Forecasts up to 15 days ahead
Our physics-based (classical) medium-range forecasting system consists of an ensemble of model forecasts (ENS) which together give detailed information about the evolution of weather up to 15 days ahead. Forecasts are run from initial conditions valid at 00 and 12 UTC, and there are also shorter supplementary forecasts run from 06 and 18 UTC. Forecasts become available to users several hours after these times.
Medium-range ensemble forecasts (ENS)
The ENS is an ensemble of 51 forecasts, all having a horizontal resolution of around 9 km. It comprises one control forecast (CNTL), plus 50 other forecasts that each have slightly altered initial conditions and slightly altered model physics.
Our medium-range ensemble forecasts are probabilistic forecasts designed to indicate the range of possible weather conditions out to 15 days ahead, including the probability of occurrence of particular events (such as high winds or heavy rain). The greater the spread of results across the ensemble, the greater the uncertainty in the forecast.
Find out more about how ENS is produced: ENS overview, ENS rationale and construction.
Find out more about model configurations.
A wide range of forecast variables
As well as atmospheric conditions, our Earth system modelling approach provides forecasts of a range of surface and ocean variables, such as snow depth, soil moisture and ocean waves.