• Meteorologist | Premium

    Look at the following meteogram with IFS : we see fog at 7 and 10.00AM
    F15A5849-7DEA-43C1-97B1-1876D1C44838.jpeg

    When I check the situation per 1h, I can only see fog at 10AM :
    A4E3CC07-99BD-47AA-A452-23F3C32684A7.jpeg

    Why ?

    The fog pictogram is displayed when specific conditions are present: for instance minimum of 95% humidity, wind below 10km/h, etc... Would it be possible to tell me the exact values of all parameters leading to display or not the fog pictogram ?

  • Meteorologist | Premium

    Any idea ?

  • Administrator

    @Yves70 Hello, there may be differences if you view 3 and 1 hour forecast. Some parameters in 3 hours interval may have been enough to display fog, however if you spread them in 1 hour forecast, it does not meet the conditions.

  • Meteorologist | Premium

    @Korina
    It could be the case but although for the rainfall it is easy to understand, for the fog, this is much more complicated to see a cumulative effect explaining fog in 3h but only at 10.00AM when it is spread by 1h,...
    This is why I also asked if you could tell me which parameters the system uses to display the fog. Knowing those parameters would be very useful to understand what it happened but also in general to understand in which conditions Windy displays the fog.
    Thanks !

  • Administrator

    @yves70 Fog is substituted from ICON forecast model

  • Meteorologist | Premium

    @ivo
    I don't understand what you are saying. Can you explain a bit more ? If I use IFS as model, fog is still substituted from ICON ?
    Do you also know what parameters are required to display the fog pictogram ? There should be kind of tree : for instance minimum 92% of humidity at 2m, if no = no fog, if yes then the wind speed should be for instance less than 10km/k. If no, no fog, if yes, then we should check the next parameter.
    Knowing what the parameters are and knowing the minimum value to be reached for each parameter will be very useful to understand when fog is displayed or not by Windy

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