Sea Surface Temperature - SSTs

[Guest North Sea Snow Convection]

There is a warm/cold/warm tripole set-up as far as I can see. From my own understanding that would support a -NAO.

[chionomaniac]

There is a warm/cold/warm tripole set-up as far as I can see. From my own understanding that would support a -NAO.

Here is the suggested SST's for +/-NAOs ( and jet stream patterns).

Taken from here: http://www.newx-forecasts.com/nao.html

Looking at that I would agree this is trending towards a -ve NAO but it is early days yet!

[Guest North Sea Snow Convection]

Here is the suggested SST's for +/-NAOs ( and jet stream patterns).

Taken from here: http://www.newx-forecasts.com/nao.html

Looking at that I would agree this is trending towards a -ve NAO but it is early days yet!

Oh indeed I agree - far too early. But just commenting following the various other differing opinions expressed further up the page.

[chionomaniac]

Oh indeed I agree - far too early. But just commenting following the various other differing opinions expressed further up the page.

One thing that I can see at this point is that the jet stream pattern from an El Nino will be totally opposed as to that from a -ve NAO. Something will have to give. If the El Nino is weak......perhaps - just perhaps. Also how will the PDO state alter this?

[Typhoon John]

Here is the suggested SST's for +/-NAOs ( and jet stream patterns).

Taken from here: http://www.newx-forecasts.com/nao.html

Looking at that I would agree this is trending towards a -ve NAO but it is early days yet!

There is a bit of a trend, the last month shows this. The chart from the 13th of August shows what looks like a strong +NAO from the charts you've posted:

And over the last month this has migrated Westward, partly aided by the recent hurricane activity:

To me this is at least a step in the right direction but the cold pool needs to slip further Southwards. But we have two months to see what will happen.

Elsewhere the -PDO looks like it's getting stronger. I'm not sure what the best scenario would be for the upcoming Winter, or what effect is will have on the NAO. El Nino still looks weak and is really struggling to have a big effect. Also SSTs have spread out a bit compared to the East based look earlier in August.

Edit:

Chart below from September 1997 isn't supposed to be in here but I can't seem to get rid of it.

Edited September 14, 2009 by fozi999

[chionomaniac]

Elsewhere the -PDO looks like it's getting stronger. I'm not sure what the best scenario would be for the upcoming Winter, or what effect is will have on the NAO. El Nino still looks weak and is really struggling to have a big effect. Also SSTs have spread out a bit compared to the East based look earlier in August.

Hi fozi,

I have searched high and low for suggested jet stream patterns for a -ve PDO to see how these could interlink with a -ve NAO but have yet to find them. If anyone has come across any please post them up. By looking at suggested slp anomalies I could hazard a guess that the polar jet may have increased amplitude across America with it heading south across W America before heading north across E America. This in my books would be more favourable to a -ve NAO. Again if anyone knows for sure please post up. Any -ve PDO will modify an El Nino to a certain extent.

http://jisao.washington.edu/pdo/

http://www.atmos.washington.edu/~mantua/REPORTS/PDO/PDO_egec.htm

c

[reef]

One thing that I can see at this point is that the jet stream pattern from an El Nino will be totally opposed as to that from a -ve NAO. Something will have to give. If the El Nino is weak......perhaps - just perhaps. Also how will the PDO state alter this?

Indeed. What happens in the Pacific can override everything.

2006/07 for example though not a particularly bad SST pattern was a very mild winter as the El Nino, associated strong jet and stubbornly cold stratosphere / strong polar vortex just completely negated everything else. Fast forward to 2007/08 and it happened again, this time with a completely different SST pattern and a La Nina instead.

I cant even begin to explain why this happens (Im sure even for the experts its a stab in the dark), but theres something in it. I guess cold lovers can just hope the El Nino remains weak (which it seems to be at the moment).

[Typhoon John]

Hi fozi,

I have searched high and low for suggested jet stream patterns for a -ve PDO to see how these could interlink with a -ve NAO but have yet to find them. If anyone has come across any please post them up. By looking at suggested slp anomalies I could hazard a guess that the polar jet may have increased amplitude across America with it heading south across W America before heading north across E America. This in my books would be more favourable to a -ve NAO. Again if anyone knows for sure please post up. Any -ve PDO will modify an El Nino to a certain extent.

http://jisao.washington.edu/pdo/

http://www.atmos.washington.edu/~mantua/REPORTS/PDO/PDO_egec.htm

c

I'm not sure either, but if you had to push me on it I would expect something similar but further East. I think the general pattern you suggest is right but with a -PDO and -NAO I would favour everything a little further East so that the North East USA is cold but the storm track is in the Atlantic so a cold but quite dry.

How the low solar activity might effect this I'm not sure, perhaps an even weaker jet? And with the -QBO surely this favours a SSW/MWW event at some point this year with substantial blocking quickly able to establish itself but will it be in the right place?

But I'm getting ahead of myself; I can still see things going rapidly pear shaped. The latest Kelvin Wave should boost the El Nino, especially as we are now into Autumn, but SOI is looking Neutral so hopefully it'll take the sting out of any warming.

[Guest North Sea Snow Convection]

The cold pool in the north pacific has been expanding over the last week or so. This is all good for sustaining a -PDO. I think it is some more evidence to illustrate that the PDO is now in general negative phase mode and this is going to discourage nino and it will also at the same time encourage the jet to stay more southerly.

If that is right then it will be an assist for winter, providing the trend is maintained.

Regarding MMW potential, then easterly QBO and solar min are good. It will indeed come down to the influence of the pacific whether we get a neutralish ENSO with the -PDO and a jet that behaves like last winter but with a -NAO that can be sustained. The NAO did not stay negative for long enough last winter, but that was largely down to the AO which failed to hold negative to lock it in place.

A stratosphere that wants to warm along with a compliant jet is needed (as always!) to help blocking hold where we want it.

Edited September 15, 2009 by North Sea Snow Convection

[Thundery wintry showers]

I think the most important thing for cold/snow lovers is that the El Nino remains weak- a weak El Nino is often correlated with frequent cold snowy weather in late winter (suggesting another cold February). The last time we had a strong El Nino, I'm sure many of us will remember February 1998.

The problem with trends at this stage is that it is so easy for them to be blown away when it really matters. In 1978 we had a very warm autumn and it was probably looking as if a cold snowy winter was exceedingly unlikely, but around the 24th November the persistent Euro high suddenly gave up, and a northerly outbreak signalled the start of an exceptionally snowy winter. Meanwhile, we had a pretty promising cold November for snow lovers in 1988, with a northerly outbreak around the 20th, and even towards early December the pattern was quite blocked with a brief 36-hour easterly on the 2nd which gave snow to high ground in the northeast. Then Mr Bartlett decided to spend a few months sitting around.

The points on the negative PDO are good, and promising, but it needs to sustain for a while, otherwise it could go the way of the Bartlett.

[tcc]

An interesting piece from a Pro-Met over on Eastern, it gives good explanations about the different teleconnections which could be of use for over here...

http://www.easternuswx.com/bb/index.php?showtopic=205478&st=0

[Glacier Point]

Net change in SSTA over the last month:

Points to note:

(1) cooling Indian Ocean which should help suppress tropical convection there and enable the centre for convection to drift eastwards allowing the ocean-atmosphere coupling to become more orientated twowards the El Nino base state;

(2) cooling NW Pacific sector - this looks very much a 'winter player' by the way the anomalies are strengthening and drawing a distinct circulation in lower tropospheric winds around the trough;

(3) warming anomaly around the Azores, cooling to either side in the Atlantic, the anomaly south of Newfoundland being the most interesting one there consistent with a neutral or developing negative NAO signal ?

I regard the NAO as being so much more than a function of the Atlantic SSTA. The overall ocean-atmsopheric coupling is much more important IMO. If we take the 10 most negative NAO winters, we see a pattern of out going long wave anomalies - the most notable being over Africa and east of Indonesia across 160W.

Comapre this to 10 most positive NAO winters and you get an impression of how the NAO is related to global weather patterns.

An eastward shift in the centre of tropical convection tied into the changes in SSTA should be viewed as an encouraging sign for -NAO however we need to see the global weather pattern pick up and run with the idea of El Nino a bit more than it is currently showing.

[chionomaniac]

Very interesting GP.

There are big differences in those OLR anomaly charts between positive and negative NAO's. Not only in extent as there seems to be far greater and widespread OLR in positive NAO years compared to negative years. As you say the differences in Africa and the Indian Ocean/Indonesia are striking with the OLR seemingly further north in Africa and absent over India in those negative years.

If anything it looks like the total global OLR is far less in a negative NAO winter than a positive one. I will be keeping a close eye on the global OLR this winter for sure! Will too much of an El Nino atmospheric state set off too much tropical convection in the 'wrong' areas though?

[Glacier Point]

Yes, -ve OLR (anomalous convection) would appear to be much more widespread during -NAO winters which is ties in with the theory that increased angular momentum and resulting of fast poleward propagating Rossby Waves during the winter time leads to blocking at high latitudes

In so far as relative strength of El Nino, I'm stilll weak to moderate in terms of atmospheric response because the developing -PDO signature will fight warm SST over the equatorial Pacific. Similar to the balance that was prevelant early doors last winter.

The real interests for me at this point are: the potential for a weakish but generally affirmative Nino base state (which is good for high latitude blocking); the phasing of the zonal wind anomalies over the polar field (positive downwelling wave at present but possibly turning back to negative on 1st December ); and, the combo of solar minima and east QBOs.

Edited September 15, 2009 by Glacier Point

[tcc]

Yes, -ve OLR (anomalous convection) would appear to be much more widespread during -NAO winters which is ties in with the theory that increased angular momentum and resulting of fast poleward propagating Rossby Waves during the winter time leads to blocking at high latitudes

In so far as relative strength of El Nino, I'm stilll weak to moderate in terms of atmospheric response because the developing -PDO signature will fight warm SST over the equatorial Pacific. Similar to the balance that was prevelant early doors last winter.

The real interests for me at this point are: the potential for a weakish but generally affirmative Nino base state (which is good for high latitude blocking); the phasing of the zonal wind anomalies over the polar field (positive downwelling wave at present but possibly turning back to negative on 1st December ); and, the combo of solar minima and east QBOs.

Just a quick question for you or C, would there be any difference to our weather here if the El Nino was west based instead of east based? Thanks

[Glacier Point]

Just a quick question for you or C, would there be any difference to our weather here if the El Nino was west based instead of east based? Thanks

I don't place much store to the relative east-west debate although the OLR anomalies for -NAO would tend to suggest west-based is more favourable to a -NAO. My key measure would be the Global Wind Oscillation / strong MJO projection in phases 7 and 8.

[chionomaniac]

I don't place much store to the relative east-west debate although the OLR anomalies for -NAO would tend to suggest west-based is more favourable to a -NAO. My key measure would be the Global Wind Oscillation / strong MJO projection in phases 7 and 8.

GP, do you think that the last 6 months OLR anomalies are trending in the right direction or are they not relevant until winter?

http://www.bom.gov.au/bmrc/clfor/cfstaff/matw/maproom/OLR/m.l6m.html

PS I almost got caught out with the difference in colour charting here and with your charts! I need to keep reminding myself -ve OLR = less radiation leaving earth = more cloud cover = more tropical convection.

[tcc]

I don't place much store to the relative east-west debate although the OLR anomalies for -NAO would tend to suggest west-based is more favourable to a -NAO. My key measure would be the Global Wind Oscillation / strong MJO projection in phases 7 and 8.

Thanks GP, this could end up being a very interesting winter (from a coldie pov!)

[Glacier Point]

GP, do you think that the last 6 months OLR anomalies are trending in the right direction or are they not relevant until winter?

http://www.bom.gov.a.../OLR/m.l6m.html

PS I almost got caught out with the difference in colour charting here and with your charts! I need to keep reminding myself -ve OLR = less radiation leaving earth = more cloud cover = more tropical convection.

I would think that they reflect the state of the GWO over the last 6 months, i.e. westerly wind burst during April and June, Nina like fall in July and slight rise in angular momentum during August. It's where the global weather pattern goes over the next 3 months that matters.

[Typhoon John]

El Nino is struggling. SOI looks likely to be positive for September; general pattern doesn't look to support El Nino.

Has it peaked?

Considering El Nino is struggling to have an influence on the atmosphere globally, will we see a weak El Nino peak with a neutral positive ENSO influence?

That would seem like a good setup going into the second half of Autumn.

Edited September 20, 2009 by fozi999

[Guest North Sea Snow Convection]

El Nino is struggling. SOI looks likely to be positive for September; general pattern doesn't look to support El Nino.

Has it peaked?

Considering El Nino is struggling to have an influence on the atmosphere globally, will we see a weak El Nino peak with a neutral positive ENSO influence?

That would seem like a good setup going into the second half of Autumn.

The cold pool in the north pacific is continuing to develop - this is going to encourage -PDO.

A -PDO is going to counter any el nino

[SteveB]

Whats with the +anomolies up in the artic, a whopping +4c in places, surely that is going to put a dent in any ice advance.

Something looks wrong???

[Snowmad79]

The cold pool in the north pacific is continuing to develop - this is going to encourage -PDO.

A -PDO is going to counter any el nino

Disagree with this post. Forgive me if im wrong but if you look at both the Oceanic Nino Index and the PDO index you'll see that since El nino conditions have returned this year the PDO has actually gone possitive. Also note that PDO was in a negative phase at some point during previous Enso years (possitve and negative enso year). So in my mind looking at both index's, -PDO only encourages La Nina Episodes but doesnt actually have an great effect when El nino conditions have already set in.

Just read Noaa's Enso update and the majority of models still going for a strengthening of El Nino conditions which are looking to peak around December but last through the winter. Remember that were already around the 1.0 moderate nino threshold and with recent kelvin wave downwelling in the pacific this is only going to add to the SST anomilies.

As for winter ahead, well I wouldnt at all be suprised if this turns out to be a late affair or something similar to 2006/2007 ( the last moderate El nino year), but i guess we'll have to wait and see what happens with regards to OA, NAO and the East QBO / solar minima thing that GP has been talking about.

Thats my quick take on things atm.

[chionomaniac]

Disagree with this post. Forgive me if im wrong but if you look at both the Oceanic Nino Index and the PDO index you'll see that since El nino conditions have returned this year the PDO has actually gone possitive. Also note that PDO was in a negative phase at some point during previous Enso years (possitve and negative enso year). So in my mind looking at both index's, -PDO only encourages La Nina Episodes but doesnt actually have an great effect when El nino conditions have already set in.

Just read Noaa's Enso update and the majority of models still going for a strengthening of El Nino conditions which are looking to peak around December but last through the winter. Remember that were already around the 1.0 moderate nino threshold and with recent kelvin wave downwelling in the pacific this is only going to add to the SST anomilies.

As for winter ahead, well I wouldnt at all be suprised if this turns out to be a late affair or something similar to 2006/2007 ( the last moderate El nino year), but i guess we'll have to wait and see what happens with regards to OA, NAO and the East QBO / solar minima thing that GP has been talking about.

Thats my quick take on things atm.

Hi SM79,

Working out how a negative PDO phase may affect a developing El Nino is complex, and I don't think that you can state that a negative PDO base state doesn't have an effect when El Nino conditions have set in. My take on it is that a negative PDO state will be bound to affect an El Nino because they are both antagonistic to each other.

I would suggest that if an El Nino is akin to boiling a pan of water, then, in a negative PDO state, one could suggest that this is akin to continuously adding cold water to that pan. The constant adding of cold water will prevent the pan heating to the same temperature that it would were it not added.

Having said that, the Pacific Ocean profile looks neither like a classic positive nor a classic negative PDO presently.

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

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

As has also been pointed out before, the global SST's are also vastly different to 2006 presently (especially the Atlantic profile) so I don't think we can use that as a good analogue to compare to.

http://weather.unisys.com/archive/sst/sst_anom-060924.gif

I would also be very cautious about reading too much into any forecast suggesting that El Nino is going to strengthen anywhere beyond the lower end of moderate. These forecasts have an extremely poor verification rate. The recent KW downwelling doesn't seem to have increased the anomaly at the 3.4 region with it remaining at +0.9 today however the full effects of this may not be felt yet.

One way of judging where we feel the El Nino may be heading is by looking at the SOI index.

http://www.bom.gov.au/climate/glossary/soi.shtml

The more negative the SOI, the stronger atmospheric El Nino conditions we are experiencing. Currently this is running at positive values with an average 2.93 for the last 30 days average.

http://www.longpaddock.qld.gov.au/SeasonalClimateOutlook/SouthernOscillationIndex/30DaySOIValues/

This is hardly what is expected of an El Nino state!

If anything it looks like we are heading into an El Nina or perhaps a La Nino! El Nino sea conditions with a La Nina atmospheric state.

c

[innov8tion]

Please could someone publish an explanation of what the multitude of 'short hand' metorological letters mean in English - for instance -ve PDO - whats that supposed to mean ?? For a newbie it makes reading and understanding post almost impossible so a little list of 'this is what it means' would make this site even more interesting - thanks !