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    • afurley

      Waves and Currents
      General Discussion • currents waves wind waves sailing • • afurley

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      idefix37

      @afurley
      All waves models don’t take into account the effect of current.

      For WAM model from ECMWF(July 2018):
      « Considerations when using output from ECWAM
      Not yet modelled are the interaction of waves with sea-surface currents. In particular areas, (e.g. Gulf Stream or Agulhas current), the current effect may give rise to localised changes of up to a metre in the wave height »
      From
      https://confluence.ecmwf.int/plugins/servlet/mobile?contentId=131397261#content/view/131397261

      For WWW3 model it seems to be different (March 2019):
      https://github.com/NOAA-EMC/WW3/wiki/Manual
      Page 1
      « The model [....] computes other transformation processes such as the effects of surface currents to wind and wave fields, and sub-grid blocking due to unresolved islands »
      Page 163
      « 3.9 Winds and currents
      Model input mainly consists of wind and current fields. Within the model, winds and currents are updated at every time step ∆tg and represent values at the end of the time step considered. »

      In any case it would be much better for you to sail downwind and down swell. But this is quite tricky in the Agulhas current area, the swell being mostly from SW. Don’t you plan a stop in Durban?

      Concerning receiving data via satellite phone:
      https://community.windy.com/topic/6601/offline-use-of-windy

    • S

      Meteogram Timeline Zoom In
      Your Feedback and Suggestions • sailing • • spencerogden

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      No one has replied

    • S

      Numeric Wind Directions
      Your Feedback and Suggestions • sailing wind direction • • spencerogden

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      idefix37

      @spencerogden

      To review small differences in models for wind prediction, your can select Wind.

      A32D71F1-634C-49B8-982C-1D6682339A5B.jpeg

      The direction of the wind is not expressed in degrees but by long arrows. They highlight small differences in direction and speed between models.

    • pavelneuman

      Windy Tutorial mit YACHT tv Chefredakteur Jochen Rieker
      Articles • article windy tutorial deutsch yacht tv sailing • • pavelneuman

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    • pavelneuman

      Hurricane Prep Week 2019: How to protect your boat when a tropical cyclone threatens
      Articles • article hurricaneseason hurricane boats sailing • • pavelneuman

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    • idefix37

      Wind colors for sailors ... and for everyone.
      Your Feedback and Suggestions • colour scale sailing wind map • • idefix37

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      idefix37

      You may try it.
      I started with the following choice of colours:
      Green: the best conditions for sailing. Enjoy wind and sea.
      Orange: conditions becoming tougher. Be careful
      Red: hard conditions for a standard 30’ - 40’ cruising boat. Better to stay sheldered.
      The result is may be not artistic but efficient.
      I like to explain the Beaufort scale also with this table from F.Singleton, with a little humour :

      0_1543477981973_88E42211-666E-4883-A140-133CED40A3E3.jpeg

      https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/wea.153