Strong winds reaching up to 70mph are expected to batter parts of the UK while half a month’s rainfall is expected in Northern Ireland.
Yellow warnings for wind covering the south and south east of England and southern Wales have been issued by the Met Office from 11am on Friday to 3am on Saturday.
The system has not been named as a storm, however the Met Office said strong winds could still bring down some trees and cause travel disruption.
Forecaster Alex Burkill said: “We are going to see very strong winds but the strongest winds will really be across north west France, maybe into the Channel Islands.
“But the UK itself, we are likely to gusts of up to 60-70mph. The strongest gusts will be around the coast, inland areas we could see 40-50mph gusts.
“I couldn’t rule out an odd gust around 80mph in very exposed parts along the south coast.”
Reports had incorrectly suggested the system would be classed as a winter storm called Doris.
Around half the average rainfall for February, 89mm, is expected over some parts on Friday.
Mr Burkill said: “We have got some pretty significant rainfall coming across, around 20 millimetres (0.7 inches) to 30 millimetres (1.1 inches) in just a few hours, over the parts of the South West.
“There could be 40 millimetres (1.6 inches) fall during Friday in north Wales, eastern Northern Ireland and the west of Scotland.”
The worst of the rain is expected to fall in the Irish Sea, however if the front deviates from its track to the east or west forecasters may issue a rain warning.
There is also the chance of isolated sleet or snow showers over higher ground (200 to 300 metres), mostly affecting the mountains of Wales, some parts of north west England and later Scotland.
A number of Environment Agency flood warnings and flood alerts covering rivers and coastal areas in the south, west, and east of England were put in place on Thursday evening.
The mercury is expected to hit around 9C (48F) in the north of the UK, with highs of around 11C (52F) in the south, Mr Burkill said.
“But in the wind, and where you see the rain it is not going to feel anywhere near that mild. It is going to be quite unpleasant,” he added.