The Met Office forecast: "The rain will turn quickly to snow on hills, then also to low levels in places".
Around 1cm (0.4 in) to 3cm (1.2in) of snow is expected to accumulate "quite widely", the Met Office said, with the possibility of 5cm (1.9in) to 10cm (3.9in) falling on higher ground.
Strong northerly winds with gusts of up to 70mph also hit the west and east coasts.
Four separate yellow weather warnings have been issued which cover most of the UK.
In northern England, temperatures could plummet to around -3C (26.6F), with some areas in the south "hovering around zero". By the afternoon, there will be a low-pressure system moving along the English Channel and, wrapped around that, an area of rain.
Despite the low figures, eastern Scotland is set for sunshine this afternoon, whereas western parts of Scotland will still grapple with snow showers.
Past year saw several inches of snow fall in North Somerset, causing widespread problems - schools closed while the public transport system also ground to a halt.
The warning is in place between 9am on Tuesday, January 29 until around midday on Wednesday.
Mr Petagna said London could see snow showers - but added they were unlikely to settle.
However, significant accumulations of snow are not expected to be widespread at lower levels.
"If you are travelling you should ensure you and your vehicle are adequately prepared for the conditions making sure you have sufficient fuel and supplies such as warm clothing, food and water in the event you are delayed for several hours".