Tropical Cyclone Programme
Tropical Cyclone Programme RA IV Hurricane Committee

At the kind invitation of the Government of Bolivarian Republic of Venezuela, the twenty-third session of the RA IV Hurricane Committee was held in Maracay from 23 to 27 March 2001. There were 36 participants at the session from 23 Members of the Association and six of regional and international organizations.

Highlights of the outcome of the session:

Coordination in operational aspects of the hurricane warning system and related matters - Numbering and headings of subtropical depressions

The Committee discussed the submission by France concerning difficulties being experienced with the numbering system and the heading for subtropical depressions (WWNT) when compared to that for tropical depressions (WTNT), as indicated in the Hurricane Operational Plan. The Chairman pointed out that there was an error in the Plan and that the heading had been changed some time ago. WTNT is the heading now used for both subtropical and tropical depressions. The Chairman alluded to the difficulties in determining the true tropical or extratropical characteristics of many systems which might end up being classified as subtropical. However, the Committee decided that one numbering system should be used for both systems.

Dropwindsondes over land areas

The Committee recalled its discussions at the previous session about the making of hurricane reconnaissance flights over land. The RSMC pointed out that pilots would not take the responsibility of releasing dropwindsondes over land because of the possibility of injury on the ground, and therefore emphasized the importance of the upper-air soundings from the land stations, including the making of special soundings.

Attachment of hurricane forecasters to RSMC Miami

The Chairman expressed his pleasure with the programme of assigning bilingual (English/Spanish) forecasters from NMHSs in the Region to the RSMC. He felt that the assignments had helped both the RSMC and the individual NMHS and urged others to make their bilingual forecasters available during hurricane season whenever possible.

Post tropical cyclone report

The Committee discussed the use in connection with tropical cyclones, of the guide to report on heavy rainfall events, which had been devised by the RA IV Working Group on Hydrology. The guide had been presented to the Committee in its full detail at its last session. The Committee decided that the Chairman and the two Vice-Chairmen would work on producing a format based on the guide for post tropical cyclone report for inclusion in the Operational Plan. The modified version would be prepared as a document for consideration and adoption by the twenty-fourth session of the Committee in 2002. NMHSs were urged to consult with the hydrological community in their countries when compiling the rainfall information.

The Committee made amendments and changes to the RA IV Hurricane Operational Plan. It recommended to XIII-RA IV the approval of the amendments to the text of the Plan. The Committee urged WMO to publish a new 2001 edition in English and Spanish, as soon as possible.

A detailed review of all components of the Technical Plan and its Implementation Programme was carried out, taking into account the development and progress made by Members since the twenty-second session of the Committee. The Committee recommended to XIII-RA IV the approval of the updated RA IV Hurricane Committee’s Technical Plan and its Implementation Programme.

The USA offered to host the twenty-fourth session of the RA IV Hurricane Committee in Orlando, Florida from Wednesday, 3 April to Wednesday, 10 April 2002, in conjunction and concurrently with the US National Hurricane Conference, which is to be held from 1 to 5 April 2002.

For more information: oarango@meteoro.imm.ac.cr