Sea Surface Temperature And Sea Ice Trends(2)

[Glacier Point]

An end to anticyclonic domination ? Possibly, but probably only temporary based on SSTAs.

La Nina continues to develop across large parts of the Pacific. Current SSTAs show particularly cold anomalies across the eastern Pacific as easterly surface winds have helped upwelling of anomalously cold subsurface waters.

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

http://www.cdc.noaa.gov/map/images/sst/sst.anom.gif

Colder waters are also showing up in Nino Region 3.4, down to -0.8:

http://www.bom.gov.au/climate/enso/indices.shtml

whilst there remains (and possibly expanding) a large body of anomalously cold sub-surface water in the eastern Pacific:

http://www.ecmwf.int/products/forecasts/d/...33;Temperature/

So a moderate strength event could well occur in the next month although Kelvin Wave and MJO activity could hinder upwelling of cold water to the surface.

What does La Nina imply for the UK?

A substantial mid latitude high in the eastern Atlantic / UK with trough over Scandinavia. Probably on the mild side given the developing warmth to our west, but it could equally provide the setting for a strong outbreak of cold air mid winter and more regular northerly incursions. What La Nina doesn't do, according to the composites, is interfere too much with what goes on over the polar field (whereas El Nino does) so my view would be that La Nina is no barrier to our cold winter aspirations if this part of the equation is favourable.

[Glacier Point]

Worth noting some changes ocurring in the North Atlantic and Polar Seas over the last 18 days:

The Barents Sea has cooled rapidly, showing a 1-1.25 C drop over this period in response to surface wind flow from the Arctic Basin, probably a response to warm surface anomalies further east.

With these surface anomalies only slowly changing, we could expect to see this area to continue to cool whilst the North Atlantic remains anomalously warm. This should help to favour a strong polar trough in the next few months.

The mid latitude Atlantic has warmed considerably, as it always seems to this time of year.

I think I would prefer to see some cooler anomalies further south-west although something of an Atlantic Tripole shaping up.

[summer blizzard]

I hav'nt commented in this thread for a while however i will try to keep upto the thread...

Well, starting in the Pacific, the sea surface temperature anomoly profile continues to indicate an amplified and subdued Pacific Jet Stream with a mid-Pacific High pressure zone and an Aloution Trough, with high pressure over Eastern Canada..

In The Atlantic, we continue to see a strong signal for high pressure in the central Atlantic, though the indications are that there is too much energy available for a full blown Greenland-Atlantic Ridge, however there does look to be a signal for high pressure over Scandinavia, though i find it doubtful that this will ridge far enougth west to provide us with an early beast..

These anomolies are for the period around the 15th-20th November...

[summer blizzard]

Pacific anomolies taking on more of a negative PNA signiture, however the most eyecatching thing is the Pacific Tripole in the central Pacific Ocean.

[AtlanticFlamethrower]

There was a somewhat similar global SSTA set up in 1955.

[summer blizzard]

I hav'nt commented in this thread for a while however i will try to keep upto the thread...

Well, starting in the Pacific, the sea surface temperature anomoly profile continues to indicate an amplified and subdued Pacific Jet Stream with a mid-Pacific High pressure zone and an Aloution Trough, with high pressure over Eastern Canada..

In The Atlantic, we continue to see a strong signal for high pressure in the central Atlantic, though the indications are that there is too much energy available for a full blown Greenland-Atlantic Ridge, however there does look to be a signal for high pressure over Scandinavia, though i find it doubtful that this will ridge far enougth west to provide us with an early beast..

These anomolies are for the period around the 15th-20th November...

Well, we did see an easterly between those dates with the snow event for England, so i'd grade this forecast pretty high..

As for the current anomolies, in the western Pacific, we see a signal for a strong Pacific Jet Stream, though in the central and eastern Pacific, there is a strong signal for a mid-lattitude high pressure zone and subsequant split Jet Stream, with a resultant +PNA signiture, though there are signs that anomolies may be beggining to trend towards a negative PNA.

In the Atlantic, we see a signal for blocking to the south western side of Greenland, and a cut off low off the east coast of the USA, though in the central Atlantic, we see a signal for a strong Jet Stream, though also a signal for a pressure build over Scandinavia and Europe.

In conclusion, it looks like any pressure build will occur too far south over Europe for anything of note, though with high pressure close to the south east of the UK, it should'nt be wet.

These anomolies correlate to the start of the new year.

[Gavin P]

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

I'm interested by the cold anomoly that seems to be developing around the coast of New Foundland and the eastern seaboard. If that continues to develop and stregnthen, with warm waters sinking south to the Azores, then I think we may have a -NAO signature by late winter. Coldest weather in February this winter?

Edited December 9, 2007 by Gavin P

[BLAST FROM THE PAST]

Gavin

I think you need a warm anomaly over a cold for a -NAO signature - or better still a cold, warm, cold tripole signature.

Tamara

That Atlantic warm anomaly has taken a smack and still shrinking. A lot of cold anomalies building to the north too.

BFTP

[Stu_London]

Gavin

I think you need a warm anomaly over a cold for a -NAO signature - or better still a cold, warm, cold tripole signature.

Tamara

Is that not several months earlier though?

[Optimus Prime]

Are the SST situation somewhat similar to November/December 1962??;

Cold pacific and warm atlantic like we have now.

Probably means nothing but is curious.

[AtlanticFlamethrower]

I think 1955 is a better fit.

However December 1955 was +AO. No Scandi high.

December 1962 was mostly +AO.

Also the North Atlantic today is probably warmer than it was in either of those years. Greater difference between warm and cold. Lots of energy for storms.

Is it possible today to get such a placid set up as this to the west of Europe?

[Optimus Prime]

Is it possible today to get such a placid set up as this to the west of Europe?

In recent years, the exceptional easterly blocking and cold of February 2005;

[AtlanticFlamethrower]

That's February. I guess I meant in December.

Edited December 10, 2007 by AtlanticFlamethrower

[suffolkboy_]

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

I'm interested by the cold anomoly that seems to be developing around the coast of New Foundland and the eastern seaboard. If that continues to develop and stregnthen, with warm waters sinking south to the Azores, then I think we may have a -NAO signature by late winter. Coldest weather in February this winter?

This is what Paul bartlett has been hinting towards on his website. He is still yet to publish his full winter forecast.

[Gray-Wolf]

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

I'm interested by the cold anomoly that seems to be developing around the coast of New Foundland and the eastern seaboard. If that continues to develop and stregnthen, with warm waters sinking south to the Azores, then I think we may have a -NAO signature by late winter. Coldest weather in February this winter?

So how do we reconcile the +5c anom to the rear of the cold coastline? Looks rather like the deeper you go the warmer you go apart from that sliver of continental coastline.

If we see cold anoms in deep water then I'd be interested but at present we still seem to have a toastie warm Atlantic.

[BLAST FROM THE PAST]

So how do we reconcile the +5c anom to the rear of the cold coastline? Looks rather like the deeper you go the warmer you go apart from that sliver of continental coastline.

If we see cold anoms in deep water then I'd be interested but at present we still seem to have a toastie warm Atlantic.

GW

I think unisys shows a more tangible picture. The anomalies in the Atlantic have lessened hugely over the last 10 days and continue to do so.

BFTP

Edited December 10, 2007 by BLAST FROM THE PAST

[BrickFielder]

Sea Surface Temperatures reflect the state of the winds above the sea. So the warm area in the north atlantic are probably the result of winds from the south and west.

Warm seas in the north atlantic are associated with easterly winds and high pressure towards greenland while cooler waters of the coast of the US. tend to migrate eastwards and result in westerly winds.

The result of the pattern tends to be a negative NAO with cut off lows comming across the Atlantic. The reality is that the Pacific is yet again dictating the pattern so we should not expect too much from the this.

[BLAST FROM THE PAST]

Sea Surface Temperatures reflect the state of the winds above the sea. So the warm area in the north atlantic are probably the result of winds from the south and west.

Warm seas in the north atlantic are associated with easterly winds and high pressure towards greenland while cooler waters of the coast of the US. tend to migrate eastwards and result in westerly winds.

The result of the pattern tends to be a negative NAO with cut off lows comming across the Atlantic. The reality is that the Pacific is yet again dictating the pattern so we should not expect too much from the this.

Thanks BF, I think [anticipating/hoping] the SSTs will play a big part this winter.

BFTP

[summer blizzard]

The lastest data which is relevant for the period around 1st-5th Feb, indicates that the negative GLAAM readings seem to be having an effect, with a convulted global Jet Stream.

Beggining in the Pacific, we see a mid-lattitude high pressure zone, perhaps caused by the increased Tropical convection in that region, while most of the Jet Stream energy is flowing into the northern arm, it is still weak due to a low thermal gradiant. In the central Pacific, we see the Jet Stream splitting, with most of the energy flowing into the southern arm of the Jet Stream and Alaskan Ridging as a response. In the eastern Pacific, we see the Jet Stream becoming confluent west of the USA, leading to the possibility of some strong winter storms across the western USA.

In the Atlantic, we do see most of the Jet Stream energy going into the northern arm, albeit weak, and perhaps caused by the heightened thermal gradiant due to high pressure over the eastern USA, however the Jet Stream is still weak, prompting the likelyhood of a mid-lattitude high, perhaps just west of the UK, but also a signiture for high pressure over Scandinavia with cold air on its southern flank.

In conclusion, we do have a very interesting set-up, with mid-lattitude high pressure zones looking to be dominant, and for the UK, we look to be under generally anti-cyclonic conditions, which at this time of year lead to colder weather, though with the Azores and Scandi-High's both strong, we could end up with a north easterly or mild north westerly, all i can say for the moment, is that we have too much of a Polar Vortex over Greenland to see height rises in the timeframe, just yet.

[Shiny_Bottom_1]

Havent got a scooby what it means, but latest SST's attached.

Doesnt look like there is much +ve anomolies, but again, I dont know if thats normal or not.

[summer blizzard]

The lastest data which is relevant for the period around 1st-5th Feb, indicates that the negative GLAAM readings seem to be having an effect, with a convulted global Jet Stream.

Beggining in the Pacific, we see a mid-lattitude high pressure zone, perhaps caused by the increased Tropical convection in that region, while most of the Jet Stream energy is flowing into the northern arm, it is still weak due to a low thermal gradiant. In the central Pacific, we see the Jet Stream splitting, with most of the energy flowing into the southern arm of the Jet Stream and Alaskan Ridging as a response. In the eastern Pacific, we see the Jet Stream becoming confluent west of the USA, leading to the possibility of some strong winter storms across the western USA.

In the Atlantic, we do see most of the Jet Stream energy going into the northern arm, albeit weak, and perhaps caused by the heightened thermal gradiant due to high pressure over the eastern USA, however the Jet Stream is still weak, prompting the likelyhood of a mid-lattitude high, perhaps just west of the UK, but also a signiture for high pressure over Scandinavia with cold air on its southern flank.

In conclusion, we do have a very interesting set-up, with mid-lattitude high pressure zones looking to be dominant, and for the UK, we look to be under generally anti-cyclonic conditions, which at this time of year lead to colder weather, though with the Azores and Scandi-High's both strong, we could end up with a north easterly or mild north westerly, all i can say for the moment, is that we have too much of a Polar Vortex over Greenland to see height rises in the timeframe, just yet.

In regards to my prediction, i anticipated too much of a anticyclonic influence, and thus we saw a more potent and snowy north westerly than i anticipated.

As for the synoptic setup between the 20th and 25th of February, lets have a look at the anomolies

Beggining in the western Pacifc, we see a very similar picture to a few weeks ago, with a weak Polar Jet Stream and the Sub-Tropical high pressure shifted northward in association with above average Tropical Convection in that region. In the central Pacific we again see the Jet Stream splitting with the majority of the energy flowing into the Sub-Tropical Jet Stream, giving skope for a very amplified Pacific Jet Stream to develop, however in the eastern Pacific, we see the Jet Stream becoming confluentindicating that we could see a major trough develop over the western USA, with a ridge over north eastern Canada.

In the Atlantic, we again see the Jet Stream splitting, but with no major activity, and only one longwave in the central Atlantic, though with the et Stream weak and amplified, this could lead to retrogression of any high lattitude high pressure zone.

In conclusion, the signs are for a more amplified Jet Stream globally than average (negative GLAAM), higher than average Tropical convection considering a La Nina year, and a fairly southerly tracking Atlantic Jet Stream, meaning that a low pressure system over the British Isles moving south east is the outlook for the 20th to 25th February.

[summer blizzard]

Will elobarote later, but the latest SST situation shows the negative PDO weakening, perhaps indicating that La Nina is losing its influence.

[James M]

If La Nina is weakening, who's to bet that come next winter we'll have El Nino to contend with

[kold weather]

Well yeah the La Nina is losing its strength now, the latest weeklies shows the 3.4 zone is now down to -1.0C, just borderline moderate, where interesting -ve NAO's are strongly favored which is interesting given the northerly airflow last weekend and also the wanten of the models to develop northern blocking again.

La Ninas nearly always decay during Spring its what happens in late summer that should prove far more interesting.

[Glacier Point]

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

Certainly one development to be aware of are cold anomalies showing up in the SW Atlantic. The projected pattern over the next 10-15 days is certainly going to reinforce this with cut off lows promoting stirring of the surface and -ve OLR anomalies.

Cold water in this area could lead to troughing / cut off lows in the area with downstream ridges over western Europe characteristic of a -ve NAO type pattern. When the cold pooling is exhausted from the pole over the next few weeks, as it surely will, and the AO returning +ve, that could be a signal for a very warm and humid pattern. Say mid May for example.

Edited March 26, 2008 by Glacier Point