raindancewx

Let's try this again: There was another big SOI crash today. As far out as it is, the three models I look at all have a day ten storm tapping subtropical moisture. Are they going to be right, or even close this far out? No. But...this is the first time they've all had something depicted that far out since the October storm. Date Tahiti (hPa) Darwin (hPa) Daily Contribution 30 day Av. SOI 90 day Av. SOI 2 Dec 2020 1014.81 1008.05 15.78 8.74 7.73 1 Dec 2020 1014.91 1007.10 21.23 8.99 7.70 30 Nov 2020 1013.51 1006.20 28.18 9.24 7.69 There was an associated SOI drop in this time frame in December 2007 ahead of a big storm. 2007 332 1012.91 1006.95 19.59 (Nov 28) 2007 333 1013.66 1009.50 8.14 (Nov 29) 2007 334 1013.05 1010.90 -4.65 (Nov 30)(-23 in two days) 2007 335 1012.80 1010.30 -6.33 (Dec 1) (-15 in two days) Ten days later in Albuquerque: Date Hi Lo Mean Dpt HDD CDD Precip Snow 2007-12-10 40 32 36.0 -0.7 29 0 0.49 T 0 2007-12-11 43 33 38.0 1.5 27 0 0.24 0.3 0 Too early to expect anything useful from the models, but it is rare to see something on all three so far out here. The GFS has actually had something around 12/11 for a while already...but I had been ignoring it.

The PDO is negative. It's not speculation. https://www.ncdc.noaa.gov/teleconnections/pdo/ 202001 -1.40 202002 -1.47 202003 -1.75 202004 -1.32 202005 -0.51 202006 -0.76 202007 -0.89 202008 -1.32 202009 -1.02 202010 -0.58 Warm North Pacific does not mean +PDO. The blob idea as a unique feature is the most over rated idea of seasonal forecasting in the past decade. Same orientation in the Fall last year and ended up with a very warm winter. The Fall pattern wasn't even that different overall despite completely different tropical patterns. The Fall this year was hot west/east, cold central. Last year had more cold West, but not that different and presumably a lot of that is how close the North Atlantic/North Pacific look.

These are likely the closest La Nina matches to November 2020 overall: Blend Nino 4 Nino 34 Nino 3 Nino 12 Match 1971 27.71 25.56 23.79 20.89 0.47 2011 27.80 25.52 23.98 21.09 0.49 1956 27.89 25.56 23.77 20.59 0.61 1962 27.90 25.75 23.98 20.78 0.75 1995 28.11 25.60 24.04 21.37 1.02 1984 27.79 25.52 24.11 21.52 1.06

I actually don't think that Euro storm is going to come back as depicted unfortunately. The GFS has had something similar a bit later though. The SOI thing I've mentioned - that's the systems now. The crash was 11/21-11/23, and the rule is you wait ten days. It more or less did work as it is snowing across our northern mountains pretty heavily (really squalls with low qpf snow). There is a low over the area in the correct time frame too. But the NAM and HRRR were hinting at snow even down here earlier today. There is a winter weather advisory out, and the local NWS learned their lesson this time, waiting for the snow to actually develop before issuing an advisory. I want to see how December goes, but I find replicating July-December precipitation patterns is a good predictor for Jan-June. So if this holds up, there is a pretty strong precipitation signal for January here. Each blue period is wetter than average. The 12/1-12/5 high for the city as currently forecast looks ~top 20 for cold for the past 100 years. So some cold and some snow isn't a terrible way to start of a La Nina down here. I'm much more concerned about the Spring than the Winter for moisture. December has a bunch of ways it can be wet regardless of the outcome the next ten days. MJO phase five is usually pretty good in December, La Nina rapidly weakening would be good, another SOI crash could help. I'm a little bit optimistic for March too, just because every year we've seen snow in October in the city has seen snow in March. The years with October snow have all seen storms come through in the time frames we've seen them this year. The weird pattern of a lot of early cold days is unusual too (highs <=55), but it has some similarities to 1936 when I looked.

When I looked at all the years after a strongly +NAO November for December, I think there were only 2/23 from 1950-2019 with a warm West / cold East look. The most common outcomes were warm everywhere, warm East/cold West, and then cold South/warm North was next most common. Some weird mixed up patterns in there too. If you look at the current CPC 6-10 and 8-14 analogs, a lot of the +NAO November years show up. Forgetting the model depictions, when I looked at Boston, Chicago, Minneapolis and Billings, temperatures looked generally +5 to +10 for 12/1-12/5. So the December 2000 and December 2010 looks for extensive and severe eastern cold are very unlikely. Boston was mid-60s today for instance. Even in the South though, this first five day period has some warmth - Jacksonville has some 70s. So it's not super hard to see how the models came in warm for the month if this is the cold part of the month.

It actually snowed a lot out here in early September, so prefer July-June for snow maps. That's why I do it that way for my snow maps. The short range models (3-km NAM and HRRR) have been trending up for mountain snow and maybe even a bit more for me tomorrow. That's the ten day lag after the last big SOI drop, so I've been watching this period for a while now. It's snowing fairly heavily at Angel Fire Resort at the moment as the snow expands. The depiction of snow has changed every six hours for like six days at this point. Not a well handled situation by the models. I don't completely buy the model outlooks for December from the CFS and Canadian. I'd expect cold to retrograde West later in the month. Locally, we seem to be running about 15 days off 2007 - the warm week one Dec 2007 was here late November (11/16-11/22 or so). That said, some of the models do have MJO phase five now later in the month which is a cold Southwest warm East look in December. Late Dec 2007 was MJO phase five too.

Pretty snowy Fall overall. Generally pretty similar to my July-June snow outlook. Interior West, Midwest and New England were favored zones. I'd like to see IL/IN/MO fill in a bit more, but the dryness recently in the Dakotas is in par with the idea. Not sure when the NYC to Richmond zone will have their best shot.

The Euro lost the storm down here on the most recent run. If that continues, we're not getting jack in the city until at least 12/10 or so. Anything that comes through with the current system(s) will be at most a dusting to an inch of snow and I expect nothing. Hoping the cold verifies at least. The local observations haven't been working so it is hard to tell if the cold front has arrived at the airport. It is windy here. Edit: I got 0.2", and the airport got nothing. But the Westside and towns north of the city got 2-6", even locally up to 8 inches of snow. So much for that. The 3-km NAM actually have a pretty good area of snow just north of the city and that worked out fine.

Ocean heat content for 100-180W at the equator came in at -1.04 - a bit lower than I had it. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt Still like this blend. Year Sept Oct Nov 1999 -1.27 -1.07 -1.48 2000 -0.12 -0.37 -0.67 2007 -1.03 -1.19 -1.19 2007 -1.03 -1.19 -1.19 2011 -1.01 -1.26 -0.92 2011 -1.01 -1.26 -0.92 Blended -0.91 -1.06 -1.06 2020 -0.87 -1.11 -1.04 Based on 1979-2019 subsurface data for November, the subsurface implies 25.67C for the La Nina in winter (-0.9C by the CPC baseline, -0.8C against 1951-2010), +/-0.6C at 85% certainty. In other words, a strong La Nina for winter (<=25.0C) is pretty unlikely now - well less than a 15% chance going by the subsurface. Solar activity, believe it or not finished at 34 sunspots in November. That's the highest reading for sunspot activity in over three years, since September 2017. Some of the things I look at are very sensitive to solar conditions, so will be interesting to see if it is trending it up rapidly or if it falls back for a bit. As recently as September, less than one sunspot was observed for the month overall.

Ocean heat content for 100-180W at the equator came in at -1.04 - a bit lower than I had it. Still like this blend. Year Sept Oct Nov 1999 -1.27 -1.07 -1.48 2000 -0.12 -0.37 -0.67 2007 -1.03 -1.19 -1.19 2007 -1.03 -1.19 -1.19 2011 -1.01 -1.26 -0.92 2011 -1.01 -1.26 -0.92 Blended -0.91 -1.06 -1.06 2020 -0.87 -1.11 -1.04

This is from one of the US seasonal forecasts, but I think it explains it well (AAM). He gives links where you can see plots of how it looks too. Atmospheric Angular Momentum: https://jimsullivanweather.com/2020/11/21/jim-sullivans-2020-21-winter-outlook-write-up/ Atmospheric angular momentum is, extremely basically, how much westerly flow there is across the globe. Typically, El Ninos feature a stronger / extended Pacific jet due to increased forcing over the Pacific, and higher AAM. La Ninas typically feature the opposite. Above is the seasonal correlation to AAM in DJF. The correlation is weak in much of the U.S., but in general higher AAM features a +PNA pattern with higher heights over Canada and lower heights over the southern U.S…basically a typical El Nino pattern. If you inverse the colors (use imagination) and emulate the correlation for a -AAM, it looks much more like a La Nina with higher heights off the West Coast and across the southern U.S. and lower heights over much of Canada. The AAM over the last year or so has been interesting. It was quite low in the fall of 2019, likely due to increased Indian Ocean forcing and limited Pacific forcing, which contributed to a very ridgey pattern in the mid-latitudes (in particular, across the Pacific) and limited disruption to the stratospheric polar vortex, allowing it to get quite strong by early 2020. It rose later in winter, though was distributed poorly and didn’t shake-up the +AO pattern. The AAM fell again over the summer as La Nina developed and strengthened. It has risen this fall and isn’t dropping back off yet. This atypical AAM for a La Ninia may explain why we’ve had cold weather over western North America and warmth nearly everywhere else in November (and quite possibly December, more later), which is not how La Ninas typically play out (usually, La Ninas start colder than they finish in the eastern US). The fact that the AAM is kind of high for a La Nina isn’t necessary bad, but how it’s currently distributed is poor for winter weather fans in the eastern U.S. and Europe to say the least:

Canadian has a similar look to the CFS for December. Huge changes from the prior monthly outlook for December in the circled areas. Winter overall trended warmer, but it did trend colder from the SE to NM and TX.

New Canadian trended La Nina weaker, with colder waters shifting West over time, other than a possible brief reversal east in March.

There is a pretty strong signal right now in Albuquerque precipitation data for a wet January. I call this the "replication" method for analogs. We get so little precipitation here that if you match monthly totals July-December within 0.2 inches of observations, you can predict Jan-Jun totals pretty well. December is obviously not in yet, so the January signal will change if the month is very wet or very dry. Will update if necessary. Blue highlighted data is a wetter than average month. Top ten matches, and a simpler are blend are shown.

The city ended up seeing nothing - not even measurable rain with the advisory storm. Latest models have the mountains getting snow the next few days, but not too much. The Euro has been showing a bigger storm grabbing subtropical moisture starting around 12/5 or 12/6. It's shown for several runs now.

For November, Nino 1.2 is likely about 21.0C on the monthly data well above the reading last month. Nino 3 is probably 23.8C or so. Nino 3.4 should be about 25.4C. Nino 4 I'd go about 27.9C. The monthly data tends to run a bit warm of the four week averages. The ONI value for SON will be around -1.2C using the rolling CPC 30-year average. Against 1951-2010 averages, it's more like -0.95C for SON. Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 04NOV2020 20.3-1.0 23.6-1.3 25.1-1.5 27.8-0.8 11NOV2020 21.2-0.3 24.1-0.9 25.7-1.0 27.9-0.7 18NOV2020 21.0-0.7 23.6-1.4 25.2-1.5 27.9-0.7 25NOV2020 21.0-1.0 23.7-1.3 25.3-1.3 27.9-0.7 The waters below the Nino zones still appear to be slowly warming. Subsurface value is around -1.1 for November as I mentioned above.

The Euro has now had a several run display of a huge storm coming into New Mexico around 12/5 or 12/6, and then leaving around 12/8. There was a huge storm in that time frame here in December 2007, on 12/10 or so. My guess is that sucker is the one that blew up into the first big snowstorm of December 2007 for Boston. We'll see how it goes, but I feel like I did my homework this year. That's the start of it. This is the peak - now shown three runs in a row.

There it is guys - the big wet storm of 12/10/2007, right on time. It actually starts much earlier than this 174 hours in terms of precipitation. The first moisture would be ~150 hours on the Euro from now. This is the last two runs. Was shown on the prior run too.

Looks like it will get pretty cold in this time frame. Not sure about moisture yet. My wild card is this system may be able to tap some moisture from the Gulf of California even if the subtropical jet isn't there. But the models don't really show it. But usually the storms that are strong that get far enough south can do it. The last system missed Albuquerque, but areas south and west had a pretty decent little snow event, with 0.05-0.20" liquid falling as snow.

I'd go 1960/2011, or 1960/2007/2011 as the blend for December going by recent conditions and what the models show. Should be an interesting month. 1959/1988 have the right feel to me for December, but they don't really look like November. 1960/2011, and 1960/2007/2011 actually match on a lot of things, +NAO November/November look, identical SOI, similar SSTs, the current CFS monthly depiction and so on. I'd warm up either blend outside the NW by 1-2 degrees though.

Top SOI Matches for Sept-Nov: SOI Sept Oct Nov 1947 11.7 -1.6 8.7 1959 0.5 4.7 11.2 1960 7.6 0.3 6.8 2007 2.2 6.1 9.9 2011 11.1 9.7 12.4 2017 6.1 10.6 10.4 Blend 6.5 5.0 9.9 2020 9.9 4.4 9.2 Simple SOI Match: SOI Sept Oct Nov 1960 7.6 0.3 6.8 2011 11.1 9.7 12.4 Blend 9.4 5.0 9.6 2020 9.9 4.4 9.2 November 1947, and November 1959 were extremely cold. Nov 2017 has intense heat too far West, with the east too cold for November. So I like a blend of 1960, 2007, 2011. The 1960 inclusion gets you a "-NAO" December look to offset 2007/2011 a bit. As a blend, it looks dead on to November. I would warm up the 1960/2007/2011 look outside the NW for December since it is centered on 1992 by 1-2 degrees. Also, in recent years when that warm Montana to Florida look appears, the SW is colder - almost always - than what the CFS depicts.

Quick round up of emerging wildcards for the winter. 1) Solar Activity is rapidly increasing. My research is that some monthly precipitation and temperature patterns are far less or far more likely when solar activity sustains above 55 sunspots/month in a July-June year (i.e. the ENSO year). If we were to sustain at over 55 sunspots in 2020-21, I'd be a lot more optimistic about March precipitation/snow in the Southwest, particularly if the La Nina were to rapidly collapse toward an El Nino. 2) Fall doesn't look like any La Nina since 1950. There is no La Nina since 1950 with a cold middle, warm East/warm West look. The closest thing to a La Nina with that look is 1959, a near-La Nina with a warm NE Pacific. Other years with this look include 2018, 2019 with 2003 and 2014 also somewhat close. 3) After researching it, heavy snow is fairly likely to dump again in the Southwest at some point. This may be the part of the pattern when the NE cashes in again, as with October.

I went through all of the La Ninas since 1950 today. None of them have the "look" of Fall 2020: A colder area in the middle third of the US relative to warmer thirds for the East and West. The closest thing to a La Nina that has the 2020 look is 1959, a cold-neutral ENSO with a very warm Northeast Pacific. That year also followed two El Ninos, with 2018-19 like 1957-58 - the stronger El Nino before a weaker event followed. The La Nina Falls since 1950 tend to have the middle third of the US warm, or the West cold. Neither feature is present this Fall overall. In that respect, 2010 (colder West), and 2016 (hotter middle of the US) are much more traditional even with their weird winter features that developed than 2020. The best matches to Fall are 1959, 2003, 2014, 2018, 2019. All of those years have a warm NE Pacific. So something to keep in mind for winter. The blend is pretty warm for December too, and actually pretty close to the CFS.

Albuquerque missed each time, but pretty decent week for snow down here. Picture is Angel Fire Ski Resort. Snow pack at Taos Powderhorn (the mountain for Ski Taos) currently is third highest snowpack since 2010 for the date. Snow pack for New Mexico is not good overall, but should improve more in the next week. Northern areas are closest to normal as expected in my forecast.