Nick Grahame, Chief Forecaster at the Met Office, talks us through the forecasting challenges this weekend.
Sometimes the atmosphere can provide a real challenge for forecasters even in the shorter range. Take for example this weekend – there’s a low pressure system over the west Atlantic and, on the face of it, appears to be heading our way. However, as it approaches our shores on Saturday night, forecast models are suggesting a large degree of uncertainty in terms of where it goes next. Some continue to bring it towards the southwest on Sunday, which would result in a rather miserable day for many southern areas. The other scenario though is for the low pressure system to stall and stay well away from us. If that happened then southern areas would stay fine and bright. In these situations, it is really important for forecasters and broadcasters to find a meaningful way to talk about the most likely outcome but then to also express the uncertainty. This is important for those who are planning events etc (it is Fathers Day on Sunday of course).
So why is there so much uncertainty?
Over the weekend, we are going to see some very complex patterns developing over the Atlantic which will ultimately determine where the low will track. For those who like technical speak, it’s called a trough disruption and forecasting this phenomenon continues to be a major challenge to both computer models and humans alike. So the best thing to do is keep up to date with the forecast to get the latest on how things are expected to develop over this weekend.