blueloo,
The AO2 means its an automated site with a automated rain guage, P0005 is the amount of rain in hundredths of an inch since last hour (its a US site measurements are in inches).
LTG DSNT ALQS, just means distant lightning over 10 miles away miles in all quadrants, sometimes will see LTG DSNT N which means lightning 25 statute miles north of the station.
DSNT means over 10 miles away.
VC means within 10 miles
Other unusual ones ..
OCNL LTGICCG OHD occasional lightning, in cloud, and cloud ground overhead
DS - Duststorm
SS - Sandstorm
MIFG - Shallow fog
DRDU - drifting widespread dust
DRSA - drifting sand
DRSN - drifting snow
VCSH W would mean precipitation of unknown intensity within 10 statute miles west of the station
PRESFR - pressure falling rapidly
TN18/16Z minimum temperature 18 degrees occurred around 1600 UTC
TX35/00Z maximum temperature 35 degrees occurred around 0000 UTC
