After some changeable weather for many over the past week or so high pressure is now building across the southern half of the UK.
This will bring settled, dry, sunny, weather for many in the southern and eastern parts of the UK. Temperatures will slowly increase day on day here. Further north the unsettled conditions are more likely to predominate with some showers possible.
Met Office Deputy Chief Meteorologist Rebekah Sherwin, said; “The influence of the high pressure is likely to continue across southern areas into the second week of July and at times could be more widespread.
“Temperatures are expected to be widely above average, especially across the south,with some areas seeing maxima in the high 20s, locally 30 Celsius by this weekend. Beyond that, the forecast becomes more uncertain and, while it may well continue warm, the extent, magnitude and duration of these above-average temperatures are not clear at this stage and won’t be known until closer to the time.”
High pressure influence
There is a consistent signal for high pressure to continue bringing settled conditions to the South and East of the UK. High pressure in the summer often brings fine, warm weather. It can lead to long warm sunny days and prolonged dry periods and in some situations, this can cause heatwaves. When looking a week or two into the future forecasters, however, focus on general weather trends and themes.
A forecast is created by observing the current state of the atmosphere, these observations are used to calculate how this state will evolve in time using a numerical weather prediction computer model.
These models are run several times a day and it is important to note an individual model run forecasting weather over the coming days or weeks is not a good indication of a fully formed weather forecast. There is simply too much uncertainty to follow single solutions confidently and numerous model runs need to be considered.
At longer lead times forecasters need to look at the general themes indicated by a range of models. This applies not only to specific temperatures on a date two weeks away but also things like rain or snow event.
Climate change has already influenced the likelihood of temperature extremes in the UK. In a recent study we found that the likelihood of extremely hot days in the UK has been increasing and will continue to do so during the course of the century, with the most extreme temperatures expected to be observed in the south east of England.