raindancewx

One thing I've looked at recently is...what the hell happens a year after Nino 4 is ..actually cold? It's been so long I honestly didn't know before looking. So last December Nino 4 fell to 27.54C. Coldest December since 2011 (27.53C). The most recent ten (non-El Nino) Decembers following a 27-28C Nino 4 are interesting years. You do have some very warm years in there (1999, 2001, 2011, 2012) but some very cold years too (1985, 2000). These are the most recent non-El Nino Decembers to follow a 27.0C-28.0C Nino 4 December. The value in ( ) represents the Nino 4 reading in the prior December. In general, the Southwest tends to be cold relative to the base ENSO pattern effect when the Tropical Pacific warms up y/y. Most of the years below are warmer than the prior year in Nino 4, that's why you see the cold signal for New Mexico. Nino 4 looks like it is running 0.1C to 0.3C warmer than last September. 1971 (27.04) 1975 (27.42) 1984 (27.71) 1985 (27.59) 1999 (27.06) 2000 (27.18) 2001 (27.59) 2008 (27.42) 2011 (27.03) 2012 (27.53) Mean (27.36) 2021 (27.54). The blend I have for December works out to ~27.71C in the "prior December" and then around 28.0C for the current December.

I'm seeing some people mention the models have a SSW already for December. Pretty sure some of the years I have like 2001 have that. But I've been having trouble finding the list of years I maintain with those SSW events.

Any of you see this? Paul Pastelok interview (lead long-range guy at Accuweather) on winter 2021-22. He does say the Accuweather winter outlook isn't done yet. Will be out 9/29. But still interesting to see what he says. He seems to like at least 2013-14 and 2020-21 as analogs. I do like 2020-21 but 2013-14 has fallen off a bit for me as an analog. https://cheddar.com/media/will-this-winter-be-the-season-of-shivers

Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 25AUG2021 20.6 0.0 25.0-0.0 26.5-0.3 28.5-0.3 01SEP2021 20.3-0.2 24.7-0.3 26.5-0.3 28.4-0.3 08SEP2021 20.7 0.2 24.6-0.3 26.4-0.4 28.5-0.3 15SEP2021 20.6 0.2 24.3-0.6 26.3-0.4 28.4-0.4 26AUG2020 20.0-0.6 24.2-0.8 26.1-0.7 28.6-0.2 02SEP2020 18.9-1.7 23.6-1.4 25.8-0.9 28.4-0.4 09SEP2020 19.5-1.0 23.4-1.4 25.7-1.0 28.5-0.3 16SEP2020 20.0-0.4 23.6-1.3 25.9-0.8 28.2-0.5 Compared to last year, we're still running 0.2-0.7C warmer than all zones this week. It's definitely not too late for a La Nina for winter. But the rule is the rule. For 1950-2020, no year has seen Nino 3.4 drop by 1.0C or more from September to Dec-Feb. So we're at 26.4C for 60% of September. There was a bit of a "downward" spike in the subsurface reading this week. Like last October. So we should see October cool off at the surface. Would not be shocked if we had an October or November peak again compared to the averages at the surface. Once we reverse upward in the subsurface, should see more Western storminess and cooler weather. Might already be on the cusp of it to be honest given some of the forecasts.

Heading into last winter, I did some data mining / statistical tests to try to predict La Nina winter precipitation in Albuquerque, not just for the season but by month. I found three pretty relevant, independent variables that work well as predictors: Major Hurricane Days in the Atlantic prior to winter. Very highly correlated to total winter precipitation. Each major hurricane day is worth a 0.0522" loss in winter precipitation roughly. It's not a strong predictor in January or February though. But it works well in December. For January, the June high minus the September high blended with the timing of the first 90 degree high works well as a predictive blend. For February, the years with much hotter June highs than September highs (theoretically could be as much as 96F - 76F difference) are the years with wetter Februaries. This year will be not be among them unfortunately. Last year had a much larger drop from the June to September high (~91 to ~82).

Most of the research out there on the Hadley Cell changing implies the migration of the subtropical (sinking air) aspect to the flow toward the Poles in each Hemisphere is stronger in the Fall and Summer than the other seasons. I would say your view of the expansion is too fast. It's more like <0.5N/S per decade toward each Pole. I'd probably put it at 0.3 degrees per decade or so myself. Don't really get why you are so singularly focused on the winter. The reliability of the monsoon West Africa, Mexico, SE Asia, India, that kind of stuff is way more impacted than something like an American winter. It seems like something you just throw out there when you feel like it. I can't find the paper my teacher wrote in 2010 or so, but the link has nearly identical findings to hers. https://www.sciencedirect.com/science/article/pii/S2095927318301919 3. Seasonality of widening trends Unlike other metrics, widening of the Hadley circulation demonstrates large seasonal variations [1]. Fig. 1 shows the poleward shifts of poleward edges of Hadley cells in both hemispheres, derived from seven reanalyses. In each hemisphere, widening trends in summer and autumn seasons are large and statistically significant in general, while trends in winter and spring seasons are much weaker and insignificant. The seasonality of widening trends implies that the associated radiative forcings either have seasonality or co-operate with the Hadley circulation only in particular seasons in causing widening trends. It was suggested that the widening of the SH Hadley cell is mainly due to the Antarctic Ozone Hole that has the largest radiative cooling effect in the lower stratosphere in austral summer [11]. Increasing black carbon and tropospheric ozone in the Northern-Hemisphere (NH) extratropics are considered the major forcing in causing widening of the Hadley circulation in boreal summer [12], which have the largest warming effect in the NH extratropics. Simulations showed that increasing greenhouse gases (GHGs) force the largest widening of the NH cell in boreal autumn [4]. Because the radiative forcing of GHGs has no seasonality, the GHG forcing must be throughout some mechanisms in causing widening of the NH cell in boreal autumn. However, the associated mechanism is unknown.

Won't set up as wildly as last year, but I do expect a fairly active Fall for storms in the West this year. The weekly data tomorrow through mid-September will be a good indicator for how cold this event can get at the surface. Suspect you'll see Nino 3.4 drop below 26.4C finally. Septembers with Nino 3.4 at about 26.4C below (weeklies were ~26.45C through last week). The bolded years are good for average to above average snow locally. 1983 is the hottest 9/1-9/18 period for highs locally, this year is third. A lot of other warm Septembers in this list too for me. The figure in the () is for the following winter reading in Nino 3.4. 1983 26.20 (26.00C) 2000 26.20 (25.87C) 1966 26.27 (26.01C) 1996 26.27 (26.11C) 2017 26.29 (25.72C) 1952 26.36 (26.85C) 1984 26.38 (25.55C) 1958 26.40 (26.96C) 1989 26.42 (26.66C) 1960 26.44 (26.34C) 1980 26.44 (26.31C) 2008 26.47 (25.79C) 2001 26.52 (26.43C) 1981 26.53 (26.55C) 2013 26.54 (26.21C) You can see if we do finish as warm as 26.4C for Nino 3.4 (50/50 I'd say) in September, then it's fairly unusual to even get below 26.0C for winter. Only four of fifteen winters on the list finish under 26.0C. But obviously several are just above at 26.0C-26.15C.

My research suggests that a lot of what you focus on for the "expansion" of the Hadley Circulation is really the shape of it changing more than anything. It doesn't expand in consistent ways each season you get "angled" looks to it sometimes. The subtropical counter to the rising air in the tropics has also changed shape a bit too. I've known that for a while. My main teacher in college wrote some of the research on the circulation expanding. Her speciality was on how changes in the Walker and Hadley cells could impact MJO intensity and timing. Long-term, I think an expanded area of tropical forcing / convection makes sense for wilder weather patterns. All that said, there have always been periods where Fall and Spring were wilder. Heavy Fall snow events here cluster every 30-years or so about half way through the AMO cycle. I get the impression that people like see the Hadley Circulation is an excuse to throw seasonal forecasting out the window to some extent. The truth is, even before recent years, it never really made much sense to base more than 25-30% of a seasonal pattern off ENSO. I actually give it less weight than that of the seven factors I use, even though it's "first among equals" for me. You can find a similar warm December in a strong El Nino just like you can in a strong La Nina. Same for cold years or other months. That's not the Hadley Cell doing that. December 1988 and December 1957 are at near opposite ends of the ENSO spectrum, and not recent years when the expansion should be subsuming ENSO. You must know that your argument is also as old as time. When ENSO was proposed as a regular recurring phenomenon in the 1920s people like Walker got push back for the patterns not working in each event back then too. The idea that ENSO+/ENSO- equals PNA in a certain period has always been kind of wrong, it's just a stronger weighted roll of the dice than the other features.

Overall, I don't know that the winter will have super different features than last year. You have a lot of warmth by Indonesia right now like last year. You have more cold to the East by Peru (although not really Nino 1.2) than to the West in the Nino zones like last year. Solar is still rising like last year. You had major -NAO blocking in April like in 2020. The big Gulf hurricanes hits (and even NE tropical hits/impacts) are there too. We're not following an El Nino this year, but one of the reasons I use ENSO order is because the warmth by Indonesia tends to be there in Fall in those La Ninas (look at 1998, 2010, 2016, 2020 as examples, opposite tends to hold for El Nino after La Nina too). Not as important this year. I do think the "weaker (surface) La Nina" after a "stronger (surface) La Nina" thing is interesting. Present in a lot of the "good" colder La Ninas/ near Ninas like 2000-01, 1974-75, 1996-97, 2011-12 out here. You can even throw in the cold-Neutrals. 2001-02, 2012-13, 1967-68 are cold here too and weaker than their predecessors. You do have exceptions, like 1985-86, 2008-09 that are a bit shit here. But they're generally very cold at times even in the Southwest. These are years with a winter reading under 26.5C, when the prior winter was also under 26.5C, but a colder/stronger La Nina. There is some estimation on my end for the pre-1950 years. So this is the more recent 60 years.

I personally think it is too late for this event to catch up to the strength of the La Nina last year. At least at the surface. Objectively, for July-September, I couldn't find a better match for the subsurface than 1992, 1995, 2020 (x2). So it is close for the subsurface.

Here is something I was toying with earlier for my outlook - What do winters look like when solar activity rises on a July-June basis, but the winter is a weaker cold-ENSO event at the surface? My criteria here are a two winter sequence where sunspot activity increased by at least ten, and each of the two winters finishes with a 26.5C or colder reading in Nino 3.4. But the second winter has to be warmer. Some borderline cases for sure, 1934, 1961, 1967, 2013. But the slam dunk years for meeting both criteria are 1956, 2001, 2011. That's it...since 1950. Pairing DJF Nino 3.4 SST / July-June Sunspots Annualized 1955-56 25.22C / 119.8 1956-57 26.10C / 237.6 2000-01 25.87C / 163.4 2001-02 26.43C / 176.0 2010-11 25.21C / 44.0 2011-12 25.76C / 94.0 2020-21 25.58C / 16.1 2021-22 25.95C (?) / 50 (?) Bolded Blend: 26.09C / +60 Sunspot Gain y/y. It's not a bad match. The ENSO match for all four zones year to date that is best is 1967, 2001, 2011. That blend is fairly similar too. 1966-67 + 2000-01 + 2010-11: 25.70C / 103.9 sunspots 1967-68 + 2001-02 + 2011-12: 25.99C / 138.3 sunspots. That transition is almost identical to what I expect - a +30 to +40 sunspot gain, with a +0.3C surface gain in Nino 3.4 Both blends (1956, 2001, 2011 and also 1967, 2001, 2011) are a warm NW to SE, cold pocket SW look. I'm pretty sure that look is going to show up again. The warmth by Indonesia should enhance it too. It's interesting though - all of the years that both match on (weaker) cold ENSO after (stronger) cold ENSO and rising solar have that look.

September looks like it is moving toward my tentative blend for winter. This is the idea for snow from the analogs. It's a decent match for ENSO strength, ENSO order, solar, the AMO and PDO, with high a lot of Gulf Coast hurricane hits, and a -QBO look too. Generally the look is more optimistic for snow in California, the mid-South and some Great Lake snow belts, but a bit less optimistic for the Northeast compared to last year. The way we get these totals by timing is also very different from 2020-21. I suspect that's true for temps too. In the West, I'm trying to balance 1974-75 and 2017-18, one very wet, one very dry, one hyper active in the Atlantic, one hyper quiet, both weak La Nina years with similar precip/temp patterns in Summer.

1933 is one of the five "shit winters" out here. It's on the Mount Rushmore of hottest, driest most boring winters locally for the SW US, alongside 1950-51, 1995-96, 2005-06, 2017-18. Virtually no precipitation for months (although 1933 had a wet November). The heat in 1933 in the West was shoved back compared to this past June-July though, so it's not quite as close as a 1961, 1974 or a 2017 in those months. The monsoon was very strong in 1933, including extremely heavy rain in September like 1995, 2005, 2013, 2017. The Mount Rushmore years tend to have one big wet September and then almost nothing for a 3-5 month period. The years out here with highs under 70 mid-June to mid-July like this year are pretty rare. 1933 does have that. I think it was 1933, 1947, 1964, 1968, 1986...and that's it since 1931. Locally, the first half of September 2017 was about 89 degrees for the high. This year is about 90. Cool down started a bit earlier that year, but we've got some western cool air-masses coming about 7-10 days after 2017 now. The cool down forecast for the West later this month should bring national temperatures close to the blend I like for winter. No MJO data for 1961. But the other years I like for overall analogs tend to feature "phase 7" occurring around 11/15, and then around 47 days after for each cycle. So it occurs around 2/16 too. That's consistent with those five years above that had highs under 70 6/15-7/15. Those years tend to feature severe cold periods here mid-Nov to mid-Dec and then mid-Feb to mid-Mar. To get both those periods cold, I think you need a 7-2 transition in late Nov/Feb, and then a 1-5 transition in early Dec/Mar. The upcoming period in the 6-10 and 8-14 does look like a 1933, 1947, 1964 blend (the non-El Ninos of the five) so that's "interesting" to me. Amazing that something as random as one cold day in June can "see" that. The years I mentioned are just similar MJO phases. I'm not actually that high on 2007 or 2008 or 1975 or 2011 or 2012 as overall analogs. 2011 is actually a real good ENSO match at the moment, but doesn't have much else going for it. Most of the year has been opposite in the US for temperatures until September.

Summer PDO was 6th most negative in the past 90 years. Don't think the dryness is really much of a surprise given that fact. Although the monsoon was actually fairly strong in a lot of places south and west of me.

When I weighted MJO timing matches to 2/3 location on 9/1 + cold ENSO + extra weight for low solar, I came up with 1975 (x2), 2007, 2008 (x2) 2011, 2012, 2020 as analogs. I gave 1975, 2008 double weight for following La Ninas while having low solar. Point is, those years feature ~1/3 of days in phase 5-6 from Oct-May. Given eight MJO phases (i.e. two divided by eight phases), you'd expect only ~25% without knowing anything. The years I like all seem to feature at least some MJO phase 5 in December. Given the warmth by Indonesia, that should be a super torch for most of you, and nice and average or cold for me as it should be. Best guess is week one of December is MJO phase five, and then we transition to 7-8 (and colder) by the end of the month for the east. Even years I like that are very hot like 2001-02 get pretty major cold shots for the East. Recurring precipitation/storm timing here since June implies a storm or storms around 11/30 and then again around 12/30. Usually moving into phase five is stormy here, and then moving out of 6-7 is stormy. We'll see. July was rainy enough that we'll get some decent storms early. These dry/hot late Summers almost always precede one or two incredible storms and snow in Oct-Nov out here too.

Have you looked at 2001-02? Little bit nutty. This is my standard scale. So it's +7 in deep red (F) to -7 in deep purple. March 2002 is kind of incredible nationally. Actually...just about every year I picked is kind of incredible in March nationally. That's one of my big hangups with using that blend. Here is MJO phase five in 2001 - my greatest ally in December. Week two is colder for me than this. The MJO was around the 2/3 boundary on the RMM index on 9/1. Those years are 1975, 2007, 2008, 2011, 2012, 2020 since the data starts. Those years average ~1/3 of days in MJO phase 5-6 at decent amplitude from Oct-May when I looked. But...eventually 7-8 take over. I mentioned in the Weather Fella thread about snow pack / ice (where i'm the only reply) that I expected a big cold outbreak in December. This is an example of it - despite a warm looking month overall.

Precipitation pattern for Summer was remarkably close to 1961. Really do like that year, although probably not going to be my main analog. The PDO in June-August by the Nate Mantua (JISAO) method was the most negative since 2012 - both around -1.4. These lighter greens / blues typically don't matter. But if an index is at one extreme, even the weaker correlations tend to work. Pretty strong dry signal for the Southeast Coast - and it's worth noting that last year, the PDO was only -0.3 or so in Jun-Aug. It's a fairly strong cold signal for south-central Canada too, which is often good for the southern Plains. The mountains of New Mexico and NE (Old) Mexico essentially exist to bound the mother-lodes of cold from big time Blue Norther / Arctic outbreak patterns, you can sort of see the mixed blue/white/green signal in light of that for temps by NM/TX/MX.

The PDO was around -0.3 last Summer. At -1.4 in Jun-Aug 2021, lowest PDO in Summer since 2012 (-1.44). That's a major dry/warm signal for the South, that was not really there last year heading into winter.

Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 04AUG2021 21.7 0.7 25.1-0.2 26.7-0.3 28.6-0.2 11AUG2021 20.9 0.1 24.8-0.4 26.5-0.4 28.6-0.2 18AUG2021 20.5-0.1 24.4-0.6 26.0-0.9 28.6-0.2 25AUG2021 20.6 0.0 25.0-0.0 26.5-0.3 28.5-0.3 01SEP2021 20.3-0.2 24.7-0.3 26.5-0.3 28.4-0.3 08SEP2021 20.7 0.2 24.6-0.3 26.4-0.4 28.5-0.3 05AUG2020 19.8-1.3 24.6-0.7 26.3-0.7 28.4-0.4 12AUG2020 19.9-0.9 24.8-0.4 26.4-0.6 28.3-0.5 19AUG2020 19.5-1.1 24.3-0.7 26.0-0.9 28.4-0.4 26AUG2020 20.0-0.6 24.2-0.8 26.1-0.7 28.6-0.2 02SEP2020 18.9-1.7 23.6-1.4 25.8-0.9 28.4-0.4 09SEP2020 19.5-1.0 23.4-1.4 25.7-1.0 28.5-0.3 Nino 4 is as cool as last year at this time. Nino 3.4 is still running +0.7C for the same week. Nino 1.2/3 are both +1.2C for the same week. Last year, the La Nina was 25.58C in Dec-Feb. There are no ENSO events more than 1C colder than September in December-February since 1950 in Nino 3.4 I've been looking at the big IOD configuration by Indonesia a lot recently. You do have it this time of year in some legitimate La Ninas. But they almost always come after big El Nino years. So it is there in 1973 and 1998 and 2010 and 2016 to some extent. Much rarer to find it in a La Nina that is weaker and after a La Nina. But you kind of have it in 1974 and 2017. For now, those are my favored analogs, with both also showing similar heat waves in the West in June-July before switching much colder. If you scroll up the page, I mentioned Carla in 1961. Look at the dates on the map - 9/9-9/15. Now look at the (albeit much weaker) system to hit Texas this week. The precipitation pattern for 1961 is a remarkably good match for Summer, and temps were close too. I'm still refining the years and weighting, but my tentative blend for winter is 1961-62, 1974-75, 2001-02, 2017-18, 2020-21, and I'm leaning toward double weighting 1974-75 and 2017-18. I do think the MJO pattern timing is off in that blend, the Sept blend looks more like Aug 2021. Nate Mantua also sent out the August (JISAO) PDO today. It was -1.12. For March-August, the six month average was -1.2. I find that Nino 1.2 in October runs counter March-August PDO values, the PDO moves toward Nino 1.2 So I am expecting the PDO to move more positively in the cold season. I'll be able to run my projections for the NAO and PDO for winter in a few weeks. https://oceanview.pfeg.noaa.gov/erddap/tabledap/cciea_OC_PDO.htmlTable?time,PDO

The long-range models are completely useless except for looking at the next month right before it starts for temperatures and precipitation. The Jamstec, when it was around did a pretty good job of accurate gauging ENSO strength. I do think right before the next month starts, the CFS and Canadian on tropical tidbits do have some skill, although much less in Fall and Spring than in Winter and Summer.

Some random thoughts for winter - - The strongest land falling hurricanes on the Gulf Coast tend to precede incredible cold waves. Not always. Not in the same location or same month. But they do appear pretty frequently: 1932, 1935, 1947, 1961, 1969, 2004, 2017, 2018, 2020 all come to mind. - Cold ENSO Junes with staggering Western heat is not common. Like...at all. It's vanishingly rare actually. But it shows up in 1961 (a year a with 932 mb hurricane to hit the Gulf v. 929 this year). - In La Nina years since 1950, April NAO patterns correlate to December NAO patterns around ~0.25 (r-squared). The correlation is positive, so like last year, the very negative April favors a -NAO in December. - Years with similar levels of warming in Jan-Aug in Nino 4 - La Nina, El Nino - whatever situation you have - tend to be fairly warm in the winter. Not always - but very few exceptions either. I am expecting a major cold wave in the East this December. But I don't think it will last the entire month, and I don't think the month will finish super cold overall.

The ENSO zones in 2021 are generally close each month to a blend of 1967, 2001, 2011. Not really expecting that to change overall. This isn't what I expect to happen in the winter regarding US weather, but I do think the event will look like this. I'm expecting what I would call "cannonically cold enough" La Nina conditions to last from about October-February, so may not be an official event.

The WPO is a pretty warm signal when positive for most of the US in late winter. I think you guys would have been colder in Jan-Mar without the record strength (strong lows over NE Asia).

September is the month I use for testing analogs I come up with in Summer. The way the month looks like it will finish does match one of the weightings I like. But still want to see how the month finishes before I go into detail. There are some unusual features I don't like for this winter, mostly because I don't know what to do with them. The level of June-July heat in the West in a cold ENSO year is hard to find. But it's pretty similar to 1961. The four years I like most right now are 1961-62, 2001-02, 2017-18, 2020-20 for the winter. You can roughly re-create the four Nino zones each month of 2021 blending 1961, 2001, 2011 together. I'm trying to decide which extra years will be in the blend at the moment. There are a lot of "B" tier analogs this year, by the system I use: A analogs - generally strong matches for temp/precip patterns in the US over long time frames. B analogs - generally strong matches for temp OR precip patterns for long time frames. Or good matches for both in short periods (can beat A analogs in small periods) C analogs - generally strong matches for temps or precip for short periods. D analogs - consistently "off" but vaguely similar. "B" analogs for me right now are 1938, 1960, 1967, 1973, 1977, 1979, 1988, 1995, 1998, 2000, 2005, 2008, 2011, 2013, 2016. I'm most tempted by 1960, 1967, and then all the years I listed from 1998 on. I'm very hesitant to use the years after the biggy-El Ninos though (2016, 1998, 1973). Pending more information, I like some kind of weighted blend of 1961, 2000, 2001, 2011, 2017, 2020 for the Fall. That's a similar QBO/AMO/PDO/ENSO/Solar/Hurricane landfall/ENSO prior year match, with nearly identical matches locally for both temperatures and precipitation for close to a year. In other words, it's a cold ENSO year, after a cold ENSO year, with relatively similar solar, a warm North Pacific, and the Indian Ocean in the right phase (1998 is the most recent year with incredible warmth east of Indonesia like this year in a La Nina, tempted to use it to reflect the IOD magnitude). Need to see if resembles September at all though.