From freeze to thaw – end of cold spell in sight
After two weeks of freezing temperatures, heavy snow and ice, an end is finally in sight to the cold weather that has had a firm grip on the UK.
From this weekend onwards, there is going to be a huge change in the weather pattern, with high pressure being eroded by vigorous areas of low pressure sweeping in off the Atlantic – bringing milder, wetter and windier weather for all.
The return to stormy weather is being fuelled by a powerful jet stream, racing across the Atlantic, high up in the atmosphere at more than 200mph.
This train of relative warmth and moisture will push back the cold air to central and eastern parts of Europe, allowing temperature to rise across the UK, with a thaw setting in this weekend.
One last spell of significant snow
As often happens when a cold spell comes to an end, there will be one last spell of significant snow as the milder, moister air moves in from the west and collides with the cold air that has been with us for the past fortnight.
This is expected to happen on Friday as strong winds and heavy rain move in from the west, readily giving a spell of heavy, wet snow – especially from the Midlands northwards.
At low levels, there could temporarily be another 2-10cm, with 15cm or more across the higher hills and mountains, drifting around given the strong wind.
In southern and western areas, the snow is expected to quickly turn to rain as less cold air arrives, but some northern and eastern areas could have 6-9 hours of snow before this happens.
Then the thaw begins
Saturday will see a window of quieter weather with a temporary ridge of high pressure. Even though the weather computer models suggest that there could be some sunshine, I think they are being optimistic.
With the ground still covered in ice and snow, warmer air moving over it will cool and condense, leading to low cloud, mist and some fog, with sunshine not guaranteed.
Saturday night will see another area of heavy rain and strong winds sweep in from the west, with each subsequent push of milder air increasing the rate at which lying snow thaws.
In fact, by Tuesday, temperatures across a large swathe of the UK could reach 8-13C, thanks to a south westerly wind bringing air all the way from the Azores.
Localised flood risk
During the next five days, not only will there be heavy rain falling, but also thawing snow. This will mean that two sources of water will be flowing into the rivers, potentially causing them to rise rapidly and give a flood risk.
The Environment Agency is already warning of a low risk of flooding across south west England on Friday due to the reasons I’ve outlined above.