On 20/08/2013 19:02, Paul wrote:
The 'new code' came in in the early nineties. I was an assistant at Rheidhalen at the time and plotting charts. On January 1st there was a mixture of old and new being used. The old was quicker to hand plot. with the new code you had to remember to check if there was any present weather after plotting the vis and to leave enough room for weather symbol.

Plotting Tephis used to be tricky at times when new radio sondes came as the messages had so many special points.

The good old days!

Hmm, I thought that it was in the early 80s, but I'm not going to argue,
especially as I can't find any details via a Google search. I left
Heathrow in 81 and my memory is that the new code came in not long
after. I can still easily 'read' the old codes (thanks to plotting
charts for ten years!) but can only do it slowly on the 'new' code (no
longer using it daily, being at Bracknell in research). Can anyone
confirm the date?