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    Yves70

    @Yves70

    Meteorologist
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    Location Grez-Doiceau (Belgium)

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    Meteorologist

    Best posts made by Yves70

    • RE: How to read Meteogram

      @korina
      Very nice summary Korina. Will be useful for a lot of users !

      posted in Frequently Asked Questions
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      Yves70
    • RE: Fronts

      @koukgr
      As explained by @idefix37, there is no way for Windy to draw fronts. There are websites where fronts are drawn tha you can use.
      Having said that, there are alternatives to visualise fronts that you can use with Windy. One way is to use the humidity map at 700 hPa. A front is materialised at this altitude with a humidity above 90%. Another way, combined with the humidity map is the temperature map at 850hPa. Ideally we should use the potential temperature (thêta’w) but still it can give you an idea of the temperatures differences between air massa so in fact discontinuity which is the sign of a front.
      Again, those 2 maps don’t replace fronts map but it works quite well

      posted in Developers
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    • RE: How to read Meteogram

      @hgk209
      First of all, we should get the confirmation about the exact meaning of the shades of grey. Is it humidity level or cloud cover ? High level of humidity doesn’t necessary mean clouds

      @Korina
      @ivo
      Could you let us know ? Thanks

      posted in Frequently Asked Questions
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    • RE: Displaying weather Fronts notations.

      @captainjack63
      Fortunately for the meteorologists working for NOAA or other national institutes, their work and analysis cannot be always replaced by an application or a computer as it is the case for the front map for instance.
      Having said that, there are couple of things you can do with Windy to try to see front, and air mass with different temperatures :

      1. check the humidity above 90% (very critical) and at 700hPa and 600hPa. You should see the fronts as illustrated :334E5AA0-8BE0-409A-B1C4-BF74F79D96DF.jpeg

      The red zone shows the front, with humidity above 90% and just after, you can see a huge drop of the humidity with the brown zone

      1. check the temperature at 850hPa to follow air mass temperatures. Ideally, you should use the potential temperature (a temperature among others which doesn’t vary with the altitude) but this temperature is not available with Windy. Nevertheless, temperatures at 850hPa will allow you to compare different air mass and follow them, especially on the sea because hills and mountains could otherwise interfere at this level.

      2D91F677-24D3-40E0-93C4-A4E8867DC642.jpeg

      Same picture as above, same moment. You can see the temperature differences, as there is an air mass at 0°C followed by an air mass at 4°C. This confirms the front identified above with the humidity map and on top, you see that it is a warm front
      This type of analysis will not replace a front map draws by professionals but at least you can get something thanks to Windy

      posted in Your Feedback and Suggestions
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    • RE: Rain Value Meaning In Meteogram?

      @nwindy
      Yes, the way the ensemble model calculates the probability is as you explain : for instance for the rain, each dot of the 21 dots can give a different level of rain (1mm, 4mm, 10mm,...). Based on that set of different levels of rain, the model can calculate several probabilistic values such as the average, variance,... This will allow you to quantify the risk of rain

      Now, if the model has to adopt the same approach for many other parameters, such as pressure, temperature,... And for each parameter do the 21 calculations (do not forget that each calculation is the equivalent of a single deterministic calculation), computional limitation will be the issue if the model keeps the same grid. To overcome this problem, grid is bigger, calculation of the 21 dots for the different parameters becomes ok but accuracy will decrease.

      Computational calculation is key. In average, weather forecast improves by one day every 10 years thanks to the computer (super calculator) progress

      posted in General Discussion
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      Yves70
    • RE: How to read Meteogram

      @idefix37
      Thanks, this is clear now. Grey shades in the meteogram are linked to relative humidity, not cloud cover

      posted in Frequently Asked Questions
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    • Mediterranean sea - Temperature

      The temperature of the Mediterranean sea is quite high this year. In some ares, temperature at the surface is around 28°C. This is of course due to the hot spring and summer.

      This situation is not without consequences :

      1. a medicane was formed close to the Libyan coasts and hit last Friday Greece creating a lot of damages because of the wind and rain

      2. yesterday, in the South of France, because (but not only !) of the intrusion of very warm and humid air from the sea, combined of course with other factors (instability, anomaly in altitude, wind shear), it created a multi cellular thunderstorm which was stationary : each new convective cell (this is why it is a multicellular system) is created in the exact opposite way of the move of the system in altitude because of the wind shear. This creates therefore a stationary thunderstorm which is terrible in terms of rain accumulation because you can get huge quantities of water at the same place during 24h or even more.
        This thunderstorm created floating and a lot of damages in France (more than 600mm of rain in 24h)

      Unfortunately, other episodes like the ones mentioned above could happen in the coming weeks,...

      posted in General Discussion
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    • RE: Windy.com updates ECMWF model each 6h, with 1h detailed resolution

      @Joerg78
      The model from ECMWF is called IFS. This model has 4 run per day: 0z, 6z, 12z and 18z. So far, Windy gave us access to only 2 run, 0z and 12z (the main run). Now, the Premium users have access to the other 2 run, 6z and 18z

      posted in Announcements
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    • RE: INFRA+

      @lbazlen
      To complete what @idefix37 said, with the infrared, the colder the tp the higher the cloud is so potentially it could be a cumulonimbus type of cloud associated with thunderstorms but cirrus is also high and cold cloud and not associated at all with thunderstorms. As always in meteo, before taking a conclusion you should check other paramters, for instance check the visible channel as well to see if the cloud is thick or not. If not, what you are seeing with the infrared is probably a cirrus

      posted in General Discussion
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    • RE: Rain forecast

      @ginop
      First of all, please start to check the posts published on this forum and discussing rainfall forecast.
      Example : https://community.windy.com/topic/13586/about-rain-calculate/2?_=1602329137551
      There are many others, use the advanced search tool to fine them and to read them. You will find a lot of advices.
      Principles are always the same :

      1. compare the different models to verify the consistency within the forecast from the different models. It is a kind of statistic approach to give you a level of confidence
      2. don’t look only the meteogram which is focus on one location. You should check with the Windy rain map, the rain forecast in an area of let’s say 20km around the location. Often, models foresees no rain at the location but for instance 5mm at only 10km from the location. Thereofore risk is high to get rain at the location.
        Combining 1) and 2) should tell you the probability of getting rain or not
      posted in Windy Translation & Localization
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      Yves70

    Latest posts made by Yves70

    • RE: Code couleur

      @Grégory-Bertrand Pour la Belgique, je suis essentiellement deux modèles : ECMWF et ICON/ICON D2. Le premier permet d’avoir une vue moyen terme assez fiable avec notamment les changements de régime et de températures. ICON / ICON D2 est très bon en cours terme pour la pluviométrie, quantités de précipitations

      posted in Non English posts
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    • RE: Forecast not correct

      @jyhshyh you should use the compare tool in order to compare the forecast from different models. You could find one which could be better than the others

      posted in Your Feedback and Suggestions
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    • RE: Weather fronts

      @gatorgrad74 there is no possibility to see the fronts but there are alternatives to see them : https://community.windy.com/topic/13381/fronts?_=1695647017813

      posted in Your Feedback and Suggestions
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    • RE: can I overlay rainfall layer on temperature layer?

      @Keith-Cohen a possibility is to select the layer you wish, here rainfall, and combine it with the measured temperatures so observations
      IMG_0752.jpeg

      posted in Your Feedback and Suggestions
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    • RE: Consult historical data

      @razo-fernando there are no historical data except from the satellite map

      posted in Your Feedback and Suggestions
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    • RE: why can't I fix a different wheather Model for my Region?

      @Moby65 in the settings, choose to open Windy with the last layer opened. If you selected a specific model with this last layer, you will open Windy with this layer and the model you selected

      posted in Your Feedback and Suggestions
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    • RE: How many desktop devices can I use a Premium subscription on?

      @chrismillard you can log on on all devices you wish to use

      posted in Windy Premium
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    • RE: How change default Weather model

      @NickBoyd in the settings, choose to open Windy with the last layer opened. If you selected UKV with this last layer, you will open Windy with this layer and UKV as model

      posted in Your Feedback and Suggestions
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      Yves70
    • RE: Wind gusts

      @shanekopcak first of all, wind gust is not wind speed. This is different. Secondly, when you check a parameter like the wind, you should always compare several models, and not rely on onky one. Now, are you using Windy app ? If yes, did you download the last version realesed recently for Android ?

      posted in Bug Reports
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      Yves70
    • RE: Map does not display correctly

      @rlaker this is both. It is a forum where you can discuss topics related to weather and weather forecast but you can also highlight here bug or issues that will be forwarded to the Windy development team

      posted in Bug Reports
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