raindancewx

European has the drop in Nino 3.4 for September.

The subsurface data for 100-180W, 300m down, has finally broken (warmer) away from 2017. This is the closest match I could easily come up with for July-Sept. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt 100-180W July Aug Sept 1984 -0.25 -0.22 -0.37 2003 0.53 0.03 0.10 2013 0.41 0.32 0.38 1984 -0.25 -0.22 -0.37 2003 0.53 0.03 0.10 1984 -0.25 -0.22 -0.37 Mean 0.12 -0.05 -0.09 2019 0.13 -0.08 -0.05 1984 (x3), 2003 (x2), 2013 as a blend actually kind of looks like what I have for winter in the US, but from completely different analogs. Look at how much colder 2017 was by this point in the subsurface data. If you plot 1979-2018 September subsurface data against Nino 3.4 DJF temps, you'd expect about 26.6C give or take a few tenths of a degree at pretty high certainty. 100-180W July Aug Sept 1984 -0.25 -0.22 -0.37 2003 0.53 0.03 0.10 2013 0.41 0.32 0.38 1984 -0.25 -0.22 -0.37 2003 0.53 0.03 0.10 1984 -0.25 -0.22 -0.37 Mean 0.12 -0.05 -0.09 2019 0.13 -0.08 -0.05 2017 0.16 -0.40 -0.79

These are the top SOI matches for July/Aug/Sept since 1931: 1946 1948 1951 1963 1969 1991 Outcome as a blend is a cold NW / warm East look for October, which doesn't seem too far off from reality, the models / CPC and my analogs all had that too. 1963-64 is a pretty extreme winter in December for the US, but it should drop out as a top SOI match soon, unless the SOI is around -15 again in October. If you look at October 1963, it is also the mother of all blow-torches for everywhere but California, so not exactly likely. Like last year, different MJO background in all likelihood.

The Canadian update for 9/30 still looks dramatically over cooled after October for the global oceans, with nearly all of Earth's cold/in blue. However, the air temperature maps and precipitation maps still look reasonable to me. October is depicted to retain the coolish Nino 1.2/3 with half of Nino 3.4 cold and half of it warm, and then Nino 4 warm. The NAO went pretty negative in late September, will be curious to see what the final NAO value is for September. The PDO also looks less positive for September. If Nino 1.2 is near average in October but the PDO is still positive in September, it is likely that the PDO will remain slightly positive through winter, but not probably positive enough to drive cold into the far SE US persistently. I have my snow map ready for the winter forecast - a lot of places in the West that had heavy snow in late Sept/early Oct show up in the analogs. If I'm right, most of you will be pretty happy, outside of some areas in the Ozarks and Lakes that may get jacked. Neutral composites for snow are pretty interesting, but do "bend" a bit to ENSO order if that makes any sense. Generally speaking, I think the heavy snows move around a lot this cold season. Heavy snow events in Fall/Spring for the NW and Northern Plains, with SW in Nov-Dec and Feb-Mar, and then the NE/MW probably due well in Jan/Mar. Anyway, I'm fairly excited, it looks like a fun winter nationally. I do think parts of the West will be pretty warm, but not to the extent of 2013-14, 2014-15 or 2017-18. I looked at snowfall in my analog years for around 25 cities in the lower 48, most places do well or are near average, not many that are well below-average.

ONI weeklies all shot up again, and the weekly ENSO update PDF from CPC/NOAA has the subsurface above average again for 100-180W down to 300m. Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 04SEP2019 19.8-0.6 24.9 0.0 26.6-0.2 29.1 0.5 11SEP2019 19.1-1.3 24.4-0.5 26.4-0.3 29.0 0.3 18SEP2019 19.1-1.3 24.2-0.6 26.5-0.2 29.3 0.6 25SEP2019 20.0-0.5 24.8-0.1 27.2 0.5 29.7 1.1 The weeklies imply 26.68C or so in Nino 3.4, which is +0.15C for September, against 1951-2010 averages. Nino 1.2 would be -1.0C, Nino 3 -0.1C, Nino 3.4 +0.15C, and Nino 4 +1.0C, all against 1951-2010, assuming the monthlies match the weeklies - and they tend to except in Nino 1.2. The SOI finished around -13 in September. CPC uses different averages for differet time frames, my table below does not. The table linked here goes to the 1800s for estimating ONI from different data. https://www.webberweather.com/ensemble-oceanic-nino-index.html Using actual SST data, not anomalies from CPC, 1992 remains a very strong match to 2019 so far in Nino 3.4 My winter analogs also look like what CPC is showing nationally for October, which I find encouraging.

The 2017-18 La Nina was developed by this point. Right now, 2019-20 still looks Neutral. Those waters north and northwest of Australia should really inhibit any major cool down in the Nino zones. Tropical Tidbits has Nino 3.4 back to near 0, with Nino 1.2/3 warming back to cold-neutral from La Nina territory. There is a lot of warmth set to come up in the West now too if you look at the 9/25 frame.

Honestly, you guys seem to be over-reacting a bit to last year. Conceptually, if you split the lower 48 into four regions, the strongest indicators for a cold winter are something like: NE 1/4: -NAO, or a Modoki El Nino with high solar (2014, 1977, 2002, 1968, etc) SE 1/4: +PDO. Much stronger correlation to southern cold than any ENSO state if you look historically. 1983-84 and 1995-96 were both +PDO years for Nov-Apr. SW 1/4: An El Nino (>=27.0C) winter after a La Nina winter (<=26.0C). This is actually becoming rarer as a lot of years are cold Neutrals now instead of weak La Ninas. (2018, 2009, 2006, 1976, 1972, 1951, 1965, etc). In the SW, warming up from a cold Nino 3.4 dramatically y/y is a pretty strong indicator for cold if in the initial year is cold. Even 2011, a La Nina but much warmer than 2010, but fairly cold in New Mexico is an example of this, despite not being an El Nino. NW 1/4: A La Nina after an El Nino (2016, 2010, 2007, 2005, 1998, 1995 etc). I believe each of these since 1995 has been cold somewhere between the Dakotas and N. California, even 2005-06 was relatively cold in this zone v. the rest of the US. Last year, conceptually fit the SW cold pattern. However, if you recognize that the SOI jumped to +9 in Dec 2018 after being -3 in Dec 2017....that's actually close to a "La Nina after an El Nino" jolt to the SOI. Shockingly, the atmosphere responded and it got stupid cold in the NW & Plains in February, it snowed in Malibu, Billings had its coldest month since 1936, and so on. For these splits, the r-squared values approach 0.5 over long periods for indicating cold. It isn't that there aren't exceptions, but I tend to view these relationships as robust, as you get the opposite effects in each region when the relevant sign is reversed. ENSO has always been over-rated as a live indicator for seasonal stuff, it's more important for telling you where things are coming and where they came from.

The IOD (Indian Ocean Dipole) is pretty interesting for how the Tropical Pacific looks right now. The set up in the Indian Ocean is more consistent with an El Nino. Part of me thinks this event will transition back to an El Nino, later in 2020 and then after that we'll get 2-3 La Ninas in a row, which will be terrible for most of the West. The SOI is still around -15 for September, which is broadly speaking a wet signal for the West but not so much where I am. The NAO looks like it will crash again for a bit late this month. I'm curious to see what the final NAO value is for September. My hunch is the NAO will be more volatile than predominantly negative or positive this winter. My tentative analogs have one -NAO month, one near average, and one +NAO month. We will see. September relative to March and May relative to April as a blend works pretty well in figuring out the predominant NAO state the next winter I find.

I was actually looking at snow for the upcoming cold season in New Mexico, and the higher elevation areas come out pretty well, the signal goes from below average snow at valley level to above average at the mountain tops. Highest terrain may be up to 20% above average. The signal I get for Albuquerque is for a lot of cold nights despite somewhat warmer than average highs. Last year, the NW 1/3 and Gila (SW NM by AZ) did well, generally normal to +80%, with the southern valleys and SE part of the state well below average. This is probably what I'll use for winter forecast, pending any last minute surprises in September (say, 2.4 inches of rain from now to 9/30 in Albuquerque).

https://www.cpc.ncep.noaa.gov/data/indices/wksst8110.for Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 28AUG2019 20.2-0.4 24.6-0.3 26.5-0.2 29.2 0.6 04SEP2019 19.8-0.6 24.9 0.0 26.6-0.2 29.1 0.5 11SEP2019 19.1-1.3 24.4-0.5 26.4-0.3 29.0 0.3 18SEP2019 19.1-1.3 24.2-0.6 26.5-0.2 29.3 0.6 Nice rebound in Nino 4. Nino 3.4 hanging tough. 30AUG2017 20.3-0.2 24.5-0.4 26.5-0.2 28.8 0.2 06SEP2017 20.4-0.1 24.3-0.6 26.2-0.6 28.7 0.1 13SEP2017 19.7-0.7 24.0-0.9 26.1-0.6 28.7 0.0 20SEP2017 19.3-1.1 23.9-1.0 26.3-0.4 28.7 0.0 A warm September in Nino 4 is a strong cold signal for a lot of the US, and that's broadly what my analogs have for October.

One of the old Jamstec runs had a cold Nino 3 / 1.2 peaking in SON, before decaying in winter. That seems more or less right to me. I don't disagree at all about Nino 1.2/3 remaining cold. But the +2 and -2 cold pools on the image above are both at the edges of Nino 3.4, at similar depth and similar magnitude. So I don't see any reason for warm west / cold east to change. The trick is Nino 3.4. This is the July run for SON. Looks like right now in the Nino zones. But then it had a decay in DJF. Nino 1.2 has a tendency to predict PDO changes, so the PDO zone is less positive than depicted, but otherwise, this was a good map. I think the weeklies will show some warmth recovery in Nino 4 and maybe Nino 3.4 this week, probably not to the extent Tropical Tidbits has though.

This would be classified as a Neutral if the look held, since CPC uses 120-170W, 5S-5N as its zone for designating El Nino and La Nina. However, the Modoki zones are 165E-140W, 10S-10N, for Box A, 110W-70W, 5N-15S for Box B, and 125E-145E, 10S to 20N for Box C. That's basically an idealized El Nino Modoki on the Japanese definition, at least for 9/22, were it to hold. Much of the warmth in Box is north of 5N and west of 170W.

Tropical Tidbits has a nice rebound in Nino 3.4 from a few days ago. Nino 3.4 was over 27.0C at around 27.2C in winter 2014-15, and the PDO was at record positive values from Nov-Apr, around +2. For the six month period, that's as high as it ever gets. The value last year was around 27.4C, but the PDO was much less positive.

The raw data CPC uses is reliable. They just think the ENSO thresholds for La Nina and El Nino are warming over time, and I don't think that is really true. So +0.5C in 2019 is warmer than +0.5C in 1959 if you look here - https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/detrend.nino34.ascii.txt YR MON TOTAL ClimAdjust ANOM 1950 1 24.56 26.18 -1.62 2019 1 27.21 26.45 0.76 The El Ninos in the 1950s with DJF Nino 3.4 readings above 27C act like modern El Ninos. The others don't, at least that is what I find. 26-27C ish works well in winter for Neutral conditions. A lot of what they think is warming thresholds seems more likely to be biases from small data where you happen to have 12 El Ninos in 30 years, instead of 10. Over 60 years, with more balanced positive PDO and negative PDO data, you find pretty steady concentrations of ENSO at 26C or less or at/above 27C in winter. For the older data sets, if you correlate the 1950s-now data with the same data, and then roll it back, you can get a good idea on older years generally. This is at attempt to do something similar to what I did, and nearly matches my data, for pre 1950 ENSO, using constant ENSO thresholds. https://www.webberweather.com/ensemble-oceanic-nino-index.html

For reference, even though it is only September, the SOI is a fairly strong temperature signal for December & February in the US. Not really true for precip. Generally the deeper correlations "win" if the SOI is extremely positive or negative. It's a cold SE/warm NW signal for February, and a cold Northern Plains signal for Dec. Wet California signal is consistent with the La Nina after El Nino signal. Dry signal over the Midwest is actually pretty strong for February. My general hunch for this winter is it will be wet for many, but fewer, stronger storms than last year. As opposed to many weak storms. We'll see. A lot of our really crappy winters out here will have like 2-4 inches of rain (2x-4x average) in September. We may get an inch or so, but it's not looking like 1995, 2013, or 2017 wetness in late September just yet - all terrible winters here - despite the possibility of a big cut off low over the SW this week.

The SOI is around -17.5 for 9/1-9/19. It looks fairly negative for October on the model pressure pattern depictions too. 1980, 1990, 1992 and a few other years with fairly cold Nino 3.4 readings have neutral or negative SOI values in September, but nothing like this year, i.e., below -8. I do think 1992 is worthy as a comparison, in at least some capacity. Nino 3.4 was 26.65C, with a +0.7 SOI. I incorporate solar stuff into my analogs, so 1992-93 is a bad match on that. It's not great since it is a volcanic winter and had a colder AMO. But it is very close, at least over the Summer for the Nino zones. 28AUG2019 20.2-0.4 24.6-0.3 26.5-0.2 29.2 0.6 04SEP2019 19.8-0.6 24.9 0.0 26.6-0.2 29.1 0.5 11SEP2019 19.1-1.3 24.4-0.5 26.4-0.3 29.0 0.3 26AUG1992 20.3-0.3 24.8-0.2 26.7-0.1 28.9 0.3 02SEP1992 20.3-0.2 24.4-0.5 26.3-0.4 28.6 0.0 09SEP1992 19.7-0.8 24.4-0.5 26.4-0.3 28.7 0.1 The blend I like for winter actually has a stronger -NAO signal than I realized for winter, but it still has a pretty extended +NAO phase in Jan and probably half of February. Will be interesting to see if Dec comes in negative, I think it is possible if Nino 4 doesn't get near 29.0C by December.

To be honest, while I don't expect a La Nina to be the "classified state" for the winter, it probably will be close enough in the eastern zones that I do plan on using some La Nina analogs in my winter blend. The La Nina winters after El Nino winters tend to be wetter in the SW as a composite too, for what it is worth. IRI was still mentioning warm neutral / El Nino as possibilities for this winter based on the dynamical and statistical models as recently as this week - which I think is a bit insane. I was playing around with re-calibrating the subsurface color scheme from CPC, since they added in a light blue/orange for -0.5 to +0.5. If you make the scale the same for 2017 and 2019 for September 10 both years, it's a lot clearer that there is just less subsurface coolness at the moment compared to 2017, and more warmth too. I've been looking at 1953/2009 (much warmer anomalies Nino 4 than Nino 1.2) at the solar minimum in a blend with some kind of combination of 1983, 1995 (positive PDO La Ninas after El Ninos), with 1992/2018 thrown in to fix a couple other issues with the blend. Still working on the weighting, but it is probably those six years that I'll use for winter.

MJO looks like it will reach phase 1 around 10/1. That is very similar to last year. September looks a lot like a blend of 1995, 1953 and 2018 at the moment.

Want to see how September finishes up here, but I'm looking real hard at 1953-54, 1983-84, 1992-93, 1995-96, 2009-2010, 2018-19 as the winter blend. Extra weight on 2009 and 1995 in all likelihood. Snow would be pretty prolific for the interior South, NE, Ohio Valley and maybe the east slopes of the Rockies. Below average north and west of NM/CO generally.

More cooling this week, especially in Nino 1.2 and Nino 3 where the subsurface is very cold. Still warmer than 2017 overall. Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 14AUG2019 20.0-0.7 24.7-0.3 27.0 0.1 29.5 0.8 21AUG2019 20.3-0.3 24.7-0.3 26.8 0.0 29.5 0.8 28AUG2019 20.2-0.4 24.6-0.3 26.5-0.2 29.2 0.6 04SEP2019 19.8-0.6 24.9 0.0 26.6-0.2 29.1 0.5 11SEP2019 19.1-1.3 24.4-0.5 26.4-0.3 29.0 0.3 16AUG2017 19.9-0.7 24.5-0.5 26.4-0.5 28.8 0.1 23AUG2017 19.6-1.0 24.6-0.4 26.7-0.1 28.9 0.2 30AUG2017 20.3-0.2 24.5-0.4 26.5-0.2 28.8 0.2 06SEP2017 20.4-0.1 24.3-0.6 26.2-0.6 28.7 0.1 13SEP2017 19.7-0.7 24.0-0.9 26.1-0.6 28.7 0.0 I'm working on my winter outlook. Will link to it in a month or so. My hunch is we're nearing the minimal depatures for Nino 1.2, probably -1 to -1.5 in Sept or Oct, and then it warms up relatively speaking. Nino 3 sees a later, but less pronounced minimum in October/November. Nino 3.4 doesn't get as cold, relatively, but remains fairly steady for a longer period. Nino 4 may briefly go negative against its long-term averages if the cold from the east washes west, but I don't think it lasts, and you'll see a rebound.

Not really seeing any reason for Nino 4 to cool off given how the subsurface looks. The Nino 3 should remain quite cold, with Nino 3.4 in between. Nino 1.2 looks like it may warm up some going forward. Less cold than in previous months underneath the surface in Nino 1.2

I'm in the cold-neutral camp myself. I don't think the tendency to be warmer but kind of similar looking to 2017 is going to change much. Blending warm Nino 4 years (El Ninos) with cold Nino 1.2/3 years seems to be matching my Summer weather. I do think Nino 3 is probably going to be essentially La Nina-ish for several months. It's hard to find big -SOI September years that are La Nina years in winter. Since Nino 3.4 was only 25.7C or so in 2017-18 (-0.8C v. 1951-2010), running 0.3-0.5 above it as we seem to be in Nino 3.4 is a cold Neutral. 2012-13 and 2013-14 were both in the 26-26.5C zone, near La Nina, not quite. 2012-13 was actually pretty cold here in the SW, but dry while 2013-14 was warm/dry. The 26.0-26.5C zone for Nino 3.4 seems to produce pretty wildly different outcomes depending on the other factors.

The Jamstec has an El Nino for winter, but the surface is fairly cold right now, as is the subsurface. Still a lot of warmth to come in at least Nino 4 though.

My hunch for the winter is that the SE will do well for some snow events, particularly in the interior. I think you'll have some unusual methods of entry for cold air into the US along with a strong subtropical jet, like in an El Nino, but it will be oriented more to come into the US via NM and TX rather than California. I haven't looked into it too much yet though. It's pretty hard to find any real dud winters out here after a big -SOI in September actually. I think Montana and the Dakotas are kind of a due for a break, three very harsh winters up there.

Latest European run has warmed a bit. I drew in yellow what I expect in Nino 3.4. At this point in recent years, the Euro September Nino 3.4 forecasts were pretty good. The SOI has been very negative in September so far, which means we should avoid La Nina conditions at least. Very hard to get below a -5 or -10 SOI in September and then a La Nina the following winter. The SOI should remain predominantly negative through at least 9/17. These are the Septembers since 1931 with a -4 to -12 SOI...it is actually currently at -16 for 9/1-9/10. The 1946 and 1932 ENSO winters were preceded by SOI Septembers under -8 and both were cold Neutrals, but almost all the others are El Ninos. Sept SOI 1976 -12.4 1951 -11.2 1987 -10.6 1969 -10.0 1957 -9.4 1939 -8.8 1977 -8.8 2018 -8.5 1932 -8.3 1941 -7.7 1990 -7.3 2002 -7.3 1948 -7.1 1993 -7.0 2014 -6.6 1934 -5.9 1963 -5.9 1980 -4.7 1986 -4.7 2006 -4.6