Hi,
I noticed that when live weather running, high altitude wind (aka wind aloft) is same as surface, such us when a METAR say 11003KT, it seems all altitude has the same wind direction and speed, I checked with IDG-A3XX and some other aircraft which could indicate outside wind, same result. I do believe it is vital for FDM of airliner aircraft because it influence the performance of a aircraft which fly higher. Due to Atmospheric circulation and less terrain influence, the high altitude wind is stronger and even total different from surface. I think if this feature implemented, some aircraft's FDM may have to redesign.
Here is a screenshot of Skyvector, it shows winds at FL180. Most wind at 20~60kt, some wind at 80~100kt, after adjust to higher altitude FL340, the wind stronger most wind blow at 80~100kt.
So, dose FG has some predefined Atmospheric circulation data or fetch live data from somewhere, and simulated?
After some research, I suppose FG could get Global Forecast System (GFS) data from NOAA, http://nomads.ncep.noaa.gov/, and a awesome project which could display global winds https://github.com/cambecc/earth