From January 2020, Commission Implementing Regulation (EU) No 2017/373 will enter into force, inter alia, change the requirements for the format of the SIGMET message.

From January 2020, Commission Implementing Regulation (EU) No 2017/373 will enter into force, inter alia, change the requirements for the format of the SIGMET message. Estonian Environment Agency is responsible for dissemination of SIGMET messages on the Tallinn Flight Region. ‘SIGMET’ means information concerning en-route weather phenomena, which may affect the safety of aircraft operations. The following changes to SIGMET messages:

• the SIGMET message number consists of one letter and two digits;
• each phenomenon is represented by one of the letters (I, F, T, U, etc) designated for that purpose.

For example, U02 means that a second SIGMET message about the occurrence of turbulence has been issued.

For more information https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32017R0373