Long-range weather prediction
Predicting how the weather will behave over the coming hours, days, weeks and months is a complex undertaking. Each timescale presents its own challenges. In an ideal world, everyone would like to know exactly what the weather will do so we can make definite plans. Nature, however, doesn't work like that. When looking at forecasts beyond five days into the future the chaotic nature of the atmosphere starts to come into play - small events currently over the Atlantic can have potentially significant impacts on our weather in the UK in several days' time. Therefore whilst we can still forecast the general feel of the weather to a relatively high level of accuracy using our ensemble models, it becomes harder to offer local detail to as high a level of accuracy as our shorter range forecasts. For this reason our forecasts for 5 days and beyond are written on the scale of the UK as a whole.
Medium range (6 - 15 days)
Medium-range weather forecasts cover anything from around three to 10-days ahead. The UK medium-range outlook is covered in the five-day location and map-based forecasts as well as the meteorologist written forecasts. The 6-10 day text forecasts provide a broad description of the weather likely to be affecting the UK, including significant changes in the type of weather. It also provides a risk assessment of severe weather, such as heavy rainfall, severe gales or an extended period of high or low temperatures.
Extended-range (10 - 30 days)
Extended-range weather forecasts cover periods between 10 and 30-days ahead. This covers the end of our 6-15 day text forecast and the whole of our 16-30 day text forecast. If you are after a 14-day weather forecast then our 6-15 day text forecast will provide a broad description of the weather likely to be affecting the UK. The 16-30 day text outlook (which is updated on a daily basis) provides an indication of how the weather might change, or be different from normal, (i.e. warmer, colder, wetter, drier) across the whole UK. Met Office meteorologists consider output from a range of weather models when writing these forecasts. These models include those from the Met Office as well as models from other global forecasting centres such as the European Centre for Medium Range Weather Forecasts ( ECMWF).