I got the following explanation.
CIS uses its own friction coefficients. However, for data disseminaton such as METAR (RSM) and SNOWTAM information, standard ICAO values would be used.
This is supported by:
- Yesterday SVO METAR-RSM showing FC at 27. Also SNOWTAM issued with "H/27/27/27 by SFT". SFT is the important part for me, RSM is just in-line with the SNOWTAM.
- On Jepp ATC chapter, national differences show no alternations in meteorological reports.
- Later on, ACARS METAR-RSM at 31, ATIS reports dry patches snow BA-3, landed and it felt like medium, marginally medium.
- ATIS English does NOT report FC but BA instead (to prevent confusion?)
Obviously ATC spoken FC infrormation is not to be trusted as there is no way of telling which coefficient they are reporting.
FD.