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    UNSOLVED Reported wind and gusts wrong

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    • markdj
      markdj | Premium last edited by

      Wind reporting for weather stations is in error. I haven't scanned every weather station but I am taking the Republic of Ireland weather stations as their data is easily accessible.

      e.g. Mace Head, West coast of Ireland.

      The official data from Met Eireann is available as a csv file as "Yesterday's Weather"

      75914925-537b-4e84-9286-2b0575c70d5e-image.png Time Wind knots Wind Gust Knots
      00:00 26 36
      01:00 29 37
      02:00 32 44
      03:00 32 45
      04:00 32 45
      05:00 37 50
      06:00 42 57
      07:00 44 64
      08:00 45 63
      09:00 43 57
      10:00 37 53
      11:00 34 50
      12:00 34 50
      13:00 37 57
      14:00 36 56
      15:00 30 46
      16:00 36 48
      17:00 37 53
      18:00 37 51
      19:00 43 56
      20:00 37 57
      21:00 45 64
      22:00 46 59
      23:00 48 59

      As you can see at 07:00, the wind was 44-64 knots. Windy reported the wind as 34-44.7 knots, and the errors continued everywhere I looked. That is a BIG problem.

      I sure hope you can fix this, as this is crucial if you are wanting to have community/personal weather stations included too.

      Gkikas LGPZ 1 Reply Last reply Reply Quote 0
      • Gkikas LGPZ
        Gkikas LGPZ Moderator @markdj last edited by

        @markdj
        Reported wind speed from Met Eireann differ from reported wind speed in Windy
        (shown if you press the wind sock symbol) ?

        OR

        do you mean reported data are different than forecasted data?

        9b43a1b3-3eb7-4e51-b5de-e3664f1948cf-εικόνα.png

        1 Reply Last reply Reply Quote 1
        • markdj
          markdj | Premium last edited by

          The reported data is different to the met Eirann reported data.

          I'm noticing that windfinder is wrong too so the data source must be the issue.

          idefix37 1 Reply Last reply Reply Quote 0
          • idefix37
            idefix37 Sailor Moderator @markdj last edited by idefix37

            @markdj
            That’s really weird because on Windy I see only Reported wind.
            You said « Windy reported the wind as 34-44.7 knots ». So where did you find Reported gust at 44.7kt ?

            On MACE HEAD, on Windy, there are no gusts in the meteo observations, only wind:

            4C8465E8-1F29-4A62-AC52-52E81920ACF7.jpeg

            As explained by @Gkikas-LGPZ, what you see in the weather picker are just forecasted figures.

            1 Reply Last reply Reply Quote 0
            • markdj
              markdj | Premium last edited by

              I'm aware the weather picker is for forecasts.

              I'm just going by the 2 speeds shown in the graph (not forecast section). There are 2 speeds shown one on top of each other. Isn't that wind speed and gust?

              Gkikas LGPZ 1 Reply Last reply Reply Quote 0
              • Gkikas LGPZ
                Gkikas LGPZ Moderator @markdj last edited by

                @markdj
                29d9e43b-1acf-44d3-86b1-c3c60453120a-εικόνα.png

                1 Reply Last reply Reply Quote 0
                • markdj
                  markdj | Premium last edited by markdj

                  Oh, that is confusing. The website showed it was forecast to the right of the current time and reported to the left but I'm not seeing the same interface as you.

                  So then the main issue now seems to be that there is no reported wind gusts.

                  Gkikas LGPZ 1 Reply Last reply Reply Quote 0
                  • Gkikas LGPZ
                    Gkikas LGPZ Moderator @markdj last edited by

                    @markdj
                    Reported wind gusts are shown.
                    Forecasted, no.

                    fae91b8b-b340-415e-bd09-64aeaf37ce90-εικόνα.png

                    idefix37 1 Reply Last reply Reply Quote 0
                    • idefix37
                      idefix37 Sailor Moderator @Gkikas LGPZ last edited by idefix37

                      @Gkikas-LGPZ
                      @markdj

                      Yes, on Windy, some Weather Stations show reported gusts, some show only wind.
                      Concerning precisely MACE HEAD weather station there is no reported gusts shown by Windy.
                      The interface you should see is this one:

                      CC843A2B-D7BD-4EDB-9982-8CEEB8191B3B.jpeg

                      In the other case, it should be interesting that you post here a screenshot of what you see.

                      I have compared the reported wind, temperature and pressure at MACE HEAD WS at 8:00. The figures are the same, except for wind :
                      9kt for 10kt reported on Windy.... due to rounding?

                      C8306AE6-5118-47BA-93FF-247A91C68C5B.jpeg

                      Gkikas LGPZ 2 Replies Last reply Reply Quote 1
                      • Gkikas LGPZ
                        Gkikas LGPZ Moderator @idefix37 last edited by

                        @idefix37
                        Wind gusts are not reported all the time from observing meteo. stations.
                        There are some interational criteria for that,
                        but also there are national deviations from the global regulations.

                        For aviation purposes, wind gust is reported when the value is ten knots or more
                        from the average.
                        Thus, for wind 12 kts with gusts 21 kts , gusts not reported.
                        for wind 12 kts with gusts 22 kts (or more) , gusts reported.

                        1 Reply Last reply Reply Quote 2
                        • Gkikas LGPZ
                          Gkikas LGPZ Moderator @idefix37 last edited by

                          @idefix37
                          Yes. 10kt instead 9 kt is due to rounding.

                          My explanation:

                          Mace head is not an airport, reporting in METAR format (wind in Kts).
                          It reports in SYNOP format https://en.wikipedia.org/wiki/SYNOP
                          and reports wind speed in m/sec

                          I read the 08Z SYNOP from Mace head and it is
                          03963 45764 /2405 10077 20053 30208 40237 52020 85/// ......

                          the code /2405 means wind from 240 degrees at 5m/sec.
                          Aprox. 1m/sec=2kts, so 5m/s=10kt

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

                            @Gkikas-LGPZ

                            That confirms my thought, by rounding the calculation to transform m/s to kt.
                            The subject of this topic was « Reported wind (and gusts) wrong ». I shall check again if Reported wind is so different on Windy and on Met Eireann as said @markdj. Gusts... we know that we can forget them in this comparison.

                            1 Reply Last reply Reply Quote 0
                            • markdj
                              markdj | Premium last edited by

                              Thank you for your replies. I see there is a new interface and a new Windy app update came to me this morning that shows gusts for a few stations, but not for Mace Head and others. I think it would be great if wind gusts could be included even if there is a less than 10 knot difference as for mariners, I feel this makes a difference in sea state and it is just nice to see a maximum wind gust in the 60 knot range as it was on Friday morning.

                              Thanks for your help, I'll be checking out this new interface today.

                              idefix37 1 Reply Last reply Reply Quote 0
                              • idefix37
                                idefix37 Sailor Moderator @markdj last edited by idefix37

                                @markdj said in [Reported wind and gusts wrong]

                                I think it would be great if wind gusts could be included even if there is a less than 10 knot difference as for mariners, I feel this makes a difference in sea state

                                Gusts are not considered to have an effect on sea state, as the avg. wind is doing.
                                In their inshore advisories the MetOffice do not give any gust forecast. In same type of advisories, Meteo France mention only gusts exceeding the wind from 10kt.
                                Gusts + 10kt to +15kt
                                Strong gusts +15kt to +25kt
                                Violent gusts +25kt
                                Gusts are important information for sail dinghies and light sail cruisers.
                                For the sea state you can take into account the wind force, only (average wind/10min.), in official marine advisories and additionally with the Wind layer on Windy.
                                But gust forecast is an important information on the land for the risks of damages they do.

                                1 Reply Last reply Reply Quote 0
                                • markdj
                                  markdj | Premium last edited by

                                  yeah, I was thinking specifically about sailing yachts where a gust could blow out a spinnaker etc.

                                  1 Reply Last reply Reply Quote 0
                                  • markdj
                                    markdj | Premium last edited by markdj

                                    Another day, and storm Gareth. Official Malin Head data 40-57 knots. Windy reports 39 knots, no gust. This morning at 9am it was 16-48 knots ! Gusts are important and should be reported if available.

                                    1 Reply Last reply Reply Quote 0
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