Wind direction in base versus airgram view
Hello, I use windy to check the wind direction mostly for N 41°35'27" E 12°57'25" at 473m of altitude. I find that that the wind direction in the base view does not always match that of the airgram wind barbs if looking at a pressure value comparable to the altitude (below 950hPa).
Why does it happen? I am new to the paragliding world and I apologize if my question is too naive or if I am missing some fundamentals of wheather forecasting.
Thank you for your time!
Could you post a screenshot of the basic meteogram and then a screenshot of the airgram showing the issue you are seeing ?
Thanks for replying and sorry for the late reply, I am uploading a matched base and airgram view, captured a few minutes ago.
Just as an example, look at Thursday (Giovedi') 31st, at 4pm (16) and 7pm (19). On the airgram the wind barbs have the same direction (both west) while on the base they are opposite (west and east, respectively).
Wind direction can completely change with the level and altitude, compared to the ground level.
In the meteogram, wind direction and speed are given at 10m, on ground level.
In the airgram you see the wind direction by « layer ». The lowest « layer » is 1000-950 hPa so up to 500m more or less. This can explain changes and differences between the meteogram and airgram
In addition to @Yves70 explanation, the Airgram shows Wind direction and speed in free atmosphere. Even if you consider the same altitude in mountains, the parameters (wind, temperature...) in free atmosphere and near ground will be often different.
It is important also in mountain areas to check different models, showing higher resolution like ICON or METEOBLUE (this last one only available with Basic diagram).
@idefix37 and @Yves70
Now it is clear. I did not know that that the meteogram wind was given at 10m, basically at ground level. That explains the differences I noticed when comparing the airgram at up to 950hPa, which is the actual altitude of the take off place I am interested in.
Thank you as well for the suggestion to look for other models, I will do it from now on.
Kind regards and happy flying 2021!