The Task Team on Aviation Data (TT-AvData) maintains and develops the ICAO Meteorological Information Exchange Model (IWXXM) within WMO-No. 306, Vol. I.3, ensuring alignment with ICAO requirements and recent WMO publications. The team updates information models, schemas, and code lists, maintains aviation-related alphanumeric codes and abbreviated headings, engages aviation stakeholders in IWXXM development, and publishes new versions to support operational use.