The theme of fluctuating temperatures will continue during the coming days, as colder air arrives this weekend, only to be replaced by milder conditions again into next week.
March has so far been a month of fluctuating temperatures, due to Britain often lying in a battleground between cold Arctic northerlies and north-westerlies and warm, moist south-westerlies. This see-saw between warm and cold weather will continue over the coming week. For most of the country, the cold air will win over the weekend, with a northerly coming into Scotland today and pushing southwards through the rest of the country on Sunday, resulting in wintry showers for some and a widespread frost early on Monday (gardeners beware, given the growth in spring plants during the recent warm weather). Beyond Monday, it looks likely that the warm air will take over again with predominantly south-westerly winds.
Tonight, cloudy weather with showery rain will persist in southern Scotland, and northern England, but the rain will slowly fizzle out. Meanwhile, an area of persistent rain will spread from the south-west into Wales and the southern half of England, reaching the south-west during the evening and spreading to other parts overnight.
This rain will be heavy in many places and may be accompanied by thunder in some places near the English Channel. Temperatures will fall close to freezing in most parts of Scotland, where there will be wintry showers in the north of Scotland. Still, it will be a mild night in most parts of England, Wales and Northern Ireland, with temperatures in central and southern England falling no lower than around 6 or 7C.
Sunday will be a colder day generally. Cloud and rain will clear the south-east during the morning, although there will be a veil of high cloud which will be slow to clear in most parts of England and Wales and Northern Ireland. Scotland and northern England will have a bright day, with wintry showers in northern Scotland, and these showers will spread southwards through central and eastern Scotland and north-east England during the afternoon. Maximum temperatures in Scotland will typically be between 4 and 6C, and elsewhere highs between 7 and 9C will be typical, but we may see 10 or 11C in the West Country.
A widespread frost will follow on Sunday night, with temperatures falling below freezing for most. However, it looks likely that much of southern and especially south-western England and south Wales will miss the coldest air and see overnight temperatures stay above freezing.
Monday will be cold and sunny with highs generally between 6 and 9C, though again, the south-west will see highs of 10 or 11C. Frost on Monday night is expected to be confined to eastern areas, as warmer air will spread in from the south-west. Tuesday will be a wet and fairly cold day, but the warmer air will become firmly established in most parts of the country by Wednesday, with highs of around 14 to 16C in most parts of England. Changeable weather with rain or showers will accompany this warmer air.
For the longer term, it looks likely that the battle between warm and cold air masses will continue. There is a signal for high pressure to build to the south of Britain, which has the potential to bring more settled and warm weather into the south. Still, there is a lot of uncertainty over how far north the high will get, and it may be that Britain remains in changeable weather on its northern flank.
