raindancewx

We're still running neck and neck with the great El Nino of 2017. Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 10MAY2017 25.3 0.7 27.7 0.4 28.3 0.4 28.9 0.2 10MAY2023 27.0 2.4 28.2 0.9 28.3 0.5 29.0 0.2 In all seriousness though, we're in May now. Nino 3.4 has never warmed more than 0.4C from May to DJF in any year since 1950. Here are the similar Jan-Apr Nino 3.4 years I listed awhile ago in May. 1957: 28.55C - we're running behind 1963: 27.63C - we're warmer 1972: 28.32C - continues to be dead on 1997: 28.58C - behind 2014: 28.25C - very close I'm increasingly convinced 28.0C for winter 3.4 (+1.5C v. 1951-2010) is the right ballpark rather than the 28.5C - 29.0C the models try to show. In the modern climate, Nino 3.4 averages around 27.9C in May and falls off by over 1.3C or so from May to Winter. So you essentially need the ONI (difference to average) to grow by over 1.3C to even offset the normal trend. If you use 2014 as an example, it fell off from 28.25C in May to 27.19C in DJF, which is pretty close to the normal 1.3C fall off. The 1997 event grew to 28.87C by DJF, one of the biggest gains ever, but only 0.3C. 1963 fell off by raw temps. 1972 was the same in May and DJF. 1957-58 cooled off 0.4C or so from May. I'd expect DJF to be around 0.4C less than whatever May finishes at in Nino 3.4, give or take 0.2C or 0.3C. We'll see though.

I'm always amused by the talk of ENSO losing effectiveness over time as a driving factor. The truth is, it was never particularly important as a driver of temperature for most of you. I talk about it, because it is actually important where I am. But it's not really relevant in the Northeast really. PDO is more predictive for temperatures by a country mile in the NE US. In the deserts, you get phenomena if you really look through the records. In the high/colder desert/steppe land, the increase in cloud cover, snow and rain is correlated to lowering highs much more than lows in El Nino. In the warmer deserts at higher lattitudes, this is also true, but the effect is much more pronounced in Spring when there is hardly any rain normally. In La Ninas, you tend to have colder nights in the deserts as the dry air is even drier. Also fewer than average cloudy nights. As an example, we had well over 110 lows 32F or colder for Oct-May 2023, most since 2009-10, and well above the 30-year average of 92. It was 21F as recently as early April with dew points near 0F. When I look at only El Nino years, the biggest y/y changes in Nino 3.4 account for anywhere from 0.25 - 0.55 r-squared for changes in winter highs in the high terrain of NM and also old Mexico, parts of AZ and TX.

Nino 1.2 leads changes in the PDO. For now I still like the PDO to be negative in the winter. But of course it's going to revert toward less negative conditions. I just noted it was third lowest in almost 100 years. It's not going to stay that severe. The entire north Pacific could warm. Without the cold tongue east of Japan, that's still a neutral or negative PDO. The PDO has a tendency to behave differently in the high-sun half of the year v. the low-sun half of the year anyway. It could easily flip very positive by winter, but won't be clear until October. The interesting thing with 1972-73 is it kept flipping positive/negative within the cold season. Part of why that's such an interesting winter. I generally think of Nino 4 as the immediate connection to the PDO. So Nino 1.2 eventually becomes Nino 4 / PDO changes because it has to spread out. But right now, Nino 4 is only slightly warm, with no immediate pressure from severe warming. The 2020-21, 2021-22, and 2022-23 winters saw very cold Nino 4 readings - coldest in over a decade at times - and so yes, the PDO went severely negative. 1972-11-01T00:00:00Z 0.26 1972-12-01T00:00:00Z -0.09 1973-01-01T00:00:00Z 0.18 1973-02-01T00:00:00Z -0.07 1973-03-01T00:00:00Z -0.32 1973-04-01T00:00:00Z -0.74

Nov-Apr PDO finished at -1.65 on the JISAO/Mantua index. That's third most negative back to 1931-32 for a Nov-Apr. These are your -1 to -2 PDO Nov-Apr years. 1971-72, 1948-49, 1961-62, 1949-50, 1990-91, 1970-71, 1975-76, 2008-09, 1950-51, 2011-12, 1973-74, 1956-57. Of those, 1971, 1990, 1975, 2008, 1950, 1956 turned into El Ninos. These are your "El Nino following major -PDO" years then. 1951-52, 1957-58, 1972-73, 1976-77, 1991-92, 2009-10. Actually not a bad match for April, which is a good sign. That blend is actually severely cold in most of the US in the Fall, but then it lets up December. Would be a pretty good winter in the Southern US, but not particularly cold anywhere in winter itself. There is some tendency for severe cold in the Fall in volcanic years - this might actually be a decent blend for now.

1995-96 is interesting as a near perfect anti-log, at least conceptually: - First full recovery from Pinatubo (2023 is still seeing volcanic distortions) - East-based La Nina (east based El Nino) - Positive PDO (Negative PDO) - Followed an El Nino (followed a La Nina) - Near solar minimum (near solar maximum) - Weak ENSO (strong ENSO)

One weird thing about this sequence is that the Modoki La Nina and traditional El Ninos often both favor the West for heavy snow. I wouldn't necessarily expect massively different snowfall patterns in a traditional El Nino - I'd look for good snows for a lot of the West, with fluky heavy snows in the South. I thought the NE would do alright for snow by Northern New England last year. But this year, you'd probably just see more fluky snows in the East generally. If you look at snow in the five years I listed (1997-98, 1991-92, 1972-73) minus (1957-58, 2014-15), it's likely quite similar. If we have a strong El Nino, that is traditional (not a Modoki and east based), with a -PDO, then the obvious years to subtract out are 2014-15 and 1957-58 which are super +PDO events and pretty snowy in the Northeast. The blend for this winter is going to need three unusual/rare components: - Huge warm up year over year in DJF (+2.0C y/y is doable - and very rare) - Volcanic winter - PDO & ENSO in opposite phases These are your "cold to warm" by +2C or greater warm up years for Nino 3.4 -

Conceptually, the Canadian look for winter is close to 1972-73, 1991-92, 1997-98 minus 1957-58, 2014-15. I did warm that blend up by 0.2C since it is centered on the mid-1980s. PDO, ENSO, and IOD are in the right phases, with the Atlantic/North Pacific not super far off. Big heat east of Japan, at 60E, 0N, El Nino centered at 120W, etc. The paper on the IOD has the right idea. I'm always a bit skeptical about the lead time, especially since the Indian Ocean seems to be warming faster than the other oceans. But the 14 month lead idea is consistent with an 11/2023 peak for this event.

I didn't run the absolute value calculation each year. But I suspect these are the closest Nino 3.4 transitions since 1950 for Jan-Apr to observations in 2023. 1957 26.04 26.54 27.46 28.23 28.55 28.36 28.17 27.69 27.44 27.42 27.62 27.90 1963 25.77 26.22 27.18 27.78 27.63 27.62 27.78 27.48 27.40 27.36 27.47 27.62 1972 25.62 26.30 27.09 27.89 28.32 28.18 28.14 27.95 27.95 28.26 28.61 28.69 1997 26.01 26.38 27.04 27.98 28.58 28.82 28.86 28.75 28.85 29.08 29.12 28.89 2014 26.05 26.14 27.00 27.90 28.25 27.96 27.23 26.82 27.01 27.16 27.46 27.31 Blend 25.90 26.32 27.15 27.96 2023 25.83 26.29 27.18 27.91 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 Those five years would be a pretty severe cold season, outside of a major warm up in January. November and March (kind of like this past year really) would likely be quite severe. The severe fall/spring should play out again in some form with the volcanic activity contributing to that. March 1973 and March 2015 have some really cold storms in the West super far south, with snow down to the suburbs of Guadalajara in March 2015, and historic late season snows throughout New Mexico in 1973. The DJF blend of the five is: 1957-58 (28.15C, +1.65C against 60-year means in DJF in Nino 3.4) 1963-64 (27.36C, +0.86C) 1972-73 (28.33C, +1.83C) 1997-98 (28.87C, +2.37C) 2014-15 (27.18C, +0.68C) Blend: (27.98C +1.48C)

It's been tough finding good matches at this time of year with the SST configuration. But 1972/2012 as a blend has been decent for the main ENSO zones. That's basically a cooler version of what the Canadian shows too, right? -PDO, core of the El Nino centered at 120W.

The great sort-of east-based El Nino of 2023-24. Up to date subsurface readings (Feb, Mar, Apr) for 100-180W, at 0-300m below the surface: 2023: +0.09 / +0.84 / +1.19 ------------------------------- 2014: +0.39 / +1.60 / +1.41 2018: -0.11 / +0.51 / +0.80 2018: -0.11 / +0.51 / +0.80 ------------------------------- Blend: +0.06 / +0.87 / +1.00 Not a lot of similar years for this Feb-Apr for the subsurface progression. Actual weather in May is forecast to be much colder than that blend too. April 1997, 2014, 2015 are the only Aprils since 1979 with a warmer subsurface for 100-180W than April 2023. The cold waters at depth in the 100-180W zone, on the west side of the image, imply an early peak and then steady weakening after the Fall - but we'll see. I don't really have an issue with this getting pretty healthy for a while. Not sold on it lasting through winter though at anything near historical strength though.

The big eruption by Kamchatka recently, Shiveluch, also happened in 1957. Wikipedia has it as a VEI 5 for 2023. I suspect it will enhance the upper level cold any +WPO lows have by Kamchatka. There has been rapid cooling of the ocean near Kamchatka since the eruption, presumably in part due to the aerosol effect from the ~200,000 tons of SO4 released into the air. Really stands out with the warm tongue from the -PDO still running east of Japan. More impressive solar weather recently. Some of the "volcanic" El Ninos also are high solar, which is nice. The high solar El Ninos are 1939-40, 1957-58, 1968-69, 1972-73, 1982-83, 1991-92, 2002-03, 2014-15 among the El Nino initiation group. 1982, 1991, followed major volcanic activity. Another visible night of the Aurora Borealis over New Mexico.

Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 19APR2023 28.0 2.5 28.2 0.6 28.1 0.3 28.8 0.3 19APR2017 26.2 0.7 28.1 0.6 28.3 0.5 28.7 0.2 We've almost caught up to the great 2017 El Nino...

One thing I'm researching is the best Western snow-pack years in a La Nina to El Nino transition. The level of snow out here is still stupid amazing. We've just about exited Rio Grande Compact restrictions locally with 400,000+ acre feet of water already, even with the mountain snow by the Rio Grande headwaters yet to melt. We're still not really seeing the typical warm Nino 1.2 response in old Mexico yet. Although the wet April in the highlands of Mexico is consistent with the -PDO. I guess you could make the case the places closer to Chiapas are seeing the more conventional (dry) response from a warm Nino 1.2 (look at 90-95W, 16-18N)

Nate is retiring from doing the PDO stuff, but he sent me this awhile ago, along with some other people - I removed his contact info. You guys are jumping the gun on the El Nino strength stuff. Just wait til May. You almost never get Nino 3.4 warmer than May in the following winter - and it's never been more 0.4C warmer. It's not some great mystery why the predictability barrier ends in late Spring. I will no longer be providing PDO index updates. You can get monthly updates for PDO index values based on NOAA's Extended Reconstructed SST (ERSST Version 5) from NOAA's Climate Prediction Center: https://www.cpc.ncep.noaa.gov/products/GODAS/multiora/index/mnth.ersstv5.clim19912020.pdo_current.txt Access to more information about the PDO, including updated graphics, is available from NOAA's Physical Sciences Lab: https://psl.noaa.gov/pdo/ best wishes, Nate ~~~~~~~~~~~~ Nate Mantua NOAA/NMFS Southwest Fisheries Science Center Santa Cruz, CA

The different PDO indexes use slightly different input and formulas for the calculations. I like the Nate Mantua index more because it has considerations regarding biological observations. It's kind of like how the Koppen classification was designed to explain why plant life and animal life changes in certain environments over very small areas. Hitting 90F in NYC at least a month earlier than the 100-year average (5/29) is a good sign for an El Nino historically. Most of the following winters have fierce cold snaps for large areas of the US. We're right between 1977/2002 with the 90F today. 2010 04-07 (2010) 92 09-08 (2010) 90 153 1991 04-08 (1991) 90 09-17 (1991) 93 161 1977 04-12 (1977) 90 09-03 (1977) 90 143 2002 04-16 (2002) 92 09-10 (2002) 90 146 1976 04-17 (1976) 91 08-23 (1976) 90 127 2009 04-26 (2009) 92 08-19 (2009) 90 114 1962 04-27 (1962) 91 08-20 (1962) 91 114 1990 04-27 (1990) 91 08-27 (1990) 90 121

Here is a better way to look at what I was saying. Look at the temperature grid v. the snowfall pattern nationally. The lightest green area is 55-60F average annual temperature. The lighter greens for snow are generally in the same spots.

Anti-logs will be pretty useful again this winter to correct for the unusual-ness of the event. There are quite a few recent La Ninas with +PDO setups - I suspect a few of them will show as useful opposites later on. There are a couple years on the old data sets in the 1930s/1940s where Nino 1.2 gets real warm, for a sustained period, but it never really spreads out (-PDO, super warm 1.2 look)

Also, the Jamstec has an east-central El Nino with a -PDO look.

The Shiveluch volcano that is erupting now has sent ash 12 miles up into the atmosphere. Interestingly, for those of you who like 1957 as an analog, there was also a major eruption that year. Also 1854. The winters of 1957-58 and 1854-55 are both pretty severe. I'd say for New Mexico and Colorado the three most severe winters since 1800 are 1854-55, 1914-15, and 1972-73. I would think a lot of the ongoing gains in +WPO setups/strength has been tied to this volcano semi-continuously erupting and shooting ash up over Kamchatka. https://en.wikipedia.org/wiki/Shiveluch March 1958 is another crazy month - doubt we reach that level of severity though.

What a stupidly amazing month March was -

One of the nice things about the Rio Grande is that the mountains that feed the headwaters of the Rio Grande in the San Luis Valley tend to do OK in La Ninas of all stripes, as well as El Ninos. With very slow population growth here, and a much colder climate than much of Arizona and Texas, the Rio Grande has a tendency to just "magically" fix itself to some extent. https://t.co/DabDm9VbZe I had mentioned in the Fall that the driest years / lowest years for the Mississippi River basin tend to precede major wet winters for the US. We've largely seen that happen - with the incredibly ridiculous March the icing on the cake. Snowfall like that pattern below does sometimes happen in the early onset El Ninos if you look - so it is good to see it.

I was playing around with anti-logs that could help produce something like the Canadian look. This would be an incredible winter for me, but I doubt it's correct. Go look at the 500 mb map of these years combined. But you do have the warm tongue east of Japan with a pretty healthy El Nino in this look. I was able to do that by using anti-log years that had cold Nino 1.2 signals with a warm PDO as opposites. You guys talking about 1972-73 are missing the key points of that winter. The Fall and the Spring both saw severe cold snaps and snowstorms nationally. I'm not completely sold on it as an analog. But it's likely similar in terms of the PDO y/y, the La Nina to El Nino transition, and it has features in Fall/Spring that I'd expect from volcanic years, so it's likely useful at some weight. https://www.tandfonline.com/doi/abs/10.1080/00431672.1974.9931676 Nov 1972 https://www.tandfonline.com/doi/abs/10.1080/00431672.1974.9931677

Also, using the most -PDO years on the JISAO index, -1 or below for Nov-Apr since 1931, you have very few cold seasons: Dec-Feb N-A PDO Next DJF 1955 -2.63 LA 1971 -1.78 EL 1948 -1.62 LA 1961 -1.53 N 1949 -1.50 LA 1990 -1.48 EL 1970 -1.45 LA 1975 -1.42 EL 2008 -1.39 EL 1950 -1.35 EL 2011 -1.28 N 1973 -1.14 LA 1956 -1.07 EL 1951 -1.02 N The PDO value for Nov-Mar 2022-23 is currently -1.54. Here is the blend of the six El Ninos after the most -PDO cold seasons. Fairly similar to what the Canadian showed for strength and placement? PDO/AMO are very different though.

The subsurface from 100-180W at 0-300m depth shows that the cold below the surface ended in February. Similar to 2016-17, another incredible winter for California late. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt The actual Jan-Feb-Mar transition in 2023 below the surface at 100-180w is: -0.24 / +0.09 / +0.84 Here is 2018: -0.16 / -0.11 / +0.51 The subsurface is actually still much colder and slower to warm than 2014: -0.33 / +0.39 / +1.60 1997 was slower to warm than 2014 too - +0.56 / +1.00 / +1.17 The closest simple match below the surface to 2023 is really a 2014/2018 blend: 2018/2018/2014: -0.22 / +0.06 / +0.87 2023: -0.24 / +0.09 / +0.84 The Nate Mantua / Jisao PDO was still running around -1.56 for March. Any type of canonical El Nino response needs to squash the -PDO. It's sort of the opposite of 2014, when the super +PDO created El Nino conditions before it was fully there.

https://twitter.com/WorldClimateSvc/status/1642980751862902785/photo/2 Generally, the warming of waters in the MJO phase 4-5-6 area (by Perth to Indonesia), and the ongoing -PDO push have all been horrible for east coast snowiness in recent months. Forget what the models show for strength in winter btw. May is a very good indicator for Nino 3.4. Since 1950, no year has featured DJF more than 0.4C warmer than May. CPC has March overall at 27.14C, and normal warming March to May would be ~0.65C. I think 27.8C - 28.2C in Nino 3.4 in May is a reasonable guess, and so an all time historical warming push would be 28.6C at most (+2.1C). But most winters actually finish below May's Nino 34 reading, even El Ninos. I don't think there is any real chance of a 28.5C Nino 3.4 for winter without at least 28.0C May, we're at ~27.5C now on the weeklies, with a month left to warm.