About a month ago, the GFS was upgraded. Among other things (like making parallel GFS data available), the upgrade notice said:
- Include hourly forecasts out to 120 hr
Now, this seemed strange to me. The NAM (which goes out to only 84 hours) outputs forecasts every 3 hours. Indeed, with the exception of very short-range models like the RAP, HRRR, and SREF (WRF), no models output data hourly. Since the NAM is intended fine-tuning shorter-range forecasts, and the GFS for longer-range patterns, why did the NWS upgrade the GFS to hourly output out to hour 120?