PRCP = Precipitation (inch)
SNOW = Snowfall (inch)
SNWD = Snow depth (inch)
TMAX = Maximum temperature (F)
TMIN = Minimum temperature (F)
TAVG = Average temperature (F)
AWND = Average daily wind speed (miles / hour)
WSF5 = Fastest 5-second wind speed (miles / hour)
WDF5 = Direction of fastest 5-second wind (degrees)

For more information, see:
ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/daily/readme.txt