NCEP/EMC 4KM Gridded Data (GRIB) Stage IV Data

NCEP mosaics the Stage III into a national product (the Stage IV). Hourly, 6-hourly and 24-hourly (accumulated from the 6-hourly) analyses are available.

The Stage IV differs from the NCEP Stage II chiefly in that the NCEP Stage II contains no manual quality control (QC), while the Stage IV benefits from manual QC performed on the Stage III data at the RFCs. As of April 2017 this data includes Alaska and Puerto Rico stations. As of 20 July 2020, data file formats changed from GRIB1 to GRIB2, with similar name changes (e.g., *.grb2).