First column is day and time (hours and minutes) UTC in DD/HHMM format.
SLP - Sea level pressure in millibars (mb)
TT - Temperature in degrees F
TD - Dew point temperature in degrees F
DIR - Wind direction in degrees of compass
SPD - Wind speed in knots
GST - Wind gust in knots
Sites starting with PH and PM represent official National Weather Service observations.
ARxx and MWxx sites are remote supplemental automatic observations
and are not quality controlled.