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SOI is still erratic -

Date Tahiti (hPa) Darwin (hPa) Daily Contribution 30 day Av. SOI 90 day Av. SOI
9 Nov 2020 1012.67 1009.40 2.48 2.57 7.60
8 Nov 2020 1014.23 1009.25 13.36 2.96 7.67
7 Nov 2020 1014.72 1010.80 6.61 3.17 7.67
6 Nov 2020 1013.29 1011.15 -4.71 3.41 7.70
5 Nov 2020 1013.57 1011.60 -5.79 4.04 7.84
4 Nov 2020 1015.26 1011.85 3.37 4.66 8.16
3 Nov 2020 1016.75 1011.55 14.76 4.88 8.41
2 Nov 2020 1017.05 1010.50 23.35 4.62 8.39
1 Nov 2020 1016.75 1009.35 28.76 4.19 8.16

NOAA PDO went a bit more neutral in October.

                Nino1+2      Nino3        Nino34        Nino4
 Week          SST SSTA     SST SSTA     SST SSTA     SST SSTA
 30SEP2020     20.1-0.5     23.8-1.1     25.6-1.1     27.9-0.7
 07OCT2020     19.5-1.2     23.4-1.5     25.5-1.2     27.8-0.8
 14OCT2020     19.6-1.2     23.6-1.3     25.3-1.4     27.8-0.9
 21OCT2020     19.9-1.1     23.8-1.2     25.3-1.4     27.8-0.8
 28OCT2020     20.0-1.1     23.5-1.5     24.9-1.7     27.9-0.7
 04NOV2020     20.3-1.0     23.6-1.3     25.1-1.5     27.8-0.8

Bit of a warm up in all zones this week outside Nino 4. Still prefer 2007 to 2010 because of Nino 4. A blend of 2007/2011 is pretty close for this week as is 1995/2007

 08NOV1995    20.6-0.8     23.9-1.1     25.8-0.9     28.1-0.5
 07NOV2007    19.3-2.1     23.0-2.0     25.0-1.6     27.5-1.1
 03NOV2010    19.7-1.6     23.4-1.6     25.2-1.4     27.0-1.6
 02NOV2011    20.5-0.8     23.9-1.1     25.6-1.0     27.9-0.8
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With the ACE index over 160 now, the La Nina composite favors essentially the entire continental US above average for temperatures. That said, I don't think it should be compared directly, since a lot of storms this year never would have been named or correctly observed at a higher intensity like this year. So I'm treating the current reading like it is still about 150 by historical standards, which is still somewhat cooler in the Northwest.

The ACE index is high enough now that places like NYC and Philly have a decent shot a snowy winter - you really can't get a snowy winter in those spots in a La Nina if the ACE is below 150. Even so, the odds are not great. The ten highest ACE La Ninas are 50/50 for above average snow in NYC, but the correlation is pretty direct, and those ten winters average ~200 ACE which is highly unlikely even with two tropical storms out there right now.

I have an experimental regression for La Ninas winter highs here. Even at 160 or 170 ACE (favoring a hot SW in a La Nina), it favors a fairly cold winter here because we hit 90 degrees so early, which is where all the cold La Ninas are clustered locally. If you try to match on the three inputs, solar, ACE, and when we first hit 90, a blend of 1954 and 2005 is pretty close.

Image

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On 11/10/2020 at 9:54 PM, raindancewx said:

With the ACE index over 160 now, the La Nina composite favors essentially the entire continental US above average for temperatures. That said, I don't think it should be compared directly, since a lot of storms this year never would have been named or correctly observed at a higher intensity like this year. So I'm treating the current reading like it is still about 150 by historical standards, which is still somewhat cooler in the Northwest.

The ACE index is high enough now that places like NYC and Philly have a decent shot a snowy winter - you really can't get a snowy winter in those spots in a La Nina if the ACE is below 150. Even so, the odds are not great. The ten highest ACE La Ninas are 50/50 for above average snow in NYC, but the correlation is pretty direct, and those ten winters average ~200 ACE which is highly unlikely even with two tropical storms out there right now.

I have an experimental regression for La Ninas winter highs here. Even at 160 or 170 ACE (favoring a hot SW in a La Nina), it favors a fairly cold winter here because we hit 90 degrees so early, which is where all the cold La Ninas are clustered locally. If you try to match on the three inputs, solar, ACE, and when we first hit 90, a blend of 1954 and 2005 is pretty close.

Image

The ACE should take a another jump with IOTA, which may get pretty strong.

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A flat blend of 1954 and 2005 is a good match for the three variables I listed above up until about 180 ACE, especially with the solar activity rising fairly rapidly now. That was why I centered the ACE at 135 in my outlook, you can justify the look I want up to about 175 ACE, after that it's not really a likely outcome for the winter anymore. All that said, only the Caribbean is really warm enough to support a big hurricane at this point in the Atlantic and the tropical storms don't add much ACE. The Northern Gulf of Mexico is like 25C right now.

The PDO hasn't really changed from October to November on the Nate Manuta index -  https://oceanview.pfeg.noaa.gov/erddap/tabledap/cciea_OC_PDO.htmlTable?time,PDO

January    -0.23
February  -0.68 
March       -0.82
April         -0.57
May           0.09
June         -0.08
July          -0.38
August     -0.28
September -0.70
October     -0.69
 
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1 hour ago, raindancewx said:

A flat blend of 1954 and 2005 is a good match for the three variables I listed above up until about 180 ACE, especially with the solar activity rising fairly rapidly now. That was why I centered the ACE at 135 in my outlook, you can justify the look I want up to about 175 ACE, after that it's not really a likely outcome for the winter anymore. All that said, only the Caribbean is really warm enough to support a big hurricane at this point in the Atlantic and the tropical storms don't add much ACE. The Northern Gulf of Mexico is like 25C right now.

The PDO hasn't really changed from October to November on the Nate Manuta index -  https://oceanview.pfeg.noaa.gov/erddap/tabledap/cciea_OC_PDO.htmlTable?time,PDO

January    -0.23
February  -0.68 
March       -0.82
April         -0.57
May           0.09
June         -0.08
July          -0.38
August     -0.28
September -0.70
October     -0.69
 

Right....Iota is in the Caribbean. Limiting factor will be central america...again.

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image.thumb.png.9a25f94d8fd39e21c726600db3fea3e6.png

Looks like trades are fixing to ramp up again following a general lull at the beginning of November, but it also looks like the Nina standing wave might re-establish a bit westward of where it was previously. More cooling of the western regions as opposed to the eastern regions?

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CPC has that warm December look through at least mid-month that we've become so familiar with over recent years.

Image

It's funny - the MJO is actually almost identical to 2000 (also a La Nina) right now but we're not getting anything like 2000 for actual weather with the Arctic behaving differently. But of course Nov/Dec 2000 are very cold.

Image

Image

Image

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5 minutes ago, StormchaserChuck! said:

I was really wrong about this La Nina, it's really asserting itself. It will be interesting to see happens going forward, I was always thinking it could be a long term dull pattern. It would make sense for an event, maybe El Nino, to follow it. 

If I may ask why do you think you’re so wrong 

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In 2000, the MJO increased in amplitude in phase 2 in mid-November like the models are showing, but then continued on through the subsequent phases. The increase in amplitude in phase 2 this year is not depicted to continue after that. I don't think I buy that completely, but we'll see soon enough. 

Very curious to see what the weekly data shows on Monday - think the eastern zones may be warming again, as some top layer cold seems to be thinning, but it is still pretty cold below the surface. I keep waiting for the MEI update too, they say on their website by the 10th of the month...but no update yet.

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The North Pacific actually looks like it is starting to respond to the La Nina with a lot of cooling in recent days. Would also say the PDO is trending toward a more normal looking negative phase.

It looks to me like the centering of the La Nina will continue to slowly shift West for a while. Don't really expect eastern Nino 3 or Nino 1.2 to cool back down again for a while. 

One of the odder things about this even is how little the North Pacific has changed to date. I included 2019-20 as an analog almost solely because I suspected the little circled area would show up (presumably from high pressure persistence - I'd have to look).

2019-20-and-2020-21-in-Nov

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               Nino1+2      Nino3        Nino34        Nino4
 Week          SST SSTA     SST SSTA     SST SSTA     SST SSTA 
 07OCT2020     19.5-1.2     23.4-1.5     25.5-1.2     27.8-0.8
 14OCT2020     19.6-1.2     23.6-1.3     25.3-1.4     27.8-0.9
 21OCT2020     19.9-1.1     23.8-1.2     25.3-1.4     27.8-0.8
 28OCT2020     20.0-1.1     23.5-1.5     24.9-1.7     27.9-0.7
 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

Pretty nice little warm up this week just about everywhere at the surface. Now well behind 2007 and 2010 for this week. Unlikely to last though.

 10OCT2007     18.8-1.9     23.3-1.6     24.9-1.8     27.7-1.0
 17OCT2007     18.6-2.2     23.5-1.4     25.3-1.4     27.9-0.7
 24OCT2007     19.2-1.8     23.5-1.4     25.3-1.4     27.8-0.8
 31OCT2007     19.7-1.5     23.2-1.8     25.2-1.5     27.8-0.8
 07NOV2007     19.3-2.1     23.0-2.0     25.0-1.6     27.5-1.1
 14NOV2007     19.2-2.3     23.2-1.7     25.2-1.5     27.3-1.3
 06OCT2010     18.7-1.9     23.2-1.7     24.8-1.9     27.1-1.6
 13OCT2010     18.9-1.9     23.0-2.0     25.1-1.6     27.1-1.6
 20OCT2010     19.1-1.8     23.2-1.7     25.1-1.6     27.0-1.7
 27OCT2010     19.8-1.3     23.6-1.4     25.2-1.5     27.0-1.6
 03NOV2010     19.7-1.6     23.4-1.6     25.2-1.4     27.0-1.6
 10NOV2010     19.5-1.9     23.5-1.5     25.2-1.4     27.2-1.5
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The European has been showing a big SOI crash (big high by northern Australia, big low by Tahiti) around 11/20 that lasts for a days. Most recent SOI value was over 20 - the highest in a while - so we could see a 20-40 point crash in a short period that should shake everything up quite a bit around 12/1. 

The subsurface actually warmed this week too, it wasn't just a surface warming - still similar to 2007 in that regard which weakened in December from an earlier peak and then briefly rallied stronger in January.

Image

We're still not particularly close to the very highest Atlantic ACE seasons, but the composite at 180 ACE in a La Nina for 1931-2020 is not exactly a cold look. 

Image

It's interesting though - four of the five "cold Neutral" years in the 140-220 range are still very much a like the 80-160 ACE La Nina composite. 

140-220-Atlantic-ACE-in-La-Ninas-2

A lot of the years on the left also have extremely high solar activity, which we don't have this year. So if you take the cold-ENSO, low solar, similar ACE years, you get this look:

140-220-ACE-in-La-Ninas-3

Here are some strengths for the blend:

1932: Only other year on record with a category five hurricane in November in the Atlantic. (Cuba Hurricane of 1932). Snowed into the valleys of the Southwest in October. Fairly similar (but much colder) look to October (coldest Plains/Central).

1964: Delta was similar to Hilda in October, and the first half of November looks a lot like 1964 high temperatures nationally. Followed a weak El Nino like this La Nina is.

1996: Snowed into the valleys of the Southwest in October. Can't really think of any other particular similarities off the top of my head. This was actually the most recent "Major" snowstorm for Albuquerque in October, with several inches. Actually, the way the Jamstec depicts Summer next year in the tropical Pacific is very similar to how the 1997 El Nino developed - so that's another feature in favor of the year.

2008: Big Gulf of Mexico activity like this year, and some months have similar spatial patterns for temperatures (notably not great in Oct-Nov which were very cold in the SE). Pretty good QBO match.

2010: Bad match for the Gulf of Mexico hurricane activity. Similar QBO, followed an El Nino. Very different for blocking patterns and La Nina development. Not a fan of the year overall.

2016: Similar QBO, followed an El Nino. Main issue is the cold patch in the north Pacific (+PDO), and warm Nino 1.2. Also much weaker La Nina. Matthew was the first landfalling October hurricane in a while on the US mainland (Sandy was subtropical).

The 1961-62 winter is a good QBO match, with similar types of Atlantic hurricane activity, and similar on NAO trends in the predictive periods for winter. But it had higher solar activity - but it looks almost identical to the six year composite.  The six year blend actually looks a lot like November (although too cold).

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SOI crash verified -

Date Tahiti (hPa) Darwin (hPa) Daily Contribution 30 day Av. SOI 90 day Av. SOI
21 Nov 2020 1011.63 1008.30 2.86 7.21 8.15
20 Nov 2020 1013.38 1007.85 16.86 7.44 8.23
19 Nov 2020 1014.15 1008.10 20.17 6.99 8.14
18 Nov 2020 1014.69 1008.65 20.10 6.27 8.18
17 Nov 2020 1014.71 1009.05 17.69 5.38 8.25
16 Nov 2020 1014.73 1010.05 11.45 4.53 8.37

 

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During the 2007-08 La Nina, you had several huge SOI crashes that preceded some big storms in the West. The crash recently is reminiscent of this period in 2007 particularly - although somewhat earlier. It's worth noting for those who like 2010, that La Nina had almost no -SOI readings at all from Sept-Dec, while this year has seen them semi-regularly, as in 2007. Think you have to assume the subtropical jet won't be super weak despite the La Nina strength.

Date Tahiti (hPa) Darwin (hPa) Daily Contribution 30 day Av. SOI 90 day Av. SOI
23 Nov 2020 1010.25 1008.60 -7.83 6.36 7.89
22 Nov 2020 1010.60 1008.90 -7.51 6.66 7.94
21 Nov 2020 1011.63 1008.30 2.86 7.21 8.15
20 Nov 2020 1013.38 1007.85 16.86 7.44 8.23
19 Nov 2020 1014.15 1008.10 20.17 6.99 8.14
2007 325 1011.01 1007.15    6.23
2007 326 1010.69 1006.85    6.11
2007 327 1012.06 1005.65   22.46
2007 328 1014.19 1007.00   27.42
2007 329 1013.41 1009.25    8.14
2007 330 1012.05 1009.80   -4.01
2007 331 1011.34 1007.85    3.88
2007 332 1012.91 1006.95   19.59
2007 333 1013.66 1009.50    8.14
2007 334 1013.05 1010.90   -4.65

The 332 to 334 represents 33 to 31 days before the end of the year, i.e. 11/29 to 12/1. The rule for the SW is a storm will appear ten days after - so 12/10-12/11 2007 saw 150% of normal (monthly) precipitation for Albuquerque. Will be very curious to see if we see a major storm in the 12/1-12/3 period this year. The big drops that go positive to negative are usually the strongest storms out here.

 

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Back to the prior level after the hiccup last week.
Nino 4 didn't change at all though. Nino 1.2 is now closer in 2010 than in 2007.
Nino 4 is still pretty warm for cold the middle zones are currently. Nino 1.2 warmed up in 2007 rapidly in December and
should come back as a better match than 2010. Right now, 2011 is closer than 2007 or 2010.
              
                Nino1+2      Nino3        Nino34        Nino4
 Week          SST SSTA     SST SSTA     SST SSTA     SST SSTA
 07OCT2020     19.5-1.2     23.4-1.5     25.5-1.2     27.8-0.8
 14OCT2020     19.6-1.2     23.6-1.3     25.3-1.4     27.8-0.9
 21OCT2020     19.9-1.1     23.8-1.2     25.3-1.4     27.8-0.8
 28OCT2020     20.0-1.1     23.5-1.5     24.9-1.7     27.9-0.7
 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
 10OCT2007     18.8-1.9     23.3-1.6     24.9-1.8     27.7-1.0
 17OCT2007     18.6-2.2     23.5-1.4     25.3-1.4     27.9-0.7
 24OCT2007     19.2-1.8     23.5-1.4     25.3-1.4     27.8-0.8
 31OCT2007     19.7-1.5     23.2-1.8     25.2-1.5     27.8-0.8
 07NOV2007     19.3-2.1     23.0-2.0     25.0-1.6     27.5-1.1
 14NOV2007     19.2-2.3     23.2-1.7     25.2-1.5     27.3-1.3
 21NOV2007     19.8-2.0     23.2-1.8     24.9-1.7     27.1-1.5
 05OCT2011     19.8-0.8     24.1-0.8     25.7-1.0     27.7-0.9
 12OCT2011     19.7-1.0     24.1-0.8     25.8-0.9     27.9-0.8
 19OCT2011     20.0-0.9     23.9-1.1     25.8-0.8     28.1-0.6
 26OCT2011     21.2 0.2     23.8-1.1     25.4-1.2     28.0-0.7
 02NOV2011     20.5-0.8     23.9-1.1     25.6-1.0     27.9-0.8
 09NOV2011     20.5-0.9     23.9-1.1     25.7-0.9     27.9-0.7
 16NOV2011     20.5-1.1     23.8-1.1     25.6-1.0     27.9-0.7

 06OCT2010     18.7-1.9     23.2-1.7     24.8-1.9     27.1-1.6
 13OCT2010     18.9-1.9     23.0-2.0     25.1-1.6     27.1-1.6
 20OCT2010     19.1-1.8     23.2-1.7     25.1-1.6     27.0-1.7
 27OCT2010     19.8-1.3     23.6-1.4     25.2-1.5     27.0-1.6
 03NOV2010     19.7-1.6     23.4-1.6     25.2-1.4     27.0-1.6
 10NOV2010     19.5-1.9     23.5-1.5     25.2-1.4     27.2-1.5
 17NOV2010     20.2-1.5     23.5-1.5     25.0-1.6     27.1-1.5
 24NOV2010     20.6-1.3     23.3-1.7     24.9-1.7     26.9-1.7

To me it looks like the subsurface is continuing to warm too, as the warmth below the western zones has had some success moving east recently.

Equatorial Pacific Temperature Depth Anomalies AnimationSubsurface-Warming-11-23-2020

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