SSEN's Weather Watch for August 2021
The mid-month heatwave in July has helped the UK to its joint fifth warmest July on record according to provisional Met Office figures, with Scotland and Northern Ireland recording their third warmest July, in a month where Northern Ireland also broke its all-time high temperature record, exceeding 31C.
Despite the dry month for western areas in particular, intense summer downpours affected some areas of the country and resulted in some places exceeding twice their average rainfall for July.
The Isle of Wight had its seventh wettest July on record – and its wettest since 1920 – with 115.4mm of rain, while parts of London recorded more than double the average rainfall they’d expect in the month. You can see this rainfall departure from normal, expressed as a percentage, in the Met Office graphic above.
As we look at August there are signals for differences between the first half of the month and the latter part. Low pressure from the nearby Atlantic will influence our weather in the first couple of weeks. This will bring spells of wet and windy weather with some localised downpours and thunderstorms. The temperature levels will likely be below average relative to the 10 year average, so the chances of a heatwave seem very small.
The cool, mostly cloudy and changeable weather pattern will tend to last for about two to three weeks, then we’ll notice some spells of high pressure influencing our weather; this is most likely to occur in the last week or two of August. During this time, most places will be fine and dry with sunny spells, and the temperature levels will be back up to average for the time of year and perhaps above average across Scotland. The wind levels are expected to be below average and some pleasant sea breezes are likely to develop around the coastlines.
The MetDesk map on our main page shows the five day rainfall anomaly starting on 7 August, expressed as a percentage of the climate normal. The blue and purple colour coding highlights above average rainfall for parts of the UK and Ireland during this time. The red shadings show where very dry weather is expected, most notable for the Mediterranean countries.
Looking at August as a whole for Europe, we expect the hottest weather with heatwaves to be concentrated in southeast Europe and the coolest weather relative to average to be across France.
We’ll return in a few weeks to talk about the weather projections for the early autumn.