“For the amber warning, potentially up to 200mm, that’s twice the normal February rainfall.”
Natural Resources Wales had issued 37 flood alerts and 11 flood warning on Friday evening, while the Environment Agency issued six flood warnings and 93 flood alerts for England.
The Scottish Environment Protection Agency issued 32 flood warnings and nine flood alerts.
The amber weather warning is in force across parts of south Wales from 8pm on Friday until 6pm on Saturday, with heavy and persistent rain expected to cause some flooding and disruption to transport and utilities.
Yellow weather warnings are also in place across large parts of west and south Wales, parts of west, south-west and central Scotland from Friday until Sunday, parts of Devon and Cornwall from Friday to Saturday and parts of Cumbria on Saturday.
Mr Petagna said that the east of the country will have a much quieter weekend with mild temperatures up to 16C in the South East, but with light and patchy rain on Sunday.
However, he warned that after a brief break in the rain, there was more wet weather due next week.
He added: “There’s more rain to come going into next week.
“There will be some respite Sunday and Monday but going into Tuesday there’s some more rainfall.
“Again the west and north-west could see further rain developing.”