Wednesday 22nd July
The temperatures by day and night continue to ease upwards again that on Tuesday resulted in a maximum of 26.4C at 18.03. Variable thin, high cloud mid-afternoon limited the rise at that time before strong sunshine late afternoon produced the peak, which was 3.5C above average. The overnight minimum was also above average at +1.5C with a low of 13.5C at 05.31, just after sunrise in Marlborough at 05.16.
Wednesday brought a sunny start through thin high cloud that restricted the initial increase in temperature, although by 08.00 the thermometer had risen to 16.6C.
Although the high pressure has begun to drift away it will continue to dominate our weather for a few more days producing strong sunshine and temperatures well above average, in fact continuing to ease upwards. The direction of the breeze will back a few degrees to have a more northerly component, but no let up in the heat. By Friday, as the anticyclone regresses westwards, a low pressure system will edge closer from the north.
After the brief cooler period last Sunday/Monday, the ground has begun to warm up again with temperatures of 17.2C, 19.5C and 21.4C over the past three days respectively. measured at a depth of 5cm 08.00 daily.
Likewise maxima over the last three days have been 23.1C, 25.8C and 26.4C respectively.
The equivalent loss of rainfall due to evaporation from ground sources continues high but reduced from figures at the beginning of the month due to lack of rain and the ground getting progressively drier, whilst plants struggle to stay alive let alone put on significant growth. Earlier in the month daily evaporation was in excess of 6mm but now has dropped away to between 4mm and 5mm daily. The month’s loss of equivalent rainfall now totals 111.6m compared against the paltry 0.2mm of drizzle on the 1st. We have now endured 20 consecutive dry days with no rain in sight at the moment. A weather front might develop over the weekend but currently it is thought very unlikely to produce any precipitation.
Sarah Keith-Lucas
Lead weather presenter
Summer so far has been exceptionally hot and dry across much of the UK, with three widespread heatwaves and the longest run of dry days in central England since 1995.
England, Wales and eastern Scotland have been the driest areas over recent weeks, and this follows a very dry spring in similar regions.
Very little rainfall is forecast through this week for most places, with only a few light showers possible, mainly close to coasts.
As we head through the second half of summer, what are the longer range predictions, and are we heading into drought for the second summer in a row?
How dry has it been?
Rainfall so far this summer has been below average across the UK as a whole, but there has been large regional contrast.
Up to the middle of summer – 15 July – parts of eastern and north-eastern England had received just 26% of their total expected summer rainfall. Areas of northern and western Scotland had more than average for the first half of the summer, though.
For central England it has been the longest dry spell since 1995. Wisley in Surrey has seen 33 consecutive dry days.
Comparisons are being made with last summer, when drought was declared across much of England, Wales and eastern Scotland. It officially ended just four months ago.
This year, drought has not developed as quickly because heavy rainfall recharged our aquifers, rivers and reservoirs during a very wet autumn and winter.
However, the UK Centre for Ecology and Hydrology says flash droughts with a sudden transition between wet and dry conditions are “likely to happen more often, and be more intense”.