APCEDI Alert 13P, Cyclone Ivy #6, 2004

Dear Colleagues

Alert 6, Cyclone Ivy 13P / 24 February 2004, Sydney 12:00 EDT

Cyclone Ivy has shown a nascent filled eye feature since about 9:00 EDT this morning indicating that an eyewall is trying to form. However, recent photos still show that the deepest convection is moving around within the large central convection area, and so it is hard to pick a defined eye feature at the moment.

Overall Ivy continues Category 1 Cyclone and may strengthen to Category 2 later today. This large central convection area is located 50-100 km east of the Banks Island moving slowly west. The large central core convection area reaches Anuta and Tikopia in the north and is beginning to approach the Banks Islands in the west. Mere Lava the southeastern most of the Banks Group and possibly northern Maewo will soon be underneath this central convection area and experiencing severe gales and heavy rains. A large feeder band with heavy rain and squalls is over the Torres Islands and Vanikolo and Utupua in the Santa Cruz and is spiralling into the core convection centre in the Anuta-Tikopia area. Therefore at this time APCEDI alerts are continued for all of Vanuatu north of Efate and for all of the Santa Cruz Group of the Solomons.

Most predictive models are showing an imminent southern shift in the storm’s track, but it does not seem to be happening yet to any major degree. The official track out of the JTWC has Ivy moving over Maewo, Ambae, Santo and Malakula and strengthening to Category 3 by the time it is west of Malakula.

Given that Ivy seems to be slowly strengthening and is forecast to strengthen to category 2-3, the situation is becoming more likely for moderate to localised severe damage especially for Northern Vanuatu from Ambrym and Malakula northward through the Torres and Banks and for the Eastern Santa Cruz Group including Anuta, Tikopia, Vanikolo and Utupea. The current situation is summarised as follows:

Sustained Severe Gales and Heavy Rain
Solomons
Anuta
Tikopia
Vanuatu
Banks Group (entire group)
Maewo

Intermittent Severe Gales and Heavy Rain
Solomons
Vanikolo
Utupea
Vanuatu
Torres Group (entire group)
Ambae Pentecost.

Given the Category 1 nature of the storm, damage at this time should be light to moderate and localised. It will likely include lowland tidal flooding and flash-flooding in hill areas. Some crop damage is also likely. As Ivy continues to be slow moving, this will likely result in heavy localised rainfall which could result in flash-flooding of mountain and hill areas as well as known flood prone areas. If a central eye wall manages to emerge later in the day, and the storm strengthens to Category 2-3, damage along its path will certainly be more severe.

A special note for the large Vanuatu Islands is that due to their very high relief and the slow movement of the storm, flash flooding will be a major threat throughout tonight and tomorrow especially if the the storms passes over the islands slowly or even stalls.

In addition to the islands and groups named above (including all small outlying islands), the following islands should remain on high alert in the next 12 hours as the storm approaches:

Solomons
Nendo
Nupani
Duffs
Vanuatu
Santo
Ambrym
Malakula

Authorities in Vanuatu from the Torres Islands to Efate (including Torres and Banks Islands, Pentecost, Ambae, Santo, Malakula, Ambrym, Paama, Ulveah, Epi, Shepherd Islands and Efate including all small islands in these areas) as well as all of the Santa Cruz Group in the Eastern Solomons should be on alert, monitor the path of the storm closely throughout the day and take immediate actions to protect people and property. People in mountain areas along the eastern and southern slopes of ranges should be on alert for heavy rain resulting in flash flooding. Low lying coastal areas especially along east and southern parts of large islands should also be on alert for tidal flooding.

Concerns in New Caledonia, the main islands of the Solomon Islands and the islands of Southern Vanuatu should continue to monitor this storm as it develops over the next few days. Feeder bands are already bringing rains and gusty winds to some of these areas, and this will likewise increase during the day.

APCEDI will continue monitoring the event. More detailed information about the storm can be found on

https://metoc.npmoc.navy.mil//jtwc.html
http://www.met.gov.fj/advisories.html
http://www.nrlmry.navy.mil/tc_pages/tc_home.html

Kevin Vang
APCEDI Coordinator