The extremely dry spring weather in north-western Europe has continued this month, with swathes of the UK, northern France, the Low Countries and Germany receiving just 10% of their normal May rainfall.
The summery conditions, caused by semi-permanent high pressure across the region, are expected to change significantly this week, ending the dry spell for many and delivering much-needed rainfall.
The northern hemisphere’s polar jet stream – a narrow corridor of fast-moving wind that blows approximately 6 miles above Earth’s surface – will intensify in the coming days as it leaves the US and heads into the Atlantic.
During the weekend and early next week, winds of more than 124mph (200km/hr) are forecast, driving in areas of low pressure from the Atlantic. As they reach north-western Europe, the winds will break down areas of high pressure and plunge much of the region into more unsettled weather, with frontal rainfall likely into next week – a welcome event at a time of year that is crucial for the development of crops.
In the run-up to these Atlantic lows, warm and unstable air could trigger showers and thunderstorms in southern France and the Alps, followed by drop in temperature that could bring snow to high altitudes on Friday.
It will also become very unsettled across parts of southern and eastern Africa over the next few days, notably South Africa, southern Mozambique and Madagascar.
Deep areas of low pressure passing eastwards off the southern tip of the continent will generate cold southerly winds and a chance of snowfall over the mountains in South Africa.
Daytime temperatures are likely to be 10-12C below the seasonal norm, such as in Bloemfontein, where it will struggle to top 10C on Wednesday, far below the 21C average in late May.
Gale-force winds exceeding 50mph are expected to trigger dangerous sea conditions along the south-eastern coast of South Africa, whipping waves above 7 metres. Strong winds and high waves will also bombard the southern Mozambique channel between Madagascar and the African mainland, posing a threat to mariners.
