update to zyGrib-6.0.1, from the ChangeLog:

2012-08-26 : zyGrib Version 6.0.1

    Update czech translation (d#kuji Pavel Kalian).
    Diagrams SkewT-LogP more complete:
    - Adjustable size.
    - Visualization of the wind (barbs + arrows) at altitudes:
1000, 925, 850, 800, 700, 600, 500, 400, 300, 200, 100 hPa.
    - Choice of the base altitude for the calculation of the convection
levels (fixed levels or average lower layers).
    - Bug fixed for the calculation of equilibrium level when the
pseudo-adiabatic saturated crosses several times the temperature curve.
    - The calculation of thermodynamic indices is not forgotten ...
but it will come later ...
    Bug fixed: POIs were sometimes misplaced when extracting images from animations.

(plunky)