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WAFSOPSG/5-IP/4
/ WAFSOPSG/5-IP/4
23/6/09

WORLD AREA FORECAST SYSTEM OPERATIONS GROUP (WAFSOPSG)

FIFTH MEETING

Paris, France, 16 to 18 September 2009

Agenda Item / 5: / Operation of the WAFS
5.6: / Other issues related to the operation and implementation of the WAFS

TRUNCATION OF TROPICAL CYCLONE NAMES IN BUFR SIGWX

(Presented by the WAFC Provider States)

1.INTRODUCTION

1.1At the present time, the WAFS BUFR encoders employed by each of the WAFCs results in the names of tropical cyclones that extend beyond eight characters being truncated. For example, Tropical Cyclone ‘Claudette’ (9 characters) would encode and be displayed as “Claudett” (8 characters) on a BUFR SIGWX product.

1.2After the WAFSOPSG/4 Meeting, the WAFCs were approached by a WAFS user seeking clarification as to whether it would be feasible and desirable to increase the BUFR SIGWX limit to more than 8 characters. Whilst it may be desirable to consider modifications to allow BUFR SIGWX to handle Tropical Cyclone names greater than 8 characters, it would necessitate a change to the BUFR encoders employed at each WAFC, plus a resultant change to BUFR decoders at every end-user location world wide. This could be at considerable cost to provider and user.

1.3The information paper summarises the number of likely occurrences of tropical cyclone names in excess of 8 characters between 2009 and 2013. The detail has been extracted from the US National Hurricane Centre (NHC) website, which summarises the likely TC names to be used globally in the present and future years.

2.discussion

2.1The following table summarises the likely occurrences of Topical Cyclone names in excess of 8 characters over the next 5 years:

Responsible TCAC/RSMC / Area of responsibility / Probable Tropical Cyclone names in excess of 8 characters in next 5 years / Percentage affected*
Miami / North Atlantic, Caribbean, Gulf of Mexico / Claudette (2009), Philippe (2011), Gabrielle (2013), Sebastien (2013) / 4%
Miami / Eastern North Pacific / Guillermo (2009), Georgette (2010), Henriette (2013), Priscilla (2013) / 3%
Honolulu / Central North Pacific / Nil / 0%
Tokyo / Western North Pacific / Prapiroon, Fung-Wong, Namtheun / 2%
Darwin / Australia and Papua New Guinea / Charlotte, Ferdinand, Gabrielle / 3%
Nadi / Western and Central South Pacific / Nil / 0%
New Delhi / Northern Indian Ocean / Nil / 0%
La Reunion / Southwest Indian Ocean / Nil / 0%

* reflects the percentage of names affected out of the total number available per area of responsibility.

2.2From the above table, it can be seen that just 14 tropical cyclone names are likely to exceed 8 characters in length over the next few years. This equates to less than 2 per cent of the total number of names available across all geographic areas.

2.3Barring any changes to the proposed list that may occur in future years, each of these names is 9 characters in length. Within the BUFR SIGWX encoding process, if these names were included, each would have the final character missing – for example, “Gabrielle” would be truncated to “Gabriell”

2.4The WAFC Provider States have consulted with the WAFSOPSG member from IATA. IATA is in agreement with the WAFCs that there are no flight safety concerns caused by a limitation within the BUFR SIGWX encoding routine. In addition, owing to the changes that would be required to provider and end-user software to resolve the situation, no modifications are necessary. The legend box of WAFS SIGWX products already advises users to refer to any SIGMET or advisory bulletins that may be in force at the time. These should provide the user with a full appraisal of the MET situation and any TCs that may be active en-route.

3.ACTION BY THE wafsOPSG

3.1The WAFSOPSG is invited to note the information contained in this paper.

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