WORLD METEOROLOGICAL ORGANIZATION
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RA IV HURRICANE COMMITTEE
THIRTY-THIRD SESSION
GRAND CAYMAN, CAYMAN ISLANDS
8 TO 12 MARCH 2011
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RA IV/HC-XXXIII/Doc. 5(1)
(28.II.2011)
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ITEM 5
Original: ENGLISH
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COORDINATION IN OPERATIONAL ASPECTS OF THE HURRICANE WARNING SYSTEM AND RELATED MATTERS
COORDINATION WITH AND WITHIN THE CMO MEMBER STATES
(Submitted by the British Caribbean Territories1)
A. Introduction and Background
1. In November or December each year, Directors of Meteorological Services of the 16 English-speaking States that make up the Caribbean Meteorological Organization (CMO), hold an early review of the past hurricane season, as well as a review of the regional coordination within the RA IV hurricane warning system. The review of these matters is then contained in a report to the Governing Body of the CMO, which is a Ministerial-level Caribbean Meteorological Council (CMC). When appropriate, these matters are also raised by representatives at the sessions of the Hurricane Committee, particularly if there are concerns or issues to be resolved.
2. This document deals with two specific matters that the Caribbean Meteorological Organization requested to be brought to RA IV Hurricane Committee.
B. Operational Aspects with respect to the passage of Hurricane Tomas in the Windward Islands
3. The weather system that had been classified as a vigorous tropical wave moving across the Atlantic was first investigated by a reconnaissance aircraft when the system was only a few hundred miles east of Trinidad and Tobago and the southern Windward Islands. The aircraft found a closed surface circulation and storm force winds that caused the immediate upgrade of the system directly from a tropical wave to Tropical Storm Tomas in the 2100UTC bulletin on 29 October, with the tropical storm then near 57 degrees West, or only about 250 miles (400km) east of Trinidad or 200 miles (320km) southeast of Barbados (see the ANNEX to this document). The forecast was then for movement towards the West-Northwest to affect the Windward Islands in about 24 hours. Tomas continued its intensification as it moved towards the northwest with its centre clipping the western parts of Barbados early on 30 October, intensifying further to Hurricane Tomas before the centre passed between St. Vincent and Saint Lucia.
4. Concern was expressed about the timing of the aircraft investigation of Tomas so late on 29 October when the system was already within 24-hours of the Windward Islands, particularly as satellite imagery suggested a circulation, whether at the surface or not, at least 24 hours before the aircraft flew into the system, and because it is well known that intense systems near or south of 10 degrees North almost always create major problems for the Eastern Caribbean. Although most countries had been alerting their nationals to the possibility of torrential rainfall associated with the intense tropical wave, nationals for the most part were not ready for Hurricane Tomas and the devastation and loss of life it caused. Tomas impacted Barbados only 14-hours after it was named. Meteorological Services received complaints or negative comments about the warnings from the general public and from national disaster agencies.
5. The Caribbean Meteorological Organization expressed its gratitude to the United States for undertaking the reconnaissance missions and recognized the logistics involved in carrying out hurricane reconnaissance flights. It was aware, however, that there had been some requests in the past few years from Member States represented on the Hurricane Committee for reconnaissance aircraft to investigate systems in the Atlantic that had the potential to make landfall in the Eastern Caribbean when the system is further east of 55°W. There was a strong view that this would greatly contribute to a more appropriate alert, preparation and reduction in loss of life due to the impact of a tropical cyclone. The WMO RA IV Hurricane Committee is therefore again requested to discuss and reconsider extending the eastern limit of the flights some distance east of 55°W.
C. Regional Arrangements for Meteorological Forecast and Warning Services to Other States
6. The Caribbean Meteorological Organization held an extensive discussion on the responsibilities of National Meteorological and Hydrometeorological Services (NMHS) of the CMO Member States. It recalled how the NMHSs developed to various scientific and technical levels over the years. When the CMO was established in 1973 to replace the Caribbean Meteorological Service (CMS) after the breakup of the West Indies Federation, there were several National Meteorological Services operating observing stations and a few Forecast and Warning Offices. In the process, the CMO set in place a set of forecast and warning responsibilities, in which the larger NMHSs provide weather forecast and warning services for neighbouring smaller Services. These arrangements have been modified by the CMO over the years and today, the forecast and warning responsibilities of CMO Member States (in RA IV) have evolved to the following:
Member States with Weather Forecast and Warning Offices
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States and Areas of Responsibility for Forecasts and Warnings
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Antigua & Barbuda
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The islands and coastal waters of Antigua & Barbuda, Anguilla, British Virgin Islands, Montserrat, St. Kitts & Nevis
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Barbados
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The islands and coastal waters of Barbados, Dominica, St. Vincent and the Grenadines
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Belize
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The islands, coastal waters and inland areas of Belize
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Cayman Islands
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The islands and coastal waters of the Cayman Islands
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Grenada
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The islands and coastal waters of Grenada and its dependencies (weather forecasts only)
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Jamaica
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The island and coastal waters of Jamaica
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Saint Lucia
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The island and coastal waters of Saint Lucia
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Trinidad and Tobago
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The islands and coastal waters of Trinidad and Tobago; tropical cyclone warnings responsibility for Grenada and its Dependencies
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By agreement between CMO and The Bahamas (non-CMO Member), the Bahamas area of responsibility for forecasts and warnings includes the islands and coastal waters of the Turks and Caicos Islands
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7. These arrangements form the basis for many other international arrangements or agreements, such as the WMO RA IV Hurricane Operational Plan (Chapter 2), and the provision of aeronautical meteorological forecasts and warnings under the auspices of the International Civil Aviation Organization (ICAO). The Governing Body of the CMO also reviewed the back-up arrangements between States for normal NMHS operations and specifically, the backup arrangements for Watches, Warnings and agreed-upon essential products, as contained in the RA IV Hurricane Operational Plan and in arrangements under the auspices of ICAO. For the CMO Member States in RA IV, these are:
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Antigua will take over the responsibility of Barbados with respect to the island and coastal waters of Dominica;
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Barbados will take over the responsibility of Antigua and/or Saint Lucia;
(b) Barbados will take over the responsibility of Trinidad and Tobago;
(c) Jamaica will take over the responsibility of the Cayman Islands;
(d) Trinidad and Tobago will take over the responsibility of Barbados with respect to the islands and coastal waters of Barbados and St. Vincent and the Grenadines;
(e) The USA will take over the responsibility of Jamaica.
8. These backup arrangements were discussed in light of the operational impact of the passage of Hurricane Tomas across the Caribbean in 2010. In the process, it became very evident that there was a real possibility of a "double whammy" situation occurring in that a Forecast and Warning Office in one State and its designated backup in another State could both be “taken out of operations” by the same weather system. For example, Saint Lucia and its backup Barbados or the Cayman Islands and its backup Jamaica could be knockout together since hurricanes can and do hit both States with the track that hurricanes generally take. The Caribbean Meteorological Council requested the WMO RA IV Hurricane Committee to discuss this matter within its Operational Plan. The CMO would then take the results of this discussion into account for its next review of its overall backup arrangements.
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