ECMWF BUFRDC software is used for encoding and decoding WMO FM-94 BUFR code messages. As a part of software there are tools for conversion between BUFR and CREX .
From version 000383 there is tool available for conversion WMO FM-12 SYNOP code to FM-94 BUFR code
Check the Releases page to see all available versions and the History of BUFRDC changes page for the release notes.