Winds gusting at speeds of up to 70mph are forecast to sweep across the UK.
The wet and wintry weather will bring a chilly start to Wednesday with sunshine and showers that may turn heavy and thundery.
The Met Office has issued yellow weather warnings for wind. One covers Northern Ireland, while the other is in force for the entire south coast of England, much of the South East, most of the South West and a large part of southern and western Wales.
The warnings, which urge the public to be wary of "likely" travel disruption and possible power cuts, are in place until 8pm on Wednesday.
Strong winds with severe coastal gales could hit the south and west, with the forecaster saying:
"West or north-west winds are expected to increase during Wednesday morning, then remain strong for much of the day.
"Gusts of 40-50mph are expected widely within the warning area, but some coastal areas, especially in parts of south and west Wales and Cornwall, could see gusts above 60-70mph during Wednesday morning.
"Outbreaks of heavy rain or showers will accompany the strong winds."
A blast of cold air into Wednesday morning could even see an "increasing risk of snow over the higher ground for parts of the UK, especially in the north", the forecaster added.
People have been warned to expect difficult travel conditions.
Parts of Northern Ireland may have to deal with gusts of 45-50mph at times inland and 60mph along northern coasts by Wednesday afternoon.
The wild weather will hit Northern Ireland while the US president, Joe Biden, is visiting to mark the 25th anniversary of the Good Friday Agreement.
The strong winds, low temperatures and heavy rain or showers being felt in many places are down to an Atlantic low-pressure system slowly moving eastwards across the UK.
Met Office chief meteorologist Matthew Lehnert said snow is likely to fall over parts of upland Scotland overnight into Wednesday.
He added:
"Some disruption due to strong winds is likely on Wednesday, especially in southern and western areas, as well as the potential for heavy rainfall and even some snow, though the latter probably confined to high ground in the north.
"It will be another cool day with temperatures of 7C to 10C in the west, with 11C to 13C possible in the southeast. However, it will feel colder in the strong winds."
The grip of the unsettled conditions is expected to last for the rest of the week, with sunshine and heavy showers for many on Thursday and persistent rain in the south on Friday.
It will then become drier and brighter into the weekend, while temperatures may start to rise next week, according to forecasters.
(c) Sky News 2023: UK weather: Winds of up to 70mph to hit Northern Ireland, Wales and souther
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