BBC monthly outlook
Warmer than normal and drier than of late
Wednesday 21 August – Sunday 25 August
Becoming warmer and less unsettled for many
A couple of unsettled days to come before the weather starts to settle down for many parts of the country as we head towards the weekend. Most places will have a dry morning on Wednesday, but a deep Atlantic low pressure system will push showers and outbreaks of rain into some north-western parts of the country, where it will also become rather breezy. Wednesday afternoon will see more widespread and occasionally heavy rain moving across Scotland and Northern Ireland into northern England and north Wales. Central, southern and eastern parts of the country should remain dry but will become cloudier and breezier.
Thursday will be a changeable day, with showers and longer spells of rain for many areas. Scotland and Northern Ireland are likely to be the wettest parts of the country on Thursday with south east England most likely to be driest. It will be another breezy day for all areas. Friday should see the start of a spell of drier, calmer and warmer weather. High pressure will keep most of England and Wales dry with sunny spells and light winds. Scotland and Northern Ireland, will probably see showers or rain, particularly northern Scotland, but there is a good chance of some drier and brighter spells. The weekend should also see a lot of dry weather across the UK with just the chance of a few showers. It looks as though it will be warm for the time of year across many areas too. For example, temperatures could reach the mid-twenties Celsius in many areas on Saturday, perhaps a little warmer in the South East.
Monday 26 August – Sunday 1 September
Warm, even hot for a time. Chance of rain later
Most of next week is expected to be warmer than normal for the time of year as broadly southerly winds bring continental air to most parts of the UK next week. The first half of the week will probably be warmer than the second half of the week, and there is a chance we will see temperatures rising significantly above normal for a time. By coincidence, this would fit into the pattern of the summer so far, which has seen spells of very warm or hot weather at the end of each June and July.
There should be a good deal of dry weather too, although with winds coming from the south there will be the chance of some heavy and thundery showers moving in from the continent. Thunderstorms are probably more likely later in the week, when we see more of a chance of weather systems starting to move in from the west. The main alternative to our expected pattern for next week is for low pressure to be more of a feature to the east of the UK, close to or over Scandinavia. If this happens, then cooler west to north-westerly winds would be more likely, so it wouldn't be as warm as we expect it to be, although the cooler weather may only be a feature later in the week.
Monday 2 September – Sunday 15 September
Unsettled at first but drier towards mid-month
Low pressure is expected to be the main feature across northern Europe at first, this expected to bring more unsettled and cooler weather to the UK. The first full week of September is likely to be a bit wetter and windier than normal for the time of year. There are signs of a change of pattern as we move towards mid-month. The most likely scenario is for the low pressure affecting northern Europe to be replaced by high pressure. This would bring drier and calmer weather to the UK, and it should become warmer too, although it is too early to say how much warmer than normal it will become.
One thing we have seen over recent weeks is that weather patterns have been a little slower to change than expected. As a result, there is a chance that the spell of unsettled weather could last a little longer into September than we expect it to. That would also mean that the drier and calmer weather hangs on a bit longer around the middle of the month, reducing the chances of another spell of wet and windy weather to around a 30% chance.
We should be able to give a bit more detail on the chances very warm or hot weather next week.