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    Sounding Plugin - for paraglider pilots

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    • tomasz.w
      tomasz.w | Premium last edited by tomasz.w

      Hey, I got a problem.
      Dunno why but when I try to use your plugin the whole windy.com freezes: the forecast page & the forum page. I have disabled the AdBlock and allowed pop-ups windows.
      Similar situation with Skew-t- it doesn't freeze but nothing is popping up.
      Does anyone know how to make it run and is willing to help me?
      ![0_1611580968863_2021-01-25 14_13_17-Windy_ Wind map & weather forecast.png](Wysyłanie 0%)!
      edit: i cannot even upload a picture here :( link
      edit: its something with my chrome, other browsers works ok for me

      Korina 1 Reply Last reply Reply Quote 0
      • Korina
        Korina Administrator @tomasz.w last edited by

        @tomasz-w Hello, image upload size has a limit, try to upload a smaller picture.

        Korina

        1 Reply Last reply Reply Quote 0
        • M
          matikru last edited by

          Hi, amazing plugin ;)

          One question (sorry if a dummy one):
          How do you determine where the green line starts on the ground?

          I see that "The green line shows the temperature of an ascending parcel" but why on the ground it has this particular temperature?

          Is there some meteorological constant or formula based on which we know that a bubble would need this-or-that higher temperature than surrounding to start rising?

          Correct me if I'm wrong, but to my mind, this starting point is crucial in understanding how strong and how high thermals will be, so I'm wondering (as a gliding pilot) how exactly to interpret this and how to actually know when during the day my lovely bubbles will start to rise.

          vicb 1 Reply Last reply Reply Quote 0
          • Yves70
            Yves70 Meteorologist | Premium last edited by

            @matikru
            It should be the temperature at 2m forecasted by the model used for the sounding

            1 Reply Last reply Reply Quote 0
            • vicb
              vicb Paraglider @matikru | Premium last edited by

              @matikru The green line starts at air temperature + some constant (4 or 5C if I remember correctly).

              Check a typical example:

              alt text

              You can see that the value of the constant usually doesn't matter that much for the days we are interested in. You have to remember that we look at a model which is an imperfect prediction plus the nature of the soil varies greatly inside a single cell of the model (cells are 9x9km for ECMWF).

              In practice it works reasonably well. The air close to the ground doesn't usually get warmer as it would start rising.

              If the cloud cover is thick it might be harder for the air temperature to become that warm.

              If the temperature (red) and green line (parcel) slowly converge instead of being parallel, that could also be due to the poor resolution of the model (there are not that many points along the altitude axis).

              Hope this helps.

              M rittels 2 Replies Last reply Reply Quote 0
              • M
                matikru @vicb last edited by

                @vicb thanks for this clarification.

                But, since as you noted "The air close to the ground doesn't usually get warmer as it would start rising" do I understand correctly that the green line should actually start (at the ground level) quite at the same temperature level that the red line starts?

                So actually this 4-5 C constant is introduced just for better usability of the diagram, as this green and the red line would just overlap usually?

                Btw - I get it now that considering model errors etc. it doesn't make such a difference, I just want to understand the logic behind.

                M vicb 2 Replies Last reply Reply Quote 0
                • M
                  matikru @matikru last edited by

                  I'm thinking, isn't it that sometimes it will be quite misleading? In this example, it doesn't look like convection at all, no chance for cumulus, since dry adiabat is steeper than air temperature change.
                  But, looking at the green line starting 4-5 C higher than the red line there's this impression that there will be convection, even a cumulus is depicted at 800.

                  Or am I missing something totally? :)

                  Zrzut ekranu 2021-04-2 o 17.40.04.png

                  vicb 1 Reply Last reply Reply Quote 0
                  • vicb
                    vicb Paraglider @matikru | Premium last edited by

                    @matikru

                    Mostly what I mean is that the rising air don't get as warm as the ground.

                    I think that rising air typically needs a few more degree than the surrounding air to rise.

                    F 1 Reply Last reply Reply Quote 1
                    • vicb
                      vicb Paraglider @matikru | Premium last edited by vicb

                      @matikru yes you still need to interpret what you see. In your screenshot the air is stable (converging lines that I mentioned in a previous message) + there seems to be stratus where the blue line is close to the red line below 1000m

                      idefix37 1 Reply Last reply Reply Quote 1
                      • idefix37
                        idefix37 Sailor Moderator @vicb last edited by idefix37

                        @vicb
                        Cirrus at this altitude? You probably mean Stratus ?
                        https://community.windy.com/topic/9778/visual-difference-between-clouds?_=1617389340187

                        1 Reply Last reply Reply Quote 4
                        • EduardoSG
                          EduardoSG last edited by

                          I tend to agree with @matikru that the green dry adiabat seems too optimistic.
                          Not only in stable days, but also in well mixed days.
                          Although the core might start at the ground a few degrees hotter than the surrounding air; by the time it reaches the top of the CBL, there is no difference in temperature for the thermal as a whole, and it is humidity that keeps "pushing" upwards.

                          Now we are on the off season in the southern hemisphere, but will compare to reality in the flying season.

                          Of course I am aware we are talking forecasts, and there is always uncertainty and error, but I think the green line adds to that error on the optimistic side.

                          1 Reply Last reply Reply Quote 0
                          • rittels
                            rittels Code contributor @vicb | Premium last edited by

                            @vicb

                            "@matikru The green line starts at air temperature + some constant (4 or 5C if I remember correctly)."

                            It looks like you add 3 degrees: https://github.com/vicb/windy-plugin-sounding/blob/ce22dc08d0d436fee4024ab54dc1642bf6762369/src/containers/containers.js#L28

                            A 2 degrees shift seems to match fairly well with the thermal top overlay, within a few 100 feet.

                            1 Reply Last reply Reply Quote 0
                            • F
                              fahad-albahoth @vicb last edited by

                              @vicb Tanks

                              Fahd bin Ali

                              1 Reply Last reply Reply Quote 0
                              • dodohjk
                                dodohjk @Gkikas LGPZ | Premium last edited by dodohjk

                                @gkikas-lgpz
                                The scale in the bottom right is an approximate scale that uses the standard height levels used in aviation like
                                950hPa / 2 000ft / 600m
                                850hPa / 5 000ft / 1500m
                                700hPa / 10 000ft / 3000m
                                300 hPa / 30 000 ft / 9000m
                                etcc
                                These are approximately equal and used for easy conversion between different unit. However they are not exact.
                                In fact heights of pressure levels changes with different weather conditions. eg cooler temps have pressure levels closer to the ground as the air is denser.
                                More info can be found here https://en.wikipedia.org/wiki/International_Standard_Atmosphere

                                Anyway the scale on the left is the model calculated height taking account of the meteo conditions (i think at least).
                                I am pretty sure that the scale on the windy map on the right is the correct values at the "model pressure height" which is an approximate height in m or feet.

                                @gkikas-lgpz said in Sounding Plugin - for paraglider pilots:

                                ..... at lower levels
                                ac6633de-53d2-412a-8258-f69850553780-εικόνα.png
                                point "B" marks the temp. at 600 hPa (13800 ft, FL140)
                                but the diagram shows 12000 ft (1800ft off).

                                1 Reply Last reply Reply Quote 0
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