PhiEaglesfan712

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.

I found the plume from July 2007, a year that developed into a strong la nina: Needless to say, most of the models got this one wrong. Some of the models even predicted a weak el nino, lol.

FWIW, 1976-77, 1995-96, and 2013-14 were 4th years following strong el ninos that produced cold and/or snowy winters, while 1977-78, 2002-03, and 2014-15 were 5th years following strong el ninos that produced cold and/or snowy winters. If there is a blockbuster winter coming up, 2027-28 and/or 2028-29 might be the sweet spot.

I'd argue that the +PDO in 95-96 was part of the secular +PDO period that started in mid-76 (when the multi-year la nina ended) and ended in mid-98 (when the 97-98 super el nino dissipated). I'd consider 98-99 as a change point winter, when we went from +PDO to -PDO, rather than 95-96. The historically strong la nina of 88-89 was really the only time between 76 and 98 when we had a sustained -PDO (kind of like how the 14-16 el nino is the only time we've seen sustained +PDO since 98). That time was predominated by el ninos, especially the strong events of 82-83, 86-88, 91-92, and 97-98.

I wouldn't put 86-87 on that list, unless you mean that 88 was the transition year. There was no cooling in June 87, as the el nino continued into 87-88, before dissipating in early 88 and producing a historically strong la nina in 88-89. That said, I'd consider the 86-88 event to be strong, since we reached over +1.5 on both the ONI and RONI. Same with 09-10, which also produced a strong la nina the following year. 02-03 didn't produce a la nina the following year. 03-04 was ENSO neutral. 91-92 didn't really cool. We didn't even get a la nina in 92-93 or 93-94. I wonder if the eruption of Mount Pinatubo affected this one. That's the only strong el nino event that wasn't followed by a la nina since 72-73.

All is not lost with the 2022-23 setup. We just need the exact pattern that was in place from March-June 2023 to be there 3 months earlier. I keep thinking what if that rainstorm in late April happened in late January/early February or if that blocking pattern that was in place in June was there in March.

If we are still stuck in -PDO, then I expect 2025-26 to be a moderate or strong la nina. I see no possible way 2025-26 being an el nino unless we shift to a +PDO. There's no way we get 2 significant el ninos in 3 years in -PDO.

I still think it's too early to rule out strong la nina. The AMJ 2024 NOAA ONI of 0.4 is still in line with the 1988 (-3 months) and 1998 analogs. 1988 (-3 months): JFM (0.5 NOAA, 0.3 ENS) 1998: AMJ (0.5 NOAA, 0.3 ENS) FWIW, the next 3 months for each analog 1988: FMA (0.1 NOAA, 0 ENS), MAM (-0.3 NOAA, -0.5 ENS), AMJ (-0.9 NOAA, -1.0 ENS) 1998: MJJ (-0.1 NOAA, -0.4 ENS), JJA (-0.8 NOAA, -1.1 ENS), JAS (-1.1 NOAA, -1.2 ENS) As you can see, those la ninas really got going over the next 3 months. Note: This is assuming the ENS ONI numbers are in line with the NOAA. (Eric Webb hasn't updated since DJF 2023-24.) If the ENS numbers are warmer than what the NOAA is reporting, then we can bury the thought of 2024-25 being a strong la nina. If the ENS numbers are colder than what the NOAA is reporting, then I'm more confident 2024-25 will be a strong la nina.

Was the January 22-23, 2016 snowstorm in MJO 8 or MJO 1?

Was 2023-24 a MJO 4-6?

I definitely agree with the strong el nino -> la nina trend. Every one since 1973 has gone that way except 1992, which was probably altered by Mount Pinatubo. But what about the MJO states during those strong el nino years?

For curiousity, what was 2009-10 and 2023-24? And if data was available, 1997-98?

Yes, you are correct. In fact, we even had an el nino continue in 1958-59 (following the 1957-58 strong el nino). Years after strong/super el nino 1958-59: Weak el nino (followed by 4 years of ENSO neutral) 1966-67: ENSO neutral 1973-74: Strong la nina 1983-84: Weak la nina 1988-89: Strong la nina 1992-93: ENSO neutral 1998-99: Strong la nina 2010-11: Strong la nina 2016-17: Weak la nina It looks like every strong/super el nino since 1973 has transitioned into a la nina (4 of them strong), with the exception of 1992 (and that was likely altered by the eruption of Mount Pinatubo). So, if we go ENSO neutral, it would buck a 50+ year trend.

2014-15 here at PHL. It would have been 2017-18, but a near record warm February skewed it.