Hello,
I would not try to prepare a time-varying SELAFIN file in your situation. Even if you manage to create a binary PCL, Blue Kenue will not be able to map it on a SELAFIN. Further, there is currently no existing public subroutine to read a time-varying SELAFIN from TELEMAC.
Since you only have 4 airports, the best way to do what you are looking for is to prepare your data into a a file similar to a LIQUIDE BOUNDARY FILE. The row of variable could be yours, for instance:
# my header text - 4 airport
T SPEED1 DIR1 SPEED2 DIR2 SPEED3 DIR3 SPEED4 DIR4
(s) x x x x x x x x
0. ....
Then, in the METEO subroutine, you can read these time series by using READ_FIC_FRLIQ('SPEED1' ...), READ_FIC_FRLIQ('DIR1' ...), etc, program you own way of interpolating spatially and finally set WINDX and WINDY for all the points in your mesh.
This is roughly how we do cyclones and huricains for instance.
Hope this helps.
Sébastien.