Following the Behaviour of the Jet Stream (by Diego Fdez-Sevilla, PhD.)

Following the Behaviour of the Jet Stream (by Diego Fdez-Sevilla, PhD.)

The 18th of Nov the Met Office has advised the population of UK to be prepared for a sudden change in the conditions of the weather for this weekend, turning for colder conditions.

“Cold weather is expected this weekend courtesy of an arctic maritime airmass spreading across the country from the north. Everyone will notice a change in the weather after the second mildest start to November on record.

In a stark contrast to recent days when temperatures have been well above average for the time of year, we can expect temperatures to be below average with maximum daytime values of around 3-7 degrees Celsius. Overnight minimum temperatures are likely to drop below freezing away from coasts, to give a widespread frost, with the risk of some icy patches where showers have fallen during the day.”

On Friday the cold air will begin to spread southwards with showers falling as snow over high ground in the north and increasingly to lower levels here later. Across northern and eastern Scotland and the northeast of England accumulations of 1-4cm are likely in places at low levels, whereas above around 150m around 5-10cm could accumulate. Furthermore, overnight Friday and into Saturday other areas of the UK could see snow, with some accumulations possible, mainly over high ground.

Strong to gale force north or northwesterly winds are also likely Friday night and Saturday across central and southern Britain and will enhance the cold feel in what will be the coldest air of the season so far. There is a risk of severe gales with gusts of 60-70mph in the most exposed locations.

Yellow ‘be aware’ National Severe Weather Warnings have been issued for the risk of impacts as a result of the snow and wind.”

Similar change is also expected in North America. (

“Following recent mild weather, some of the coldest air of the season so far will impact much of the nation east of the Rockies from this weekend into early next week.

The cold will dive southward on the heels of a storm that will bring a plowable snowfall to portions of the Midwest Friday and Saturday.

“After the snow comes to an end, a surge of cold air will rush into the Upper Midwest this weekend,” said AccuWeather Meteorologist Becky Elliott.”

A wobbly Polar Jet Stream

The possibility of facing a weakening Jet Stream due to a decrease in the Thermal contrast between the Subtropical and Polar atmospheric regions has created scenarios in which the variations in meteorological conditions for a particular location can come without a transition. One week is pretty warm and the next freezing cold. How can that happen?

Polar masses of air and warm mid-latitude masses create a thermal contrast which generates powerful winds moving from west to east, called the Polar Jet Stream. The differences are not only in temp, also humidity and therefore, density. As a result, we can see the behaviour of the boundary layer in motion as two fluids mixing in a turbulent flow.

Here I have prepared an animation with the forecast generated from the 18th November to the 29th 2015 by the GFS model, applying images generated by Metogroup. This animation illustrate the actual state of the Polar Jet Stream in temp and pressure at 500mb, and the conditions in the mixing layer generating the weather events associated for North America and Europe.

Following the Behaviour of the Jet Stream

Back on November 14, 2014, I published an article discussing the reasons behind the wobbly behaviour of the Jet Stream and its consequence on weather events. One year later I can use a portion of this publication, with the same words, to explain what the previous video shows over the behaviour of the Polar Jet Stream.

Why there is no need for the Polar Vortex to break in order to have a wobbling Jet Stream and polar weather? (by Diego Fdez-Sevilla) Posted on November 14, 2014.

Implications in the State of the Climate

Based on the present atmospheric circulation, it seems that there is an agreement between present atmospheric circulation and all the clues gathered in a previous post addressing the possible configuration of the Polar vortex and Jet Stream for this winter. The only missing link is that there is no need to have a broken Polar Vortex in order to have a wobbly Jet Stream and all the weather events associated.

Based on previous comments presented here and in previous posts, I purpose for discussion a theory to explain the behaviour of the Polar Vortex, Jet Stream and Atmospheric Circulation at global scale. A decrease in the differential gradient of energy in altitude would allow cyclonic and anticyclonic events to not dissipate their energy easily, and consequently to grow in altitude and resilience reducing the differential gradient of energy between Polar and Sub-polar circulation, weakening the steadiness of the Jet Stream to keep unbroken.


North Hemisphere Atmospheric Circulation.

 If my intuition is right, based on what I shared in the other post giving “A New theory proposal to assess possible changes in Atmospheric Circulation.“, it will become more frequent to see polar masses of air getting introduced in lower latitudes as part of having a low differential gradient of energy between the Jet Stream and cyclonic (L and H) events, allowing frequent transition of masses of air getting from both sides of the Jet Stream.

Masses of air crossing the Jet Stream

Actually, even considering that such exchange it has been always there throughout past Winters, if my theory is right, this pattern of unsteady Jet Stream and masses of air crossing through would start earlier in Autumn and resume closer to summer.

The transition from Summer to Winter and from Winter to Summer will be a transition between “more frequent exchange of masses of air” to “less frequent”. Instead of having a constant gradual change in atmospheric conditions, we will have pockets of air moving across the Jet stream defining the weather wherever they move.

In more recent publications, I have extended my interpretation over the mechanisms involved and the teleconnections implicated. All the data supplied and analyses that I have performed looking at the state of related players seem to support my points of view.

Back in March 7th 2015 I also discussed the behaviour of the Jet Stream and published a video illustrating the wobbly behaviour of the Polar Jet Stream. However, if in the present post we can see its behaviour in the period of transition from Summer to Winter, in the previous article I showed the transition between Winter to Summer:

Drops of weather by Diego Fdez-Sevilla

The wobbliness of the Jet Stream means unstable interchange of masses of air between both sides. The cold air being pushed down is consequence of warm air moving up. The volume shared by both masses of air, at this level, is finite. So when a volume of air moves Northward, another volume of air has to move Southward. That opens the possibility of seeing warmer temp and colder temp in both sides of the Jet Stream, like those at UK. The question about where can we see patterns of cross latitudinal transport being repeated is what has pointed the attention to blocking patterns. And I propose that those blocking patterns are originated as a consequence of a decrease in the differential gradients of energy in atmospheric circulation.

State of the Climate

Based on the behaviour of the Polar Jet Stream since I started to follow it in 2013 I actually believe that the high SST at the Mediterranean sea and the Barents sea with the low SST at the North central Atlantic are better indicators to understand links between oceanic and atmospheric dynamics than the SST anomalies at the 3.4 Eq. Pacific. Just my opinion.

Nov temp state 2015 by Diego Fdez-Sevilla

Last comments

I am in moody waters here. Those in a position as part of an institution have time, resources and a team of people with whom to validate postures and points of view. I am on my own relying on feedback from out there, and even though I believe in the validity of what I do, I assume my limitations. I can give my personal take on things, like many, but the right way would come from coordinating a multidisciplinary group of people uniting different approaches in validating a unified criteria describing things. So I would invite other scientists to evaluate my approach, data and analyses and add their postures and comments.

—- xxx —-

(This post is part of a more complex piece of independent research. I don´t have founding, political agenda or publishing revenues from visits. Any scientist working in disciplines related with the topics that I treat in my blog knows how to judge the contribution that my work could potentially add to the state of knowledge. Since I am in transition looking for a position in research, if you are one of those scientists, by just acknowledging any value you might see from my contribution, would not only make justice to my effort as independent researcher, but ultimately, it will help me to enhance my chances to find a position with resources to further develop my work.

I believe that the hypothesis that I have presented in previous posts in this blog (here,here and here) could help to understand present and possible future scenarios in atmospheric circulation. However, this is an assessment based on observation which needs to be validated throughout open discussion and data gathering. So please feel free to incorporate your thoughts and comments in a constructive manner.

If you feel like sharing this post I would appreciate to have a reference about the place or platform, by private or public message, in order for me to have the opportunity to join the debate and be aware of the repercussion which might generate d.fdezsevilla(at)

For anybody interested in the posts related with this discussion here I leave you those more relevant in chronological order (there are comments bellow some of them. Please check them out):



About Diego Fdez-Sevilla, PhD.

Citing This Site "Title", published online "Month"+"Year", retrieved on "Month""Day", "Year" from By Diego Fdez-Sevilla, PhD. More guidance on citing this web as a source can be found at NASA webpage:! DOIs can be generated on demand by request at email: d.fdezsevilla(at) for those publications missing at the ResearchGate profile vinculated with this project. **Author´s profile: Born in 1974. Bachelor in General Biology, Masters degree "Licenciado" in Environmental Sciences (2001, Spain). PhD in Aerobiology (2007, UK). Lived, acquired training and worked in Spain, UK, Germany and Poland. I have shared the outcome from my work previous to 2013 as scientific speaker in events held in those countries as well as in Switzerland and Finland. After 12 years performing research and working in institutions linked with environmental research and management, in 2013 I found myself in a period of transition searching for a new position or funding to support my own line of research. In the current competitive scenario, in order to demonstrate my capacities instead of just moving my cv waiting for my next opportunity to arrive, I decided to invest my energy and time in opening my own line of research sharing it in this blog. In March 2017 the budget reserved for this project has ended and its weekly basis time frame discontinued until new forms of economic and/or institutional support are incorporated into the project. The value of the data and the original nature of the research presented in this platform and at LinkedIn has proved to be worthy of consideration by the scientific community as well as for publication in scientific journals. However, without a position as member of an institution, it becomes very challenging to be published. I hope that this handicap do not overshadow the value of my achievements and that the Intellectual Property Rights generated with the license of attribution attached are respected and considered by the scientist involved in similar lines of research. **Any comment and feedback aimed to be constructive is welcome as well as any approach exploring professional opportunities to be part of.** In this blog I publish pieces of research focused on addressing relevant environmental questions. Furthermore, I try to break the barrier that academic publications very often offer isolating scientific findings from the general public. In that way I address those topics which I am familiar with, thanks to my training in environmental research, making them available throughout my posts. (see "Framework and Timeline" for a complete index). At this moment, 2017, I am living in Spain with no affiliation attachments. Free to relocate geographically worldwide. If you feel that I could be a contribution to your institution, team and projects don´t hesitate in contact me at d.fdezsevilla (at) or consult my profile at LinkedIn, ResearchGate and Also, I'd appreciate information about any opportunity that you might know and believe it could match with my aptitudes. The conclusions and ideas expressed in each post as part of my own creativity are part of my Intellectual Portfolio and are protected by Intellectual Property Laws. Licensed under Creative Commons Attribution-NonCommercial conditions. In citing my work from this website, be sure to include the date of access. (c)Diego Fdez-Sevilla, PhD, 2017. Filling in or Finding Out the gaps around. Publication accessed 20YY-MM-DD at
This entry was posted in Energy Balance, Extreme climatic events, Filling in, Polar vortex and Jet Stream, Water vapour and tagged , . Bookmark the permalink.

68 Responses to Following the Behaviour of the Jet Stream (by Diego Fdez-Sevilla, PhD.)

  1. Pingback: Global Mixing in Atmospheric Dynamics (by Diego Fdez-Sevilla Ph.D.) | Diego Fdez-Sevilla, PhD.

  2. Pingback: Energy in our environmental systems. Follow-up on previous assessments. (by Diego Fdez-Sevilla, Ph.D.) | Diego Fdez-Sevilla, PhD.

  3. Pingback: Another Heat Wave Another Polar Vortex II … Broken (by Diego Fdez-Sevilla, Ph.D.) | Diego Fdez-Sevilla, PhD.

  4. Pingback: From Juno and Jonas to Janet (By Diego Fdez-Sevilla, Ph.D.) | Diego Fdez-Sevilla, PhD.

  5. Pingback: Forecast Unusual (by Diego Fdez-Sevilla PhD) | Diego Fdez-Sevilla, PhD.

  6. Pingback: Atmospheric Thermal Conductance (by Diego Fdez-Sevilla, PhD) | Diego Fdez-Sevilla, PhD.

  7. Pingback: Just Thinking on Climate (by Diego Fdez-Sevilla, PhD) | Diego Fdez-Sevilla, PhD.

  8. Pingback: “The Answer to the Ultimate Question of Life, the Universe, and Everything” is … 42 (by Diego Fdez-Sevilla, PhD) | Diego Fdez-Sevilla, PhD.

  9. Pingback: RECAP on previous assessments (by Diego Fdez-Sevilla, PhD) | Diego Fdez-Sevilla, PhD.

  10. Pingback: Worst than a change is a pattern of no change ( by Diego Fdez-Sevilla, PhD) | Diego Fdez-Sevilla, PhD.

  11. Pingback: Orbital Melting vs Kinetic Melting (by Diego Fdez-Sevilla, PhD) | Diego Fdez-Sevilla, PhD.

  12. Pingback: The value of having a point of view (by Diego Fdez-Sevilla PhD) | Diego Fdez-Sevilla, PhD.

  13. Pingback: Temp Displacements. Solid Water In A Dessert Which Is Not At The Poles. (By Diego Fdez-Sevilla, PhD) | Diego Fdez-Sevilla, PhD.

  14. Pingback: Following The Herd on Assessing Climatic Dynamics (by Diego Fdez-Sevilla PhD) | Diego Fdez-Sevilla, PhD.

  15. Pingback: Breaking Stereotypes Assessing Climatic Dynamics (by Diego Fdez-Sevilla PhD) | Diego Fdez-Sevilla, PhD.

  16. Buenos Dias Estimado Diego Fdez, muchas gracias pelo brilhante texto de investigação científica, estás de parabéns, depois de ler com muita atenção, vou humildemente tecer algumas considerações dada a relevância deste tema para qualquer meteorologista como eu.. Vou começar por fazer referência ao Met Office, serviço britânico de meteorologia que acredita já saber o bastante: a circulação do ar sobre o Leste Europeu e a Ásia sofrem interrupções e a a chamada Jet Stream, corrente de ar em jacto que circula nas altas altitudes, muitas vezes fica bloqueada por semanas. Tal corrente é conhecida da aviação: as aeronaves aproveitam-se da jet stream para encurtar o tempo de viagem. No verão de 2010, se não me engano, a jet stream esteve excepcionalmente estável e fixa, devido a uma zona de alta pressão. O que houve foi um bloqueio dizem os meteorologistas. O Clima ficou de certa forma bloqueado e o jacto de ar moveu-se para o sul. O ar frio das montanhas das zonas temperadas moveu-se sobre as monções, de ar quente e húmido, o que provocou tempestades no sul da Ásia e trouxe chuvas adicionais. Vladmir Rzdinin vê ligações entre estas duas situações extremas: ” As condições meteorológicas na Rússia práticamente não permitiram que o ar deixasse o local que recebe as chuvas de monções. De uma lado, há a cadeia montanhosa elevada de Himalaia. Do outro, havia essa zona de alta pressão que , segundo acho, também não conseguiu deixar o local devido ao ar quente que se encontra sobre a península arábica. No fim, as chuvas extremas atingiram a China..
    Algumas conclusões desta parte: com o aquecimento global, nós esperamos, primeiramente que as monções fiquem mais fortes. Todos os modelos indicam isso. Isso traz grandes problemas, com o aumento das chuvas. E as chuvas ficarão mais extremas, causando deslizamento de terras e coisas semelhantes. Os investigadores querem entender os motivos que provocaram as situações extremas vistas naquele verão no hemisfério norte, além de procurar meios para prever esses fenómenos meteorológicos no futuro.. OBS: De seguida irei referir-me a essa grande ‘controvérsia’ para aquilo que está a ser designado por ’emergência climática global’ sobre o deslocamento da jet stream, ou seja, se o fluxo de jacto do hemisfério norte foi ‘encontrado por se ter cruzado a linha de Equador, trazendo mudanças “sem precedentes” para os padrões de clima no mundo. Tentarei demonstrar a necessidade de muito cuidado, na abordagem desta questão sempre com uma base física forte baseada em observações, dados concretos e observações físicas – o processo de provar a causa e o efeito.


  17. Continuação: São 2 ambientalistas que fizeram essa declaração de ’emergência climática global, mas convém assinalar que alguns cientistas descartar essas reivindicações descrevendo sua preocupação sobre o vento cruzando o Equador como um “absurdo total”. Esses 2 ambientalistas disseram que as anomalias foram provávelmente precipitadas pelas alterações climáticas artificiais, que causou a corrente de ar desacelerar e criar ondas maiores. Um deles tentou explicar num ‘blog’ a barreira entre as duas corrente de jacto gera a forte divisão entre verão e inverno, e que a “morte de inverno” poderia começar se ele é corroido como clima quente que vaza para a zona de “inverno” do ano. Ele continuou. “como os polos aquecem-se devido às aletreações climáticas forçadas pelos humanos, os fluxos de jet amtosféricas têm saído mais de latitudes médias. Enquanto isso, o outro colega dele ambientalista também, corroborava que as alterações climáticas iriam inaugurar um período sustentado de “caos no sistema climático” que poderia revelar-se difícil de resolver. Ele terminou com algum ‘catastrofismo’ ao afirmar que “o comportamento do nosso sistema climático continua a manifestar-se de formas novas e assustadoras, que nunca tínhamos atingido ou visto antes. Remata com “Bem-vindo ao caos climático. Nós devemos declarar um clima global de emergência” Termina ainda mais com o tom ‘catastrofista ao dizer que. “o comportamento do fluxo de jacto sugere enormes sistemas de alimentação (global) e o potencial de enorme instabilidade geopolítica. Há coisa muito estranhas a acontecer agora no nosso planeta Terra”
    Caro Diego a minha concordância com estas afirmações ´catastrofistas’ é demasiado pequena, pois , como tu sabes existem 2 formas de correntes: polares e subtropicais – e os hemisfério norte e sul tem cada um. Esses fluxos são produtos de aquecimento atmosférico pela radiação solar e mantido no lugar pela força da inércia. Para não ser muito maçador, gostaria que “2016 fosse o ano que as pessoas se lembrassem que a ciência é um método de investigação e não um sistema de crença”. É importante não nos esquecermo, que usamos recursos com gás, carvão, petróleo – para produzir energia. Esses recurso contêm carbono que produzem água, CO2 e hidrogénio. Ambos são essenciais para a vida na Terra. Eu gosto de fazer perguntas para obter a verdade: qual foi a maior tendência da temperatura nos últimos 130 anos? Também não tem sido categóricamente mencionado que foi a partir da década de 1930 para 1970, durante o período da industrialização, o maior da história humana, quando a nossa saída de CO2 aumentou bastante, temperaturas atmosféricas ‘refrigeradas’ durante 40 anos.. Outro facto inconveniente : as temperaturas estatísticamente não tem sido aquecidas desde 1995 saída de CO2 aumentou bastante, temperaturas atmosféricas ‘refrigeradas’ durante 40 anos.. Uma coisa é certa: as temperaturas agora são mais fiáveis do que há 130 anos. Isto é o contrário que o IPPC e outras instituições tem dito, porque tem tendências de arrefecimento incorporadas com tendências de aquecimento., Temos aqui factos inegáveis comprovados por dados: em 1º lugar, as alterações no nível de CO2 são um resultado de mudanças de temperatura, não uma causa. Isto é o contrário do que comunicam aos ‘leigos’. Em 2º Lugar, nós não podemos afectar o CO2 no ar. O contrário do que nos dizem. Não podemos e não afectamos o clima global. Em 3º lugar, o aquecimento é benéfico…depois de tornar a cidade aquecida por períodos mais quentes, como optimus do clima. Isto é básico: O Sol aquece a superfície da Terra. A superfície de contacto aquece a atmosfera circundante. Isso significa que a atmosfera esfria a superfície. Como qualquer coisa que esfria a superfície pode aquecê-lo? Não pode. é por isso que os modelos de computador estão ‘errados’. As vezes ‘algumas declarações da ONU soam um pouco de ‘absurdas’ aos olhos de especialistas como tu Diego e eu, não achas? Não gostaria de concluir estes meus 2 extensos comentário sem afirmar que “as mudanças extremas podem não necessáriamente caminhar lado a lado com as alterações do estado médio” Apesar do progresso inequívoco na compreensão do clima e condições meteorológicas extremas, sua estimativa é ainda muito imprecisa. Grandes incertezas resultantes da qualidade insuficiente e amostragem de dados observacionais e de resolução inadequada de simulações. Inadequada qualidade de resolução de dados observacionais e de modelo torna difícil a aplicação de metodologias estatísticamente avançadas. Além disso, os mesmos métodos aplicados aos dados de diferentes resoluções exigem abordagens diferentes numa análise mais aprofundada. Finalmente, avançados métodos estatísticos para a estimativa dos extremos se ainda não forem exploradas ao máximo e exigir a validação e melhoria. Isso dificulta a eficaz validação dos dados observacionais e resultados do modelo, incluindo comparações entre as estimativas provenientes de pontos de dados observacionais e resultados do modelo. Estas complicações impedem o uso eficiente de modelos para compreender os mecanismos de condução e a evolução da previsibilidade dos extremos. Bem haja a todos.
    Observação fundamental: O jet stream no sentido usual da palavra é causado pelo vento térmico, que não pode existir no Equador, porque não há nenhuma força de Corilois. Na medida que há fluxo cruzado-Equador em níveis de corrente de jacto, é geralmente de ar fluir em sistemas de chuva convectiva profunda. Esta saída muitas vezes entra no fluxo de jacto subtropical , que é parte da circulação média da célula de Hadley.. Isto de fluxo cruzado-Equdor e que o fluxo pode conectar uma corrente de jacto subtropical, mas isso sempre aconteceu e sempre acontecerá, com os sem ajuda dos seres humanos


  18. Thanks Joao for your comment. I will try to address some of your points in the next days.
    By now I would invite you to read some previous publications where I describe my take over Atmospheric developments and climatic alterations.
    – A roller-coaster of temperatures in South Europe. Spain (by Diego Fdez-Sevilla)
    Posted on May 14, 2015
    – September 8, 2015 A Climate “Between Waters” (by Diego Fdez-Sevilla).
    – October 7, 2015 Arctic Intake of Water Vapour (by Diego Fdez-Sevilla)
    December 17, 2016 Orbital Seasonality vs Kinetic Seasonality. A Change Triggered from Changing the Order of The Factors (by Diego Fdez-Sevilla, PhD)


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s