afi met bulletins exchange (ambex) handbook - ICAO

AFI Regional SIGMET Guide Page 21/60
The location of the TC centre is given by its lat, lon coordinates following the general
rules of reporting lat, lon information provided in Appendix F to this Guide.
Examples:
FCST 1200Z TC CENTRE N1430 E12800
3.4.6 Cancellation of SIGMET
3.4.6.1 If during the validity period of a SIGMET the phenomenon for which the SIGMET had
been issued is no longer occurring or no longer expected, the SIGMET should be cancelled by the issuing
MWO. The cancellation is done by issuing same type of SIGMET with the following structure:
- WMO heading with the same data type designator;
- First line that contains as period of validity the remaining time of the original period
of validity;
- Second line, which contains the name of the FIR or CTA, the combination CNL
SIGMET, followed by the sequential number of the original SIGMET and its validity
period.
Examples:
1. WS SIGMET:
WSZR31 FZAA 101200
FZAA SIGMET 5 VALID 101200/101600 FZAA-
FZAA FIR KINSHASA…
Cancellation of WS SIGMET:
WSZR31 FZAA 101430
FZAA SIGMET 6 VALID 101430/101600 FZAA-
FZAA FIR KINSHASACNL SIGMET 5 101200/101600=
2. VA SIGMET
WVCG31 FCBB 131518
FCCC SIGMET 03 VALID 131515/132115 FCBB-
FCCC FIR BRAZZAVILLE…
Cancellation of a VASIGMET:
WVCG31 FCBB 132000
FCCC SIGMET 04 VALID 132000/132115 FCBB-
FCCCFIR BRAZZAVILLE CNL SIGMET 03 13151500/132115=
or, in case that the volcanic ash cloud moves to an adjacent FIR:
WSZR31 FZAA 132000
FZAA SIGMET 04 VALID 132000/132115 FZAA -
September 2007 Amend1/2010 Ninth Edition