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sebastiaan1973

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  1. Amazing EC control run this morning. http://kachelmannwetter.com/de/modellkarten/euro/europa/m0_luftdruck/20180128-1200z.html
  2. Abstract We investigate the connection between the equatorial Madden-Julian Oscillation (MJO) and different types of the Northern Hemisphere mid-winter major stratospheric sudden warmings (SSWs), i.e., vortex-displacement and vortex-split SSWs. The MJO-SSW relationship for vortex-split SSWs is stronger than that for vortex-displacement SSWs, as a result of the stronger and more coherent eastward propagating MJOs before vortex-split SSWs than those before vortex-displacement SSWs. Composite analysis indicates that both the intensity and propagation features of MJO may influence the MJO-related circulation pattern at high latitudes and the type of SSWs. A pronounced Quasi-Biennial Oscillation (QBO) dependence is found for vortex-displacement and vortex-split SSWs, with vortex-displacement (-split) SSWs occurring preferentially in easterly (westerly) QBO phases. The lagged composites suggest that theMJO-related anomalies in the Arctic are very likely initiated when the MJO-related convection is active over the equatorial Indian Ocean (around the MJO phase 3). Further analysis suggests that the QBO may modulate the MJO-related wave disturbances via its influence on the upper tropospheric subtropical jet. As a result, the MJO-related circulation pattern in the Arctic tends to be wave number-one/wave number-two ~25–30 days following phase 3 (i.e., approximately phases 7–8, when the MJO-related convection is active over the western Pacific) during easterly/westerly QBO phases, which resembles the circulation pattern associated with vortex-displacement/vortex-split SSWs. http://web.gps.caltech.edu/~kfl/paper/Liu2014.pdf
  3. You can check the EC-Oper, control and it's members overhere http://kachelmannwetter.com/de/modellkarten/euro/europa-afrika/m48_geopotential-500hpa/20180115-0600z.html
  4. You can find the individual EC-members over here. E.g. is control-member http://kachelmannwetter.com/de/modellkarten/euro/europa/m0_luftdruck/20180111-0600z.html
  5. Catacol, your comments about the MJO reminds me of this research http://onlinelibrary.wiley.com/doi/10.1002/2017GL072832/abstract
  6. Model Output Discussion 01/09/17

    Yes, the control is very cold at the end of the run. Easterly winds! https://www.weerplaza.nl/15daagseverwachting/?r=midden&type=eps_pluim
  7. HI guys, Via https://kachelmannwetter.com/de/vorhersage you can get a plume for many places in the world, including the British Isles. Type the place you need in 'ort' (german word for place) and select ECMWF (EURO) and press 'suchen' (search). E.g. Altough you can't see every member, I think it's valuable. You can select 2m-temperature, 850 hPa, niederschlag (rainfall), luftdruck (air pressure), windboen and umwetter (cape)
  8. Seems to me the MJO gets alive. The Madden-Julian oscillation (MJO), also known as the 30–60 day oscillation, is the strongest of the intraseasonal climate oscillations in the tropics and has significant derivative effects on extratropical circulation and intraseasonal climate. It has recently been shown that the stratospheric quasi-biennial oscillation (QBO) modulates the amplitude of the boreal winter MJO such that MJO amplitudes are larger on average during the easterly phase (QBOE) than during the westerly phase (QBOW). A major possible mechanism is the decrease in static stability in the lowermost stratosphere under QBOE conditions resulting from relative upwelling associated with the QBO-induced meridional circulation. Here evidence is presented that tropical upwelling changes related to the 11 year solar cycle also modulate the boreal winter MJO. Based on 37.3 years of MJO amplitude data, the largest amplitudes and occurrence rates, and the weakest static stabilities in the tropical lower stratosphere, occur during the QBOE phase under solar minimum (SMIN) conditions while the smallest amplitudes and strongest static stabilities occur during the QBOW phase under solar maximum (SMAX) conditions. Conversely, when the QBO and solar forcings are opposed (QBOW/SMIN and QBOE/SMAX), the difference in occurrence rates becomes statistically insignificant. During the coming solar minimum, at least one additional winter in the QBOE/SMIN category should occur (possibly as early as 2017/2018) during which especially large MJO amplitudes are expected and an initial test of these results will be possible. http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html Interesting to follow this winter.
  9. I think everybody noticed the predicted transition of the polar vortex to the east part of Siberia. Which would enhance the North pacific jet.
  10. 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
  11. http://www.lightinthestorm.com/archives/1108 http://easternmassweather.blogspot.nl/2017/11/winter-2017-2018-year-of.html two forecasts
  12. http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-16-0259.1 And he refers to this article.
  13. 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)
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