The Met Office has been looking into the possibility of a "beast from the east" weather system striking the UK as temperatures have started to drop again. Cold weather is expected for much of the rest of this week and there is a possibility of snow in some parts of the country by Wednesday next week.
Parts of Mid Wales hit -1C overnight, with temperatures expected to drop to 0C across the country in the early hours of Friday morning. Looking at the Met Office weather map, temperatures are forecast to be around freezing in parts of the country on Sunday night.
But the real cold spell is expected to hit later in March, and the outlook from March 9 to March 23 says: "In this period, spells of rain or snow, are more likely than earlier in the month, with a low chance that some wintry episodes could be disruptive, though northwestern areas most likely to see the driest conditions. Winds could often be from a northerly or easterly direction, and temperatures are more likely to be below-average than above-average overall, but later in the month, colder air will be fighting against a strengthening sun."
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These low temperatures could be brought on by the phenomenon of Sudden Stratospheric Warming (SSW). Maps from WXCharts show that the mercury could drop to -10C in Scotland as well as there being sub zero temperatures across the country on March 5.
And there are could be widespread flurries of snow that could be more than 30 centimetres deep in central and northern Scotland. The Met Office has confirmed that there has been an SSW where the effects can take three weeks to impact on the UK and that colder weather is more likely.
Met Office meteorologist Aidan McGivern explained: We're not expecting any impacts from the sudden stratospheric warming to take place for the UK until around the first week of March. Also, there's another thing happening on the other side of the world, an uptick in thundery activity over the Pacific and that can lead to perturbations in the jet stream and that can lead to a reinforcement of large areas of high pressure. And so the impact of those two outside factors are looking increasingly likely to affect our weather from next weekend, from the fourth, fifth of March onwards.”
But crucially for the UK's weather is the position of that high pressure. Aidan said there is a 31% possibility of the high pressure staying almost where it is now - just to the north west of the UK.
This would keep things roughly as they are now and not particularly cold. But there is another scenario appearing on the computer models, also with a 31% possibility.
This scenario pushes the high pressure towards Greenland, allowing much colder northerly winds to arrive. Weather charts show the precipitation which with the colder northerly winds could end up with sleet, snow, hail and so on.
He added: “And those are the scenarios that start to play out as we get into the following weekend and the week beyond. With the sudden stratospheric warming and with those thunderstorms in the Pacific helping to reinforce high pressure close to the UK.”
But he stressed the computer models differ on where the high pressure is, if it’s closer to the UK things will stay largely as they are. If it’s further north it could bring those northerly winds and colder weather.
The outlook in Wales
Today's weather forecast, from the Met Office:
A much chillier feel to the morning than of late. Some cloud lingering during the morning, possibly some light rain too, but this eventually clearing leaving sunny spells for the rest of the day. Feeling cold, particularly around breezier coastlines. Maximum temperature 9 °C.
Tonight:
A fine evening with cloud thickening overnight keeping the night largely frost-free. Staying mostly dry but a risk of some light rain in the early hours. Staying breezy around coasts. Minimum temperature 0 °C.
Friday:
A cloudy picture to start with spots of rain around. Slowly brightening up through the day with some brighter spells by late afternoon. Another chilly day especially in coastal breeze. Maximum temperature 12 °C.
Outlook for Saturday to Monday:
Remaining settled over the weekend and into Monday, but often cloudy with patchy fog possible. Risk of overnight frost where skies clear, and feeling much chiller overall than of late.
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