Previsões longo prazo (Outono/Inverno 2018/2019)

Tópico em 'Seguimento Meteorológico' iniciado por Davidmpb 24 Jul 2018 às 20:06.

  1. Orion

    Orion
    Expand Collapse
    Furacão

    Registo:
    5 Jul 2011
    Mensagens:
    15,677
    Local:
    Ponta Delgada, Açores
    ECMWF, Probabilidade de precipitação acima da média em Fevereiro e Março.

    [​IMG]

    [​IMG]
     
    Collapse Signature Expandir Assinatura
  2. Tonton

    Tonton
    Expand Collapse
    Nimbostratus

    Registo:
    23 Dez 2017
    Mensagens:
    810
    Local:
    Mactamã
    Circulação actual na estratosfera (10 hPa), completamente alucinada, com o anticiclone, que já foi predominante perto do Pólo, a enfraquecer e a vaguear perto do Estreito de Bering, enquanto o "vórtice polar" (a normal circulação ciclónica sobre o Pólo) está partido em 3 núcleos, os 2 mais fortes sobre ao Canadá e a Sibéria, e o mais fraco, centrado na zona dos Pirinéus:

    [​IMG]


    E, digam-me lá, se não parece mesmo uma carantonha alucinada??? :lol:
     
    XtraNO, jonas_87, RStorm e 13 outras pessoas gostaram disto.
  3. luismeteo3

    luismeteo3
    Expand Collapse
    Furacão

    Registo:
    14 Dez 2015
    Mensagens:
    14,274
    Local:
    Fatima
  4. dvieira

    dvieira
    Expand Collapse
    Cumulus

    Registo:
    22 Mar 2017
    Mensagens:
    194
    Local:
    Fátima (326 m)
    Previsão de longo prazo - Previsão mensal - 21 jan. a 17 fev. 2019
    Precipitação com valores acima e temperatura com valores abaixo do normal

    Na precipitação total semanal, prevêem-se valores acima do normal, para a região Sul na semana de 21/01 a 27/01 e para todo o território nas semanas de 28/01 a 03/02 e de 04/02 a 10/02. Na semana de 11/02 a 17/02 não é possível identificar a existência de sinal estatisticamente significativo.

    Na temperatura média semanal, prevêem-se valores abaixo do normal, para todo o território na semana de 21/01 a 27/01, para as regiões Norte e Centro nas semanas de 28/01 a 03/02 e de 04/02 a 10/02 e para as regiões Centro e Sul na semana de 11/02 a 17/02.

    IPMA, I.P.. 2019-01-18
     
    c0ldPT, joselamego e Ricardo Carvalho gostaram disto.
  5. Tonton

    Tonton
    Expand Collapse
    Nimbostratus

    Registo:
    23 Dez 2017
    Mensagens:
    810
    Local:
    Mactamã
    Para já, "na precipitação total semanal, prevêem-se valores acima do normal, para a região Sul na semana de 21/01 a 27/01", não parece nada, nem há actualmente nehuma chuva prevista pelo IPMA no Sul........
     
    dvieira e joselamego gostaram disto.
  6. Tonton

    Tonton
    Expand Collapse
    Nimbostratus

    Registo:
    23 Dez 2017
    Mensagens:
    810
    Local:
    Mactamã
    Warming in the stratosphere leads to cold winters
    29.01.2019 | News

    By: Peter Rüegg | 1 Comment

    In the first week of January, the Arctic stratosphere suddenly warmed up, an occurrence known as “sudden stratospheric warming” (SSW). This phenomenon results in cold winter weather, just the kind we are facing now – ETH researchers have visualised the event that was observed before the current one – in February 2018. Daniela Domeisen explains how this phenomenon occurs in an interview.


    A sudden stratospheric warming divides the polar vortex (Video: Daniela Domeisen & Alexander Wollert, ETH Zürich)
    Finally, another winter that truly deserves its name. Is the current cold weather related to the phenomenon of the sudden stratospheric warming (SSW) that occurred in early January?
    Daniela Domeisen: The cold and snow are simply due to the fact that it is winter. But while the current cold winter weather in Europe may not yet be related to the SSW, this event may be responsible for the cold to persist for several weeks to come.

    How are you so sure?
    Following a SSW event, northern Europe and Eurasia most often experience colder than normal temperatures, as was the case after last year’s occurrence, while it will be more rainy in Spain and the Mediterranean. Last year, the effect of the SSW was observed at the surface only ten days after the event in the stratosphere. This year, however, the development of our weather has been different and the influence from above has not yet fully reached the ground. It is therefore difficult to say at present whether the current cold is related to the SSW.

    [​IMG]
    Daniela Domeisen.
    Most people are likely unfamiliar with sudden stratospheric warming as a trigger for cold weather. What's going on over our heads?
    Every autumn, about 20 to 50 km above the Earth’s surface, a polar vortex forms in the stratosphere, circulating from west to east around the North Pole. The associated winds can be extremely fast, locally up to 300 km/h. If the stratosphere suddenly heats up – sometimes by up to 80°C – this circulation collapses. The strong winds reverse and the vortex then shifts away from the North Pole or breaks into two smaller vortices. The break-up that occurred in the winter of 2017/18 is visualised in our video.

    How often do such events occur?
    On average, six times per decade, but with large variability: in the 1990s, there were only two such events, but in the 2000s we saw nine. At the South Pole, only one has been observed so far – in 2002. This was surprising, as scientists had long assumed that SSW events do not occur there. Due to the event no ozone hole formed over the South Pole that year for the first time since the occurrence of the ozone hole.

    How long does the disturbance of the polar vortex last?
    In the upper stratosphere, it takes a few weeks for the two vortices to reunite. In the lower stratosphere, it may take several months, which is often the remainder of winter until the polar vortex breaks up for good every spring.

    Does climate change increase the occurrence of these events?
    This is currently unknown. We have only been aware of the phenomenon since the 1950s, so our observations cover only a few decades. This makes predictions of future SSW frequency challenging. In fact, we currently observe opposing tendencies: the stratosphere generally cools due to climate change. At the same time, Arctic sea ice is melting. This can affect how large-scale waves, which span the entire planet, move up into the stratosphere, where they can trigger SSW events. If wave propagation changes, SSW frequency may be affected. Some models say that SSWs are becoming more common, while other models predict fewer events. We do not currently have conclusive forecasts.

    How do you know in advance if a SSW will take place?
    We can estimate the probability of a SSW several weeks or even months in advance. Factors that facilitate stratospheric warming events include the El Niño phenomenon, which is associated with warmer ocean surface temperatures in the tropical Pacific. El Niño has been active this winter, suggesting a higher probability for a SSW event, and indeed it happened. I was hoping for a Christmas event, but so far, a SSW event has never happened around the holidays – that would be a nice Christmas present for us atmospheric dynamicists!

    About Daniela Domeisen
    Daniela Domeisen has been a Professor of Atmospheric Predictability at the Institute of Atmospheric and Climate Science at ETH Zurich since 2017.

    https://www.ethz.ch/en/news-and-eve...n-the-stratosphere-leads-to-cold-winters.html
     
    Aristocrata, joselamego e luismeteo3 gostaram disto.
  7. Aurélio Carvalho

    Aurélio Carvalho
    Expand Collapse
    Cumulus

    Registo:
    5 Out 2018
    Mensagens:
    398
    Local:
    Faro
  8. Tonton

    Tonton
    Expand Collapse
    Nimbostratus

    Registo:
    23 Dez 2017
    Mensagens:
    810
    Local:
    Mactamã
    Em relação à situação actual, salienta-se:

    The cold and snow are simply due to the fact that it is winter. But while the current cold winter weather in Europe may not yet be related to the SSW, this event may be responsible for the cold to persist for several weeks to come.

    This year, however, the development of our weather has been different and the influence from above has not yet fully reached the ground. It is therefore difficult to say at present whether the current cold is related to the SSW.

    Embora o frio actualmente pela Europa possa não estar ainda relacionado com o fenómeno, este poderá ser responsável pela persistência do frio nas próximas semanas.

    O fenómeno estratosférico ainda não se reflectiu completamente nas camadas mais baixas, daí que seja difícil, neste momento, garantir que a actual vaga de frio seja sua consequência.
     
  9. Aurélio Carvalho

    Aurélio Carvalho
    Expand Collapse
    Cumulus

    Registo:
    5 Out 2018
    Mensagens:
    398
    Local:
    Faro
    Tal como eu havia referido ... os modelos estão a dar como resposta o que supostamente deveria ter acontecido . .. Mas é aquilo a que estamos a assistir... Embora sem ser excessivamente seco este Inverno
     
    joselamego gostou disto.
  10. hurricane

    hurricane
    Expand Collapse
    Nimbostratus

    Registo:
    11 Nov 2007
    Mensagens:
    1,060
    Local:
    Bruxelas, Bélgica
    Mas nos US é claro que o vortice polar quebrou e a causa foi muito provavelmente o SSW. Nem sempre o SSW afecta o hemisferio norte da mesma maneira. O ano passado tivemos muito frio depois do SSW mas os US nao tanto
     
    joselamego gostou disto.
  11. Orion

    Orion
    Expand Collapse
    Furacão

    Registo:
    5 Jul 2011
    Mensagens:
    15,677
    Local:
    Ponta Delgada, Açores
    Collapse Signature Expandir Assinatura
  12. Aurélio Carvalho

    Aurélio Carvalho
    Expand Collapse
    Cumulus

    Registo:
    5 Out 2018
    Mensagens:
    398
    Local:
    Faro
    Óbvio que a chuva vai ser acima do normal .. Em toda a Europa como mostra ... Tão certo que acertem como eu ganhar o euro milhões.
     
  13. Orion

    Orion
    Expand Collapse
    Furacão

    Registo:
    5 Jul 2011
    Mensagens:
    15,677
    Local:
    Ponta Delgada, Açores
    [​IMG]
     
    Collapse Signature Expandir Assinatura
    Aristocrata e joselamego gostaram disto.
  14. Aristocrata

    Aristocrata
    Expand Collapse
    Super Célula

    Registo:
    28 Dez 2008
    Mensagens:
    5,606
    Local:
    Paços de Ferreira, 292 mts
    AEMET
    Previsão das anomalias de precipitação para o período de 4 a 24 de fevereiro
    [​IMG]
    [​IMG]
    [​IMG]
    Precipitação ligeiramente abaixo até dia 18, depois na média.
    Temperatura abaixo\na média até dia 18, acima até dia 24.
    Não são boas notícias no que diz respeito à precipitação para o centro\sul...
     
    Collapse Signature Expandir Assinatura
    MSantos, luismeteo3 e joselamego gostaram disto.
  15. Aurélio Carvalho

    Aurélio Carvalho
    Expand Collapse
    Cumulus

    Registo:
    5 Out 2018
    Mensagens:
    398
    Local:
    Faro
    Fevereiro já se está a compor para vir a ser extremamente seco, o resto que falta.
    Março e Abril logo veremos qual o comportamento.
    Em relação às barragens eu disse que as mesmas estavam bastante bem... Mas em boa verdade estão até algo idênticas a Janeiro de 2005.
     
    joselamego gostou disto.

Partilhar esta Página