Wales has seen nearly a whole month without rain, and while it has been sunny temperatures have not been particularly high. This has meant that an official heatwave has not been declared - until now.
The area of high pressure which has been responsible for the last couple of weeks of settled weather for much of the UK will drift away towards Scandinavia, allowing a plume of warmer, humid air from the south to influence the weekend weather for much of the UK.
Temperatures began to climb on Friday with a high of 30°C recorded in Porthmadog, and despite the threat of thunderstorms over this weekend the highs are expected to last into next week. BBC Wales weather presenter Derek Brockway says this meant that the heatwave criteria "could be met in some parts of the country".
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He added that for most of Wales, there will be "at least three consecutive days with maximum temperatures reaching or exceeding 25°C. 26°C or higher in the southeast".
The Met Office definition of a heatwave says: "A heatwave is an extended period of hot weather relative to the expected conditions of the area at that time of year, which may be accompanied by high humidity. A UK heatwave threshold is met when a location records a period of at least three consecutive days with daily maximum temperatures meeting or exceeding the heatwave temperature threshold. The threshold varies by UK county."
This is the map they use:
The Met Office outlook for Wales for Monday to Wednesday says: "Remaining warm with a continued risk of heavy showers, perhaps thundery at times on Monday. Rather humid, perhaps feeling uncomfortable overnight. Fine and sunny for most on Tuesday and Wednesday."
This is the Met Office weather map for Tuesday (June 13):
There is not a heat warning in Wales, but the UK Health Security Agency, which covers the healthcare sector in England, has issued a Heat Health Alert.
Dr Agostinho Sousa, head of extreme events and health protection said: “In the coming days we are likely to experience our first sustained period of hot weather of the year so far, so it’s important that everyone ensures they keep hydrated and cool while enjoying the sun.
“Forecasted temperatures this week will primarily impact those over the age of 65 or those with pre-existing health conditions such as respiratory and cardiovascular diseases.
“If you have friends, family or neighbours who you know are more vulnerable to the effects of hot weather, it is important you check in on them and ensure they are aware of the forecasts and are following the necessary advice.”
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