally is boring so I have to find something to talk about.

[tron777]

The extremely -PDO is a big reason why I am going mild for the upcoming winter. We just had the lowest -PDO June and July since 1950 at -3.16 and -2.97. The -PDO has been relentless!

https://www.ncei.noaa.gov/pub/data/cmb/ ... v5.pdo.dat

[tron777]

The Farmer's Almanac's entertaining winter forecast is now out. For us, it says "cold, wet, and white." You can read the entertaining article here:

https://www.farmersalmanac.com/extended-forecast

FarmersAlmanac.png

[tron777]

A few thoughts this morning....

La Nina continues to struggle. Per the TAO maps below, you can see some cooler waters but they are still subsurface. The surface itself is warm to neutral. As long as that continues, we will either see a cold ENSO neutral winter or a weak La Nina in my opinion.

TAO Maps.gif

Per the SST anomaly map below, the Japanese heat wave continues with no end in sight. Just like last year. This is the result of a record setting and extremely -PDO again. This is a big reason why it is hard for me to go cold for the upcoming winter. Although, this summer was supposed to be hot and dry. It has had hot and dry stretches but the last blast of Sept air and the next one coming in... was completely unexpected. So this La Nina has not yet influenced the pattern. It could be the result of last year's El Nino so it's a hangover effect if you will. It'll be interesting to see how the Fall plays out to see if these cool shots continue or not.

ssta.daily.current.png

Here is the PDO data and you can go here and click on the blue view data button to see it for yourself.

https://www.ncei.noaa.gov/access/monitoring/pdo/

I took a screen of it for you going back to Sept of last year just so you can see how severely negative it is. Again, this is by biggest worry for the upcoming winter. I don't see it changing anytime soon.

PDO.png

I have two positives though. The La Nina so far is not gaining steam and the QBO will be Westerly or positive so that's a good combination to have. Below is the QBO plot for you to look at which can be seen here:


https://acd-ext.gsfc.nasa.gov/Data_serv ... o_plot.png

qbo_plot.png

So drink some coffee, read this post a time or two and let's see what you all think. Thanks!

[tpweather]

Les thanks for all the updates on La Nina. I believe on this forum we warned about the models rushing the La Nina and I believe we were correct. Sometimes these models will get a month that in this case shows the cooling but its a quick shot and one that does not last. A smoother ride into a La Nina imo is the best way for us to get a decent winter and like you mentioned the QBO is in our favor this month. Again way too early for a winter forecast and won't start that until October or so but the summer for us locally has been a bust for the models and many met's and forecasters. I still believe the warmer waters especially around Japan has much to do with underwater Volcano's. This is something that is not studied but imo makes so much sense. Volcano's on land and especially in the northern regions of earth can cool us down for a period of time because of the ash,smoke and whatever you want to call it does block out some of the suns rays. Volcano's under the ocean though will send the heat up to the surface of the ocean but it does not go any further and where they are located just boils the water and yes the oceans have so much influence on weather patterns around the world.

[tron777]

Thanks Tim! I also believe the Japan heat wave is a by product of the severely -PDO that we're in too. With regards to volcanic eruption back in 2022 with Hunga Tonga, this is all new to us as well as scientists so we are all learning as we go there with regards to impacts. A lot of the water vapor was injected into the stratosphere so that certainly could have been one contributing factor to the string of mild winters in addition to ENSO, IOD, -PDO, etc etc. Having high solar activity isn't helping either.

[tron777]

ENSO 3.4 is starting to cool some now but it still doesn't look to get out of hand. This winter might be the first season in a while where the ENSO state is neutral or weak at the worst. I think this winter the ENSO state will be cool neutral or a weak Nina at best. That is good news IMO for a change. However, the severely -PDO and -IOD are still pause for concern with regards to a -PNA pattern taking place and the dreaded SE ridge. The -IOD may act to keep the MJO in the dreaded phases 4-6 (Maritime forcing) which is death for winter lovers in the East. The last several winters, the MJO has had a difficult time getting into phases 8, 1, and 2. This is caused by the ENSO 4 region (West Pac) in other words being cool. The tropical convection hits it and it's like a brick wall lol We'll see though... wit the ENSO state staying on the weaker ide, maybe this winter could have a different outcome then what we've seen previously. You never know. Lots of time to watch. I will keep my thoughts on the milder side for now based on reasons that I continue to post about. I have no trouble changing my call should conditions warrant. It'll be interesting to see how the Fall goes to see if we get any clues about the upcoming winter. One thing that may happen is an early start and this is due to the ENSO state being weak. Could we get a decent December for a change? That would be nice.

[Bgoney]

3.4 region only down to - 0.2c . So the expectation from AV of cool neutral/to possibly weak sst remains on track

[tron777]

3.4 region only down to - 0.2c . So the expectation from AV of cool neutral/to possibly weak sst remains on track

I know I have posted a lot of "doom and gloom" with regards to the potential of having a mild winter largely due to the insanely -PDO. However, something else that is important to note is the WPO. It has been positive the last few winters. CFS and CAN SIPS have a colder look this winter and it is because they are projecting the -WPO to be more negative. This would imply that the North Pacific high is more poleward in the Aleutians versus being more flat allowing the trough to dig into the West. If the ridge is more poleward, then we can get bouts of -EPO which would help with getting cold air into the Eastern US. So in short, we need to keep an eye on the WPO to see how it responds as we go deeper into the Fall season.

[tron777]

An interesting article talking about SSW events over the South Pole! I wish I was smart enough to know if this would impact our weather this winter in North America? We see SSW events on avg once a year over the Arctic. The Antarctic about once every 5 years. There have been two so far. One in July and another in August.

https://www.wdrb.com/weather/wdrb-weath ... EXS-PF9Bmw

[tron777]

JMA's first call for the winter.

https://ds.data.jma.go.jp/tcc/tcc/produ ... pztmap.php

Also... from Meteo France:

C3S.png