"Key to symbols and terms" "Key to symbols and terms" "Key to symbols and terms" "Key to symbols and terms" "Key to symbols and terms" UK Met Office http://www.metoffice.gov.uk/guide/weather/symbols UK Met Office "Key to symbols and terms" http://www.metoffice.gov.uk/guide/weather/symbols Key to Weather Map Symbols and Terms "Key to symbols and terms" "Key to symbols and terms" weather charts