PhiEaglesfan712

I feel that an active season is more likely if after the 2nd year of a la nina, we get a neutral, rather than a 3rd year la nina. None of the 3rd year la nina seasons (1956, 1975, 2000, or 2022) were particularly active. Meanwhile, 2012 (a neutral season) was just as active as 2010 and 2011. First year la ninas are either hit or miss. Years like 2005 and 2020 were hyperactive and 2010 active, but years like 1970, 1973, 1988, and 2007 were not really big seasons. Second year la ninas seem to be the sweet spot, like 1999, 2008, 2011, and 2021. Next year, assuming the la nina continues (which is a high chance given the -PDO), is probably going to be the active season.

Maybe we could carve out a 1998-99 type season. That was a very warm first 3 weeks of December. We got most of our snow from Dec 23 to mid-January. We got no snow and it was warm until the 3rd week of March, which produced one more snow event.

If we go by the MEI, which has 2023-24 as a weak el nino, then 2007-08 is the closest match. Next best would be 2020-21. I guess our best hope is the la nina goes east-based. Then maybe we could squeeze out a 2021-22 or even 2017-18 type winter.

Euro hinting at a cooler beginning, but a warm end, to September:

My top analog years: 1998: 4 named storms by Aug. 30 (14 total named storms) 2007: 5 named storms by Aug. 30 (15 total named storms)

The cold winters of 2014 and 2015: The rest of 2015 was warm, especially May, November, and December:

If we're talking about 2013-14, then that one tipped its hand in July with the ridge building in the PNW. I mean, we got a big flip in the temperature pattern midway through the summer. The change in PDO pretty much sealed the deal. If we're talking about 2014-15, well that was just a continuation of the +PDO/PNW ridge. JFM 2014 and 2015 were the coldest this side of 1980. Even the summer of 2014 was cooler than average (the coldest since 2010, though some places were cooler last summer). The PNW ridge finally subsided in spring 2015 (which is why we got a very warm May here, and a cold May in most of the West).

13-14 and 14-15 were more straightforward to me than 17-18. In 17-18, the record warm October threw me off. That one and a record warm February really skewed things.

2021-22 analog if 2024-25 turns to an east-based la nina: As you can see, the classic one cold month and the rest warm in the Eastern US.

For 13-14, the pattern changed long before Sept/Oct. I think it changed some time in mid-July. I've never seen a summer all of a sudden turn from hot to cold in the middle like that one. But that was a very wet summer from start to finish. Of course, that was a sign of things to come.

Didn't Felix (Cat 5) also develop in that window? I believe it was Aug 31.

Don't worry, 2022 is very low on my list. I have years like 1998 and 2007 very high up (and you can possibly talk me into 2016). Not the best for winter weather in the mid-Atlantic, but could be very good for the Midwest and New England. What we have here is a developing first year la nina with a very cold subsurface. 1998, 2007, and 2016 all have those characteristics. We don't have that in 2022. That was a dissipating la nina, which peaked moderate early in the season (and in fact, you could argue was a carry over from the previous season). [I mean, in hindsight, it was easy to see coming with the very warm subsurface in summer 2022.] Now, here's the wrinkle: If the la nina peaks late into the season and turns more east based, then 2021-22 is going to look like a very good analog in hindsight. (I can see the late peak and carry over into 2025-26, but don't see an east based la nina right now.)

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.

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.]

August 2024 IRI update:

I wonder if the MEI has a cold bias since 2021-22. It shows 2023-24 (a consensus strong el nino) with about the same strength as 2006-07 (a weak el nino). Also, 2021-22 and 2022-23 are shown as super la ninas, even though they were only moderate la ninas in the ONI. But if we use the MEI, then 2007-08 is a perfect analog, lol.

So why did 2008-09 work out and produce a decent winter, but not 2022-23? Was it a timing issue or is there something more to it?

2008-09 was essentially 2022-23 if it had panned out:

Other than the -PDO, I really don't see the similarities with 2022. I've settled on 1998 and 2007 being the best fit years, with maybe 2016 as the 3rd analog. This is an el nino -> la nina transitioning year, with a very cold subsurface. I just can't get passed how far apart the subsurface pictures of 2022 and 2024 (it's almost as if they're anti-logs off each other):

Most of 2013-15 didn't really have an ENSO signal. The full-fledged el nino really started to develop in early 2015. So why were those winters blockbusters? Was it the +PDO?

Okay, so next time a 2022-23 pattern comes along, I just have to hope for -AO in September then. This would mean a very warm October and November, but at least we'll get a decent winter. That said, I don't like 2022-23 as an analog for this winter. That one was a ready made la nina that peaked early, dissipated during the winter, and had a warm subsurface. We have the opposite of that here. If I was using an analog year from that triple la nina group, I'd use 2020-21 instead (and even that one isn't the best).

It depends on the context, but the one thing you can rule out is the emergence of a strong/super el nino (these will only form if the subsurface has been warm for several years). If the prior pattern is a la nina, I'd think almost certainly the momentum from that pattern would continue into the following year. There are even some la ninas that continue when the subsurface turns warm. Although if an el nino somehow came from this, I'd think it would be weak because there is no warm water in the subsurface to support a full-fledged el nino.

Not everyone got screwed. The midwest got a good November/December and March/April out of this. Timing is what screwed it up on the East coast. When you break 2022-23 down into 2-month blocks, it gets very interesting. If only May/June was January/February instead.

The way the last week of April, and all of May and June were cold shows that the 2022-23 set-up can work. However, the pattern that came on in March needs to be in place 3-4 months earlier (in November or December) to work. The potential is there for snow with a cold January/February or February/March. We're not going to get snow with a cold May/June.

The CFS is now showing a cold September, as well as a cool autumn: