raindancewx

I'm looking forward to seeing if any flakes will make it into Albuquerque. I don't expect any accumulation, it is after all going to be 95 or so on 9/7. I'm also very curious to see what the US national temperature anomalies look like after this plows through next week, my tentative winter analogs from August are remarkably close for September so far, but it may change dramatically this week and I'll have to see if a re-weighting is necessary.

One thing I've been looking at lately is how the ACE Index relates to severe cold outbreaks in La Ninas in the Southwest. In general, there are more cold days in lower ACE La Ninas if you use 10F below average in Nov-Feb as the threshold. But it doesn't hold super well for the rarer, more intense cold waves. Current ACE index is 45 - and we're about half way through the season now. The chart shows subsets, i.e. 1933-34 had four days in Nov-Feb that were at least 10F below average, of which, one was 15F below average. Cold Days Nov-Feb in Albuquerque by ACE Index La Nina ACE Index <=-10F <=-15F <=-20F 1933 258.6 4 1 0 1938 77.6 25 10 3 1942 62.5 3 0 0 1949 96.4 10 2 0 1950 211.3 11 5 4 1954 110.9 6 2 0 1955 158.2 12 5 2 1956 56.7 8 3 0 1964 169.8 10 3 0 1970 40.2 8 6 5 1971 96.5 11 7 1 1973 47.9 15 5 3 1974 68.1 21 10 4 1975 76.1 10 4 0 1983 17.4 5 2 0 1984 84.3 15 3 2 1988 103.0 13 2 2 1995 227.1 1 0 0 1998 181.8 4 0 0 1999 176.5 1 0 0 2000 119.1 11 2 0 2005 250.1 3 0 0 2007 73.9 10 0 0 2008 145.7 2 0 0 2010 165.5 11 7 3 2011 126.3 2 0 0 2016 141.3 3 0 0 2017 224.9 0 0 0 Weatherbell has this for the winter, if anyone is curious - fairly typical low-average ACE La Nina winter look.

CPC has August Nino 3.4 SSTs 0.60C below the 1985-2014 average for Nino 3.4.The 26.3C value for August is still only 0.35C below the 1951-2010 average. Nino 4 is actually still about 0.1C above the 1951-2010 average in August (although a degree colder than last year). The official ONI value for JJA is -0.4C. The Nino 3 and Nino 3.4 readings for August are the coldest they've been awhile but both were -0.35C against 1951-2010. Nino 1.2 was -0.75C in August against 1951-2010. The figure in Nino 3.4 for August is almost identical to August 2016, but that La Nina (and it doesn't even qualify as one by older standards such as 1951-2010) ended in January in a CPC/ONI sense. I don't get the sense that this event will be as weak - the 2016-17 event finished with a 26.3C reading for Winter 2016-17 - the average in that zone is 26.5C long term and 26.58C for the CPC period - so the La Nina was over by then.

It's very difficult to get a good subsurface match for June-August that respects a) the big subsurface warm up in July, and b) the big subsurface cool down in August. A blend of 1984, 2003, 2010 has both rapid changes but isn't quite right on their severity, and has a fairly cool September for the middle of the US as the CFS/Canadian depicted for September. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt Year Jun Jul Aug 2010 -1.34 -1.36 -1.74 2003 0.13 0.53 0.03 1984 -1.15 -0.25 -0.22 Blend -0.79 -0.36 -0.64 2020 -0.62 -0.17 -0.81 There is a strong correlation in the subsurface data for August to Nino 3.4 Dec-Feb temperature - the historical data (1979-2019) implies a 25.74C Nino 3.4 in winter, plus/minus 0.72C at 80% certainty. That's an 80% chance of a cold ENSO between +0.00C and -1.50C against 1951-2010 Nino 3.4 averages. Worth noting, the severity of the cold below the surface may be flat lining again, or even set to rise again. It is interesting to me that the cold peak in May has not be matched again, at least so far.

Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 29JUL2020 20.1-1.1 24.7-0.7 26.3-0.8 28.4-0.4 05AUG2020 19.8-1.2 24.6-0.6 26.3-0.6 28.4-0.3 12AUG2020 19.9-0.9 24.8-0.3 26.4-0.5 28.3-0.4 19AUG2020 19.5-1.1 24.3-0.7 26.0-0.8 28.4-0.2 26AUG2020 20.0-0.6 24.2-0.7 26.1-0.7 28.6-0.1 Some warming this week in all zones in absolute SSTs outside Nino 3 which cooled. Still need Nino 3.4 to get colder than it is now for La Nina conditions in winter.

If the weeklies end up jiving up with the monthly data, by CPC standards, August 2020 will be La Nina level cold in Nino 3.4 (they use a 1985-2014 basis). On an older baseline, still kind of borderline, but very close. What's interesting is using 1951-2010, Nino 4 was still +0.4C in July, and even if the weeklies are right and August finishes at 28.4C in Nino 4...that's still average for Nino 4 which implies that zone will hinder a stronger La Nina from developing. If the subsurface cold is to reverse in Fall (if the Western warmth isn't destroyed in the coming weeks), you'd probably see the subsurface monthly data start to match up with 2000, which had some pretty cold Fall weather as the subsurface peaked and then reversed early by historical La Nina standards.

Another thing is, when the ACE index is over 160 in the Atlantic heading into a La Nina winter, the composite pattern is very different from when the ACE is below 160. The recent La Ninas that were good for the West, 2000, 2011, 2016 - were all well below 160. While 1995, 2005, 2017 had values in the 200+ range and saw essentially no moisture or cold in the Southwest especially. The current ACE value is about 42 through 8/28. We're entering the peak of the Atlantic hurricane season, but it looks quiet through early September. so that 42 value should move closer to average than it is now. I don't really expect an ACE value under 80, but the meaningful point is around 150/160 - at that level is becomes almost impossible for the West to have a cold winter in a La Nina.

One thing to watch with the La Nina is when the event peaks. If you look at it on a constant 1951-2010 basis, the La Ninas that peak in the Fall (coldest Nino 3.4 relative to monthly average) are much colder in the US than the La Ninas that peak in the winter. In fact, none of the La Nina with a peak in the Fall are warm US wide, although 2011-12 was really only cold in NM and West Texas. There are some very hot winters included in the mix when you get a winter La Nina peak - 1998, 1999, 2005 are all in there. I'd imagine 1933, 1942, and 1949 are in the right grouping too, with 1938 in the left group.

If La Nina persists into say, February, August is looking like the first La Nina month. Magnitude of the cold is La Nina, just have to see the duration now. Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 01JUL2020 21.1-1.1 25.5-0.5 27.3-0.1 29.1 0.3 08JUL2020 21.1-0.8 25.3-0.5 27.2-0.1 29.1 0.3 15JUL2020 20.2-1.5 25.1-0.6 27.0-0.2 28.8 0.0 22JUL2020 20.2-1.2 25.0-0.5 26.8-0.4 28.7-0.1 29JUL2020 20.1-1.1 24.7-0.7 26.3-0.8 28.4-0.4 05AUG2020 19.8-1.2 24.6-0.6 26.3-0.6 28.4-0.3 12AUG2020 19.9-0.9 24.8-0.3 26.4-0.5 28.3-0.4 19AUG2020 19.5-1.1 24.3-0.7 26.0-0.8 28.4-0.2 There is still a lot of heat below the western part of Nino 4 that should move east or spread out with time, but the cold should hold on in Nino 3.4 through at least September. I still expect something a fall peak in severity and some of the ENSO models show that.

Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 03JUN2020 23.1-0.3 26.0-0.7 27.3-0.4 29.0 0.2 10JUN2020 22.2-0.8 25.7-0.9 27.1-0.6 28.8 0.0 17JUN2020 22.2-0.5 25.7-0.7 27.2-0.4 29.1 0.2 24JUN2020 21.6-0.8 25.8-0.4 27.6 0.1 29.3 0.5 01JUL2020 21.1-1.1 25.5-0.5 27.3-0.1 29.1 0.3 08JUL2020 21.1-0.8 25.3-0.5 27.2-0.1 29.1 0.3 15JUL2020 20.2-1.5 25.1-0.6 27.0-0.2 28.8 0.0 22JUL2020 20.2-1.2 25.0-0.5 26.8-0.4 28.7-0.1 29JUL2020 20.1-1.1 24.7-0.7 26.3-0.8 28.4-0.4 05AUG2020 19.8-1.2 24.6-0.6 26.3-0.6 28.4-0.3 12AUG2020 19.9-0.9 24.8-0.3 26.4-0.5 28.3-0.4 There is some erosion in the cold near South America, but still borderline La Nina conditions overall. If Nino 3 and Nino 4 remains above -0.5 though it is likely Nino 3.4 will warm up a bit eventually, for a little while anyway..

The subsurface is now pretty supportive of a La Nina compared to a few weeks ago, although I think the cooling will reverse to some extent over the next few weeks.

Best shot at a -NAO this winter is January from the NAO predictors I have. Still early though. Change from April to May and March to September as a blend is a strong NAO predictor over the past 20 years. If the NAO is near 0/neutral in September, the best blend for matching the NAO will be 1966-67 (x2), 2003-04, 2007-08. There is some tendency for very cold years to come after the solar min year (July-June basis). NAO Sept-Mar May-Apr DJF 1975 2.17 1.08 0.23 2018 2.60 0.88 0.50 NAO Sept-Mar May-Apr DJF 2017 -1.35 -3.64 1.30 1994 -2.58 -1.71 1.36 2017 -1.35 -3.64 1.30 2017 -1.35 -3.64 1.30 2017 -1.35 -3.64 1.30 Mean -1.60 -3.16 1.32 2019 -1.39 -3.09 1.27 NAO was positive in March, so it will be hard for Sept-Mar to be too negative - but obviously if the NAO is very positive or very negative in September, this will change - NAO Sept-Mar May-Apr DJF 1966 -1.01 0.97 0.01 1966 -1.01 0.97 0.01 2003 -0.31 0.19 0.07 2007 -0.72 0.49 0.65 Blend -0.76 0.66 0.18 2020 ?? 0.61 This blend seems solid intuitively - you have four years following El Ninos, and it is a La Nina-ish blend. Blend Dec Jan Feb Mar 1966 0.7 -0.9 0.2 1.5 1966 0.7 -0.9 0.2 1.5 2003 0.6 -0.3 -0.1 1.0 2007 0.3 0.9 0.7 0.1 Mean 0.6 -0.3 0.2 1.0

The latest subsurface update does look a bit better. European is still not 100% on board with a La Nina, but I've been expecting a ~26.0C Nino 3.4 in Dec-Feb, and that still looks about right, whether its a hair on the Neutral side or a hair on the La Nina side. The cold water has really thinned by South America though, and there is still a lot of warmth below Nino 4. To me there is some potential for a cool peak in Fall for Nino 3.4 - maybe to near -1.0 as the cold comes up - and then it warms fairly consistently through winter. There is some intense cold right now in Nino 3/3.4 but it isn't a very large or deep area. Once that surfaces, you'd expect the warmth west of it and below it to have a shot at coming up.

Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 01JUL2020 21.1-1.1 25.5-0.5 27.3-0.1 29.1 0.3 08JUL2020 21.1-0.8 25.3-0.5 27.2-0.1 29.1 0.3 15JUL2020 20.2-1.5 25.1-0.6 27.0-0.2 28.8 0.0 22JUL2020 20.2-1.2 25.0-0.5 26.8-0.4 28.7-0.1 29JUL2020 20.1-1.1 24.7-0.7 26.3-0.8 28.4-0.4 05AUG2020 19.8-1.2 24.6-0.6 26.3-0.6 28.4-0.3 Nino 3 has been in La Nina conditions for three months now. Nino 3.4 / 4 keep warming up each time a cold pulse reaches them. I'm starting to think this will be a "Nino 3" La Nina, but an official Neutral. August is still cold below the surface so far, but barely. The level of coolness is actually very similar to last year, which is interesting since August looks very similar so far.

CPC is set to update its baseline averages in 2021 for El Nino and La Nina. It looks to me like the new winter average (DJF) in Nino 3.4 is going to be right around 26.63C for 1991-2020, whereas the 1951-2010 average is 26.50C. Any event that can finish below 26.15C or so will be classified as a La Nina in 2020-21. I've been pretty impressed with 2003/2010 for how close that blend is to the tropical pacific and has been for a while now. I'll have my winter outlook out in October - but this looks like an easier forecast than last winter to me. For the past three months, the subsurface is a very strong match to 1984, 2003, 2003, 2010 as a blend too. My general sense is the NAO will be positive, with the PDO negative, and La Nina/near La Nina conditions. Solar activity has been increasing lately, but not dramatically. That's similar to 2009, when the absolute floor was in February. That's a bit of a wildcard. My current leading analog blend for winter has an ACE index around 160 for the Atlantic in 2020, which currently looks about right - we'll see it goes. 100-180W May June July 1984 -1.11 -1.15 -0.25 2003 -0.85 0.13 0.53 2003 -0.85 0.13 0.53 2010 -1.00 -1.34 -1.36 Blend -0.95 -0.56 -0.14 2020 -0.92 -0.62 -0.17

For reference. The European had a substantial warm up in Nino 3.4 (slightly different from CPC - they only show slight warming because they use a different baseline for what is average each month).

Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 03JUN2020 23.1-0.3 26.0-0.7 27.3-0.4 29.0 0.2 10JUN2020 22.2-0.8 25.7-0.9 27.1-0.6 28.8 0.0 17JUN2020 22.2-0.5 25.7-0.7 27.2-0.4 29.1 0.2 24JUN2020 21.6-0.8 25.8-0.4 27.6 0.1 29.3 0.5 01JUL2020 21.1-1.1 25.5-0.5 27.3-0.1 29.1 0.3 08JUL2020 21.1-0.8 25.3-0.5 27.2-0.1 29.1 0.3 15JUL2020 20.2-1.5 25.1-0.6 27.0-0.2 28.8 0.0 22JUL2020 20.2-1.2 25.0-0.5 26.8-0.4 28.7-0.1 29JUL2020 20.1-1.1 24.7-0.7 26.3-0.8 28.4-0.4 CPC had May-July at -0.2C. The current weekly data actually looks like a La Nina - we'll see if it continues.

The heat content of the upper 300m of 100-180W at the equator warmed to near average temperatures in July. Still colder than in 2017 which did become a La Nina late. But, the trend in 2017 was already sharply down by this down by point - not up. In 2017, you had across the board cooling in July. We've had across the board uninterrupted warming since May. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt YR MON 130E-80W 160E-80W 180W-100W 2017 4 0.34 0.28 0.06 2017 5 0.37 0.36 0.30 2017 6 0.21 0.22 0.22 2017 7 0.13 0.15 0.16 2017 8 -0.19 -0.21 -0.40 2020 4 -0.20 -0.24 -0.30 2020 5 -0.51 -0.70 -0.92 2020 6 -0.35 -0.54 -0.62 2020 7 -0.10 -0.22 -0.13

Closer this week. Nino 4 continues to resist cooling meaningfully. Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 27MAY2020 23.3-0.4 26.3-0.5 27.3-0.5 28.7-0.1 03JUN2020 23.1-0.3 26.0-0.7 27.3-0.4 29.0 0.2 10JUN2020 22.2-0.8 25.7-0.9 27.1-0.6 28.8 0.0 17JUN2020 22.2-0.5 25.7-0.7 27.2-0.4 29.1 0.2 24JUN2020 21.6-0.8 25.8-0.4 27.6 0.1 29.3 0.5 01JUL2020 21.1-1.1 25.5-0.5 27.3-0.1 29.1 0.3 08JUL2020 21.1-0.8 25.3-0.5 27.2-0.1 29.1 0.3 15JUL2020 20.2-1.5 25.1-0.6 27.0-0.2 28.8 0.0 22JUL2020 20.2-1.2 25.0-0.5 26.8-0.4 28.7-0.1

I've been updating my sheets that compare solar tendencies to weather in Albuquerque. First look since 2015-16 data was in. - Snowfall frequency in March & April now looks like it may be significantly impacted by the sun, with two of the last four low solar years seeing snow in April in Albuquerque (way above average frequency for four years) and none of the last four Marches seeing snow (way below average frequency, especially with two El Ninos). Over the next 10 years, I think snow frequency for March & April will both become statistically significant between the high and low parts of the solar cycle here - both have p-values of around 0.05-0.10 if you do a difference in proportions test right now. - Cold winter highs in Albuquerque are still far more common with low solar activity. This held up to some extent in the last four years, with 2018-19 about 2F below the 30-year average (1991-2020), and 2019-20 about 0.5F below the 30 year average, with the winters also below (2018-19) and dead on average v. the past 100 year average highs. - Heavy snow months are much more likely in high solar winters, despite the tendency for low solar winters to be colder. The data now includes 89 years, up from 85 before, with a substantial growth in low solar years (32, +4). I waited until we had two more La Nina and two more El Ninos for the update too. Long term, the odds of very heavy precipitation in a high solar winter also seem to be nearing statistical significance relative to low solar winters. For snow, it looks like there is an extra 19 percentage point shot at getting 2", 3", 4", 5", or 6" of snow in a month with high solar activity, compared to low solar activity.

For reference: Big time cooling from a warm MJJ in 2017 is not happening right now. Instead, there is a warming trend for May. This is consistent with the SW cooling off recently. When there are big drops in subsurface heat, we fry with almost no moisture. When there is a big warm up, it cools off and gets stormier - pretty much immediately. We were very hot here in Apr/May but have cooled off in June, and have trended much colder lately in July. January 2017 was also extremely wet.

Hurricane warning for Texas! Putting a lot of moisture in the Rio Grande Valley is probably good for us to the West though.

I don't see anything to force big changes in Nino 3.4 at the moment, for say 2-4 weeks. Everything is remarkably near average below the surface down to 200m in Nino 3.4

We're still in a non-Nina Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 06MAY2020 24.8 0.2 27.4 0.2 28.0 0.2 29.0 0.3 13MAY2020 24.5 0.2 27.0-0.1 27.6-0.3 29.0 0.3 20MAY2020 23.9-0.1 26.4-0.6 27.4-0.4 28.9 0.1 27MAY2020 23.3-0.4 26.3-0.5 27.3-0.5 28.7-0.1 03JUN2020 23.1-0.3 26.0-0.7 27.3-0.4 29.0 0.2 10JUN2020 22.2-0.8 25.7-0.9 27.1-0.6 28.8 0.0 17JUN2020 22.2-0.5 25.7-0.7 27.2-0.4 29.1 0.2 24JUN2020 21.6-0.8 25.8-0.4 27.6 0.1 29.3 0.5 01JUL2020 21.1-1.1 25.5-0.5 27.3-0.1 29.1 0.3 08JUL2020 21.1-0.8 25.3-0.5 27.2-0.1 29.1 0.3 15JUL2020 20.2-1.5 25.1-0.6 27.0-0.2 28.8 0.0 The 2017 event came on super late though - have to watch for that. The very cold water below eastern Nino 3/1.2 seems to be surfacing now. 10MAY2017 25.4 1.0 27.8 0.6 28.3 0.5 29.1 0.4 17MAY2017 25.2 1.1 27.6 0.5 28.2 0.4 29.0 0.3 24MAY2017 24.2 0.4 27.5 0.6 28.4 0.6 29.1 0.3 31MAY2017 23.7 0.2 27.2 0.5 28.3 0.6 29.2 0.4 07JUN2017 23.1-0.1 26.9 0.3 28.1 0.4 29.3 0.5 14JUN2017 22.9 0.0 26.7 0.2 28.2 0.5 29.4 0.6 21JUN2017 22.9 0.3 26.7 0.4 28.3 0.7 29.5 0.7 28JUN2017 22.8 0.4 26.5 0.4 28.1 0.7 29.4 0.6 05JUL2017 21.7-0.3 26.1 0.2 28.0 0.6 29.4 0.6 12JUL2017 21.8 0.0 26.1 0.4 27.8 0.5 29.3 0.5 19JUL2017 21.4-0.1 25.7 0.2 27.6 0.4 29.2 0.4 26JUL2017 21.3 0.0 25.5 0.1 27.1 0.0 28.9 0.2 02AUG2017 20.9-0.1 25.4 0.1 27.2 0.2 28.9 0.2 09AUG2017 20.5-0.3 25.1 0.0 26.7-0.2 28.7 0.1 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

Looks like the cold east / warm west should continue for a bit in the Nino zones. Not really a whole lot of intense warmth or cold in the Nino 3.4 zone. The Euro is still more on board with a cold Neutral than a La Nina too -