2019 ENSO

[StormchaserChuck!]

NAO sometimes switches around the Winter solstice, or up to 2 weeks later. I found that connection to be true. 

[raindancewx]

The +NAO Nov, -NAO Dec thing is pretty unusual if it verifies, regardless of ENSO - but there are no La Ninas with the combo. These are the only years to do it since 1950. You can see it is a mixed bag for January. Of the years in the chart 1953 is closest to US conditions for Nov-Dec.

Also very curious to see the weekly data tomorrow. Should give a good idea if December is really going to finish warmer than November in Nino 3.4.

The SOI is around +13 for the past 30 days despite the big crash recently. Has been similar to 2007-08 since October on that indicator. https://www.longpaddock.qld.gov.au/soi/

[StormchaserChuck!]

Yeah, I found there's about a 60% correlation to NAO from November to December based on data, probably closer to 55-58% in reality. 

[raindancewx]

                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
 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

I don't know that Nino 1.2 averages really change as rapidly as depicted, but that's the only region that cooled off by actual temperatures this week. Nino 3.4 is at 25.5C for the month, which is about -1.0C for 1951-2010. Nino 4 is still pretty cold. Nino 1.2 averages 22.58C for 1951-2010 in December, so that's still the laggard in terms of coolness. The 20.86C last month was about -0.6C against 1951-2010.

[raindancewx]

I'm starting to see a lot of speculation about an active tornado season. One thing that is against that is the current WPO / Nino 4 blend. The WPO is a very strong signal for a cold SW / warm Central US in April if it is positive, and the opposite if negative. A blend of a +WPO December and a cold Nino 4 December (27.6C or so) is unusual. The blend I get is something like this:

That favors a pretty -WPO in April, which is actually a warm Southwest/cold Central pattern, i.e. not real tornadic. The WPO correlations change dramatically in May. But if you want a big tornado season, you should be rooting for the WPO to hang on positive through April.

WPO     Feb       Mar         Apr
1953     1.38      0.58       -1.86
1972     -2.26    -1.87       -0.01
1985     -1.12     1.81       -0.53
2008      0.01     -1.35       0.28
2009      1.71      0.22       0.02
Blend     -0.06    -0.12      -0.42

 

[andyhb]

Active tornado season in Dixie, not necessarily the Plains.

That, and weak La Niña (which is what the weeklies have been shifting towards in 3.4) has not been friendly to tornado season as of late (2006, 2009, 2012, 2017, 2018).

[raindancewx]

The 30-day SOI has run up to +14. If we hold at +10 to +18 like in December 2007, you should see pretty strong warmth develop in the South either in or by February. None of the years in the +10 to +18 SOI range are cold in the South in February. It's arguably the strongest correlation for the SOI of the entire year. The coldest major +SOI December years are still 'slightly warm' in the South the following February.

[raindancewx]

My best guess is the SOI finishes around +14 in December at the moment. If you match similar SOI years to December temperature observations in the US, I think a look similar to 1955, 1960, 2000, 2008 as a blend is likely for January. It's kind like a colder January 1989. The January look below is pretty similar to my winter forecast idea too.

If the SOI goes a lot higher or lower by the end of the month, will have to change the mix to match observations.

Jan	WPO	EPO	PNA	AO	NAO	D SOI
2008	0.92	-1.25	-0.32	0.82	0.89	13.3
2000	-0.21	-0.92	-0.82	1.27	0.6	12.4
1955	0.4	-1.32	0.4	-1.16	-1.84	11.5
1960	-0.03	-0.76	0.38	-2.48	-1.29	6.9
Blend	0.27	-1.06	-0.09	-0.39	-0.41	11.03

[raindancewx]

When I try to match the idea in my head about how the La Nina will weaken based on its current strength and trends, this was the simplest blend I could find.

Until more data comes in, I'm assuming this is a decent blend for US Spring weather. The blend would have the WPO & NAO favorable for pretty extensive US cold in March, but after that, would probably become pretty tornadic. I'll obviously refine this, but it does get you a cold NW / warm SE look in aggregate. This is a very dry look for the Southwest for Spring, something like 60% below average down here, so I'm hoping something changes materially. This is a +AMO, -PDO, low-sunspot blend with a weakening La Nina of similar strength compared to December 2020, so barring the weather not matching in Jan-Feb, I bet it's a decent match. Will change my blend as needed ahead of my Spring Outlook. This blend also looks quite close to how Nino 4 and Nino 3.4 will finish for December, maybe Nino 1.2 and 3 also, pending the weeklies tomorrow. 

[raindancewx]

               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

[raindancewx]

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

[raindancewx]

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.

[raindancewx]

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

[andyhb]

13 hours ago, raindancewx said:

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

Looks like the two years that had big -NAOs in January out of that composite are 1955 and 1960. The former just seems to be a pretty good analog in general the more I filter.

[raindancewx]

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.

[andyhb]

1955 was a very active spring over the Southern Plains severe weather wise, especially for the time.

[raindancewx]

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 -

[raindancewx]

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.

[StormchaserChuck!]

That is some warm subsurface water building in the western subsurface. I wouldn't be surprised if we just rollercoaster this pattern until May-June. 

If we see a La Nina develop in April, I would be surprised, and it would definitely mean something else. 

[raindancewx]

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.

[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.

[raindancewx]

The weeklies had a bit of a rebound this week. I think you see that for another week or two before the real weakening push starts. The monthly data was the most different from the weeklies it has been in a while too.

                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
 30DEC2020     22.2-1.3     24.4-0.9     25.4-1.2     27.3-1.1

https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/detrend.nino34.ascii.txt

2020  10   25.46   26.75   -1.29
2020  11   25.30   26.75   -1.45
2020  12   25.43   26.65   -1.22

Even so, the monthly data warmed quite a bit. Against the 1951-2010 standard that I like, the December reading is -1.03C

[raindancewx]

Nino 4 in 2007 looks like it is still behaving pretty similarly to 2020. But Nino 3.4 is really starting to fall behind the pace. That's not super surprising to me, I had other years in my winter blend to warm up 2007-08. It is worth noting in December, the 2017-18 event was colder/stronger in Nino 1.2 and Nino 3 in December, but warmer to the West.

This is what I get for the four zones compared to 1951-2010 averages and some recent events in December. The closest match to December is easily 2011, within 0.2C in all zones, and then 1974 and 1983 are close outside Nino 1.2. These are all standardized against 1951-2010 averages. If you look at what the CFS / Canadian tried to do for US temperature anomalies in January, the models look a lot like January 1975, 1984, 2012 as a blend.

[raindancewx]

QBO now appears to be in decline. It's been very similar to 2010 for four months, but not close for actual US weather. https://psl.noaa.gov/data/correlation/qbo.data

2010  -16.02  -16.98  -19.68  -23.57  -26.28  -25.05   -9.84    1.45    6.58   10.83   12.16   10.97

2020   -2.51   -3.20   -4.36   -5.03   -4.86   -2.78    0.34    4.78    7.95   10.80   11.15   10.37

[raindancewx]

Euro still has Nino 4 cooling off through January. The end of the La Nina could be as soon as March - most of the ensembles are above -0.5C in April as they were last month.  

Nino 4 is still forecast to be very cold this month before slowly warming. It should still be below average in Spring & early Summer if the Euro is right.

If we see a cold Nino 4 verify for winter and spring it is a fairly strong cool signal in the Summer for the US in some areas.

 

[raindancewx]

SOI has really kicked into high gear recently. Over +19 for the past 30 days. Historically, the top SOI values in January don't actually favor a La Nina the next winter though. The winters after a +10 SOI in January for the prior 90 years have tended to see warmer conditions in Nino 3.4. I think the push for the SOI now reflects the fairly quick cooling we've seen in Nino 4 more than anything.

[raindancewx]

MEI finally updated after close to two months.

https://psl.noaa.gov/enso/mei/

YEAR

DJ

JF

FM

MA

AM

MJ

JJ

JA

AS

SO

ON

ND

2007

0.6

0.4

-0.2

-0.4

-0.4

-0.9

-0.8

-0.9

-1.1

-1.1

-1.1

-1.2

2020

0.3

0.3

0.2

-0.1

-0.2

-0.7

-1

-1

-1.2

-1.2

-1.1

-1.2

 

 

[raindancewx]

I mentioned this in the winter thread, but there is a theory in long-range forecasting that North Pacific (Bering Sea) patterns will show up in the US in 17-21 days. The big storm by Kamchatka over 12/28 is now supported by the SOI thing I use to pass over the SW - somewhere - in about 10 days given the recent big crash in the SOI. The 12/28 storm supported 1/14-1/18 for a storm passage, and now it looks like 1/17 or so using the SOI rule.

Over the past few weeks the eastern Nino zones have really been getting their asses kicked by warming even as the western zones remain quite cold. Nino 3 and Nino 1.2 are already close to not being in "La Nina territory".

 

[jaxjagman]

On 1/8/2021 at 7:49 PM, raindancewx said:

I mentioned this in the winter thread, but there is a theory in long-range forecasting that North Pacific (Bering Sea) patterns will show up in the US in 17-21 days. The big storm by Kamchatka over 12/28 is now supported by the SOI thing I use to pass over the SW - somewhere - in about 10 days given the recent big crash in the SOI. The 12/28 storm supported 1/14-1/18 for a storm passage, and now it looks like 1/17 or so using the SOI rule.

Over the past few weeks the eastern Nino zones have really been getting their asses kicked by warming even as the western zones remain quite cold. Nino 3 and Nino 1.2 are already close to not being in "La Nina territory".

 

Severe dixie alley getting primed into spring

[raindancewx]

Nino 4 has emerged as the coldest zone on the weekly data. Pretty neat to see that after it's warmth for the past decade.

                Nino1+2      Nino3        Nino34        Nino4
 Week          SST SSTA     SST SSTA     SST SSTA     SST SSTA
 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
 30DEC2020     22.2-1.3     24.4-0.9     25.4-1.2     27.3-1.1
 06JAN2021     23.1-0.8     24.7-0.8     25.5-1.1     27.1-1.2

For all the hype about this event ending up a strong La Nina in the Fall, it's not even close to recent big La Ninas like 1988, 1999, 2007 or 2010. It's really a bit behind 2011 overall.

 07DEC2011     21.4-1.0     23.9-1.2     25.5-1.1     27.5-1.0
 14DEC2011     21.5-1.2     24.1-1.0     25.6-1.0     27.4-1.1
 21DEC2011     22.1-1.0     24.5-0.7     25.6-1.0     27.2-1.3
 28DEC2011     22.6-0.9     24.4-0.9     25.5-1.1     27.1-1.3
 04JAN2012     22.7-1.1     24.6-0.8     25.5-1.0     27.2-1.2

Part of why I used 2007-08 as a major analog for winter is because it does get very cold - eventually - in Nino 4 that event. But it's much slower than in 2010-11. We're still pretty close to 2007-08 in Nino 4 even as the other areas drift away from. In 2011-12, the La Nina didn't really drop Nino 4 below 27.0C - I think this event may still briefly get significantly under that threshold. We've been running 0.2C or so above 2007-08 Nino 4 readings pretty consistently. 

 26DEC2007     21.9-1.4     23.7-1.6     24.9-1.6     27.0-1.4
 02JAN2008     22.6-1.1     23.9-1.5     25.0-1.6     26.8-1.6
 09JAN2008     23.3-0.8     24.0-1.5     24.8-1.8     26.6-1.7
 16JAN2008     24.1-0.4     24.0-1.6     24.6-2.0     26.6-1.7
 23JAN2008     24.1-0.7     24.1-1.7     24.4-2.2     26.4-1.8
 30JAN2008     25.1-0.1     24.7-1.3     24.9-1.7     26.5-1.7
 06FEB2008     25.9 0.3     24.8-1.4     24.6-2.1     26.4-1.8
 13FEB2008     25.9-0.1     24.7-1.7     24.5-2.2     26.4-1.7
 20FEB2008     26.7 0.6     25.1-1.4     24.9-2.0     26.4-1.7
 27FEB2008     27.2 0.9     25.8-0.9     25.3-1.6     26.3-1.8
 05MAR2008     27.3 1.0     26.3-0.6     25.7-1.3     26.6-1.5
 12MAR2008     27.2 0.7     26.5-0.5     26.0-1.1     26.7-1.4
 19MAR2008     27.3 0.9     26.7-0.5     26.2-1.1     26.8-1.4