Storm Bram has been named by the Irish weather service - with warnings for strong winds and heavy rain issued for parts of the UK and Ireland.
More than half a month's rainfall could hit some parts of the UK in just a 24-hour period, the Met Office has warned.
Parts of Scotland are also facing a "danger to life" warning due to the "very strong" winds on Tuesday.
Yellow and orange warnings are in place across Ireland today and tomorrow, with "very strong to gale force" winds forecast on Tuesday.
Check the forecast for your area
The Met Office said strong winds forecast from Monday evening through until Wednesday could cause disruption, with gusts of 50-60mph predicted widely and 70-80mph in some places.
A yellow weather warning for rain comes into force from 6pm on Monday, and will be in place until 2pm on Tuesday, covering parts of southwest England and Wales, and stretching to parts of Herefordshire and Hampshire.
The Met Office has also issued a yellow warning for high winds from Dorset to Cornwall and up to north Wales, in place from 10pm on Monday until 4pm on Tuesday.
It said transport networks could face disruption, with delays for high-sided vehicles on exposed routes and bridges, and coastal roads and seafronts affected by spray and large waves. Power outages are also possible.
For 24 hours from 6pm on Monday, up to 40mm of rain could fall in some areas, with 60-80mm of rain over Dartmoor and high ground in South Wales, which would amount to more than half the average monthly rainfall in December.
The predicted rainfall across southwest England and South Wales is expected to hit already saturated ground and could lead to difficult travel conditions.
An amber warning for wind has been issued for northwest Scotland on Tuesday, from 4pm until the end of the day.
Flying debris "could result in a danger to life" - and there could be damage to buildings and homes along with the risk of roofs being "blown off" due to the "very strong and disruptive winds", the Met Office warned.
Forecasters added there was the potential for large waves and beach material "being thrown" across sea fronts, roads and properties.
There are also further yellow warnings for wind and rain on Tuesday across Northern Ireland, Scotland, Wales and northern England.
Yellow warnings for wind have been issued for Scotland and parts of northern England on Wednesday.
The Met Office's deputy chief meteorologist, Steven Keates, said: "A deepening area of low pressure will approach the UK from the southwest later on Monday, bringing with it heavy rain and strong winds, which are likely to affect the UK between late Monday and early Wednesday.
"The exact track, depth and timings of this low are uncertain, which makes it harder to determine where will be most impacted by strong winds and/or heavy rain.
"This system has the potential to cause disruption, and severe weather warnings are likely to be issued over the weekend as details become clearer. We therefore urge people to keep up-to-date with the latest Met Office forecast."
Read more from Sky News:
City may have to evacuate as water supplies run low
UK unveils undersea military technology
Sky News meteorologist Dr Christopher England warned many areas could face disruption from "damaging gusts".
"There could also be ferry disruption and that even outside the warning areas, potentially damaging gusts of over 50mph are possible," he said.
"It only takes one tree falling in the wrong place at the wrong time to have a significant impact."
The Met Office said the rest of the month remained unsettled, with further periods of low pressure predicted.
It said it is too early to provide an accurate forecast for the Christmas period.
(c) Sky News 2025: Storm Bram named as weather warnings issued for UK and Ireland
Ex-footballer Joey Barton sentenced for X posts sent to Jeremy Vine, Eni Aluko and Lucy Ward
Adolescence stars among host of Britons nominated for Golden Globes
Nurse Sandie Peggie who complained about sharing changing room with transgender doctor wins part of employment tribunal
Thailand launches airstrikes against Cambodia as deadly border clashes reignite
Woman jailed for blackmailing ex-Tottenham Hotspur footballer Son Heung-min with pregnancy claim
Syria jubilantly marks a year since Assad's fall with parades - and leader makes new pledge
Former Radio 1 DJ Tim Westwood pleads not guilty to rape and sexual assault
Two police officers and another man seriously hurt in three-vehicle crash
