Sunday 9th August
The heat continued to build on Saturday, eventually peaking at 27.2C, which was just above the heatwave threshold. The maximum was logged early in the afternoon at 14.14 as just before 14.00 cloud began to drift across then thicken as the afternoon progressed thus limiting any further rise in temperature. The past night was not quite so chilly as the previous two nights, dropping to a minimum of 8.6C at 06.08, which was 3.2C below average. The sun’s strength was very limited after sunrise, due to considerable cloud cover, hence the much later time when the thermometer reached the minimum.
Due to the cloud cover the thermometer had only reached a temperature of 14.0C by 08.00 on Sunday, making it the second coolest start to a new day at that time, Friday read 13.7C. The back track of the cloud radar showed bands of cloud arriving from the east just before 06.00. The cloud will be variable with sunny periods this morning, that are likely to intensify and lengthen after around 13.00, which will likely push the temperature very high again late afternoon.
The depression between Iceland and Norway will attempt to push a cold front down across the country overnight, sadly no rainfall within it, that will slowly peter out and leave us with perhaps a cloudy start to Monday. The air behind the weather front, as the name indicates, will mean a less hot day on Monday. By Tuesday the high-pressure will be a little further to the east that will once again push hot Continental air across the country, which will mean temperatures will be well above the heatwave threshold, likely 30+C.
I regularly monitor the Thames Water website for date on the Groundwater situation and on local rivers. All the local Groundwater boreholes say the State of all eight are ‘Normal’ with the close by Draycot borehole, near Chiseldon, stating the Trend is ‘Falling’, all the other seven show the trend is ‘Steady’. However, I was concerned yesterday when looking at the river data that the depth gauge for the River Og at Poulton Farm registered ‘Height’ 0m, ‘Trend’ ‘Steady’ and ‘State’ ‘Low’ and that it had registered the height of 0m at 03.30 on August 4th. I wandered down to the river by Poulton Bridge fearing the site of a dry river bed, but thankfully found that in fact it had not dried up, however the average depth must have been around 2/3cm and it was flowing so very slowly.