What does the "COR" mean in this METAR I downloaded this morning? The rest of it is easy, I've just never seen the COR before.
METAR KPDX 071455Z COR 28004KT 1/8SM R10R/1600V2000FT FG VV001
04/04 A3057 RMK AO2 SLP349 T00390039 51009
METAR KPDX 071455Z COR 28004KT 1/8SM R10R/1600V2000FT FG VV001
04/04 A3057 RMK AO2 SLP349 T00390039 51009