High pressure has been building from the south allowing warm air from Spain and France to move across the UK, which means, we've got a sunny weekend ahead.
Laura Tobin tells us more in her blog...
Are we having a heat wave?
While many papers have been reporting that we’re having a heat wave, that temperatures will reach 80F and we will be hotter than Mediterranean destinations like Corfu, this, as usual is an exaggeration. I've been looking online and the technical definition of a heat wave is that while we will be warmer than Corfu, we aren’t technically having a heat wave nor will we reach 80 degrees (26 degrees Celsius). However it’ll be beautiful to start the weekend with summer like warmth and blue skies giving the warmest spell of weather so far this year but it won’t last for everyone.
Why is it not a heat wave?
A heat wave is defined as ‘five days when the temperatures is five degrees above average or more.’ The average temperature for Aberdeen in Mid May is 13 degrees and 17 in London. This means we’d need Aberdeen to be 18 degrees for five days and London 22 degrees for five days; we will reach or even break these temperatures on one or two days but not five consecutive days.
Why is it so warm?
The jet stream is always responsible for shifts in our weather, this week it has moved to our north along with the wet and windy weather. High pressure has been building from the south allowing warm air from Spain and France to move across the UK.
How warm will it be?
Friday is when we will see most widespread warmth and sunshine across the UK with 19 degrees in Edinburgh, Belfast and Cardiff and a top temperature of 23 or 24 degrees in or around London. This would make it the warmest day of the year so far (previously 22 degrees in Scotland on end of April). The last time we reached 24 degrees was 24th September last year. This would make us hotter than Corfu, Majorca and Ibiza.
Will it last all weekend?
Not for everyone. On Saturday a weather front will move intoScotland and Northern Ireland and slowly slip into northern England and Wales by Sunday evening.
Saturday will be a gorgeous dry and sunny start for everyone. Through the morning Scotland and Northern Ireland will become increasingly cloudy with outbreaks of patchy rain, still mild with temperatures up to 18 degrees. England and Wales will have unbroken blue skies followed by patchy fair weather cloud. Winds will be light allowing the temperature to rocket up to 20 degrees in Manchester and Cardiff and possibly 25 degrees in the southeast.
Sunday will be very similar. However a cloudier, wetter,windier and cooler day for Scotland and Northern Ireland with 15 degrees at best. England and Wales, another warm one, mostly dry, just a small chance of the odd shower and clouding over from the north through the evening.
Beware of rising pollen and UV
Pollen has been low recently due to the rain and strong winds. The sunshine means that hay fever sufferers have been suffering more this week and will rise further into the weekend. In the sunshine Birch and grass pollen will be moderate across most of the UK and will drop to low in rainfall. The prolonged sunshine also means that UV levels are rising too. Low in the far north, moderate for many and high in the far southwest. If you are out for any length of time you will need to wear sun cream. Plus don’t forget the sun is as strong now as it is in early August.
Will the sunshine last into next week?
Unfortunately not, the weather front that will bring rain into Scotland and Northern Ireland over the weekend will spread across the rest of the country through Monday. So we loose the sunshine but not the warmth. The humidity will rise mid week and we are likely to see a ‘thundery breakdown’.This means thunderstorms across France will head our way giving torrential showers and thunderstorms. The outlook remains unsettled but still mild.