ENS is an ensemble of 51 forecasts with a horizontal resolution of around 9 km. It comprises one control forecast (CNTL) plus 50 forecasts each with slightly altered initial conditions and slightly altered model physics.
ENS is a probabilistic forecast system 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.
from: https://www.ecmwf.int/en/forecasts/documentation-and-support/medium-range-forecasts
TODO:
Resolves #29