RSMC NADI - TROPICAL CYCLONE CENTRE

ROLE AND RESPONSIBILITIES

RSMC Nadi –TCC is one of six Regional Specialized Meteorological Centres (RSMCs) with activity specialization in tropical cyclones designated under the World Weather Watch (WWW) Programme of the World Meteorological Organisation (WMO) tasked to provide "first level" information on tropical cyclones (i.e. basic information covering the tropical cyclone's present and forecast position, movement and intensity) in the South-West Pacific Ocean.

Approved by the forty-seventh session of the WMO Executive Council (Geneva, June 1996), the RSMC is incorporated within the Weather Forecasting Division of the Fiji Meteorological Service (FMS), a department operating under the Fiji Government. The Division has provided weather forecast and cyclone warning services for bulk of the tropical South Pacific for many years prior to its formal recognition as an RSMC.

RSMC Nadi-TCC is primarily responsible for the South Pacific area extending from the Equator to 25 degrees South Latitude and from 160 degrees East to 120 degrees West Longitude. It names and tracks all tropical cyclones in the area, and issues regular warnings and advisory information for marine and public interest and safety. It also serves as a Tropical Cyclone Advisory Centre (TCAC) for an extended area down to 40 Degrees South Latitude under the International Civil Aviation Organisation (ICAO).

Some of the typical products and services issued by RSMC Nadi-TCC in conjunction with the Regional Weather Forecasting Centre at Nadi are:

1. International Marine (or High Seas) Forecasts & Warnings

Area covered - Equator to 25 South Latitude, 160 East to 120 West Longitude

Marine forecasts for international waters issued twice daily at 0820 and 2020 UTC

Marine Warnings issued six-hourly at 0115, 0715, 1315 and 1915 UTC when warranted. These are internationally disseminated on the GTS circuit and also broadcast at regular intervals from the transmitting station in Auckland, New Zealand.

2. Tropical Disturbance Summary

Area covered - Equator to 25 South Latitude, 160 East to 120 West Longitude

A Tropical Disturbance Summary is issued twice daily at 1100 UTC and 2300UTC listing and giving a short summary of tropical disturbances in the region. This bulletin is available during the South Pacific Tropical Cyclone Season from 1 November to 30 April of the following year only.

3. Tropical Disturbance Advisory

Area covered - Equator to 25 South Latitude, 160 East to 120 West Longitude

A Tropical Disturbance Advisory is issued six-hourly on tropical depressions and tropical cyclones occurring in the area. The bulletin is addressed to all national meteorological services in the region and is intended to update them with information concerning a tropical cyclone’s current location, its direction/speed of movement, intensity and wind distribution, and anticipated change in movement & intensity in the next 24-48 hours. It includes 12-hourly forecast positions for the next 48 hours.

4. Special Advisory (for Samoa, Vanuatu only

Special Advisory bulletins are issued for Samoa and Vanuatu and are intended to assist the National Meteorological Services (NMSs) of these countries to develop their national warnings and advisories. The bulletins contain essential information like a tropical cyclone’s location, movement, intensity and anticipated changes in intensity/movement with areas likely to be threatened. The bulletins are issued at least six-hourly.

5. Daily Weather Forecasts for Island Countries

A major role of the FMS besides its national responsibilities, is to assist in providing weather forecasting and cyclone warning services to the many other national meteorological services in the South Pacific region that possess little or no forecasting capabilities of their own. Some ten countries are served in this capacity by the Regional Weather Forecast Centre at Nadi incorporating RSMC Nadi TCC, including Fiji itself, as listed below.

Cooks Islands

Fiji

Kiribati

Nauru

Niue

Tokelau

Tonga

Tuvalu

Wallis and Futuna

Weather bulletins are issued two to four times daily for these countries to cater for public and marine interests; however for Fiji and some other countries separate marine bulletins are also issued. Warnings on tropical cyclones and other severe weather systems are generally issued every three hours. Special Advisory Bulletins are issued to Samoa and Vanuatu to assist its meteorological service in preparing its own domestic warnings.

Cyclone Advisory System

6. The cyclone advisory system adopted for the Nadi RSMC area by the Tropical Cyclone Committee for the South Pacific and Southeast Indian Ocean is described in the Operational Plan for the region. The system has two phases -

ALERT phase, and

WARNING phase.

7. All alerts and warnings are issued in the form of SPECIAL WEATHER BULLETINS which are numbered sequentially for each island state under threat as different from the normal weather bulletins. The criteria for their issue is given below.

8. A tropical Cyclone ALERT is issued about six-hourly to give information on the development of an incipient cyclone or the progress of a cyclone still some distance away, if there is significant probability that it could cause gale force or stronger winds over some part of a country 24 to 48 hours from the time of issue of the bulletin. It is intended to place the community on alert, giving enough time to check their preparedness and take precautions, as necessary.

9. Tropical Cyclone Warnings are issued generally every three hours for specific areas as:

· Gale warning if sustained winds over 33 knots and up to 47 knots

(40% higher gusts) are expected within the next 24 hours.

· Storm Warning if sustained winds are expected to range between

48 and 63 knots (40-50% higher gusts) in the area within the next 24 hours.

· Hurricane warning if sustained winds over 63 knots (50% higher gusts)

are expected in the area within the next 24 hours.

Dissemination of Warnings, Forecasts and Advisories

These are disseminated generally by the most efficient and economical means available to the Centre. For majority of the countries this means the use of the WMO’s Global Telecommunications Systems (GTS) and/or the Aeronautical Fixed Telecommunication Network (AFTN) of the International Civil Aviation Organization which offer dedicated links to most countries in the region. Telefax and electronic mail (e-mail) are also used together with distribution via the Emergency Managers Weather Information Network (EMWIN) Satellite Broadcast System operated by the US National Weather Service. All products including weather forecast, warnings and advisories are placed in the FMS Web Site www.met.gov.fj. FMS operates a polling fax and auto fax delivery system as well. A satellite telephone system (INMARSAT-M system) is used for backup to the national communications link.

Upon arrival of a bulletin at a country from Nadi, the responsibility for its internal distribution lies with the national authority, which is usually the country’s meteorological service. Bulletins are usually converted to local times and local languages while the English version is broadcast directly via the local radio stations. All Special Weather Bulletins are sent to Radio Australia (ABC) and Radio New Zealand International (RNZI) for broadcast on shortwave radio. A system has been devised whereby RSMC Nadi is kept aware of any deficiencies in the communication system. As part of this system, the receipt of the first Special Weather Bulletin issued for a country must be acknowledged by the respective country. The TCWC Wellington serves as backup to RSMC Nadi-TCC.

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