PhiEaglesfan712

Maybe some activity in the Atlantic:

I was not expecting the subsurface to look like that, especially after 3 years of mostly el nino. I would have thought there would be a strong cold layer below it. Amazing to think that a strong la nina could develop with this subsurface.

The 1954 one may have been a weak la nina the first year, but it eventually peaked as a strong la nina in the second (1955-56). That transition was years in the making. The preceding el nino technically peaked as a moderate in 1951-52, before becoming disjointed in 1952-54. I wonder what the subsurface looked like in summer 1954, and if it had that cool pool that is present in both 2007 and this summer.

Moderate el ninos (+1 to +1.4C) seem to be the sweet spot for cold/snow. 76-77, 77-78, and 02-03 are very good examples. The only one that really didn't work out was 94-95, and even then, we got one decent month of cold/snow in February out of it. I got to think we're well overdue for a moderate el nino. We haven't had one since 02-03.

I mean, if you looked at the subsurface, it was pretty obvious that a full-fledged la nina was developing. We're going to reach the strong la nina threshold at some point between the fall/winter 2024-25 and fall/winter 2025-26. I'll be absolutely shocked if 2024-25 and 2025-26 aren't both la ninas.

2020-21 was more a one-month winter (February), and even then it was hit or miss. If you really think about it, it was a reversal of 2017-18 (which had that outlier warm February). Those north and west of Philly really got hammered, but it was a non-existent winter south and east, especially in places like ACY. In fact, ACY got hammered worse in 2021-22 (another one-month winter, January) than in 2020-21.

And it really wasn't a true ENSO neutral season. One could argue it was a weak el nino, since we were at 0.5 for more than 3 trimonthlies. 2018-20 was more of a disjointed el nino like 1952-54. (Oddly enough, both were followed by a triple la nina [1954-57 and 2020-23] then a strong el nino [1957-58 and 2023-24].) FWIW, 1958-59 was a weak el nino, but I don't think we're getting that in 2024-25. The last true ENSO neutral season was 2013-14, which was a blockbuster winter. However, ENSO neutrals are hit or miss. For every cold/snowy winter (2003-04 and 2013-14), there's a warm winter (2001-02 and 2012-13) that balances it out. That said, the chances of an ENSO neutral season the next 2 years are very low. The subsurface is screaming la nina in 2024-25 and 2025-26. Maybe we'll get an ENSO neutral season in 2026-27. Moderate el ninos (76-77, 77-78, and 02-03, for example) seem to be more favorable for snow than ENSO neutrals. We haven't had one since 02-03, which is now over 20 years ago, so we're overdue.

I got to think the cold pocket eventually has to bubble up to the surface. Like in 2007-08. I'm almost certain 2024-25 and 2025-26 are going to be la nina seasons, with at least one being a strong la nina. After that, it's too early to tell what will come next. All options are open for 2026-27 (3rd year la nina, ENSO neutral, el nino).

Yeah, I got to think that pocket of cold in the subsurface has to bubble up to the surface at some point, whether it be 2024-25 or 2025-26. We might even have the anti-86/87 scenario, where a strong la nina peaks in the summer/early fall 2025. (Though, I don't expect a quick flip to super el nino right after, like the 88-89 la nina followed the 86-88 el nino.)

At some point, it's time to let go of the hyperactive hurricane season forecast. If there was truly going to be one, like in 2005 or 2020, we wouldn't be stuck in this extended lull, and outside of Beryl, we've been quiet for much of the season. 2005 got the late start like this year, but it was active for 4-5 months straight.

Probably not going to happen, but anti-86/87 would be a really fun next 3 years. We'd be getting a strong la nina that peaks in the summer/early fall 2025, followed by super el nino in 2026-27 (the anti-88/89). That would be unprecedented, so I expect the anti-86/87 analog to fall apart within 3 years. Or if the super el nino still forms, there would be an ENSO neutral season or two first (following the 2024-26 la nina). The anti-76/77 analog does better in the long run. We'd be getting record warm winters and cooler springs here at PHL the next 3 years. 77-78 is pretty much the same setup as 76-77 (which we would be getting in 2024-25 and 2025-26), and anti-78/79 is pretty much 2019-20 (which we would be getting in 2026-27), before a weak la nina in 2027-28.

By the way, here's the mid-July IRI plot:

2007-08 is a really good analog at this point. Just look at the subsurface.

Yeah, if there was a winter that was cooked in November, it was 2011-12. We got the famous storm in October, and the pattern just suddenly flipped after that. The warmth continued well after the 'winter', with extreme above average temperatures especially in March, May, and July.

We've had colder days than Valentine's Day 2016 (20/8) at PHL. There was the prolonged arctic outbreak of late Dec 2017/first week of Jan 2018 (16/7 on the 6th and 19/4 on the 7th), as well as 1/31/2019 (18/5). Even the flash event of Christmas Eve 2022 (18/7) was colder than Valentine's Day 2016.

Come to think of it, the closest thing to 18-19 and 19-20 was the disjointed el nino of 52-53/53-54. In fact, the last 6 years closely resemble 52-53 through 57-58. You got the disjointed el nino (52-54, 18-20) followed by a triple la nina (54-57, 20-23), and a strong el nino (57-58, 23-24). I just realized that 64-65 was the only la nina of the 1960s. If not for that, we would have 13 years between la ninas (from the dissipation of the triple la nina in 57 until the 70-71 la nina). Despite the lack of la ninas, PHL had stretch of cold and snowy winters during this time. The only other time we followed a triple la nina with an el nino was in 76. Like after 57, there was a stretch of a lack of la ninas. The next one would be in 83-84 (which would continue into 84-85), after a failed la nina in summer 78. Like with the 60s, 76-77 through 82-83 produced some historically cold and snowy winters at PHL. Heck, even the la nina winters (Jan 84 and Jan 85) produced historical cold, something we've only seen one time since (1/19/94).

Common theme with those cold winters were a lot of ENSO neutral (78-79, 03-04, 13-14), weak el ninos (04-05, 14-15), and moderate el ninos (76-77, 77-78, 02-03). Also interesting to note that each one of those la nina blocks had a strong (09-10) or super el nino (72-73 and 97-98) in between.

I wonder how much this map changes if we considered 51-52 through 58-59 a 5/8 el nino, and included the years 59-60, 60-61, and 61-62. Those were some cold and snowy winters here at PHL based on my spreadsheet.

The top one turned into a strong la nina, while the bottom one stayed a weak la nina, and we can see why. From the animation, 2024 looks closer to 2007. I see a pocket of cool in both years (-3 and -4), while 2017 doesn't even have a -2.

I disagree about 17-18. We were coming off a near record warm October. 21-22 almost felt the same as 17-18 (both followed an extremely warm October with a normal November). Warm Octobers don't normally produce blockbuster winters. Funny how 17-18 got ended up getting the one warm month (February) that skewed the winter, while 21-22 ended up getting the one cool (and snowy in some locations) month (January) that skewed the winter. I felt that 18-19 had a better set up for cold and snow than 17-18. We even got a snowstorm in mid-November 2018.

The extremely warm February really skewed the winter of 17-18. The months surrounding it (December, January, March, and April) were all well below average temperaturewise.

Yep, any chance of a hyperactive season is pretty much over. 7 days takes us to July 22, and despite Beryl, we've still only had 3 systems. We're not only well behind the pace of 2020 and 2021, we're even behind last year's pace as well. This is looking more like a 2007-type season than a hyperactive one.

Dec 1989 was a historically cold month in the East, then all of a sudden the pattern changed. The rest of the winter was well above average temperaturewise. At PHL, Jan 1990 was 15 degrees warmer than Dec 1989. That's one of the strangest temperature oddities ever. It was another one of the unicorn winters (like 2019-20 and 1978-79), which was a very weak la nina (really a carry over from the previous year's strong la nina) in the fall that dissipated to an ENSO neutral as we went to winter. Now, watch how the pattern flips in January 1990:

This is more like 1996. A cloudy day and there was rain, but there was a window when you could do outdoor activity. It really came down at night and the next day as Bertha came in. 2004 was heavy rain all day.

Looks like we're in for a rainstorm: The last time it rained on my birthday was in 2013. And who could forget about the historical July 12, 2004 event, which was my 16th birthday. Hard to believe that was 20 years ago already.