The June heatwave in the UK

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  • Palm trees by the beach front in Weymouth and cooling down with ice cream in Lyme Regis.

  • The June heatwave in the UK
    24.06.2017 17:23

     

    What is a heatwave?

    There is no universal definition for a heatwave, however according to The World Meteorological Organisation a heatwave is defined as five or more consecutive days whereby the maximum temperature is 5C above the average.


    Five days of temperatures equal to or greater than 30C were recorded in the UK this week (17th-21st June). The highest temperature was reached at Heathrow, here 34.5C was reached. This made it the hottest day of the year, so far and also resulted in the hottest June day since 1976. The record is 35.6C in Southampton, June 1976. There have also been some impressive contrasts between minimum temperatures, one particular morning at 6am a chilly 0C was recorded at Tulloch Bridge, Scotland…meanwhile 19.4C was recorded at Mumbles, North Wales, that’s an impressive nearly 20C difference.

    Why did this heatwave occur?

    High pressure that originated from the Azores persisted over the UK, high pressure leads to largely dry conditions and the fact that the air originated from the Azores meant that our air came from a tropical maritime airmass. Another reason is the jetstream was located further north, which also allowed air to feed in from southerly latitudes, including places like Iberia.

    Strong sunshine led to high or very high UV levels, and pollen levels also reached high or very high levels too.  Overnight, it was muggy, particularly in the south, resulting in an uncomfortable nights sleep for some. Some areas of the UK were hotter than our European holiday destinations for example Ibiza, Istanbul and Rome.

    A change to unsettled conditions this week

    They say all good things must come to an end, and as usual in the UK showers or longer spells of rain are never far away...as of course us Brits are infamously known for our cloud and rain. A change in the weather has occurred as high pressure slipped away into the North Sea and was replaced by lower pressure. This has allowed weather fronts to move into the UK, hence why unsettled and fresher conditions are now in the forecast, with temperatures returning closer to average for this time of year. We expect some unseasonably high rainfall accumulations this coming working week for some places, so make sure you keep that umbrella handy!

    By: Sabrina Lee