PhiEaglesfan712

1992-93 and 1993-94 were good seasons as well. 1993 had the famous blizzard in mid-March and 1994 had a cold wave in January as well as above average snow in February.

Regarding the 2009-10 snow season, I know there was a strong el nino and that likely contributed to record snow in the Mid-Atlantic, but why did the snow come to an abrupt end in places like Washington DC and Baltimore after the February 9-10 snowstorm?

The crazy part about that 50 inches of snow in February 2010 is that almost all of it took place during the first 10 days of the month, with a tenth of an inch of snow on the 15th, and then the snow just suddenly stopped for the season. At that point in the season, Baltimore had more snow than Syracuse (and any other city) in the Golden Snow Globe contest in 2009-10: https://goldensnowglobe.com/baltimore-storms-past-syracuse-for-the-lead/ https://goldensnowglobe.com/stwc-vol-2-update/ Baltimore was passed by Syracuse on Valentine's Day and never looked back: https://goldensnowglobe.com/stwc-vol-2-outcome/ 50 inches of snow in 10 days and 80 inches of snow is something that will almost likely never happen again in Baltimore.

Even 2020-21 and 2021-22 were one month winters (February 2021 and January 2022) that were hit and miss here in the Philly viewing area. The early February 2021 snowstorm was a blockbuster to the north and west (not so much in the south and east), while the late January 2022 snowstorm was a blockbuster to the south and east (not so much north and west). PHL topped out at about 7.5 inches on both storms. There hasn't been a true blockbuster storm for the whole Philly viewing area since January 2016.

I highly doubt we're going to have a JFM colder than 2015 any time soon. Didn't JFM 2015 set a record for the coldest JFM in the Eastern US?

I think it was more of a case where the pattern formed way too late in the season for anything to really happen. Had that pattern formed in late December 2022 instead, we would have gotten a very cold February and March 2023, as seen by the blocking pattern we got in June 2023. That late April rainstorm would have been a big blizzard in early February, followed by a dry cold pattern most of February and the first half of March, and exited that with another snowstorm near the spring equinox. (Remember the record cold highs around the summer solstice last year. Now imagine how cold that would have been if that was late March instead.)

2016-17 wasn't enso neutral. It was a weak la nina. We had the 5 trimonthlys of -0.5 on the NOAA ONI, and got down to -0.7 on both the Eric Webb Ensemble and NOAA ONI. We even got down to -1.09 on the RONI. 2014-15 has a better argument for enso neutral than 2016-17. That one had the same strength as 2016-17 on the ONI, and only 0.58 on the RONI. So, the only ones that can be considered enso neutral are 2001-02, 2003-04, 2012-13, 2013-14, and maybe 2019-20 (an ENSO neutral on the RONI, but you could argue a continuation of a weak el nino on the ONI that began in 2018).

It was just too late in the season. However, we did get a nice blocking pattern in June (who could forget about the smoke out). June 2023 was the coldest June since 1985. Would have been nice if we had -NAO and -EPO in late December or even early February.

I know 2024-25 is not likely going to be an ENSO neutral season (we haven't really had a true one since 2013-14), but I've noticed that since 1950, we've pretty much come out of every ENSO neutral phase with an el nino, and never a la nina. (If you don't count 2019-20 as an ENSO neutral season, in which a stubborn weak el nino refused to dissipate, then the last time we exited an ENSO neutral phase with a la nina was in 1949.) Is there a reason why ENSO neutral phases generally lead to el ninos, or is this just a coincidence?

I'm not sure if it's a shift to summer because the Northeast Pacific blocking pattern was there in the summers of 2014 and 2015, maybe even late summer 2013. The onset was about the same for both seasons (2013 or 2014), it's just that the pattern never seems to be in place in the winter after 2015. The most amazing thing about this 10+ year Northeast Pacific summer blocking pattern is that the only summers here in the Eastern US that were below average were 2014 and 2023. Oddly enough, both of those years were pre-nino summers. 2016 and 2020, the post-nino summers, were well above average (only trailing 2022). Those three summers were among the warmest ever in many places in the Eastern US. As for 2019-20, that was one of the weirdest years ever. There was a stubborn weak el nino that just refused to dissipate. It didn't until fully until the spring.

That RONI plot is just a combination of the 2010-11 and 1998-99 peaks. I used the 2010 analog through OND, and then changed to 1998-99 starting with NDJ. I'm not so sure we even hit the 2010-11 peak of -1.7 now that we've fallen behind the pace. The ONI is just 1988 shifted 3 months until OND, then change to 1998-99 starting with NDJ.

My prediction for 2024-25 ONI & RONI: AMJ 2024 ONI: +0.3; RONI: -0.45 MJJ 2024 ONI: 0.0; RONI: -0.87 JJA 2024 ONI: -0.5; RONI: -1.17 JAS 2024 ONI: -1.0; RONI: -1.42 ASO 2024 ONI: -1.4; RONI: -1.61 SON 2024 ONI: -1.5; RONI: -1.70 OND 2024 ONI: -1.4; RONI: -1.70 NDJ 2024-25 ONI: -1.4; RONI: -1.65 DJF 2024-25 ONI: -1.3; RONI: -1.53 JFM 2025 ONI: -1.1; RONI: -1.24 FMA 2025 ONI: -0.9; RONI: -1.00

MAM ONI (NOAA): + 0.7C Best analog: 1988 (-3 months) JJA 1987: +1.6 -> SON 2023: +1.6 JAS 1987: +1.7 -> OND 2023: +1.7 ASO 1987: +1.8 -> NDJ 2023-24: +1.8 SON 1987: +1.7 -> DJF 2023-24: +1.7 OND 1987: +1.4 -> JFM 2024: +1.5 (NOAA) NDJ 1987-88: +1.1 -> FMA 2024: +1.1 (NOAA) DJF 1987-88: +0.7 -> MAM 2024: +0.7 (NOAA) MAM RONI: + 0.11C Best analog: 2010 NDJ 2009 1.57 DJF 2010 1.45 JFM 2010 1.09 FMA 2010 0.62 MAM 2010 0.07 NDJ 2023 1.47 DJF 2024 1.21 JFM 2024 0.86 FMA 2024 0.48 MAM 2024 0.11

I figured that it would be performing ahead of 1998 at this time, as that was a stronger nino that dissipated later. However, the fact that it is performing ahead of 2010 suggests this is going to be a strong la nina. Remember, the 2009-10 el nino peaked lower than 2023-24 (at least on the ONI).

Spring 2024 at PHL ends up at 57.1F, which replaces Spring 2022 as the 6th warmest spring on record. It also brings up the average spring temps for the 2020s to 55.69F, which pushes it past the 2010s: 1890s - 51.84 1900s - 52.51 1910s - 52.98 1920s - 53.23 1930s - 53.18 1940s - 52.81 1950s - 52.83 1960s - 51.31 1970s - 53.16 1980s - 52.89 1990s - 53.85 2000s - 54.17 2010s - 55.38 2020s - 55.69 (through 2024)

Don't forget that the El Nino (which started in 1986) dissipated much earlier in 1988 than this year. The extra 3 months allowed the 1988-89 to develop into that strength. The La Nina strength was already at -1.4 by MJJ in 1988 and hovered in that -1.4/-1.5 range until ASO, before deepening in strength. If we shift that 3 months forward, then we'd be getting into the -1.4 in ASO, and hover around there through NDJ, but by this point, most La Ninas have reached their peaks. It's going to be interesting to see if the RONI converges back towards the ONI. If not, the 1973-74 and 1988-89 values for the RONI could be breached. My guess is that 2024-25 ends up being a moderate la nina on the NOAA ONI (not meeting the criteria of 3-trimonthlys of -1.5C), and a strong la nina on the Eric Webb Ensemble ONI.

I still like the 1988 (-3 months) analog on the ONI until NDJ 2024-25. I think we're going to peak at -1.4 or -1.5C in ASO 2024 through NDJ 2024-25.

It's possible. The storm just needs to continue with its slight north trajectory. This is the current radar:

I get the feeling 2024-25 is going to be a below average temperature winter. We are just well overdue for one. The last one that came below normal was at PHL was in 2014-15, which is going to be ten years ago. We came close in 2017-18 (the first half of that winter was very cold), but February was well above average, pushing that winter to an above average temperature finish.

1975-76 was the opposite of this year. That one was considered a strong la nina by the NOAA ONI (peaked at -1.7), while the RONI only peaked at -1.14 1976 clearly marked the transion from a la nina state (which began in 1949-50) to an el nino state. The question is whether this current la nina state started in 1998, 2005, or 2007. If it started in 1998, then the la nina state should be coming to an end soon. If in 2007, we might have another decade before we transition back into an el nino state.

I was in grade school when Windows 95 and 98 came out. That was peak Microsoft.

For starters, I think we can throw out 1949-50. That one came after several enso neutral seasons (1946-47 is the only one in the previous 5 years that resembled an el nino, but that was very weak and very short). 1949-50 is the last first year la nina that didn't result from an el nino transition. I don't like the 2020-21 analog either. The preceding el nino (which started in 2018) was weak, and 2019-20 was a unicorn season that hovered around 0.4 or 0.5 until it dissipated (this hasn't happened in over 75; the aforementioned 1946-47 comes the closest). 1970-71 and 2007-08 can be okay analogs. The only thing is the el nino of those preceding years was weak. I guess 1970-71 could pass if you consider the first year of the preceding el nino (1968-69) was moderate. This leaves 1998-99 and 2010-11 as the best of the six analogs on the list. I'd replace 1949-50 and 2020-21 with 1973-74 and 1988-89. My list of six best analogs, at this point, would be 1970-71, 1973-74, 1988-89, 1998-99, 2007-08, and 2010-11.