@idefix37 thanks for the explenation.

@Gkikas-LGPZ Thanks you dear now I get it .

@Borys-Wolak I KNOW THAT ! Who said the jet stream is on the surface? I said that if you change the wind color scale to a gray tint below 40 kt, you will clearly see the jet stream, but looking at the surface wind, you will not see the lighter winds below 40 kt!