Tropical season reports and submitted by New-Caledonia

Transcription

1 Tropical season reports and submitted by New-Caledonia RA V Tropical Cyclone Committee 16th session Honiara, Salomon Islands 29 Aug 2 Sept 2016

2 Tropical cyclone warning system: Warning zones Météo-France New Caledonia Met service provides tropical cyclone forecast for New-Caledonia and Wallis-and-Futuna Islands, and so has defined two tropical cyclone warning zones, one for New Caledonia (Fig.1) and one for Wallis-and- Futuna (Fig. 2) Fig. 1 Fig. 2

3 Tropical cyclone warning system: Definition Four levels of warning: Pre-alert : a tropical cyclone, category 2 or more, enters or is forecasted to enter in our cyclone warning zone, with a potential threat for the country Alert 1: a tropical cyclone, category 2 or more, is forecasted to threaten or strike the country within 18 hours. Schools and businesses have to close and people are supposed to secure their housing and belongings Alert 2: a tropical cyclone, category 2 or more, is forecasted to threaten or strike the country within 6 hours. Population must shelter in sturdy buildings Save Phase : the tropical cyclone is moving away but dangers persist. Do not go outside unless necessary

4 A season less active than usual, especially across the Southwest Pacific basin where only 7 phenomena were observed. However, phenomena were often intense: the number of severe tropical cyclones is more than half the total, including 2 category 5 tropical cyclones (Pam and Marcia)

5 New Caledonia warning zone: Three phenomena moved over the warning zone of New Caledonia (OLA, PAM, SOLO). Severe tropical cyclones Ola and Pam moved remotely enough and had no significant impact. Solo directly concerned the country, but at a modest stage of intensity (category 1) Wallis-and-Futuna warning zone: Only the tropical cyclone category 1 Reuben moved into the southern part of the Wallis-and-Futuna zone, with no activation of the warning system

6 French Polynesia: Niko (category 2) was the only tropical cyclone observed during the season Niko moved quite close to Tahiti and caused mainly heavy rainfall

7 Severe tropical cyclone OLA (01/30 02/03) OLA: MTSAT-2 (2015/02/01 at 06 UTC)

8 Severe tropical cyclone OLA (01/30 02/03) Pre-alert : issued on 31 January at 06 UTC. Alert 1: issued on 31 January at 20 UTC on the North of the main island. Alerts were lifted on 2 February.

9 Severe tropical cyclone OLA (01/30 02/03) Heavy rainfall was observed. It was mainly located both on the eastern coast of the main island and on the relief (fig.3), and caused flash floods, cut roads and power outage. Values range from 150 to 300 mm in 48 hours. Gusts up to 100 km/h were observed, particularly in the far North. Figure n 3: Radar s rainfalls in 48 hours

10 Severe tropical cyclone PAM (03/07 03/16) PAM: MTSAT-2 (2015/03/14 at 04 UTC)

11 Severe tropical cyclone PAM (03/07 03/16) Pre-alert : issued on 12 March at midday. Alert 1: issued on 13 March at midday both on Loyalty Islands and the extreme South of the main island. Alert 2: issued on 13 March at midnight on Loyalty Islands (Lifou and Maré). Alerts were lifted on 15 March early in the morning.

12 Severe tropical cyclone PAM (03/07 03/16) Heavy rainfall was observed in the South of the main island but they were not exceptional. Gusts up to 130 km/h were observed on Maré Island. Damage was minor: some blown off roofs and power cuts. Figure n 3: Radar s rainfalls in 48 hours

13 Tropical cyclone cat. 2 SOLO (04/09 04/22) OLA: MTSAT-2 (2015/04/10 at 06 UTC)

14 Tropical cyclone cat. 2 SOLO (04/09 04/22) Pre-alert : issued on 11 April at midday. Alert 1: issued on 11 April in the evening on the North of the main island. Alert 2: issued on 12 April early in the evening on the North of the main island. Alerts were lifted on 12 in the evening.

15 Tropical cyclone cat. 2 SOLO (04/09 04/22) Heavy rainfall was observed. It was mainly located on the eastern coast of the main island (fig.4), and caused flash floods and cut roads. Values range from 100 to 200 mm in 24 hours. Gusts up to 90 km/h were observed, particularly in the far North. Figure n 4: Radar s rainfalls in 24 hours

16 Season This season took place during a strong phase "El Niño". The cyclonic activity was focused on the centre of the basin. Note the unusual tropical cyclone tracks of Ula and Winston which had a very long life cycle. These two phenomena affected both our warning areas

17 Season Four cyclonic phenomena crossed New Caledonia warning zone (Ula, Tatiana, Winston, Zena), moving remotely enough to have no significant impact. Pre-Alert was only issued when severe tropical cyclone Ula and tropical cyclone category 2 Tatiana moved closer to New Caledonia ULA : 2016/01/10 at 0500 UTC

18 Season Four cyclonic phenomena also crossed the warning zone of Wallis-and-Futuna (Tuni, Ula, Winston,Amos). Only severe tropical cyclone Amos generated some light impacts (high swell on the coast of Futuna, some gusts near 100 km/h in Wallis causing a significant power fail and uprooted trees). Amos moved closer to Wallis island during the night of April 22 to 23, about 90 km in the North. Alert 2 was issued on Friday, 22 April in the evening and was taken off on 23 early in the morning. Amos: 2016/04/22 at 0530 UTC

19 Season French Polynesia: This season took place during a strong phase "El Niño". We expected a cyclonic activity more important than usual on French Polynesia. But finally it was not the case, the activity was focused on the centre of the basin and Yalo (category 1) was the only tropical cyclone observed In French Polynesia during the season Yalo didn't have significant impact. Despite this, several tropical lows had affected the country during the season, bringing many heavy rainfall episodes.

20 Summary Good tropical cyclone forecasted tracks More difficulties with intensity forecasting, especially for systems with rapid intensification New tropical cyclone track map since April 2016

21 Merci RA V Tropical Cyclone Committee -16th