Files for Special Purpose Files created to meet specific user requirements. The data in these files include reproductions of data sent on certain dedicated circuits from the Gateway, specific individual collectives or groups of collectives, or specific types of data. NCEP files made available from the Model or data sets of observations used in the model production. The message layout within the file follows a Draft Standard . The code forms are all WMO standard code forms and the codes are documented by WMO Manual 306 .
Some files contain data sets, which have no WMO abbreviated headings, but are in GRIB format.