The NOMAD GFS system creates files on a 4 times a day cycle.
The file naming specification is:
cc is the model cycle runtime (i.e. 00, 06, 12, 18) xxx is the forecast hour of product from 00 - 384 YYYYMMDD is the Year, Month and Day
'cc' is stated as the cycle run time, so it is reasonable to assume that that is the time the processing begins.
How do I know what time the cycle actually is finished so that the grib2 files can be downloaded?