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WAFSOPSG/5-WP/11
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International Civil Aviation Organization
WORKING PAPER / WAFSOPSG/5-WP/11
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
5.4: / Coordination between WAFCs and TCACs

COORDINATION BETWEEN WORLD AREA FORECAST CENTRES AND TROPICAL CYCLONE ADVISORY CENTRES

(Presented by the WAFC Provider States, in coordination with WMO)

SUMMARY
This working paper summarises a WAFC–TCAC coordination trial that took place in March 2009, and considers the feasibility and benefits for the WAFS of continuing with this collaborative effort.

1.INTRODUCTION

1.1The group will recall that it formulated Conclusion 4/8 inviting the WAFC Provider States to assess the feasibility of, and benefits for the WAFS from, establishing and maintaining contact with the TCACs (Tropical Cyclone Advisory Centres) in order to harmonise the information on tropical cyclones (TC) in the WAFS significant weather (SIGWX)forecasts and the TCAC advisories, and to report the findings back to the WAFSOPSG/5 Meeting.

1.2This paper has been drafted by the WAFC Provider States in co-ordination with WMO (including the TCACs) and summarises a web chat coordination trial that was conducted between the WAFCs and TCACs in March 2009. Based on the outcomes of the trial, invites the group to consider whether such co-ordination activity is deemed beneficial for the WAFS and should continue.

2.discussion

2.1From 2 March to 31 March 2009, the WAFCs and TCACs conducted an interactive web chat portal (hosted by WAFC Washington) to coordinate the inclusion of tropical cyclone information on WAFS SIGWX forecasts.

2.2Each of the designated TCACs was provided with a user account login and asked to participate in the 6-hourly coordination chats already undertaken between the WAFCs to harmonise volcanic ash (VA) and TC information.

2.3During each 5-minute session, the WAFCs listed the name and position of any TC that they were including on the upcoming issue of T+24 SIGWX forecasts, based on TC advisory bulletins (FK**** bulletins). Each participant TCAC was then required to review the list and post either their affirmation of the information or propose a correction. There was to be no dialogue relating to which global model was best.

2.4Of seven TCACs invited to participate in the trial, five participated on a regular basis – namely Darwin, Honolulu, Nadi, New Delhi and Tokyo. During the trial period, seven tropical depressions reached TC intensity – namely Gabrielle, Hamish, Ilsa and Jasper in Darwin TCAC area of responsibility; Joni and Ken in Nadi TCAC area of responsibility; and Izilda in La Reunion area of responsibility.

3.WAFC Provider States perspective of the Co-ordination trial with the tcac’s

3.1From a WAFC London and WAFC Washington perspective, the coordination gave WAFC forecasters reassurance that the TC information being placed on the T+24 SIGWX forecasts was in agreement with the advisory information originating from the designated TCAC. In particular, where a tropical depression was developing but had not yet reached TC intensity or been given a name, the dialogue ensured attention was drawn to the situation by all parties. This allowed the WAFCs to be given an indication of when the storm might be expected to reach TC status or be given a name.

3.2On the rare occasion when a named TC was occurring, but the responsible TCAC did not participate in the conference, the WAFC forecasters simply relied on the TC advisory information, as normal.

3.3From a WAFC Provider States perspective, the continued involvement of TCACs in the co-ordination effort would be a welcome one, requiring little additional effort on the part of the WAFC forecasters.

4.TCAC prespective of the co-ordination trial with the WAFC’s

4.1Feedback provided by participant TCACs immediately following the trial indicated that the sessions were easy to access, easy to understand and of satisfactory duration. However, there appeared to be mixed impressions regarding the following three key areas:

a)the allotted time of the co-ordination sessions;

b)sustained involvement during the “off-season”; and

c)resource constraintsand potential language barriers.

4.2Regarding point a), several TCACs cited that they issue TC advisories at synoptic time plus n hours. For example, RSMC Nadi issues TC advisories at 0100, 0700, 1300 and 1900 UTC (synoptic time plus 1 hour), whilst RSMC Honolulu issues at 0300, 0900, 1500 and 2100 UTC (synoptic time plus 3 hours). Therefore, to conduct the WAFC-TCAC coordination sessions at 0030, 0600, 1230 and 1800 UTC meant that the TC forecast was being worked on and had not been finalised. The previous bulletin issue had to be used instead, which was several hours old by that stage.

4.3Regarding point b), it is recognised that that TCs tend to have distinct “seasons” and favoured parts of the world where they develop. For example, the Southern Pacific Ocean tends to see TCs from November to May, with peak activity around February/March. For the remainder of the year (i.e. the “off-season”), TCs are not usually expected. During the off-season, it was highlighted that some TCACs would not have the necessary resources to participate in the web coordination sessions. So, whilst participation might be quite high initially, after a period of time this may wane unless incorporated into local staff instructions.

4.4Regarding point c), it was expressed by one TCAC that due to the other operational work, they were only able to participate in the trial during normal working hours, and only through the involvement of day-working (English speaking) support staff. It is unclear whether this would remain to be a problem if the coordination sessions were implemented operationally.

5.Conclusions

5.1The WAFCs would like to pass on their gratitude to the TCACs for participating in the co-ordination trial. The activity is deemed to have been a success, with good participation and valuable feedback. The sessions are considered to be beneficial for the WAFS, since there is greater awareness, coordination and harmonisation regarding the TC information being placed on the SIGWX charts.

5.2Noting the concerns expressed by some TCACs regarding the allotted time of the coordination sessions, sustained participation during the off-season and resource/language constraints, the group may wish to agree that the involvement of the TCACs in the coordination sessions should be voluntary rather than mandatory. Due to SIGWX production procedures, the WAFCs are not in a position to conduct the co-ordination sessions at any other times of the day.

5.3The WAFCs are content to provide this web-chat facility throughout the year for the designated TCACs to access as they wish – notably during the active TC season in their particular part of the world. The WAFCs would not wish, however, to extend the coordination session beyond simple confirmation of the name(s) and position(s) of TCs that are active or expected to develop by T+24.

5.4Accordingly, the group is invited to formulate the following decision:

Decision 5/ — Coordination between WAFCs and TCACs
That, the WAFC Provider States continue their efforts to maintain contact with the Tropical Cyclone Advisory Centres in order to harmonise the information on tropical cyclones in the WAFS SIGWX forecasts and TCAC advisories, by making available a web-based Internet chat-room facility, to be hosted by WAFC Washington.
Note 1.— Coordination sessions are conducted by the WAFCs at 0030, 0600, 1230 and 1800 UTC; and
Note 2.—TCAC participation at the coordination sessions is not mandatory, but considered beneficial during the active TC season within their area of responsibility.

6.ACTION BY THE wafsOPSG

6.1The WAFSOPSG is invited to:

a)note the information contained in this paper; and

b)decide on a draft decision for the groups consideration.

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