Default Pressure Color Scheme Is Confusing



  • On the pressure map, red = high pressure. On the temperature map, red = high temperature. IRL, high pressure ≠ high temperature. The colors don't match up correspondingly. Why is this an issue?

    Someone might look at the pressure map, scroll over a red zone, see a high pressure reading, and mistakenly assume that high pres = high temp.

    An inversion of the color scheme of the pressure map would help to clear up possible confusion, and make the inverse relationship between pressure and temperature more apparent to those learning.


  • Meteorologist

    @Ridagstran
    Windy allows you to change the colours and define the scale as you wish and according to your préférences, for many different maps, pressure, temperature,...

    There are a lot of good posts on this community explaining how to do it :
    https://community.windy.com/topic/10336/customize-the-color-scales-of-windy-layers?_=1596358666767



  • @Yves70 Thank you for the info, but what about the fact that this confusing color scheme is the default?


  • Sailor

    @Ridagstran
    This is not a confusing color scheme. High-pressure systems are generally associated with warm air.
    End of this week the high pressure will invade most part of Europe including Scandinavia. The temperature anomaly will be clearly positive.
    As shown by GFS on Friday 7th at 8:00

    6601EAED-88AA-4B6A-A441-53FE39F18903.jpeg



  • @idefix37 Sorry for the confusion. Different sources online are giving me different answers and it seems difficult to get a straight answer. This one from wxdude.com says:

    "Since warm air is less dense and creates less air pressure, it will rise; cold air is denser and creates greater air pressure, and so it will sink."

    I'm assuming a more in-depth knowledge of how weather works would be needed to reconcile the conflicting information.


  • Sailor

    @Ridagstran

    Large areas showing high pressure are generally due to dynamic anticyclones e.g. the Azores anticyclone : the air is sinking (subsidence) and resulting in a compression which increases the temperature.
    However there are also thermic anticyclones observed in winter due to the accumulation of cold air e.g. the Siberian anticyclone. Not sure that you get it in Ireland.
    Some additional information:
    https://content.meteoblue.com/nl/meteoscool/large-scale-weather/high-low-pressure
    The explanation you give from this website is not wrong but as a general rule it applies mainly for local phenomenons (convection).
    I may add that with high pressure conditions it is possible that you get a cold weather.
    For instance if you are on the boundary of the anticyclone and you get a north wind, of course the temperature will not be mild. But it is due to the wind, not directly to the pressure itself.
    Another reason for getting low temperature with anticyclonic conditions: they bring generally clear skies which allows the ground and the air layer near the ground to cool during the night (Clouds prevent this drop of temperature due to the radiative lost of heat). But this is due to clear sky, not to the high pressure directly. And during the day the temperature increases much more with clear sky.



  • @idefix37 That clears things up (pun intended). Thanks for your explanation!


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