Hi all,
As we continue with the testing phase of the AI Weather Quest, we wanted to highlight ECMWF’s open data catalogue. Here you have access the most recent IFS and AIFS operational forecasts. Data is available for the previous three days and, most of the time, becomes accessible at 0700 UTC. Timestep 0 can be treated as ECMWF’s analysis.
You may also choose to initialise your models using dynamical sub-seasonal forecast data. Such data is available via ECMWF-hosted sub-seasonal forecast portal.
As written in today’s email to participants, we are currently in Week 9 of the JJA testing phase, which is the last week in which a submission will complete a full cycle of evaluation within the test phase 
We encourage all teams intending to compete to test their forecast submission workflows now.
Testing your submission ensures compatibility with the evaluation system and helps avoid errors during the competition. We particularly recommend practising automated submissions, as missed weeks during the competition will disqualify teams from period-aggregated RPSS (Ranked Probability Skill Score) evaluation.
Good luck,
Josh