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    Wrong wind data

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    • V
      vojkob last edited by

      Hi
      Can anybody explain why windy miss All wind speeds in ionian? Every day i moyice agsin failures in winds speed of 100 percent.really anoying

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

        @vojkob
        Why do you think that windy miss all wind speeds in Ionian?
        I compare observed data (e.g. from meteo. stations in the coast) with forecast data
        and I don't see any great difference.
        79f29428-8587-4433-9e02-87b95b15b18e-εικόνα.png

        f345e79f-84c3-46c3-805b-9f2ddcdb7c0c-εικόνα.png
        .......

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

          .......
          today (13 July) ECMWF gives 5 max 6 BFT.
          3c3e67eb-4a44-4170-9419-84416480a378-εικόνα.png

          with gusts up to 8 BFT in the Otranto strait
          12fada04-6529-4e3a-9635-7dc76e25f73a-εικόνα.png

          For tomorrow the forecast is for 3~4 BFT.
          2938efd5-eed5-42ae-b084-0c94c08782f4-εικόνα.png

          In what area you observed 100% failure?

          1 Reply Last reply Reply Quote 1
          • V
            vojkob last edited by

            We are in euffemia kefalonija, windy shows 8 knots wind, instead is 35knots

            I have same experience begore. Data are not precise enouvh to be usefull

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

              @vojkob
              Thank you for providing the location where you observed such a big difference
              between reported and forecasted wind speed.

              The phenomenon you report is called "wind funnelling effect".
              50c85599-e10c-4d18-bdd6-53c7189b0483-εικόνα.png

              Agia Effimia (Keffalonia, Greece) is located in the south of narrow valley.
              d9449567-9160-433c-904f-b55d7cca9df1-εικόνα.png

              Steep mountains, 900m high, rise in the north and south of the valley
              with peaks only 2 milles away from each other.
              These days, the NW wind is funnelled, especially during the afternoon,
              resulting gusty northwesterlies.
              Light winds can often become much stronger when they are forced
              to converge and funnel through a narrow mountain pass.
              Unfortunatelly, a weather model with a 9 km resolution is unable
              to accurately depict the topography around the valley,
              and therefore will not accurately model the winds at Agia Effimia.
              Only human forecaster with knowledge of the local topography,
              as well as historical knowledge of how the land affects the wind in the area,
              can therefore predict the NW'ly wind at Agia Effimia with accuracy.

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

                ....
                Following images show how a weather model with a finer grid,
                gives better forecasts in such conditions.
                8b03b589-f8af-4379-b3c4-b1cff0391d41-εικόνα.png

                But, for even better forecasts in such a complex terrain,
                high resolution (grid=1 km) weather models needed.

                1 Reply Last reply Reply Quote 3
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