APCEDI Alert SP/FJ Cyclone Vaianu (TD12F) #5-2006: Cyclone Vaianu Gives a Glancing Blow to Tongatapu

The RSMC-Nadi Tropical Cyclone Centre and the Joint Typhoon Warning Centre continue to issue guidance on Cyclone Vaianu.

Cyclone Vaianu is currently at Category 1 intensity on the Saffir Simpson Scale and is expected to slowly intensify over the next 24 hours.

Cyclone Vaianu is starting to make its pass to the west of the main Tongan Island of Tongatapu. Vaianu is currently 170 km to the northwest of Tongatapu, and tonight it is expected to pass about 140 km to the west of the island before going into the Southern Ocean. Tongatapu is reporting widespread minor damage such as sporadic power outages, some lines down, sporadic damage to trees and crops and some flooding in low lying areas. Schools, Government Offices and some businesses were closed today and will likely be closed again tomorrow.

However, damage should continue to be light with possible patches of locally moderate damage in flood and wind-prone areas. Standing water will be a problem and combined with downed powerlines, caution should be taken when venturing outside after the storm has passed. However, given the distance of the storm, major to sever damage is not expected. The situation on 'Eua will be much the same. Also the far southern part of the Southern Lau Group of Fiji should maintain vigilance especially the southeastern-most islands of Vatoa and Onoilau.

Vaianu is moving south at about 06 knots (11 km/h) and should continue moving southward into the Southern Ocean during the next 24 hours.

All interests in Tonga, Fiji and Niue should closely monitor the progress of this storm, and undertake any actions as advised by the local authorities. Although the storm is moving away from Wallis and Futuna and Samoa, all interests should maintain vigilance due to continuing rough seas, winds and heavy rains.

CURRENT ADVISORIES AND WARNINGS

TONGA
A GALE WARNING REMAINS IN FORCE FOR NOMUKA GROUP, TONGATAPU GROUP AND NEARBY SMALLER ISLANDS.
A STRONG WIND WARNING REMAINS IN FORCE FOR NIUAS AND VAVAU AND HA'APAI GROUPS.

SAMOA
WIND ADVISORY IN FORCE FOR SAMOA
FLOOD ADVISORY REMAINS IN FORCE
LANDSLIDE ADVISORY REMAINS IN EFFECT

NIUE
A STRONG WIND WARNING REMAINS IN FORCE FOR NIUE.

FIJI
A STRONG WIND WARNING REMAINS IN FORCE OVER LAND AREAS OF THE LAU GROUP.
A DAMAGING SWELL WARNING REMAINS IN FORCE FOR FIJI.
A STRONG WIND WARNING REMAINS IN FORCE FOR ALL FIJI WATERS.

WALLIS AND FUTUNA
A STRONG WIND WARNING REMAINS IN FORCE FOR WALLIS AND FUTUNA WATERS.

AMERICAN SAMOA
SMALL CRAFT ADVISORY
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From the RSMC-Nadi Tropical Cyclone Centre

Tropical Disturbance Advisory Number A12 issued from RSMC NADI
Feb 13/0149 UTC 2006 UTC.

Tropical Cyclone VAIANU [975hPa] centre was located near 20.1 South 176.8 West at 130000 UTC. Position fair and based on MTSAT EIR and VIS imagery with animation and peripheral surface reports. Repeat position 20.1S 176.8W at 130000 UTC. Cyclone moving south-southwest at about 05 knots but is expected to eventually turn southeast in the next 24 hours. Cyclone intensifying. Maximum 10-minute average winds estimated at 60 knots close to the centre, increasing to 65 knots in the next 6 to 12 hours. Expect winds over 47 knots within 30 miles of centre and winds over 33 knots within 100 miles of centre in sectors from north through east to southwest and within 80 miles elsewhere.

Overall organisation good. Low-level circulation exposed in west semi-circle. Entrainment of environmental air together with diurnal influence affecting further development. Cyclone lies under the 250-hPa ridge in a diffluent region. Outflow good to south and north and restricted elsewhere. Shear remains minimal. SST in the area is about 29-30C. Further intensification anticipated. Dvorak analysis based on a 1.3 wrap on log10 spiral. yielding DT=4.0. PT=MET=4.0, thus T4.0/4.0/D1.0/24hrs. Cyclone is being steered southward by a deep northerly steering flow. An eventual southeast turn is expected in the next 24 hours. Global models generally agree on this with further intensification.

FORECAST:
12hrs valid at 131200 UTC near 21.3S 176.18W mov S at 06kt with 65 kt close to the centre.
24hrs valid at 140000 UTC near 22.0S 176.8W mov S at 05kt with 65 kt close to the centre.

OUTLOOK:
36hrs valid at 141200 UTC near 22.9S 176.2W mov SSE at 05kt with 60kt close to the centre.
48hrs valid at 150000 UTC near 23.9S 175.2W mov SSE at 05kt with 60kt close to the centre.

The next Tropical Disturbance Advisory on Tropical Cyclone VAIANU will be issued around 130800 UTC.
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The TONGA FORESCAST from RSMC-Nadi Tropical Cyclone Centre

Special Weather Bulletin Number NINETEEN for Tonga on TROPICAL CYCLONE VAIANU issued from RSMC NADI
Feb 13/0557 UTC 2006 UTC.

TROPICAL CYCLONE WARNING.

A GALE WARNING REMAINS IN FORCE FOR NOMUKA GROUP, TONGATAPU GROUP AND NEARBY
SMALLER ISLANDS.
A STRONG WIND WARNING REMAINS IN FORCE FOR NIUAS AND VAVAU AND HA'APAI GROUPS.

Tropical Cyclone VAIANU [970hPa] centre was located near 20.8 South 176.9 West at 130500 UTC. Position fair and based on MTSAT VIS/EIR satellite imagery with animation and peripheral surface reports. Repeat position 20.8S 176.9W at 130500 UTC. Cyclone moving southward at about 06 knots. Maximum 10-minute average winds estimated at 65 knots close to the centre. Expect winds over 47 knots within 40 miles of centre and winds over 33 knots within 100 miles of centre in the eastern semicircle and within 80 miles elsewhere.

On its current track, the cyclone is expected to be located about 95 miles west-northwest of Nukualofa or 135 miles southwest of Nomuka at 131100 UTC and 110 miles southwest of Nukualofa or 160 miles southwest of Nomuka at 131700 UTC.

FOR NOMUKA GROUP, TONGATAPU GROUP AND NEARBY SMALLER ISLANDS:
Expect damaging gale force winds with average speeds of 35 to 45 knots and momentary gusts of 50 to 65 knots. Frequent heavy rain and squally thunderstorms. Flooding including sea flooding of low-lying coastal areas expected. High seas. Damaging heavy swells.

FOR VAVAU GROUP, HA'APAI GROUP, NIUAFO'OU AND NIUATOPUTAPU:
North to northwest winds 25 to 30 knots, gusting to 45 knots. Further periods of rain, heavy at times, with squally thunderstorms. Flooding including sea flooding of low-lying coastal areas expected especially over the Vavau group. Very rough seas. Damaging heavy swells still expected over Vavau but easing over the Niuas.

THE FOLLOWING INFORMATION IS PROVIDED ESPECIALLY FOR MARINERS:
Expect sustained winds of 65 knots close to the centre. Expect winds over 63 knots within 20 miles of centre with phenomenal seas. Winds over 47 knots within 40 miles of centre with very high seas and winds over 33 knots within 100 miles of centre in the eastern semicircle and within 80 miles elsewhere with high seas. Damaging heavy swells.

The next Special Weather Bulletin for Tonga on Tropical Cyclone Vaianu will be issued around 130900 UTC. TONGA PSE ACKNOWLEDGE THE RECEIPT OF THIS BULLETIN.
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APCEDI will continue to monitor the progress of this system.

Kevin Vang
APCEDI Coordinator
http://www.afap.org/apcedi/

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