Windy Community
    • Unread
    • Categories
    • Groups
    • Go to windy.com
    • Register
    • Login

    Cloud tops are lower that cloud base !

    Your Feedback and Suggestions
    2
    5
    4.2k
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • PropellerheadP
      Propellerhead
      last edited by

      Forecast for S34° E20.5° for 21-Dec-2017 at 10 am local time shows the following:
      Cloud base = 17272 ft Cloud tops = 13000 ft.

      Suggests the forecast model does not check for inconsistencies, leading to questionable reliability??

      TZT 1 Reply Last reply Reply Quote 0
      • TZT
        TZ Administrator @Propellerhead
        last edited by

        @propellerhead Hi, thank you for the question. These are two different parameters.
        Cloud Base is the level of first layer covering more than 50% of the sky. It is using ECMWF Ceiling parameter. We decided to use it instead of ECMWF Cloud Base Height parameter, which has a threshold at 1%.
        For more details on these ECMWF parameters see: https://software.ecmwf.int/wiki/display/FCST/43r1+new+parameters%3A+Ceiling
        So the parameter displayed on Windy can be described as "Cloud base of significant cloud layer".
        Now to the Cloud tops. This parameter does not have necessarily direct relation to the forementioned parameter, because it displays tops of convective clouds. It is mainly intended for prediction of large convective clouds which may reach top of troposphere. These clouds are very dangerous because of massive air turbulences.
        Details of the ECMWF parameter: https://software.ecmwf.int/wiki/display/FCST/43r1+new+parameters%3A+Height+of+convective+cloud+top
        And now about the reliability: We believe that both parameters can be useful for general aviation, so we added them to Windy, but we are not able to guarantee or even measure the reliability of them. We are happy for any feedback from pilots. The best feedback is experience from concrete flights. So if you or anybody else uses Cloud Base or Cloud Tops parameters in your briefing, please let us know how the prediction was successful and if it was useful for you or not.

        1 Reply Last reply Reply Quote 3
        • PropellerheadP
          Propellerhead
          last edited by

          Thank you for taking the time to provide a detailed explanation.

          In reality, would never use a single source in flight planning (I go IFR anyway), but I thought it was pleasantly absurd to put the problem in perspective :o))

          1 Reply Last reply Reply Quote 0
          • PropellerheadP
            Propellerhead
            last edited by

            Just noted that cloud tops are shown in feet, but cloud base in metres!! Can't see how to change this. Used to be both feet, so something has changed recently.

            1 Reply Last reply Reply Quote 0
            • PropellerheadP
              Propellerhead
              last edited by

              Found out how to change to feet clicking on the ribbon at the bottom of the screen !

              1 Reply Last reply Reply Quote 1
              • Gkikas LGPZG Gkikas LGPZ referenced this topic on
              • idefix37I idefix37 referenced this topic on
              • rittelsR rittels referenced this topic on
              • idefix37I idefix37 referenced this topic on
              • First post
                Last post
              Windyty, S.E. - all rights reserved. Powered by excellent NodeBB
              NodeBB & contributors, OSM & contributors, HERE maps
              Terms of Use     Privacy Policy