Reply to Simone in WXHK

thanks reminding me that the number of radiosonde observations is fewer at 12Z than at 00Z. That's a plausible reason that the 00Z runs are more accurate. However, that couldn't be an explanation for the presence of TC in the 00 run but absence in the 12Z run yesterday (In fact there was also a TC just off Luzon in the previous 12Z run).

In principle, the smaller the lead time, the more accurate the EC forecasts. So when the target time is the same, the 10 day forecast issued yesterday at 00Z shouldn't be as accurate as the 9.5 day forecast issued at 12Z yesterday.