The Thames usually begins in the English market town of Cirencester, part of the green and hilly Cotswolds countryside, and flows through the capital, London, and then out into the North Sea.The start of the river has moved 5 miles (8 kilometers) downstream to Somerford Keynes, according to the Rivers Trust, which works across the UK and Ireland. The flow there is weak and only just discernible. “What we’re seeing at the source of the iconic River Thames is sadly emblematic of the situation we’re facing across the country, now and in future,” Christine Colvin, Advocacy and Engagement Director for the Rivers Trust, said in a statement sent to CNN. Southern England recorded its “We could see parts of the UK entering heatwave conditions if the above-average temperatures last for three days or more,” Met Office chief forecaster Steve Willington said. “As the high pressure builds there is very little meaningful rain in the forecast, especially in those areas in the south of England, which experienced very dry conditions last month.”Rebekah Sherwin, deputy chief meteorologist at the Met Office, said that early August sunshine in the UK didn’t have the same heating potential of mid-July, because the sun is lower in the sky and the days are shorter. “Both of these factors suggest that we’re very unlikely to see temperatures peak much above low to mid 30s,” she said. “However, this would still be a hot spell of weather.” On mainland Europe, some countries, including France, are experiencing their third heat wave of the summer and pockets of the continent are in drought.