Quote from Anvaldra:
"So runway state 24/59//32 corresponds to POOR braking action with undetermined depth of wet snow"
In post #5 I guessed wrongly that a braking coefficient of 0.32 was equivalent to medium-poor. In fact it's medium.
That "R24/59//32" observation of runway state was attached to the 2100Z METAR, which I assume to be an observation officially current when the aircraft landed. But, as the reported wx was a heavy shower of rain and snow, it seems probable the braking action would have been deteriorating rapidly.
The 2130z METAR retained the same figures of runway state, but in view of the accident it seems unlikely that staff would have been available to take a new measurement in the interim. Consequently the actual braking action at the time of landing is open to speculation.