As promised, we are sharing the Ranked Probability Skill Scores (RPSSs) for dynamical forecast models. These scores will be updated weekly, throughout the training period, and the latest data is available in the attached file.
JJA25_DYNforecast_evaluation.xls.zip (20.7 KB)
Currently skill scores are provided for forecasts initialised up to week 5 (12th June 2025) of the testing JJA period.
Dynamical forecast data has been downloaded from the WMO lead centre for the sub-seasonal multi-model ensemble database . We are providing RPSSs for six dynamical models. For all models, except WASHINGTON, the reforecast period spans 2006 to 2016. Details regarding the selection of reforecasts and the configuration of each dynamical model can be found here.
The attached file is organised by forecast window, forecast variable and skill score type:
· fcwin1 = Week 3 forecast
· fcwin2 = Week 4 forecast
· tas , mslp, pr = Forecast variables
· period = period-aggregated RPSS.
· weekly = single weekly RPSS.
You can now evaluate your own forecast and compare it directly to dynamical forecast skill scores. Detailed guidance on forecast self-evaluation can be found in ReadTheDocs Python documentation. 
If you encounter any issues or have questions regarding the self-evaluation process, feel free to reach out - we’re here to help!