That was used by the Two Ronnies in an episode of The Phantom Raspberry Blower of Old London TownIn the old days they used velco symbols of cloud, sun, rain etc but, they had no symbol for fog other than to spell the word F-O-G in the rough area on the map it was expected. One evening with Fog anticipated the velcro letter " F " fell off the weather map during the broadcast....at the end the presenter, I think it was Fish again said "Sorry about the F in Fog " ! priceless