Weak La Nina Winter

[40/70 Benchmark]

4 hours ago, raindancewx said:

The La Nina is now warming/weakening again on Tropical Tidbits.

I threw in 2012 as an analog to winter, and sure enough a weird hybrid tropical/cold system, ala Sandy or the Perfect Storm may develop off of the East Coast this week. Should be fun. Atlantic can do some crazy things in late October.

My theory is that its the climatological nexus of burgeoning baroclinic dynamics and residual tropical energy.

[raindancewx]

If we go by Tropical Tidbits, Oct has had 16 days at -0.5C or higher in Nino 3.4, and 10 at below -0.5C. Five more to go, but the latest warm water incursion is warming the anomalies in Nino 3.4.

[AfewUniversesBelowNormal]

Subsurface -anomalies continues to strengthen.

[raindancewx]

I don't know if you guys ever look at local seasonal outlooks from (professional) forecasters on Youtube, but some of the guys in the NW are expecting a much drier winter than last year based on local trends and speculation. It's interesting since WA was actually pretty dry last year with the La Nina in July - Jan.

 

[40/70 Benchmark]

On October 26, 2017 at 9:12 PM, StormchaserChuck said:

Subsurface -anomalies continues to strengthen.

That is losing relevance quickly within the context of winter outlooks.

[raindancewx]

Couple random ideas - these La Ninas were all opposites to this October nationally with a substantial cold East / warm West pattern:

Based on ONI v.4, these are the warmest (+0.5C or greater DJF) Nino 1.2 Decembers nationally since 1950. Note that 2016-17 was among these warm Nino 1.2 winters:

Based on ONI v.4, this is December when Nino 1.2 is -0.4C to -0.8C in DJF. It is much colder in the east, and only somewhat warmer in the West.

[Stebo]

7 hours ago, raindancewx said:

Couple random ideas - these La Ninas were all opposites to this October nationally with a substantial cold East / warm West pattern:

Based on ONI v.4, these are the warmest (+0.5C or greater DJF) Nino 1.2 Decembers nationally since 1950. Note that 2016-17 was among these warm Nino 1.2 winters:

Based on ONI v.4, this is December when Nino 1.2 is -0.4C to -0.8C in DJF. It is much colder in the east, and only somewhat warmer in the West.

Here is 3 years I am using, they aren't exact ENSO locks but they are Ninas and the falls of all 3 have been very similar to this current fall.

and adding in September

[raindancewx]

Here is a look at October in years when Puerto Rico had its worst storms since 1895:

I could have thrown in 1916 and 1931 but they didn't have the big time impacts as the six storms I listed. The storms in 1899, 1928, 1932 are all legendary, 140 - 160 mph hurricanes, similar to Maria. Georges wasn't that strong, but it went across the whole island as a weak hurricane. Hugo kind of missed much of the island, but was very strong where it did impact, so I threw in 1989. 

[stadiumwave]

Differences between east-based La Nina's & central-based La Nina's

Figure A is east-based. Figure B is central-based

Currently this La Nina would be considered more of an east-based La Nina

DJF 500mb for East-based years:

DJF Temps

 

However, ironically in east-based years JFM is colder than Dec. DEC is typically the warmest month in the east-based years.

JFM 500mb east-based years

JFM Temps

 

Compare all of that to central-based La Nina years:

DJF 500mb

DJF Temps

December being the coldest month for central-based Nina's. One noticeable difference is that east-based La Nina's are more prone to have a -NAO, especially during the JFM period.  Central-based Nina's are more prone to having a +NAO.

One thing worth noting is not all East-based Nina's are frigid. You can have warmth. Some years were warm like 2005-06. This information is just something to think about.

Also worth nothing is that you can have a Nina that's kind of a mix of east-based versus central-based.

Here are 2 peer-reviewed studies discussing east-based La Nina's versus central-based La Nina's:

https://link.springer.com/article/10.1007/s11434-012-5423-5

https://link.springer.com/article/10.1007/s00382-014-2155-z

[raindancewx]

7 minutes ago, stadiumwave said:

Differences between east-based La Nina's & central-based La Nina's

Figure A is east-based. Figure B is central-based

Currently this La Nina would be considered more of an east-based La Nina

DJF 500mb for East-based years:

DJF Temps

 

However, ironically in east-based years JFM is colder than Dec. DEC is typically the warmest month in the east-based years.

JFM 500mb east-based years

JFM Temps

 

Compare all of that to central-based La Nina years:

DJF 500mb

DJF Temps

December being the coldest month for central-based Nina's. One noticeable difference is that east-based La Nina's are more prone to have a -NAO, especially during the JFM period.  Central-based Nina's are more prone to having a +NAO.

One thing worth noting is not all East-based Nina's are frigid. You can have warmth. Some years were warm like 2005-06. This information is just something to think about.

Also worth nothing is that you can have a Nina that's kind of a mix of east-based versus central-based.

Here are 2 peer-reviewed studies discussing east-based La Nina's versus central-based La Nina's:

https://link.springer.com/article/10.1007/s11434-012-5423-5

https://link.springer.com/article/10.1007/s00382-014-2155-z

I saw you post this on the Accuweather forums, was interesting seeing it. My analog system is based on a possible 15 points across seven variables - Modoki status using the raw values from the Jamstec for the three "boxes" definitely improves US analogs for winter. I give similar Modoki status two points, and that seems to work pretty well. That guy who keeps insisting this winter is like 1999-00 given 1998-99 was like 2016-17 should look at how dissimilar (near perfect opposites) 1998-99 and 2016-17 were for precipitation:

1999-00 is nearly opposite to the current October pattern as well - presumably because it was a much stronger La Nina. I'm not a fan of using one month to make a prediction, but the Summer pattern for 1999 & 2017 were just about dead opposites as well. It's useful looking at 1999 for what didn't happen actually, as it is one of the coldest Summers on record in the SW, as opposed to this Summer, which had a very warm June and then near normal temps July-Aug. As an example, 1999 had 40 days over 87F here, this year had 96. Just a wee bit different.

 

 

[Stebo]

I wouldn't be using 99-00 as an analog even if it is similar for ENSO, everything else surrounding that year doesn't add up at all.

[40/70 Benchmark]

Stadiumwave, thank you so much for that post.

Awesome research.

[stadiumwave]

30 minutes ago, raindancewx said:

I saw you post this on the Accuweather forums, was interesting seeing it. My analog system is based on a possible 15 points across seven variables - Modoki status using the raw values from the Jamstec for the three "boxes" definitely improves US analogs for winter. I give similar Modoki status two points, and that seems to work pretty well. That guy who keeps insisting this winter is like 1999-00 given 1998-99 was like 2016-17 should look at how dissimilar (near perfect opposites) 1998-99 and 2016-17 were for precipitation:

1999-00 is nearly opposite to the current October pattern as well - presumably because it was a much stronger La Nina. I'm not a fan of using one month to make a prediction, but the Summer pattern for 1999 & 2017 were just about dead opposites as well. It's useful looking at 1999 for what didn't happen actually, as it is one of the coldest Summers on record in the SW, as opposed to this Summer, which had a very warm June and then near normal temps July-Aug. As an example, 1999 had 40 days over 87F here, this year had 96. Just a wee bit different.

 

 

 

I've never seen a reason yet to think 1999-2000 either.

#1 1999-2000 was a central-based Nina. 

#2 1999-2000 was a +QBO winter

I also disagreed with his thinking last year was 1998-1999. Sensible weather, warm, was correct but for totally different reasons.

I'm not sure what to expect this winter...still just observing. 

[40/70 Benchmark]

Why anyone would be using strong la nina analogs is beyond me.

[stadiumwave]

Just now, 40/70 Benchmark said:

Stadiumwave, thank you so much for that post.

Awesome research.

 

My pleasure 

[40/70 Benchmark]

Do you guys know if central based la ninas are positively correlated to strength, as east based el nino events are with the warmth centered in region 1.2?

My guess if that they are.

[stadiumwave]

8 minutes ago, 40/70 Benchmark said:

Do you guys know if central based la ninas are positively correlated to strength, as east based el nino events are with the warmth centered in region 1.2?

My guess if that they are.

 

Not sure what research has shown, I'm sure there has been some. The thought crossed my mind last winter. Forcing is not the same; however the correlation to a warm east U.S. sure seems to be.

[40/70 Benchmark]

3 minutes ago, stadiumwave said:

 

Not sure what research has shown, I'm sure there has been some. The thought crossed my mind last winter. Forcing is not the same; however the correlation to a warm east U.S. sure seems to be.

Just going by the fact that the 1998 and 1999 la ninas were both strong and central based.....good start.

[40/70 Benchmark]

Probably not a big deal, but you included 2007 instead of 2009 in the central based H5 composite....2007 was an east based el nino.

[stadiumwave]

26 minutes ago, 40/70 Benchmark said:

Probably not a big deal, but you included 2007 instead of 2009 in the central based H5 composite....2007 was an east based el nino.

 

Ah...good catch. Temperature composites for DJF ask for the year of first month, while H5 ask fiir year of last month. I thought I had checked them all but obviously missed. With a blend of all those years it doesn't affect it much, but thanks!

[40/70 Benchmark]

Yea, negligible impact.

Nice work.

I'll probably be using it and will give you a shout out in my outlook.

[stadiumwave]

11 hours ago, 40/70 Benchmark said:

Yea, negligible impact.

Nice work.

I'll probably be using it and will give you a shout out in my outlook.

 

Look forward to your lookout this year

[AfewUniversesBelowNormal]

As of the latest subsurface image...

 

I think this La Nina goes Moderate, the image resembles Strong, especially with the +gradient building west, but warmer surface tendency may be the difference between a Moderate and Strong event. 

[40/70 Benchmark]

That would be unprecedented given where we stand now.

We'll see.

[fountainguy97]

Does this more accurately represent sub-surface temps?  I believe it uses actual bouy reports? 

This paints the Niña as much more anemic under the surface. 

[Isotherm]

All moderate and strong La Nina's since 1950 had a JAS trimonthly ONI of -0.7c or colder in the preceding autumn. The latest JAS trimonthly ONI is -0.1c, which is a significant difference from all other onset moderate to strong La Nina's. Statistics are meant to be broken (occasionally), but I don't see any robust, scientific reason in support of the argument that the subsurface anomalies will largely surface. Can you post scientific references that corroborate?

I would be surprised to see a trimonthly ONI peak colder than -1.0c at this juncture.

[40/70 Benchmark]

1 hour ago, Isotherm said:

All moderate and strong La Nina's since 1950 had a JAS trimonthly ONI of -0.7c or colder in the preceding autumn. The latest JAS trimonthly ONI is -0.1c, which is a significant difference from all other onset moderate to strong La Nina's. Statistics are meant to be broken (occasionally), but I don't see any robust, scientific reason in support of the argument that the subsurface anomalies will largely surface. Can you post scientific references that corroborate?

I would be surprised to see a trimonthly ONI peak colder than -1.0c at this juncture.

This is exactly what I was referring to...the JAS ONI.

It's def. going to be weak imho.

[raindancewx]

The -0.1C for JAS is using the colder ERSST V.5 for the La Nina though. On the older data set, which is probably what the models are using, and what we all used in the Summer, JAS was -0.5C. The issue is NOAA is using 30-year means that change every five years now, so you get little hiccups up and down in certain months since 30 years is pretty short for climatology, given some 30 year periods will have 12 La Ninas and maybe 8 El Ninos or vice versa. If I was dictator of Earth, everyone would be required to use 60-year climatology.

http://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v4.shtml

Tropical Tidbits is back to -0.5C in Nino 3.4 for 10/30. As long as the waters 0-5N in the Tropical Pacific stay warm at the surface, there is a cap on this event.

 

[40/70 Benchmark]

13 minutes ago, raindancewx said:

The -0.1C for JAS is using the colder ERSST V.5 for the La Nina though. On the older data set, which is probably what the models are using, and what we all used in the Summer, JAS was -0.5C. The issue is NOAA is using 30-year means that change every five years now, so you get little hiccups up and down in certain months since 30 years is pretty short for climatology, given some 30 year periods will have 12 La Ninas and maybe 8 El Ninos or vice versa. If I was dictator of Earth, everyone would be required to use 60-year climatology.

http://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v4.shtml

Tropical Tidbits is back to -0.5C in Nino 3.4 for 10/30. As long as the waters 0-5N in the Tropical Pacific stay warm at the surface, there is a cap on this event.

 

Regardless, it's a long shot climatologically speaking...I mean...-.06?

Big gap...regardless of how cold the set is.

[raindancewx]

This is the change in SSTA for 10/19 to 10/28. Blue/purple means 2017 is colder than 2016 in the area, yellow/green/red is warmer. Still catching up to the 2016-17 La Nina in Nino 3.4. Nino 1.2 & the Gulf of Alaska are much colder, as is much of the Western Atlantic (remember, the areas by the equator are "bigger" than those by the North Pole, so the Atlantic is much colder).

Here are the weeklies, its Nino 1.2, Nino 3, Nino 3.4, Nino 4. Second column is anomalies for each.

 05OCT2016     20.8 0.1     24.3-0.6     25.8-0.9     28.1-0.6
 12OCT2016     21.8 1.0     24.8-0.1     26.1-0.6     28.2-0.4
 19OCT2016     20.7-0.2     24.4-0.6     26.1-0.6     28.4-0.2
 26OCT2016     21.3 0.2     24.4-0.5     25.9-0.8     28.2-0.4
 02NOV2016     21.2 0.0     24.3-0.6     25.8-0.8     28.0-0.6
 09NOV2016     21.8 0.4     24.5-0.4     26.0-0.7     28.1-0.5
 16NOV2016     21.5-0.1     24.7-0.3     26.2-0.4     28.3-0.3
 23NOV2016     21.6-0.3     24.7-0.3     26.3-0.4     28.3-0.3
 30NOV2016     22.2 0.1     24.5-0.5     26.2-0.4     28.4-0.2

 04OCT2017     19.3-1.4     24.7-0.2     26.7 0.0     28.7 0.1
 11OCT2017     19.5-1.3     24.4-0.5     26.2-0.5     28.5-0.1
 18OCT2017     19.5-1.4     23.9-1.1     25.9-0.8     28.3-0.4
 25OCT2017     19.6-1.4     24.2-0.8     26.2-0.5     28.5-0.2

These weeklies are "centered" on the date, so Oct 1-28 2017 is -0.45C, and Oct 2-29 2016 was -0.725C. In pure temperatures, Nino 3.4 was 25.975C in October last year, this year it was 26.25C. October & September will thus both be right at the edge of Neutral / La Nina status (-0.5C) while in 2016 they were both safely in La Nina status.

This event does have a much colder Nino 1.2, which I think is the bigger deal. Nino 1.2 was -1.375C in Oct 2017 (!), but it was +0.275C in Oct 2016. That's a huge, huge change.