Thursday 4th September
The high of 19.1C on Wednesday mid-morning, rather than late afternoon, indicates that we had little sunshine to boost the temperature thanks to the predominantly cloudy skies. The first precipitation came just after 11.00 with heavy showers noted at 12.45, 13.15 and then later at 14.35 when the rate of rainfall was equal to 155.7mm per hour. It was the wettest day since 24th November when 36.6mm was recorded. The total rainfall for the past twenty-four hours amounted to 20.6mm. As on previous nights the cloud cover meant another mild night with the minimum of 12.1C logged at 04.38 being 3.4C above average.

The depression just off the southwest coast of Cornwall began to move northwards overnight of Wednesday into Thursday and threw an extensive arc of cloud over the UK driving a wide band a rain within it. I would estimate from the back track of radar that the cloud built up from around 04.00, which would tie in with the minimum temperature at 04.38. This arc produced heavy rain starting just before 06.00 that was heavy for a period. Behind the main weather front are a rash of heavy showers that are likely to ease and clear around midday.

The jet stream will arc above the UK briefly on Friday and Saturday that will allow a temporary ridge of high pressure to form over the UK with a couple of fine days ahead before it turns south of the UK again from Monday with more unsettled weather to follow.

We look west over the Atlantic for disturbed weather driven along by the jet stream. The hurricane website currently shows an area of showers and thunderstorms associated with a tropical wave located over the eastern Atlantic just to the west of the Cape Verde Island where these disturbances begin to form. At the moment a watch is being kept on this development as it is forecast to have an 80% chance of forming a cyclone that could eventually be whisked across to the UK in a week or so, having travelled in an arc to the north of the Caribbean before heading northeastwards.