Grey Relative Humidity in Meteogram

[chzhh]

In the Meteogram, the lowest Relative Humidity layer is 950hPa. Can we add a new 1000hPa RH layer at the bottom? The Relative Humidity of 1000hPa is important for low altitude plain areas, where heavy fog or very low stratiform clouds usually appear. However, I cannot see the clouds represented by this layer in the Meteogram.