Meanings:
N:Eighths of the sky covered at 12UTC
dd: Wind direction at 12 UTC in degrees
ff: wind speed at 1UTC in kmh
fx: wind gusts in kmh measured from 6UTC untill 6UTC Monday
wv: weather before noon.
wn: weather in the afternoon.
ppp: pressure reduced to sea level at 12UTC
ttm: maximum temperature from 6 to 18UTC
ttd: dewpoint at 12 UTC
rr: rain ammount in 24 hours (from 6 to 6 UTC Monday