A Complaint & some Questions about Map.



  • Hi, Everyone!

    Here I've complaint that in Pakistan, the Wind Speed and Directions are always comes as wrong. I use Windy on Android. Whenever I see wind direction, it comes wrong. Even I change the model but it still gives wrong reading. Kindly take a glance at.
    https://ibb.co/k2LrzsY

    How we can understand 3 to 4 hrs ago that a specific cloud will come to a specific place? See in image, I've circled a cloud which came to Faisalabad in 3 to 4 hours but I didn't know about that because I don't know the wind direction or any other formula. So kindly tell me how we can determine that a cloud can go to where?
    https://ibb.co/g3PYS8v

    Last one is that what is meant by >240 in this map?
    https://ibb.co/qnnzDky

    Regards,

    Qasim
    Faisalabad, Pakistan.



  • No one replying.



    • Wind Speed and Directions are always comes as wrong: please compare with real-time observations; Windy just plots on maps model forecasts provided by weather centers, it doesn't compute any forecast. Moreover, model forecasts computed on grids with 25 km / pixel resolution cannot be too precise over mountain/valley areas, where wind forecast values are particularly hard to predict.
    • How we can understand 3 to 4 hrs ago that a specific cloud will come to a specific place?: just watch the forecast for next 3-4 hours (use the time bar).
    • What is meant by >240 in this map: which data layer did you selected on that screenshot?
    • No one replying: please, next time you post a question on such a community site, wait a bit more than 6 minutes for an answer...

  • Sailor

    @Qasim206 said in A Complaint & some Questions about Map.:

    Last one is that what is meant by >240 in this map?
    https://ibb.co/qnnzDky

    On Satellite layer this is the brightness temperature measured from cloud tops in °Kelvin. It is more useful and obvious with INFRA+ layer (Click More in low right corner of you mobile screen and move the picker on a colored cloud to see this temperature changing).
    https://community.windy.com/topic/8960/suggestion-ability-to-change-units-in-infra/2?_=1591178728939
    On the mobile app this temperature is expressed in °K and you cannot change it. This is only possible on desktop.
    This temperature gives an idea of the cloud top altitude and so the risk of severe thunderstorms.

    IMG_0882.PNG



  • @idefix37 said in A Complaint & some Questions about Map.:

    @Qasim206 said in A Complaint & some Questions about Map.:

    Last one is that what is meant by >240 in this map?
    https://ibb.co/qnnzDky

    On Satellite layer this is the brightness temperature measured from cloud tops in °Kelvin. It is more useful and obvious with INFRA+ layer (Click More in low right corner of you mobile screen and move the picker on a colored cloud to see this temperature changing).
    https://community.windy.com/topic/8960/suggestion-ability-to-change-units-in-infra/2?_=1591178728939
    On the mobile app this temperature is expressed in °K and you cannot change it. This is only possible on desktop.
    This temperature gives an idea of the cloud top altitude and so the risk of severe thunderstorms.

    IMG_0882.PNG

    Ok Thank you @idefix37 for telling me about Kelvin. I've understand now. Can you tell me one more thing that if it's 240K or 300K, then what should we think how much high this cloud is and how much thunderstorm it can produce? Take some random values and kindly tell me. At 100K, 200K, 50K etc...



  • @vsinceac said in A Complaint & some Questions about Map.:

    • Wind Speed and Directions are always comes as wrong: please compare with real-time observations; Windy just plots on maps model forecasts provided by weather centers,

    Yes I do compare with real date and even I take the METARS of my nearest airport every hour. I'm afraid to say both things don't match with Windy.

    • How we can understand 3 to 4 hrs ago that a specific cloud will come to a specific place?: just watch the forecast for next 3-4 hours (use the time bar).

    Ok, thank you. I will see the forecast now.

    • What is meant by >240 in this map: which data layer did you selected on that screenshot?

    This is satellite layer Sir.

    • No one replying: please, next time you post a question on such a community site, wait a bit more than 6 minutes for an answer...

    Yes, this was wrong thing I did. Sorry!



  • > Yes I do compare with real date and even I take the METARS of my nearest airport every hour. I'm afraid to say both things don't match with Windy.

    Weather forecast models don't always match real observations; Windy doesn't compute forecast models, it just displays models computed by meteorological organisations. Thus the best practice is to always compare different available forecast models to observed values for your location, then to use the model which has best fit over your region.

    Unfortunately, weather forecast is not an exact science (like poetry and mathematics are)...


  • Sailor

    @Qasim206
    Difficult to say precisely which is the altitude of cloud tops when considering their temperature. For mid latitudes here is a rule of thumb :

    E2017001-B812-40E7-9D75-68165EFE8AB5.jpeg

    But it also depends on latitude so for Pakistan these values are probably shifted:
    https://community.windy.com/topic/8820/windy-launches-satellite-layer/16



  • @idefix37 said in A Complaint & some Questions about Map.:

    @Qasim206
    Difficult to say precisely which is the altitude of cloud tops when considering their temperature. For mid latitudes here is a rule of thumb :

    E2017001-B812-40E7-9D75-68165EFE8AB5.jpeg

    But it also depends on latitude so for Pakistan these values are probably shifted:
    https://community.windy.com/topic/8820/windy-launches-satellite-layer/16

    Ok. Cannot we find the altitude of cloud using Sounding Forecast? If yes then kindly tell me how to read Sounding Forecast graph? Thanks


  • Sailor

    @Qasim206
    In Sounding, the right colored line(red) is predicted temperature based on height. The left (blue line) shows dew point i.e. temperature at which will condense water in given height. If those two lines are in any point close to each other it will meant that at this height there will be clouds/fog, further they are apart there is smaller probability of clouds.

    I can’t give you more details about these sounding forecasts, there are aviation specialists in Windy community who can but I’m not one of them. Furthermore you can explore by yourself all the topics posted here in relation to your questions. That should already satisfy your curiosity
    Then note that Windy shows 5 layers about cloud altitude (forecast):
    Low clouds
    Medium clouds
    High clouds
    Cloud base
    Cloud tops
    In addition to Satellite layers (observation):
    Visible (high/low clouds shown bluish/yellowish)
    Infrared with brightness temp.

    And back to your first question « How we can understand 3 to 4 hrs ago that a specific cloud will come to a specific place? ».
    You must look at the wind direction and speed at same altitude as the cloud, mainly between 850hPa (1500m) and 500hPa (5500m). The ground wind direction has no influence on cloud motion obviously.



  • @idefix37 Thank you dude for your detailed replying. I've understand a lot from you. Thank you.

    I hope the aviator will help me more. Thanks.


  • Moderator

    Windy also has a feature which may be of some help:

    How To Use The "Observation vs Forecast" Feature

    https://community.windy.com/topic/9425/how-to-use-the-observation-vs-forecast-feature

    This feature enables you to compare what the "Weather Station Observed" with what the various "Forecast Models Predicted" during the last few days.



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