The Met Office has recently released its contingency planners’ outlook covering the period for June, July and August, with some sources suggesting this is predicting a summer heatwave.
But what does this early look at what might be in store for the summer actually say?
This summer, long-range weather systems show a slight increase in the chance of high pressure patterns across the UK and with this we see an increase in the chance of above-average temperatures. The point about the seasonal outlook, however, is that it gives us the more likely trends within the coming season. As a result, below-average temperatures, although less likely, remain a realistic possibility. A summer in which temperatures are more frequently slightly above average is the most likely scenario at this stage, but the fact that warmer and cooler outcomes than this are possible is a feature of the kind of information we are dealing with in long-range forecasting .
The outlook also gives an increase in the likelihood of drier-than-average conditions. The summer period is one of the driest times of year across the UK; with rainfall coming in short, occasionally intense, showery rain affecting some places but leaving nearby locations dry. On balance, below-average rainfall is more likely than above-average rainfall.
Jeff Knight, manager of modelling of climate variability at the Met Office, said: “Our long term outlook for the summer suggests a greater chance that temperatures will be above average, than below average. However, our outlook certainly doesn’t imply a 3-month heatwave. As always with our climate there are likely to be large day-to-day and week-to-week variations the period. This is an outlook for the general themes over the summer and does not give detailed guidance on events like heatwaves.”
Perception of good weather is often more dependent on rainfall amounts than temperature. For example, even though the UK had a run of ‘poor’ summers between 2007 and 2012, half of these summers had temperatures above the long-term average. The long-range outlook is primarily aimed at giving government departments and agencies a forward view of potential weather hazards in the months ahead. As such, it is a risk assessment rather than a more traditional type of forecast of what the weather is going to be. Using evidence from global weather observations and computer forecast systems, we can estimate the chances of different types of UK weather and how they could be modified in the coming months.
When you look back at the average mean temperature for the UK both 2017 and 2016 saw temperatures above the 13 C long-term average, with 14.5 C and 13.9 C respectively, and for summer as a whole the mean temperature was 14.7 C in 2017 and 14.9 C in 2016, both also above the long-term summer average of 14.4 C
You can find the current forecast on our website or mobile App or follow us on Twitter or Facebook, and as always our forecasts from one day to one month ahead can be relied upon to provide the best guidance on what to expect whatever weather patterns emerge.