METWSG/2-IP/8
20/4/09
METEOROLOGICAL WARNINGS STUDY GROUP (METWSG)
SECOND MEETING
Montréal, 19 to 21 May 2009
Agenda Item 5: Content and issuance of SIGMET
5.1: Improved issuance of SIGMET
EFFECTIVE SOLUTION OF DEFICIENCIES IN EMISSION OF SIGMET
(Presented by Juan Ayón)
SUMMARY
This paper presents the concern regarding the effective solution of deficiencies in the
emission of SIGMET by MWO, with the only regionalization of the generations and
issue guidance to MWO.
1.
INTRODUCTION
1.1
The ways for improving the exchange of OPMET information in the CAR/SAM Regions
has been analyzed in several occasions by the MET Subgroup of the CAR/SAM Regional Planning Group
(GREPECAS). The SIGMET information has called special attention and some actions were developed to
improve the exchange of this type of information. Among these actions can be mentioned the designation
of fixed dates to carry out exchange controls, coordinated tests between the VAAC of Washington and
Buenos Aires and the meteorological watch office (MWO) for the emission of volcanic ash SIGMET,
projects of Special Implementation Plans (SIP) and regional seminars.
1.2
The last test carried out in the CAR/SAM Regions for the emission of volcanic ash
SIGMET showed that in spite of the coordination done with the VAAC of Washington and Buenos Aires,
and all the MWO of both Regions, the results were not those that were expected because many MWO
didn't emit volcanic ash SIGMET, some of them emitted several, and few of them prepared and emitted
all the expected SIGMETS, although the VAAC sent the advice messages.
2.
ANALYSIS
2.1
The designation of Advisory Centres to provide guidance to MWO for the issuance of
volcanic ash and tropical cyclone SIGMET, gave the possibility to homogenize the SIGMET prepared by
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those MWO, taking into consideration that these Advisory Centres has the NWP capacity for these great
scale type of phenomena and send to the MWO an effective advisory information to prepare their own
SIGMET.
2.2
For the volcanic ash SIGMET, there is an entire structure that supports this work that
involves the volcano observatories, the International Airways Volcano Watch (IAVW), Advisory Centres
with capacity to evaluate and forecast the transport of the volcanic ashes and also there is an ICAO
Handbook on the International Airways Volcano Watch (IAVW) — Operational Procedures and Contact
List (Doc 9766) to guide the work of the meteorological offices.
2.3
Tropical hurricanes are of such a magnitude, not only because of the wide area that
affects the FIR, but also because of the associated severe meteorological conditions. These phenomenon
by themselves draw the attention of the aviation community because of the dangerous threat and
devastation that cause. The Tropical Cyclone Advisory Centres (TCAC) has also enough tools to advise
the MWO in the preparation of tropical cyclone SIGMET.
2.4
However, the reality in the CAR/SAM Regions shows that although the MWO have had
those advices, not all have prepared and emitted volcanic ash and tropical cyclone SIGMET.
2.5
The appearance and dissipation of convective clouds areas take place in many cases due
local conditions that correspond to the meso and microescale that can not be managed by an advisory
centre as soon as it is needed, like the proper MWO that better knows his own area of responsibility.
2.6
The MET Subgroup of GREPECAS has analyzed in several occasions, the inconsistency
of the MWO for the preparation and emission of SIGMET, not only for volcanic ash and tropical cyclone,
but also for those linked with the presence of storms, severe convective areas, hail, turbulence and other
dangerous phenomena for the aviation that require the preparation of SIGMET information.
2.7
The ICAO Manual of Aeronautical Meteorological Practice (Doc 8896) offers a clear
orientation for applying the SARPs of ICAO Annex 3 — Meteorological Service for International Air
Navigation for the preparation of SIGMET. In general, the aviation community has the necessary advice
documentation for the elaboration and diffusion of the SIGMET.
3.
CONCLUSION
3.1
The regional advisory centres could help to solve the inconsistency of the MWO in the
preparation and dissemination of SIGMET, but not the unique solution. Not all the ICAO Regions have
the same situation. This would require of several supplemented actions.
3.2
Among of them for example, the establishment of a minimum qualification requirement
for the forecasters of the MWO; the obligation of establish and implements a properly organized quality
system that includes the obligation of possessing a certified quality system that includes procedures to be
audit in the preparation and emission of SIGMET messages; periodic audit to these MWO by the ICAO
Regional Offices, etc. And lastly, but not less important, it will be necessary to carry out specific seminars
to improve the required qualification of the MWO personnel.
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