PDSEXT 

    PDSEXT is a logical flag which only becomes applicable when a PDS
    extension exists in the GRIB message. 

	YES or NO

    If PDSEXT is YES, then a sequence of characters specifying the extension 
    information will be appended onto the standard GEMPAK parameter name.  
    If PDSEXT is NO, then the append will not be performed. For instance, if 
    the parameter is HGHT and the PDS extension is an ensemble extension 
    indicating that this particular height field is an ensemble mean average, 
    then the PDS extension suffix will be "ENMA". The final GEMPAK parameter 
    name will be "HGHTENMA" and must be referenced as such in any GEMPAK 
    program.