A clarification has been posted on the website:
Participants may use any data with a timestamp strictly prior or equal to Thursday 00 UTC to initialise their models, regardless of when the data becomes available . The four-day submission window allows participants to process initial data with relatively long latency (e.g. dynamical sub-seasonal forecast data which has a two-day delay) and provides additional time for those with limited computational resource to submit their forecasts.
I’d like to suggest modifying this to earlier or equal to 00 UTC. 00 UTC is an extremely important data collection time, rivaled by only 12 UTC. It would surely improve the forecasts. Indeed, when I asked a question about data in the March 17th meeting, the answer then was that 00 UTC data could be used.
Hello Dale,
Thanks for the comment! Indeed, that was what was meant and it has now been precised on the website (Submitting Forecasts • AI Weather Quest): Participants may use any data with a timestamp strictly prior or equal to Thursday 00 UTC to initialise their models, regardless of when the data becomes available .