La Niña/Winter 2016-17 Discussion

[snowman19]

The Euro has the strongest trades of this developing event so far over the next 10 days.

CiDfZSHUkAA_0Tv.jpg-small.jpg

Following the trend of Nina's over the last 25 years or so, this Niña is shaping up to be a west-based (region 4 and 3.4) event. The "traditional" Nina's prior to 25 were ago were almost all east-based (region 3 and 1+2) centered events...

[Isotherm]

Latest JAMSTEC update has trended more robust with the La Nina. The mean is around -1c (moderate) with some members in the strong category. My thinking right now is that models will probably correct more intense w/ the peak magnitude over the next few months. Subsurface temperature anomalies also tend to support - at minimum - a moderate intensity La Nina. Will be interesting to track this transition. More interesting will be the progression of the PDO. 

[snowman19]

Latest JAMSTEC update has trended more robust with the La Nina. The mean is around -1c (moderate) with some members in the strong category. My thinking right now is that models will probably correct more intense w/ the peak magnitude over the next few months. Subsurface temperature anomalies also tend to support - at minimum - a moderate intensity La Nina. Will be interesting to track this transition. More interesting will be the progression of the PDO.

That is what intrigues me, the PDO. A high end moderate to strong La Niña is looking more and more likely, question is, does the PDO turn negative come fall, which I think is likely, or does it stay positive? If it stays positive we will certainly be in uncharted territory, with no analogs for such a setup assuming a high end moderate or strong Niña is in place by then...

[dmillz25]

Would a + PDO throw off a la niña pattern?

[snowman19]

Would a + PDO throw off a la niña pattern?

We don't know. There has never been a high end moderate or strong La Niña along with a +PDO as long as weather records have been kept. That said, a Niña of that strength definitely will have a major impact on the long wave synoptic pattern either way

[dmillz25]

We don't know. There has never been a high end moderate or strong La Niña along with a +PDO as long as weather records have been kept. That said, a Niña of that strength definitely will have a major impact on the long wave synoptic pattern either way

So unless we get blocking again this upcoming winter it'll be another ratter for alot of people

[snowman19]

So unless we get blocking again this upcoming winter it'll be another ratter for alot of people

Way, way too early to think about but if there is a high end moderate or strong west-based La Niña, you will absolutely need the NAO and AO to cooperate or there will be big problems because the SE ridge will be flexing its muscles. That ENSO setup would also strongly favor a lot of -PNA

[dmillz25]

Way, way too early to think about but if there is a high end moderate or strong west-based La Niña, you will absolutely need the NAO and AO to cooperate or there will be big problems because the SE ridge will be flexing its muscles. That ENSO setup would also strongly favor a lot of -PNA

My bad i meant to say could but yeah I'm hoping for blocking. Hopefully we get a SSWE but it's a wait and see

[Wannabehippie]

Pretty good article

http://arstechnica.com/science/2016/05/current-el-ninos-strength-due-partly-to-an-earlier-fizzle/

[uncle W]

strong la nina winters with an oni -0.9 or lower for DJF without blocking mean little in the way of snowfall...

the winters with the most consistent blocking were 1995-96, 1955-56, 1970-71, 1984-85, 2010-11...1973-74 had a lesser negative ao winter...The winters with no blocking to speak of are...1975-76, 1988-89, 1999-00, 2007-08, 1949-50, 1998-99...the only cold winter with no blocking was 1975-76...but all six with no blocking had less snow than average...the only winter with less snow than normal with blocking was 1970-71...only 1955-56, 1995-96 and 2010-11 had major blizzards and above average snowfall...

[snowman19]

The latest ssta charts for the tropical pacific are showing a very rapid decent into La Niña. We are now way ahead of where we were in May of 1998

[snowman19]

My bad i meant to say could but yeah I'm hoping for blocking. Hopefully we get a SSWE but it's a wait and see

What you don't want to see is a GOA vortex develop this fall (+EPO), which likes to setup in the stronger Nina's. That would support a dropping PDO and upwelling and cooling ssts in the GOA and along the west coast, especially in combination with a -PNA. The EPO and WPO have been the wildcard over the last few winters and served to offset a "bad" AO and NAO. Plenty of time of watch this though

[Morris]

Latest values:

Nino 1.2: +0.5 (+0.1)

Nino 3: +0.4 (-)

Nino 3.4: +0.6 (-0.2)

Nino 4: +0.6 (-0.2)

http://www.cpc.ncep.noaa.gov/data/indices/wksst8110.for

[snowman19]

We just set the record for the highest April PDO on record.

http://research.jisao.washington.edu/pdo/PDO.latest

2.62....2016

2.37...1940

2.16...1987

2.10...1926

The PDO should begin dropping dramatically as the La Niña continues to strengthen. ENSO forces the PDO, not the other way around. There was extensive research on this. Take a look at this article: http://www.esrl.noaa.gov/psd/people/gilbert.p.compo/Newmanetal2003.pdf

[snowman19]

This was an interesting case where the +PDO first flipped positive during the 13-14 winter and the 2 year El Nino

followed for 14-15 and 15-16. It seems like the -EPO lead the +PDO when it switched into a more negative

phase during 2013 after being mostly positive since late 2005.

I suspect the PDO goes negative once again when the Niña establishes itself and forces it. That research is very convincing

[bluewave]

I suspect the PDO goes negative once again when the Niña establishes itself and forces it. That research is very convincing

 

It will be interesting to see how long this +PDO lasts. Notice how much different the Pacific looks with

the La Nina surrounded by so much warm water on all sides. This is a first for such a contrast

between a developing La Nina and a record +PDO for April.

 

May much stronger +PDO than 2010.

 

 

[snowman19]

It will be interesting to see how long this +PDO lasts. Notice how much different the Pacific looks with

the La Nina surrounded by so much warm water on all sides. This is a first for such a contrast

between a developing La Nina and a record +PDO for April.

May much stronger +PDO than 2010.

globe_oisst_anom_20160518.png

globe_oisst_anom_2010.png

I had mentioned it before but there has been a rather dramatic change in how La Nina's have been setting up over the last 20 years. Prior to that almost all Nina's were "east-based". The last several that have developed have been classified as either "west-based" or "modoki" (central based) La Nina's. Following that trend, this one is shaping up to be no different. Looking at the subsurface, this one looks to be a west-based Niña in the making as well. Question is, what caused this major ENSO alignment change with Ninas?

[dmillz25]

Does having a west based central based or east based nina make a difference like ninos do?

[snowman19]

Does having a west based central based or east based nina make a difference like ninos do?

Yes because it alters where the main tropical convective forcing sets up

[thunderbolt]

Yes because it alters where the main tropical convective forcing sets up

and what are the effects if it's more West based or Central based or east based?

[dmillz25]

And what kind of nina would help in our case?

[snowman19]

And what kind of nina would help in our case?

You want an east-based Niña as a general rule if you want cold and snow. West-based and central-based (modoki) La Ninas typically are not friendly. Just the opposite holds true for El Ninos

[Morris]

Latest values:

Nino 1.2: +0.2 (-0.3)
Nino 3: -0.1 (-0.5)
Nino 3.4: +0.2 (-0.4)
Nino 4: +0.6 (-)

 

http://www.cpc.ncep.noaa.gov/data/indices/wksst8110.for

 

Here we go....

[dmillz25]

You want an east-based Niña as a general rule if you want cold and snow. West-based and central-based (modoki) La Ninas typically are not friendly. Just the opposite holds true for El Ninos

So what kind of a niña was 2010-11? Just trying to get the basics and learn

[UnionWeatherWx]

So what kind of a niña was 2010-11? Just trying to get the basics and learn

From my knowledge, started out as a east based La Nina and transitioned into a more of a central nina throughout the winter. Although in 2010-2011, we wanted a East La Nina which would have lead to a more colder east.

[snowman19]

So what kind of a niña was 2010-11? Just trying to get the basics and learn

It was a weak modoki type Niña, as the winter wore on it became more west based

[UnionWeatherWx]

 

It was a weak modoki type Niña, as the winter wore on it became more west based

It started out as a east based Nina as well.

[snowman19]

It started out as a east based Nina as well.

The 2010-2011 Niña was interesting. The early part of that winter's pattern (Nov-late Jan) was highly unusual and featured a really robust southern stream (STJ) which is more typical of El Niño, not La Niña. Lag effects from the previous Nino?

[UnionWeatherWx]

The 2010-2011 Niña was interesting. The early part of that winter's pattern (Nov-late Jan) was highly unusual and featured a really robust southern stream (STJ) which is more typical of El Niño, not La Niña. Lag effects from the previous Nino?

One of those lucky years, we also had a -NAO around the early part of winter. Just a perfect setup.

[snowman19]

One of those lucky years, we also had a -NAO around the early part of winter. Just a perfect setup.

Yes, had it not been for the AO and NAO blocking, the outcome of the early part of that winter would have been vastly different. We got a seasons' worth of snowfall between December 1st and February 1st, a true front end loaded winter. Once the blocking left in early February, it never came back