O
OAC - Oceanic area control center
OAT - Outside Air Temperature OBND - Outbound
OBS - Observe or observe or observation
OBSC - Obscure or obscured or obscuring
OBSCD - Obscured
OBSCG - Obscuring
OBST - Obstacle
OCFNT - Occluded front
OCLD - Occlude
OCLDD - Occluded
OCLDG - Occluding
OCLDS - Occludes
OCLN - Occlusion
OCNL - Occasional or occasionally
OCNLY - Occasionally
OCR - Occur
OCRD - Occurred
OCRG - Occurring
OCRS - Occurs
OCT - October
OFC - Office
OFF - Offshore Forecast
OFP - Occluded frontal passage
OFSHR - Offshore
OH - Ohio or Office of Hydrology, located in Silver Springs, MD.
OHD - Overhead
OHP - One-Hour Rainfall Rate
OK - Oklahoma
OML - Operations Manual Letter
OMTNS - Over mountains
ONSHR - Onshore
OPA - Opaque, white type of ice formation
OPMET - Operational meteorological (information)
OPN - Open or opening or opened
OPR - Operator or operate or operative or operating or operational
OPS - Operations
OR - Oregon
ORGPHC - Orographic
ORIG - Original
OSV - Ocean station vessel
OTLK - Outlook
OTP - On top
OTR - Other
OTRW - Otherwise
OUBD - Outbound
OUTFLO - Outflow
OVC - Overcast
OVNGT - Overnight
OVR - Over
OVRN - Overrun
OVRNG - Overrunning
OVTK - Overtake
OVTKG - Overtaking
OVTKS - Overtakes
