In sports betting, probability forecasts may not be published as such, but may underlie bookmakers' activities in setting pay-off rates, etc.
The probability information is typically derived by using several numerical model runs, with slightly varying initial conditions.
EPS does not produce a full forecast probability distribution over all possible events, and it is possible to use purely statistical or hybrid statistical/numerical methods to do this.
In practice, forecasters try to guess a small number of perturbations (usually around 20) that they deem are most likely to yield distinct weather outcomes.
Canada has been one of the first countries to broadcast their probabilistic forecast by giving chances of precipitation in percentages.
These probabilities provide a broader assessment of the risk attached to their central forecasts and are influenced by unexpected or extreme shifts in key variables.
This was discussed in a 2000 research paper by Anthony Garratt, Kevin Lee, M. Hashem Pesaran and Yongcheol Shin entitled 'Forecast Uncertainties in Macroeconometric Modelling: An Application to the UK Economy'.
[12] If an ensemble-based approach is being used, the individual ensemble members need first to be combined and expressed in terms of a probability distribution.