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    Hourly forecast quite different from 3-hourly

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    • ronwnzl
      ronwnzl | Premium last edited by

      The 3-hourly forecast is quite a bit colder and more rainy than the hourly forecast (see below).
      I'm not sure how the two forecasts are produced, but they look different on every day.
      It seems fine for all other models apart from ECMWF. The screenshot below is for London, but it looks wrong for other places as well.
      Let me know if you need anything else.

      Problem: 3 hour and 1 hour forecast quite different.
      Location: All locations
      When: Always (tried on multiple days)
      Model: ECMWF
      Where: Website and app

      Screenshot from 2021-05-11 19-08-47.png
      Screenshot from 2021-05-11 19-08-32.png

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

        @ronwnzl
        Could be explained like that
        https://community.windy.com/topic/16430/forecast-change-from-3-hour-to-1-hour-view/4?_=1620756990698

        ronwnzl 1 Reply Last reply Reply Quote 0
        • ronwnzl
          ronwnzl @idefix37 | Premium last edited by ronwnzl

          @idefix37
          There is absolutely no rain at all displayed in the 3-hour forecast. For that to work every rain displayed in the forecast has to be less than 0.3mm, so that it's hourly less than 0.1mm.
          But almost all values are more than 0.3mm and some even 1.8mm, 1.9mm, 2.5mm. Not sure how this would work?
          Also the temperature look off as well. Where does the 12C on Thursday 13:00 come from if every temperature in other forecast for the 3 hours before and after is 16C?
          The gusts are at 5bft for Thu for 7 hours as well, which is 3bft in the other forecast.

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

            @ronwnzl
            Are you sure that both Meteograms are from same update?
            In addition it would be useful that you say where you observe them to allow checking.

            ronwnzl 1 Reply Last reply Reply Quote 0
            • ronwnzl
              ronwnzl @idefix37 | Premium last edited by ronwnzl

              @idefix37
              Yes, both said '5 hours ago', sorry it's cut off. You can't reproduce it?

              I wrote above 'London' - if you click on London and open the meteogram. But it happens for every place I've checked.
              https://www.windy.com/51.510/-0.130

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

                @ronwnzl
                You are right. I’ve checked on London (sorry I missed it). The 1h/3h rain forecast is not consistent especially on next Thursday.
                There is probably something wrong. I’ve never seen such discrepancy before.

                1 Reply Last reply Reply Quote 2
                • ronwnzl
                  ronwnzl | Premium last edited by

                  FWIW the two forecasts align currently. Not sure if something has been fixed or if this is a transient bug.

                  1 Reply Last reply Reply Quote 1
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