Warm SE Pacific to blame for stormy winter?

[damianslaw]

Interesting to hear John Hammond saying the key factor for this consistently stormy winter is down to a warm SE pacific and its influence on the pattern upstream..

 

I'm not technical enough to know how a warm pacific impacts on events over northern hemisphere - anyone better in the know care to explain..

 

Is it to do with the PDO - which I believe has been conducive to strong heights over aluetian area locking the PV into position over NE Canada?

 

With no influence from the stratosphere - this is a reason for the stuck pattern?

 

Where exactly are these warm seas? - How warm were they in late autumn/early winter - must have had to have been preety warm- how do they compare to other years.

 

Lots of questions... and if the Met understand the relationship of warm seas in this region then why couldn't then have foreseen such a pattern developing.. not one forecast was suggesting such intense stormy wet conditions this winter, especially given how other factors were suggesting against northern height development.

[winterof79]

Interesting to hear John Hammond saying the key factor for this consistently stormy winter is down to a warm SE pacific and its influence on the pattern upstream..

 

I'm not technical enough to know how a warm pacific impacts on events over northern hemisphere - anyone better in the know care to explain..

 

Is it to do with the PDO - which I believe has been conducive to strong heights over aluetian area locking the PV into position over NE Canada?

 

With no influence from the stratosphere - this is a reason for the stuck pattern?

 

Where exactly are these warm seas? - How warm were they in late autumn/early winter - must have had to have been preety warm- how do they compare to other years.

 

Lots of questions... and if the Met understand the relationship of warm seas in this region then why couldn't then have foreseen such a pattern developing.. not one forecast was suggesting such intense stormy wet conditions this winter, especially given how other factors were suggesting against northern height development.

I caught John saying that too on the One Show.I would also be interested to hear from someone in the know.

Guess it shows just how complicated the fluid dynamics of the atmosphere are to our weather.

Edited February 12, 2014 by winterof79

[Snowyowl9]

Theres lots of others factors aswell I`d imagine,global weather is very complex.

[damianslaw]

Just got my answer - BBC news said it is the rains over Indonesia that have influenced the position of the Jetstream, not the warmth of the pacific as such although too may go hand in hand.

 

I don't recall anyone taking note of the potential repurcussions of heavy rain in Indonesia on our weather pattern. I wasn't aware there were particularly heavy rains..

 

It seems all a bit too simple. The warmer atlantic interacting with cold polar air over Canada has certainly been a key important ingredient - creating a very marked temperature gradient fuelling the atlantic, a much cooler atlantic would not have had such affect.

 

Were the rains over Indonesia particularly bad - and when exactly..

[summer blizzard]

Just got my answer - BBC news said it is the rains over Indonesia that have influenced the position of the Jetstream, not the warmth of the pacific as such although too may go hand in hand.

 

I don't recall anyone taking note of the potential repurcussions of heavy rain in Indonesia on our weather pattern. I wasn't aware there were particularly heavy rains..

 

It seems all a bit too simple. The warmer atlantic interacting with cold polar air over Canada has certainly been a key important ingredient - creating a very marked temperature gradient fuelling the atlantic, a much cooler atlantic would not have had such affect.

 

Were the rains over Indonesia particularly bad - and when exactly..

 

Just got my answer - BBC news said it is the rains over Indonesia that have influenced the position of the Jetstream, not the warmth of the pacific as such although too may go hand in hand.

 

I don't recall anyone taking note of the potential repurcussions of heavy rain in Indonesia on our weather pattern. I wasn't aware there were particularly heavy rains..

 

It seems all a bit too simple. The warmer atlantic interacting with cold polar air over Canada has certainly been a key important ingredient - creating a very marked temperature gradient fuelling the atlantic, a much cooler atlantic would not have had such affect.

 

Were the rains over Indonesia particularly bad - and when exactly..

 

Rains over Indonesia refer to the MJO as you'll have heard it here.

[Bobby]

The Met Office discuss this in more detail in this briefing on the winter storms, look to page 12

 

http://www.metoffice.gov.uk/media/pdf/n/i/Recent_Storms_Briefing_Final_07023.pdf

[Gael_Force]

Just got my answer - BBC news said it is the rains over Indonesia that have influenced the position of the Jetstream, not the warmth of the pacific as such although too may go hand in hand.

 

I don't recall anyone taking note of the potential repurcussions of heavy rain in Indonesia on our weather pattern. I wasn't aware there were particularly heavy rains..

 

It seems all a bit too simple. The warmer atlantic interacting with cold polar air over Canada has certainly been a key important ingredient - creating a very marked temperature gradient fuelling the atlantic, a much cooler atlantic would not have had such affect.

 

Were the rains over Indonesia particularly bad - and when exactly..

 

There were some huge precipitation totals during December (up to 500%) as you can see from the ratio map provided by Tokyo Climate Centre. Not so much in January but the pattern was maybe set by then.

 

[laserguy]

So now a rainy SE Pacific is being touted as the root of our storms. Ten minutes ago it was the extreme and protracted cold which has plagued North America most of the winter. Whatever - one way or another you can guarantee the global warming fraternity will have a say in it. Why, they've already started. Keep driving those hybrids and don't forget to switch things off and everything will be alright.

[4wd]

But what caused the rain in Indonesia  
That was probably something to do with the Monsoon being affected by that intense cold pool in SIberia.
If someone gives me £2m I will research this.

Edited February 13, 2014 by 4wd

[hillbilly]

Maybe they are wrong.....it is the stormy weather here that makes the south pacific warm!!!!!!!

[Gray-Wolf]

It is very sad to see the less enlightened of us "pooh, poohing" teleconnections? Butterflies wing an' all that?

 

If one is looking for a 'beginning' then look North!

 

The impacts of AGW upon the PDO may well be one such area in the north Pacific? The High pressure pulling up the high sst's under it? ( cold horse shoe with cold waters around the coast and warm core?) impacts of said H.P. on the trades to its southern flank??

 

Or perhaps the impacts of the record low ice year of 2012 followed by the record high energy year , across the Arctic, last summer?

 

Never one thing alone but the interplay between 'normal' and 'affected'......

 

Never mind, Nino a comin'.... and it's tendency to 'Chinook' the Arctic..... low ice years in 14' and 15'?

 

When you look at the SST's that the IPO 'deep ocean warmth' has driven (Typhoon Haiyan fuelled from surface to 100m depth) then the recent '500% rainfall over the same region?

 

Make no mistake we lose the Sea ice we lose the polar jet and inherit Tropical outbreaks ( in the way we currently natter about polar outbreaks) then when you cool that air on it's travels guess what ? 

Edited February 13, 2014 by Gray-Wolf

[knocker]

Incredible that nobody can be bothered to read the link that Bobby posted and then if they wish post some scientific comment. I thought I was in the sceptic thread for a minute. I'll post the relevant section without the diagrams. I've highlighted the relevant piece regarding Indonesia.

 

Global Context of recent UK Weather

 

The exceptional weather experienced over the UK in December and January was part of a hemispheric pattern of severe weather. This included exceptionally low temperatures across Canada and the US from the mid-west to the eastern seaboard and reaching as far south as Texas (Figure 12). The peak of this cold event occurred on the 5th and 6th January, coinciding with the storminess over the UK. Early estimates suggest that in the US alone over 200 million people were affected with costs in excess of $5bn.

 

These extreme weather events on both sides of the Atlantic were embedded in a persistent pattern of perturbations to the upper tropospheric jet stream2 (Figure 13). The climatological distribution of the winter jet streams (Figure 13, left panels) shows the well-known Asian-Pacific jet stream, which extends across North Africa and out into the North West Pacific, close to Japan. A second jet stream forms over the US, extending in a north-easterly direction across the North Atlantic towards the UK. The North Atlantic jet stream acts to steer weather systems towards the UK, but there also exists a symbiotic relationship between the jet stream and the depressions that form on its flanks. The jet stream provides the atmospheric conditions that are favourable for cyclogenesis (the formation of depressions), but it also depends on the momentum from the depressions to maintain its own strength. So it is possible on occasions to observe a strengthening of the jet stream when there is a particularly active sequence of depressions, as was the case in December 2013 and January 2014 (Figure 13, right panels).

 

During December and January 2013/14 the pattern of winds over the North East Pacific and North America was very disturbed (Figure 13, right panels). The North Pacific jet was deflected a long way north, with a secondary branch extending southwards into the tropical Pacific accentuating the separation of the Pacific and Atlantic jet streams. The effects of this over North America and into the North Atlantic were profound. The deflection of the jet to the north led to colder air being carried south over Canada and the northern US (as seen in Figure 13) to enter the North Atlantic jet and establish a stronger than normal temperature gradient at the entrance of the North Atlantic Jet. This acted to strengthen the jet and provide the conditions for active cyclogenesis, which in turn led to a sequence of strong storms across the UK throughout December and January. As Figure 13 indicates, the North Atlantic jet was, on average, as much as 30% stronger than normal. Similar, but weaker, conditions can be seen in the southern hemisphere, mirroring those to the north and supporting the view that the tropics were driving at least some of what has been experienced this winter.

 

In the lower troposphere, at 850mb (Figure 14), the winds over the North Atlantic were much stronger than normal during December and January 2013/14. Likewise the perturbed flow over the North Pacific is also very clear with an anomalous anticyclonic system off the west coast of North America, which has been a persistent feature of this winter’s weather. At these lower levels in the atmosphere, the clash between the cold northerly airstream from North America with the warm, moist airstream from the tropical Atlantic is notable (see circled areas on Figure 14). Not only would this act to invigorate storms forming on the jet stream, but the inflow of warm, moist air from the tropics would enhance the moisture being carried by the storm systems and potentially lead to higher rainfall downstream over the UK.

 

It is clear from Figures 13 and 14 that there is a strong association between the stormy weather experienced in the UK during December and January 2013/14 and the up-stream perturbations to the jet stream over North America and the North Pacific. So what might be the drivers of the changes over the Pacific?

 

It is well understood that El Nino and its cold counterpart La Nina have major effects on weather patterns around the globe3. Indeed the changes in the jet stream over the North Pacific, described above, are typical of what is observed during La Nina events (Figure 15), with the jet being deflected to the north by anomalously high pressure off the western seaboard of the US, and with a variable jet to the south along which disturbed weather forms. The polar jet stream is then deflected a long way south over the US bringing cold air with it before re-joining the southern branch of the Pacific jet stream at the start of the North Atlantic jet stream, essentially as described in Figure 13 for December and January 2013/14.

 

It is reasonable therefore to argue that the weather that the UK has experienced has its roots in the tropics. However, the current sea surface temperature anomalies (Figure 16, left panel) suggest that neither El Nino nor La Nina were active, with temperatures in the equatorial East Pacific Ocean being close to normal. The West Pacific remains anomalously warm, as it has done for much of the past decade. Elsewhere in the Pacific the patterns of sea surface temperature anomalies still display elements of the negative phase of the Pacific Decadal Oscillation (PDO) that has contributed to the recent pause in global surface warming4. Likewise the very warm waters in the North Pacific (Figure 16) are a result of the systematic weakening of the Aleutian Low during the last decade, driven by the negative phase of the PDO.

 

In the North Atlantic, ocean temperatures continue to be above normal near 300N which would also contribute to a strengthened north-south temperature gradient across the storm track, aiding the development of storms. As Figure 16 shows, the sub-tropical Atlantic is currently warmer than the average for the last 30 years (1981-2010), but substantially warmer than it was 30 years prior to that (1951-1980). This in itself will potentially increase the moisture being held in the atmosphere, above the ocean, and entering the storm systems as they moved towards the UK.

 

In terms of the global influences of El Nino/La Nina, it is the changes in tropical rainfall patterns that ultimately drive the perturbations to the atmospheric circulation described by Figure 15. So whilst the sea surface temperatures suggest neutral conditions in the tropical East Pacific, it seems that tropical rainfall patterns in December and January are consistent with a La Nina signal, with higher than normal rainfall over the West Pacific, Indonesia and the eastern Indian Ocean throughout December and January (Figure 17). Bearing in mind that the average rainfall in this region is between 8 and 12 mm/day, these anomalies in rainfall are substantial. This distribution of rainfall across the tropical Pacific is consistent with the warmer than normal sea surface temperatures in the tropical West Pacific (Figure 16, left panel). 

As well as the above normal rainfall over Indonesia, Figure 17 also highlights the sequence of disturbances entering the tropical East Pacific as part of the southern branch of the Pacific jet stream described by Figure 15 and evident in Figure 13. Even in these monthly mean fields it is possible to see the continuity between the disturbed weather over the tropical East Pacific and the run of depressions that brought heavy rain to the UK throughout the winter.

 

Taking all the evidence from the winds and the rainfall, a notable feature of this winter’s storms is the unusual reach of the North Atlantic jet stream back into the East Pacific and the continuous feed of disturbances from the tropical Pacific into the storm track. The disturbances in the tropical East Pacific come, themselves, from the North Pacific, and are able to propagate into the tropics because of the westerly winds in the upper troposphere over the East Pacific (Figure 13); they themselves are part of the response of the winds to the enhanced rainfall over Indonesia. Known as the westerly duct, this is an important conduit through which the tropics and extratropics are able to interact5; in La Nina-like conditions, as experienced this winter, the duct is stronger than normal and the propagation of disturbances from the North Pacific more significant.

 

As is evident in Figure 13, the ‘buckling’ of the jet stream over the Pacific and North America became much more pronounced during January 2014, as the precipitation anomaly over Indonesia and the West Pacific strengthened (Figure 17). A notable feature of this anomalous area of tropical precipitation is its northwards extent into the winter hemisphere where it is able to interact with the North Pacific jet and generate Rossby waves6 that propagate along the jet and act to reinforce the huge meander of the jet stream off the west coast of North America. At the same time, Rossby waves propagate along the southern branch of the jet stream and enter the tropical East Pacific through the westerly duct, creating weather disturbances that can then get caught up in the entrance region of the Atlantic jet stream.

 

These Rossby wave interactions are very complex but appear to be fundamental to understanding this winter’s weather. The influence of the Pacific is very clear in the days preceding the major storm of 5/6th January. Figure 18 contains a sequence of maps from 31st December to 5th January showing satellite infrared observations of cloudiness on the left and 250mb winds on the right. The wave disturbances entering the tropical East Pacific westerly duct can be clearly seen in the wind fields throughout the period. These waves move into the entrance region of the North Atlantic jet which reaches unusually far west into the tropical Pacific. At the same time it is evident that waves are also entering the North Atlantic jet from the north via the polar jet. The sequence of satellite imagery of cloudiness shows how these waves translate into the development of the major cyclone over the North Atlantic by 5th January.

 

What Figure 18 also demonstrates very nicely is that the jet stream is highly variable day by day. It acts as a guide along which the Rossby waves propagate and is also strongly influenced by those waves. Early in the sequence shown in Figure 18 the jet stream over the North Atlantic is strong but as the major storm develops on 4th and 5th January the jet stream weakens as the storm takes momentum from it. Understanding these complex interactions between atmospheric waves and the jet stream is at the heart of understanding and forecasting our weather. 

Edited February 13, 2014 by knocker

[BrickFielder]

  The simple explanation is the jet stream across the atlantic has been very strong and further south than normal this winter. Looking further afield then it is down to abnormal jet stream patterns across the Pacific. To my way of thinking this should correspond to a la nina event where thunderstorm activity shifts from of the coast of south america towards Indonesia. Floods in Jakarta this year would tend to back this up, yet sea temperature anomalies across the pacific dont look that exceptional, neither does the SOI (Southern Ocean Index) which tends to drive el nino and la nina  (Heat waves in Australia do show some abnormal activity though).

  Monsoon variability is driven by more than one factor and since the 1970's the dominant factor has tended to be el nino. Secondary factors have tend to be the southern indian ocean and the north west pacific. Looking at the 500mb height anomalies for the last 180 days something significant shows up.

http://www.esrl.noaa.gov/psd/map/images/fnl/500z_180b.fnl.htmlhttp://www.esrl.noaa.gov/psd/map/images/fnl/250wnd_180b.fnl.html So maybe this year the monsoon was influenced by none el nino factors but it is not exactly a convincing argument. How about the strong westerly QBO which should give rise to a stronger polar vortex, but may allow more upward propagating waves to affect it. The vortex does seem strong and we have had a split vortex although displaced in a way to enhance current patterns. To me it looks like the vortex has been displaced towards the north atlantic, much as it does towards late autumn, but has never moved closer to the pole as it tends to do in the winter months as it gets stronger. Not convinced by the QBO argument (me neither). Well how about a completely off the wall explanation where I get to add 2 and 2 and come up with 10. It seems to me that the jet stream across the UK has been further south than normal for a couple of years, its just this year events have combined to make it more noticeable.  How about the phase transition of the solar magnetic field (no not sun spots) around 2007 being the begining of the change.

http://www.cdejager.com/wp-content/uploads/2013/10/2013-CdeJ-HN-Sun-climate-NS-5-1112.pdfReading the article in the link above would tend to confirm some sort of change occured. It might be a bit of a reach to conclude it affects weather patterns and the jet stream though.

http://iopscience.iop.org/1748-9326/8/4/045001/articleOK so that article confirms there is a link between the solar magnetic field and weather patterns. May be I should build an Ark. The answer of course is that I am still confused about why the weather has been fixed in the pattern and no doubt it is a combination of climate change ,QBO and other factors , but just maybe there are some other forces in effect as well. Food for discussion anyway? 

[hillbilly]

It is very sad to see the less enlightened of us "pooh, poohing" teleconnections? Butterflies wing an' all that?

 

If one is looking for a 'beginning' then look North!

 

The impacts of AGW upon the PDO may well be one such area in the north Pacific? The High pressure pulling up the high sst's under it? ( cold horse shoe with cold waters around the coast and warm core?) impacts of said H.P. on the trades to its southern flank??

 

Or perhaps the impacts of the record low ice year of 2012 followed by the record high energy year , across the Arctic, last summer?

 

Never one thing alone but the interplay between 'normal' and 'affected'......

 

Never mind, Nino a comin'.... and it's tendency to 'Chinook' the Arctic..... low ice years in 14' and 15'?

 

When you look at the SST's that the IPO 'deep ocean warmth' has driven (Typhoon Haiyan fuelled from surface to 100m depth) then the recent '500% rainfall over the same region?

 

Make no mistake we lose the Sea ice we lose the polar jet and inherit Tropical outbreaks ( in the way we currently natter about polar outbreaks) then when you cool that air on it's travels guess what ? 

You are right to make comments on those that ridicule and for those like me who no practically nothing about metreoligical science or statistics but the plain fact is you have only slightly more chance of getting it right than my 10 year old daughter and that is why you should understand where some of them comments come from,whether they are said as a little banter or by someone is just winding us all up!

[knocker]

  The simple explanation is the jet stream across the atlantic has been very strong and further south than normal this winter. Looking further afield then it is down to abnormal jet stream patterns across the Pacific. To my way of thinking this should correspond to a la nina event where thunderstorm activity shifts from of the coast of south america towards Indonesia. Floods in Jakarta this year would tend to back this up, yet sea temperature anomalies across the pacific dont look that exceptional, neither does the SOI (Southern Ocean Index) which tends to drive el nino and la nina  (Heat waves in Australia do show some abnormal activity though).

  Monsoon variability is driven by more than one factor and since the 1970's the dominant factor has tended to be el nino. Secondary factors have tend to be the southern indian ocean and the north west pacific. Looking at the 500mb height anomalies for the last 180 days something significant shows up.

 

 

And perhaps before that.

 

http://forum.netweather.tv/topic/64228-when-the-monsoon-failed/

[BLAST FROM THE PAST]

For me the perturbation cycle changed in Feb 2007, from then on we have seen the jetstream shift south and become very meridional in behaviour.  Solar driven with lunar and planetary modulation. The shifting of the jestream will affect the weather events hemispherically.  And its a very good point that if it was the warm SE Pacific, or the rains in Indonesia...why didn't 'mainstream' forecasters forecast these storms?

Re GW saying maybe the low arctic ice....maybe it was the 'record breaking' antarctic ice that has caused it? 

 

BFTP

Edited February 13, 2014 by BLAST FROM THE PAST

[johnholmes]

The Met Office discuss this in more detail in this briefing on the winter storms, look to page 12

 

http://www.metoffice.gov.uk/media/pdf/n/i/Recent_Storms_Briefing_Final_07023.pdf

 

that looks like a very good article to print and sit reading slowly with a coffee this weekend or whenever-thanks for posting the link

So now a rainy SE Pacific is being touted as the root of our storms. Ten minutes ago it was the extreme and protracted cold which has plagued North America most of the winter. Whatever - one way or another you can guarantee the global warming fraternity will have a say in it. Why, they've already started. Keep driving those hybrids and don't forget to switch things off and everything will be alright.

 

have you read the Met O article referred to?

why oh why cannot folk think before they hit the post button, read the arguments put forward never mind by whom, and make some kind of constructive input to however disstrous for very many people in this country has been totally fascinating and well worth trying to find out why it has occurred?

Edited February 13, 2014 by johnholmes

[knocker]

that looks like a very good article to print and sit reading slowly with a coffee this weekend or whenever-thanks for posting the link

 

have you read the Met O article referred to?

why oh why cannot folk think before they hit the post button, read the arguments put forward never mind by whom, and make some kind of constructive input to however disstrous for very many people in this country has been totally fascinating and well worth trying to find out why it has occurred?

 

Indeed it is John. I posted it in the climate area a couple of days ago and printed it to digest which I'm still doing. Your other point I'm afraid is wishful thinking.

[Gael_Force]

For me the perturbation cycle changed in Feb 2007, from then on we have seen the jetstream shift south and become very meridional in behaviour.  Solar driven with lunar and planetary modulation. The shifting of the jestream will affect the weather events hemispherically.  And its a very good point that if it was the warm SE Pacific, or the rains in Indonesia...why didn't 'mainstream' forecasters forecast these storms?

Re GW saying maybe the low arctic ice....maybe it was the 'record breaking' antarctic ice that has caused it? 

 

BFTP

 

If climatologists and forecaster are using Clipper, the new jetstream mode will be catching them out. Nice flat pattern, everything in its usual place, no probs. Big wavy jetstream that has the temerity to split with branches going north....and ....south??? ...oops, models and forecasts are a bust. In plain, practical terms - wild weather swings and maybe stuck under a pile of keech for some considerable time.

 

Look to the sun folks and please read the link in Brickfielder's post - it makes a lot of sense when read in conjunction with other reports on climate impacts for Europe during previous low cycles.

[laserguy]

 

have you read the Met O article referred to?

 

 

No, because there's a very high probability that 'CO2-inspired climate change' will be mentioned in there, somewhere. In which case my time would be better spent reading the barcode on a bag of cat litter. If I've presumed wrong, let me know. Thanks.

[johnholmes]

No, because there's a very high probability that 'CO2-inspired climate change' will be mentioned in there, somewhere. In which case my time would be better spent reading the barcode on a bag of cat litter. If I've presumed wrong, let me know. Thanks.

 

I won't bother-keep your blinkered view, fortunately the majority of people have a more open mind, dare I say  ? more common sense than a lot of your posts suggest with you

[laserguy]

I won't bother-keep your blinkered view, fortunately the majority of people have a more open mind, dare I say  ? more common sense than a lot of your posts suggest with you

 

I take it then that it must've contained 'AGW' references? Well thanks for saving me from wasting my time. This winter is just what the AGW faithful have had their fingers crossed for, for a very long time. Had to happen sooner or later - law of averages an' all that.

[johnholmes]

I take it then that it must've contained 'AGW' references? Well thanks for saving me from wasting my time. This winter is just what the AGW faithful have had their fingers crossed for, for a very long time. Had to happen sooner or later - law of averages an' all that.

 

2+2=4 ls, I have no idea as I have not ye had time either to dowload it nor read it

[Roger J Smith]

Hot air escaping from Fleet Street is the most obvious reason for the stormy winter.

[cooling climate]

No, because there's a very high probability that 'CO2-inspired climate change' will be mentioned in there, somewhere. In which case my time would be better spent reading the barcode on a bag of cat litter. If I've presumed wrong, let me know. Thanks.

Your right of course.Just read the article and they are still banging on about the fallacy of

global warming. There has been a hiatus of warming for the past 16 plus years and there own

predictive forcasts over the last several years have all been found to be to warm compared to

what actually verified.They go on to say and I quote "the warming we are already  committed to

over the next few decades". Does that mean that even if the climate which hasn't warmed shows

a cooling trend they will ignore it and continue to promote global warming.

In summary they say it is down to a number of varibles although my bet would be that the very

strong westerly QBO played an important part and perhaps along with a sun that was at times

asleep and the next very active which may have aided the strength of the QBO.

On the BBC one morning last week they blamed it on a cyclone in the southeast pacific in

November that led to the winter we have had. Had a laugh over that one.