raindancewx

One of my favorite things about this winter so far is it doesn't fit at all with the QBO/ENSO/Solar ideas. The -ENSO, +QBO years have all been terrible matches so far in low solar years. Those are your +QBO years in low solar with a -ENSO. Year D QBO 1964 0.04 1973 2.31 1975 10.95 1985 9.51 2008 10.46 2010 10.97 2016 15.09 The only +QBO/-ENSO years to look like December were 1959 and 1999, both high solar, and 1999 had a very +NAO all winter to me it is sort of a fluke that it matches December.

The Euro initializations do show that Nino 3.4 warmed in December. The peak was likely in the Fall for this event in an ONI sense. We're probably at or nearing the point in real-time when Nino 4 will be colder than Nino 3.4 in an anomaly sense. Long time since we've seen that.

Early part of January will verify warm for most. Will be curious to see how the later parts come in.

Albuquerque has been dry and cold lately. No 60 degree temperatures since November 23. May not sound like much, but it's already one of the longest periods in a La Nina without hitting 60 degrees at any point. We're at 39 through today. This week should see some highs in the mid-50s, but I doubt we'll get to close to 60. My hunch is the streak lasts until at least mid-January. The list below is only La Nina years.

Looks like Boston's December high went from an average of 41.7F in 1981-2010 to 42.5F in 1991-2020. A year like December 2020 is now about average.

Any idea on how long it will take NWS to switch to the 1991-2020 normals? It'd be weird seeing a month calculated against one baseline, and then a sudden shift to another.

The subsurface warmed to -0.93 for 100-180W in December. Strongest month by this measure was October, at -1.11. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt Very simple blend works for Oct-Dec for the subsurface: Year Oct Nov Dec 1995 -1.03 -0.86 -0.84 2007 -1.19 -1.19 -1.08 Blended -1.11 -1.03 -0.96 2020 -1.11 -1.04 -0.93 But I don't expect the US temperature anomalies to look like the blend of those years. If you plot the December subsurface data against the following March in Nino 3.4, March should be around 26.4C (-0.8C by the current CPC standard). Now that it is 2021, CPC should be updating the baseline for La Nina and El Nino since they use a rolling five year average in their current ONI methodology. So this event will probably magically look stronger in a few days once the baseline warms up another 0.1C or so with 1997-98 and all of 2015-16 in the same 30-year period.

Here is how I am doing so far. Most of the US verified within 3 degrees of the blend I had for December from October. The blend improved quite a bit compared to observations in the South, Midwest, Texas, and Southern Plains from 12/21 to 12/31.

As with December, I think the CFS & Canadian know a +WPO look weakly favors cold in the interior West but they can't' quite figure out where to place the cold spot. I like a colder blend of the CFS/Canadian looks for the month though.

Canadian is really ramping down on expectations for the La Nina. Nice west-based look for JFM now. I think that model has a decent handle on La Ninas generally, it did quite well for December -

CPC final update. Don't shoot the messenger. Their final outlook was pretty decent for December.

My interior West cold idea for this winter has held up pretty well so far. This is your first third of winter 2020-21.

The 1954-55 La Nina is actually an uncannily good match for precipitation patterns here from July-December, and it did peak pretty early in Fall as one of the strongest early peak events before warming a lot in winter. It was like 25.26C (-1.3C v. 1951-2010) in Aug-Oct, which is nuts. It would be -1.5C on the modern baseline CPC uses for Aug-Oct, comparable to 2010 in that time frame before rapid warming. I like 1955 temporarily, for Spring. But I'll abandon ship in Summer. There is a lot of crazy stuff later in 1955. Nino 3.4 goes all the way down to 24.25C in November 1955, which is the coldest monthly reading in that zone since 1950. My big issue with that year is...we probably can't keep getting these double same-sign ENSO events right? 2014-15/2015-16 --> EL 2016-17/2017-18 -> LA 2018-19/2019-20 -> EL 2020-21/2021-22 -> LA? (I have my doubts) Strictly speaking 2016-17 isn't really cold enough to be a La Nina. But I count it as one because the oceans were running +0.7C compared to 1981-2010 at the time, and the subsurface was almost as cold as in this event or 2017-18. If you end up around 25.7C in Nino 3.4 in Dec-Feb, the plurality of most similar winters is to go to an El Nino the next year. I say 25.7C in winter because December looks like it is ~25.6C, and then even if January doesn't weaken at all, February should be a lot warmer.

The December SOI finished at +16.63. That is the 5th highest value in the past 90 years for December, behind 1950, 1975, 2010 and 2011. The SOI values in Oct-Dec match pretty well to observed US weather the past few months if you use a blend of 1954, 1959, 1961, 1999, 2011. SOI Oct Nov Dec 1954 2.2 2.3 11.5 1959 4.7 11.2 6.9 1961 4.7 6.8 12.5 1999 9.5 11.6 12.4 2011 9.7 12.4 22.2 Blend 6.2 8.9 13.1 2020 4.4 9.2 16.6

We actually pulled out a cold/wet month by the headwaters of the Rio Grande, which will help keep that river running for a while. Albuquerque will finish the month around 1F below the 1931-2019 average high, and with the coldest average low since 2009 or 2011, pending whether we drop to 25, 20, or 15 tomorrow. My idea for the winter has been that the northern mountains here would be "OK", and the southern mountains would get...jack. That seems about right so far. This storm really saved the northern snow pack for the green range at the end of the month.

The models seem to like the first half of January 2021 as a clone of January 2008. What do you think? Do we get the cold of January 2008 too? This image of 2021 is from BAM's twitter. I see a strong resemblance to the warm half of January 2008. So the question is whether the cold half is there too if the warm half verifies.

Works for me.

The north-central mountains here have been doing OK, but it's not been good elsewhere. The north-central part of the state near the Colorado border did finish pretty close to normal though for December precipitation with the recent system.

Assuming this is calculated the same way as CPC, the WPO is supposed to be very positive into early January. There are only 10 cold-ENSO years with a +WPO look in January from 1950-2019. It's quite warm for the US without the Greenland block, but that is forecast to happen for a while. The CFS temperatures currently look a lot like the +WPO, cold ENSO look without blocking though. I would say at least for December, 2011 has taken over as the best La Nina match. Other years that are similar in Nino 3.4 are pretty different in the other zones. The stronger La Ninas like 1973, 1975, 1988, 1999, 2007 and 2010 all had more darker blues and even purples by the equator at this time. In 2017-18, and a lot of other 'weak' La Ninas, you actually have a lot of deeper blues right next to South America, east of Nino 3.4.

I agree with that. It was never really supposed to be a carbon copy of 2007-08 though. 2012-13 is a hell of a lot warmer than 2007-08 in December in your area if my memory is right, that was one of the things I liked about it. I gave 2012 the next highest weight after 2007-08 because I never really bought the La Nina being able to keep pace with 2007-08, and I wanted a lot of super low-sea ice years with a cold ENSO. So 2012-13 fixed the sea ice and ENSO strength. 2003 and 1995 and 2019 were in there for more complicated reasons.

Looks like my analog blend had Boston snowfall at 19.8 inches through 12/28, compared to the 17.3 inches observed through 12/28. Will be curious to see how the season finishes. The weighting was 2007-08 (x5), 2012-13 (x2), with the others at x1. This is Boston snow totals from xmACIS through 12/28. 1995-12-28 28.2 2003-12-28 21.5 2007-12-28 26.9 2012-12-28 1.2 2019-12-28 11.5

I hate using this scale. So imprecise. But it clearly shows the La Nina weakening:

Nino 4 in the prior winter and December SOI values are both good predictors for the NAO to go positive in February. Will be curious to see if that happens in February or if it sets up before. You have 1/20 years with a -NAO in February after Nino 4 is above 28.7C in the prior winter, and no meaningfully negative -NAO February years after the the SOI is above +12 in December. SOI is currently about +16 for the month, and Nino 4 was 29.20C or so last winter. The +22 SOI in December 2011 and and the +26 SOI in December 2010 ate the NAO alive the following February. The transition in 2011 is kind of amazing since it ended a 14-month period with the NAO well into the negative phase (Dec 2009, +2010, +Jan 2011). https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table 2011 -0.88 0.70 0.61 2.48 -0.06 -1.28 -1.51 -1.35 0.54 0.39 1.36 2.52 2012 1.17 0.42 1.27 0.47 -0.91 -2.53 -1.32 -0.98 -0.59 -2.06 -0.58 0.17

January 2021 apparently has a 2007-08 winter look on the European.

Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 02DEC2020 21.8-0.5 24.4-0.7 25.5-1.1 27.6-1.0 09DEC2020 22.4-0.1 24.3-0.8 25.4-1.2 27.7-0.8 16DEC2020 22.0-0.8 24.3-0.8 25.6-0.9 27.8-0.7 23DEC2020 22.1-1.1 24.5-0.7 25.7-0.9 27.6-0.8