e3afa375_on_and_or_cloud_microphysics____What
[When] 2004/11/04/12 [Who] Ferrier [What] 
A new cloud cover scheme is introduced in order to increase the presence of forecast partial cloudiness. Two adjustable parameters in the scheme have been tuned to match the AFWA total cloud cover product. The first parameter (STSDM) is the assumed standard deviation of total grid-scale relative humidity in the grid box, and it is set to 2%. The second parameter (RHsat) is the total relative humidity associated with an assumed cloud fraction of 50%, and it is set to the average of the threshold relative humidity for the onset of grid-scale condensation (RHgrd) and a value of 100% (i.e., 98.3% for the 32-km runs).
Mesoscale Parallel Experiment Change Log for " Eta-32 with winter 2005 Eta change package, experimental changes to GFS radiation and/or cloud microphysics "
What