Wind arrows direction



  • Why are the wind arrows backwards? They show the way the wind is blowing, not where the wind is coming from as is normal. This continues to confuse me. Is there a setting to change this on my computer?



  • Hi @svSecondChance , can you please send us a screenshot of the situation? Also what device + OS are you talking about? Thank you.


  • Sailor

    @svsecondchance
    That’s absolutely normal. The arrows are in the same direction of the « particule animation ». In the conventional way to show the wind direction i.e. with the arrows type called « wind barbs », these arrows are also in the same direction of the wind flow and not from where it come.

    0_1544106629105_ED923754-99CC-413F-B1A9-66A87389A329.jpeg



  • @idefix37
    Sorry but this last response is utterly incorrect, and the barbs example image given has been completely misconstrued by the author.
    I came across this thread trying to find anyone who'd raised the issue before, having been a bit confounded by it myself.
    @svsecondchance is right, Windy.com vanes are 180° out of phase; @idefix37 is very wrong, vanes_always_point into the direction of flow, this is a convention since first use of the wind rose. Anyone who's ever sailed beyond passive crewing could not confuse the rule for reading wind barbs, especially given the powerful feedback even a motor launch gives from actual winds.
    I think the mistake here is confusing vectors for vanes. On a chart displaying vectors there are arrows, yes. N.B. however, vector arrows have a set form, and representing a vector they convey direction and magnitude, i.e. velocity.
    For Windy.com to correctly display winds using arrows pointed along flow direction would require adhering to the international conventions for displaying meteorological data, which are published by WMO, in other words, thin arrows with relative velocities represented by center line length.
    Note also, vector maps have equidistant data plots. Anything with direction display set to station locations is not a vector chart.
    It's just a hokey idiosyncracy given the app/site is a toy, but it's wrong and as such, should be fixed.
    Showing colleagues the app, everyone points out this as the first deficiency they notice.
    It's a bit surprising that there could be any diversity of views on something so elementary as the global standard for representing wind data, but as we all know there's really no limit to how wrong each of us will be about things at various times of the day.
    The arrow mixup should be fixed pronto. It's not hard, just reverse/change the symbol. If anyone needs help with the coding my neighbour's 12yr old can do it, I'm pretty sure.
    I bet, though, the issue is well known, but leadership paralysis set in at the '..but what will users do when the symbols they're used to suddenly reverse polarity?'. I say this after finding other discussions about wind direction issues here, where people fear users might confuse 300° for 300°F (I'm not joking, just search this forum).



  • @xiyakl
    BTW, here's the wind barb image from NOAA, reflecting WMO standard (https://www.wpc.ncep.noaa.gov/html/stationplot.shtml), which an earlier author posted as explanatory. I think this is the source of earlier confusion. Note the text ('outer' is relative to station position, in other words, the foot of the barb is at the station, the barb points 'out' into the wind, not along) above the image reads:

    "Wind is plotted in increments of 5 knots (kts), with the outer end of the symbol pointing toward the direction from which the wind is blowing. The wind speed is determined by adding up the total of flags, lines, and half-lines, each of which have the following individual values:

    Flag: 50 kts
    Line: 10 kts
    Half-Line: 5 kts

    If there is only a circle depicted over the station with no wind symbol present, the wind is calm. Below are some sample wind symbols:"

    alt text


  • Sailor

    @xiyakl
    You said that the « last response is utterly incorrect, and the barbs example image given has been completely misconstrued by the author ». Sorry to say that you are wrong!
    And be sure that I use to « sail beyond passive crewing » and that I do « not confuse the rule for reading wind barbs ».
    Here is a map using the traditional way of showing wind direction around a low in the north hemisphere.

    89E9F311-7ADD-4D8C-A8A6-A5F2A385187A.jpeg

    Compare it with the way that Windy show the wind flow around a cyclone. For example today near the Azores archipelago.

    C686F10E-FFF8-4394-87FC-79B82BE9BC17.jpeg

    There is no reason the change the « animated particles » on Windy. This should be really crazy to do it !



  • 43.gif/84a928a8-3389-4690-8453-005a9c15f906?t=1369746553556)
    ..or:
    alt text
    ..or:
    alt text
    ..or, well, maybe that's enough.


  • Sailor

    @xiyakl
    Instead of long explanation you'd better show a screenshot of what you want to explain.
    The arrows shown at weather stations for the observed wind show the same conventional direction as the wind forecast which is displayed by the « animated particles ».

    Then, here is the way how the wind direction is shown at a station for a WSW Wind:

    EF1F1F9B-4463-4634-9D75-F5C70BD7A360.jpeg

    And how Windy figure a wind with the same direction:

    189BC270-E951-434E-842C-C6D47028A5BF.jpeg

    For me these two ways to show the wind direction are absolutely consistent.



  • @xiyakl
    What do you think is the wind direction over North Sea (today) ?
    wind 23 Feb 2019.jpg



  • @Gkikas-LGPZ
    I hope I'm right. If I'm not I'm going to have to resign my job, then sell it. It's OK, I'm getting sick of the smell of kerosene anyway ;)



  • @idefix37
    Makes us, formally speaking, polar opposites ha



  • @xiyakl

    You could just look up the Doppler.



  • @WXcycles
    Lols



  • @idefix37
    You do understand the pennants go to windward, right? The little circle isn't the head of an arrow or something like that.


  • Sailor

    @xiyakl
    Yes, exactly, you must imagine an arrowhead in the circle. The old drawings of windbarbs were showing an arrowhead, as this first french isobaric map from 1863.

    1F1E7E9F-A618-4C13-8AE7-8A107B2AD359.jpeg

    Then a circle has been used together with the arrowhead, as this American map from 1888.

    31B4511F-1F4A-4636-A976-D498F5FD69D8.jpeg

    Finally the drawing has been simplified and the arrowhead has disappeared. But you must remember that the « windbarb » symbol is based on an arrow drawing with an arrowhead and feathers or feather barbs at the back.

    790EA149-EE75-4A42-BEB9-57CA84FBFF56.jpeg

    So you may consider that the arrowhead is no longer used to show the direction of wind by official weather offices according to WMO recommendations, but is still used on Windy app. For a west wind, blowing from the West, the arrowhead is oriented toward the East ! The direction of a west wind is NEVER given by an arrow pointing to the West, even if the wind bearing is 270° on the wind rose. So the way how Windy app represents the observed wind direction is correct and is not «180° out of phase » as you said.

    OK, Mate? Is it clear for you now? So you may explain to your colleagues why the way how Windy app figures wind direction at weather stations is correct.



  • @idefix37
    Well, really you're so way off, beyond help.
    I like the old charts you found on Google, nice bit of research. I think you nailed it.
    In case we end up discussing chemistry I decided to play the trump card early, because I've got this, which by its vintage has to evidence of something, right?
    alt text
    There's such a list of reasons as to how come your wrong, but on casual examination apparently right, that there not time in a productive day.
    I would say though, you got a bunch of pilots laughing our asses off.
    I was thinking to donate something useful to this outfit, but after seeing the (now shrouded) unethical conduct in 2017, and the determination to stay wrong/in-toytown, the taste seems all gone.
    The right thing to do if so obvious, but somehow invisible for some because operating in a standardised manner is some kind of anathema.
    The little arrows you're so keenly advocating for are just hokey little things someone has just made up in their head.
    It's a toy and something like this it's diagnostic.
    Now here's a question for you. Given we are at an impasse, do you need to have the last word? I'd say I've got money on it, but nobody here will bet against.



  • This post is deleted!


  • @xiyakl must be trolling here.

    For interactive data rich map Windy has made good choice with wind arrows.


  • Moderator

    Here another explanation how to read wind barbs
    http://weather.rap.ucar.edu/info/about_windbarb.html



  • @Tomber42 hi Tomber, on my windy app, the forecast is showing a barb about half the length of all the other barbs with a line about half the length of the 5knt line, does that mean less than 5knt
    Thank you


Log in to reply
 

Windyty, S.E. - all rights reserved. Powered by excellent NodeBB
NodeBB & contributors, OSM & contributors, HERE maps