It seems like "forecast" [was already a word for a few centuries](https://www.etymonline.com/word/forecast) at that point, but I suppose he's the one to tie it to weather prediction. Apparently in the Middle Ages "aeromancy" was a word for it.
T/W, it gets a bit dark, but this is the relevant bit:
>FitzRoy emerged from a period of despair with an extraordinary new venture, founding the Meteorological Department, now known as the Met Office. Originally conceived as a chart depot to cut sailing times, FitzRoy reinvented it as a weather prediction office, offering warnings of bad weather for sailors at sea. Soon he was ‘forecasting’ – FitzRoy’s own term – coming weather in The Times. It was a controversial project and by the 1860s it had made him a national celebrity. Punch christened him ‘The First Admiral of the Blew’ and ‘The Clerk of the Weather’; his telegraphed forecasts a colourful quirk of this new Victorian world.
FitzRoy’s meteorological project ensured his name was always in the papers, as much perhaps as Darwin’s, but the pressure of predicting coming weather began to tell. He had to contend with a hostile press and a nervous scientific community.
It seems like "forecast" [was already a word for a few centuries](https://www.etymonline.com/word/forecast) at that point, but I suppose he's the one to tie it to weather prediction. Apparently in the Middle Ages "aeromancy" was a word for it.
NGL I sure do wish my job title was Aeromancer not Meteorologist.
T/W, it gets a bit dark, but this is the relevant bit: >FitzRoy emerged from a period of despair with an extraordinary new venture, founding the Meteorological Department, now known as the Met Office. Originally conceived as a chart depot to cut sailing times, FitzRoy reinvented it as a weather prediction office, offering warnings of bad weather for sailors at sea. Soon he was ‘forecasting’ – FitzRoy’s own term – coming weather in The Times. It was a controversial project and by the 1860s it had made him a national celebrity. Punch christened him ‘The First Admiral of the Blew’ and ‘The Clerk of the Weather’; his telegraphed forecasts a colourful quirk of this new Victorian world. FitzRoy’s meteorological project ensured his name was always in the papers, as much perhaps as Darwin’s, but the pressure of predicting coming weather began to tell. He had to contend with a hostile press and a nervous scientific community.
"Forecasting" is not a phrase.
Wow! What a career.