Sea Surface Temperature - SSTs

[chionomaniac]

West-based Nino events tend to result in a trough down the western Atlantic:

This is just one factor pointing towards a mean trough solution for the western Atlantic right now. Tellingly, Atlantic surface temperatures have started to fall. This reanalysis (change in SSTA) shows a 1 - 2 degree fall over October so far.

I'm thinking this winter is going to be decided by the strength of Siberian High pressure cell and the feedback loops that this generates on the Asian and Pacific Jets.

Thanks GP, that first chart certainly leads to interesting thoughts and would also fit in with the direction that the Atlantic is headed currently.

The Siberian snow cover has grown considerably in the last few days which is promising..... could it lead to a knock on effect stratospherically come January????

El nino predisposes a +PNA with high pressure belt around Hawaii and jet flow goes around the top.

Last winter, under the nina conditions we saw a far amount of blocking over the Canadian arctic and this assisted a -PNA with the jet splitting and being squeezed further south. As we saw with the NW-SE tilted jet stream in the first part of the winter quite a bit and with split flow sending some energy into the STJ and a relative absence of the corridor of death..

So more reasons it seems, to want el nino to wane

West and weak sounds good to me.

[Glacier Point]

Thanks GP, that first chart certainly leads to interesting thoughts and would also fit in with the direction that the Atlantic is headed currently.

The Siberian snow cover has grown considerably in the last few days which is promising..... could it lead to a knock on effect stratospherically come January????

West and weak sounds good to me.

I don't have an issue with strong west-based Nino at all. The Nino events upon which the theory of strong=blowtorch were both strong across the entire Pacific, especially the east.

Compare that with the current and high unusual evolution where the east is +0.3 and west +1.4. There were also a couple of events where angular momentum was below average despite Nino events in place (1965/6 and 1986/7). Current angular momentum is close to average and there are no guarantees that it will increase markedly in the next few weeks before we hit winter.

[Typhoon John]

El nino predisposes a +PNA with high pressure belt around Hawaii and jet flow goes around the top.

Last winter, under the nina conditions we saw a far amount of blocking over the Canadian arctic and this assisted a -PNA with the jet splitting and being squeezed further south. As we saw with the NW-SE tilted jet stream in the first part of the winter quite a bit and with split flow sending some energy into the STJ and a relative absence of the corridor of death..

So more reasons it seems, to want el nino to wane

Or maybe we just don't want angular momentum to increase. It's surpressed state would seem tied to the solar minimum.

In this case maybe a moderate West based Nino wouldn't be so bad because it would encourage a favourable Atlantic pattern. SSTs are encouraging too.

[chionomaniac]

GP,

I have been looking further at the North Pacific pressure pattern that could evolve with a west based El Nino. Do you have a composite that would show what exactly what the pattern would be for a more regular east based El Nino? It would be interesting to compare with the west based El Nino.

Looking at the scenario that Tamara described with the +PNA leaving a high pressure belt around Hawaii with the jet riding high above, I could see a modified version of this with the west based El NIno, with the high pressure belt based more towards the dateline which, if it is west enough, would allow the jet stream to have enough amplification with possible splitting and buckling on the East Pacific. This could leave the jet coming off the east coast of America with far better amplification and not hitting us dead on along an unfavourable sw/ne axis.

When I look at the west based El Nino composite I am sure that this is how the default jet stream would behave in that case.

c

[Guest North Sea Snow Convection]

GP,

I have been looking further at the North Pacific pressure pattern that could evolve with a west based El Nino. Do you have a composite that would show what exactly what the pattern would be for a more regular east based El Nino? It would be interesting to compare with the west based El Nino.

Looking at the scenario that Tamara described with the +PNA leaving a high pressure belt around Hawaii with the jet riding high above, I could see a modified version of this with the west based El NIno, with the high pressure belt based more towards the dateline which, if it is west enough, would allow the jet stream to have enough amplification with possible splitting and buckling on the East Pacific. This could leave the jet coming off the east coast of America with far better amplification and not hitting us dead on along an unfavourable sw/ne axis.

When I look at the west based El Nino composite I am sure that this is how the default jet stream would behave in that case.

c

That could work, but it may be a 'high risk strategy' without the jet splitting at all. With the amplification you mention we might get a few northerlies out of it - but they might well be of the toppler variety as too much energy is going north. Doesn't sound a good recipe for a stable block of any kind to me

A split jet with plenty (not all) of the energy going into the STJ would be much safer - especially if we can engage that potential -NAO pattern (along with a -AO to sustain the -NAO courtesy of a decent arctic stratospheric warming event!)

Edited October 27, 2009 by North Sea Snow Convection

[chionomaniac]

That could work, but it may be a 'high risk strategy' without the jet splitting at all. With the amplification you mention we might get a few northerlies out of it - but they might well be of the toppler variety as too much energy is going north. Doesn't sound a good recipe for a stable block of any kind to me

A split jet with plenty (not all) of the energy going into the STJ would be much safer - especially if we can engage that potential -NAO pattern (along with a -AO to sustain the -NAO courtesy of a decent arctic stratospheric warming event!)

Envisaging the forthcoming winter jet stream pattern is certainly not a forte of mine. The jet stream strength and position depends upon all the other factors put together and is more than likely a chicken/ egg situation. Does a block influence the direction that the jet stream takes or does the jet stream direction influence the position of the block? Neither - it is all synergistic imo - the end result is the product of all the parts.

[Guest North Sea Snow Convection]

Envisaging the forthcoming winter jet stream pattern is certainly not a forte of mine. The jet stream strength and position depends upon all the other factors put together and is more than likely a chicken/ egg situation. Does a block influence the direction that the jet stream takes or does the jet stream direction influence the position of the block? Neither - it is all synergistic imo - the end result is the product of all the parts.

I agree with you - I'm not exactly a wiz either on this matter!

Whatever happens this winter, there are a lot of especially interesting factors in play that are finely balanced in terms of what sort of winter we will see. Plenty to look out for and talk about

[chionomaniac]

The latest SST's show the intensification of the El Nino when compared to a week ago. Even though this still remains a mainly west based phenomenon we can see signs of intensification further east.

The Atlantic SST's creep ever closer to a negative NAO signature.

24/10

30/10

-ve NAO

[karyo]

The latest SST's show the intensification of the El Nino when compared to a week ago. Even though this still remains a mainly west based phenomenon we can see signs of intensification further east.

The Atlantic SST's creep ever closer to a negative NAO signature.

Thank you for the update.

Not good to see the continuing strengthening of the el nino, in particular further east! I think it is unlikely to weaken in time for winter so remaining west based is our last hope!

Karyo

Edited October 31, 2009 by karyo

[Guest North Sea Snow Convection]

The latest SST's show the intensification of the El Nino when compared to a week ago. Even though this still remains a mainly west based phenomenon we can see signs of intensification further east.

The Atlantic SST's creep ever closer to a negative NAO signature.

24/10

30/10

-ve NAO

We do need to watch the east side cautiously but I am not too discouraged at all at this time. As you say, prospects for a -NAO are not being done any harm at all and if the nino can remain principally west based then the pacific will play ball in allowing that -NAO signature to bear fruit.

[BLAST FROM THE PAST]

With the waters remaining cold along coast of Chile, and cold pool growing to NW of NNorth America again then I see no concern there re El Nino.

BFTP

[Guest North Sea Snow Convection]

There are developing cold anomalies surrounding the nino warm anomaly area. This is a good sign

[Glacier Point]

This is just one factor pointing towards a mean trough solution for the western Atlantic right now. Tellingly, Atlantic surface temperatures have started to fall. This reanalysis (change in SSTA) shows a 1 - 2 degree fall over October so far.

This cooling has continued and expanded to cover a substantive part of the western North Atlantic.

http://weather.unisys.com/surface/sst_anom.html

Reanalysis of years with a similar profile (including the cool equatorial Atlantic) identifies the last time we saw something similar was the autumn and early winter of 1986. Other years as a base composite:

The theoretical response to this cold pool should be for a mean trough to develop as the jet stream is deflected south and split flow develops forcing height rises over Greenland. This can be tested by renalysis of the December - February mean 500 hPa geopotential height anomalies for those years with the similar SSTA:

Definately a negative NAO signal arising from oceanic signals.

[phil nw.]

There are developing cold anomalies surrounding the nino warm anomaly area. This is a good sign

Hi Tamara,

Have you seen any later chart than this?

It shows the Colder Waters off the S.American West coast,but is that not the omnipresent Peruvian Current?

Having said that the Warmest Waters still seem more West based on the above chart but i am anxiously waiting for an update.

[chionomaniac]

There are many pointers to 1986/87 as a good analogue for this winter. What I would like to see this January is a negative NAO such as Jan 1987 (but I don't know how much we can read into that).

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table

[Guest North Sea Snow Convection]

Hi Tamara,

Have you seen any later chart than this?

It shows the Colder Waters off the S.American West coast,but is that not the omnipresent Peruvian Current?

Having said that the Warmest Waters still seem more West based on the above chart but i am anxiously waiting for an update.

I'm looking at the latest unisys plots

[MR EXTREMES]

This cooling has continued and expanded to cover a substantive part of the western North Atlantic.

http://weather.unisy...e/sst_anom.html

Reanalysis of years with a similar profile (including the cool equatorial Atlantic) identifies the last time we saw something similar was the autumn and early winter of 1986. Other years as a base composite:

The theoretical response to this cold pool should be for a mean trough to develop as the jet stream is deflected south and split flow develops forcing height rises over Greenland. This can be tested by renalysis of the December - February mean 500 hPa geopotential height anomalies for those years with the similar SSTA:

Definately a negative NAO signal arising from oceanic signals.

Seems like you clever fellas know your stuff and this surely is a step in the right direction for winter.

Not only this,

but it would seem it renforces the idear of the solar minimum doing its stuff,

after all 1986 was a minimum if i remember rightly.

Its good to see whats going on,

because BFTP was not overall concerned about el nino although more time to see what happens is needed once again the clever fellas in here are getting it right.

[Methuselah]

Didn't the winter of 1947 occur at a Solar max?

[BornFromTheVoid]

Hi Tamara,

Have you seen any later chart than this?

It shows the Colder Waters off the S.American West coast,but is that not the omnipresent Peruvian Current?

Having said that the Warmest Waters still seem more West based on the above chart but i am anxiously waiting for an update.

This is the latest chart I could find from October 31st, shows the cold anomoly spreading out from Newfoundland

[phil nw.]

This is the latest chart I could find from October 31st, shows the cold anomoly spreading out from Newfoundland

Thanks for that seems a better picture wrt spread of colder anamolies.I have now kept that link.

[chionomaniac]

Thanks for that seems a better picture wrt spread of colder anamolies.I have now kept that link.

There is also the NOAA/NESDIS site which differs slightly when you compare to the Unisys site and I find it more difficult to see the anomalies on it. I don't know which one is more accurate.

http://www.osdpd.noaa.gov/ml/ocean/sst/anomaly.html

[MR EXTREMES]

Didn't the winter of 1947 occur at a Solar max?

yes there was and it was a beast of a winter,

so SSTs with solar cycles might not have a direct link.

but a neg NAO MUST BE A GOOOOOOD THING SURELY thats if it happens and judging by the charts posted its possible this could be a likely out come with nino weakening rapidly.

[Methuselah]

yes there was and it was a beast of a winter,

so SSTs with solar cycles might not have a direct link.

but a neg NAO MUST BE A GOOOOOOD THING SURELY thats if it happens and judging by the charts posted its possible this could be a likely out come with nino weakening rapidly.

Yes BB, I agree with that...I'm even starting to have my annual 'snow dreams'!

[azores92]

Yes BB, I agree with that...I'm even starting to have my annual 'snow dreams'!

it is a good thing, but things need to fall into place properly, i.e its all good having a scandinavian high, but we need to tap into that cold before it benefits us. mind you, its a trillion times better than positive NAO conditions for cold lovers

[chionomaniac]

Didn't the winter of 1947 occur at a Solar max?

The QBO data from around that time is sketchy to say the least. But, I bet, Pete, having read GP's link in the strat thread to west/east QBO's, solar min/max, and +/-NAO's, that the winter of 1947 was during a west QBO, which combined with a solar max would have been favourable for a -NAO.