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sebastiaan1973

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  1. I think everybody noticed the predicted transition of the polar vortex to the east part of Siberia. Which would enhance the North pacific jet.
  2. Abstract A Northern Hemisphere (NH) polar stratospheric pathway for La Niña events is established during wintertime based on reanalysis data for the 1958–2012 period. A robust polar stratospheric response is observed in the NH during strong La Niña events, characterized by a significantly stronger and cooler polar vortex. Significant wind anomalies reach the surface, and a robust impact on the North Atlantic–European (NAE) region is observed. A dynamical analysis reveals that the stronger polar stratospheric winds during La Niña winters are due to reduced upward planetary wave activity into the stratosphere. This finding is the result of destructive interference between the climatological and the anomalous La Niña tropospheric stationary eddies over the Pacific–North American region. In addition, the lack of a robust stratospheric signature during La Niña winters reported in previous studies is investigated. It is found that this is related to the lower threshold used to detect the events, which signature is consequently more prone to be obscured by the influence of other sources of variability. In particular, the occurrence of stratospheric sudden warmings (SSWs), partly linked to the phase of the quasi-biennial oscillation, modulates the observed stratospheric signal. In the case of La Niña winters defined by a lower threshold, a robust stratospheric cooling is found only in the absence of SSWs. Therefore, these results highlight the importance of using a relatively restrictive threshold to define La Niña events in order to obtain a robust surface response in the NAE region through the stratosphere. The Stratospheric Pathway of La Niña Maddalen Iza and Natalia CalvoDepartamento de Física de la Tierra II, Universidad Complutense de Madrid, Madrid, Spain Elisa ManziniMax Planck Institute for Meteorology, Hamburg, Germany
  3. http://www.lightinthestorm.com/archives/1108 http://easternmassweather.blogspot.nl/2017/11/winter-2017-2018-year-of.html two forecasts
  4. http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-16-0259.1 And he refers to this article.
  5. Yes, I know and it's probably the reason for their positive NAO forecast. http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf Page 24 you can read that UKMO is on the lowest side of the forecast (of course course it can be right)
  6. They expect a weak La Nina. According to research by Hood we should expect the large amplitudes and occurrence rates, and the weakest static stabilities in the tropical lower stratosphere, because we are in a state of QBOE and under solar minimum (SMIN) http://onlinelibrary.wiley.com/doi/10.1002/2017GL072832/abstract
  7. Oh dear, a positive NAO and to warm winter.
  8. Latest EC plume De Bilt shows nothing special.
  9. Hi, you can read it here http://onlinelibrary.wiley.com/doi/10.1002/qj.2346/abstract
  10. Please read this tweet and the converstion.
  11. Hi guys you can also use https://kachelmannwetter.com/de/modellkarten/euro/2017110900/england/luftdruck/20171116-0000z.html Please check the right parameters. Different models, you can zoom in, different countries and/or regio's within countries. E.g. Northpole
  12. Yes, once again the control goes wild. With a very cold scenario. There is not much support (at the moment)
  13. https://link.springer.com/content/pdf/10.1007%2Fs00382-014-2155-z.pdf https://www.americanwx.com/bb/topic/50432-griteaters-winter-outlook-17-18/ He expects an EP La Nina which would favor a negative NAO. 1) December Forecast: -PNA pattern. Western U.S. trough and Eastern U.S. ridge. Good pattern in general for early snow at western ski resorts. 2) January Forecast: In my view, January holds the most promise for the development of a -EPO, -AO/NAO pattern, with possible bowl-shaped trough over the lower 48 at times. 3) February Forecast: There is a Cool ENSO tendency for the North Pacific Ridge to retrograde farther to the west into the Bering Sea during the month of February, opening up the door for increased southeast U.S. ridging. 4) March Forecast: I’m calling for a similar pattern to March last winter, but slightly cooler, with cool anomalies draped across the northern U.S and warm anomalies to the south and southwest. 5) As previously mentioned, It’s my belief that we will see a few quality AO/NAO blocking episodes this winter that are more than transient in nature.
  14. https://www.americanwx.com/bb/topic/50432-griteaters-winter-outlook-17-18/ IMO an excellent read. The author says we get an EP La Nina, based on ENSO of this autumn and this research https://link.springer.com/content/pdf/10.1007%2Fs00382-014-2155-z.pdf
  15. An interesting read http://ionlyusethegfs.blogspot.nl/2012/04/qbo-aleutian-high-relationship.html?m=1
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