| Category 2 cyclone (Australian scale) | |
|---|---|
| Tropical Storm (SSHS) | |
| Tropical Cyclone Lin | |
| Formed | March 31, 2009 |
| Dissipated | April 8, 2009 |
| Highest winds | 10-minute sustained: 110 km/h (70 mph) 1-minute sustained: 100 km/h (65 mph) |
| Lowest pressure | 975 mbar (hPa; 28.79 inHg) |
| Fatalities | None reported |
| Damage | $1,000 (2009 USD) |
| Areas affected | Fiji, Tonga |
| Part of the 2008-09 South Pacific cyclone season | |
Tropical Cyclone Lin (RSMC Nadi designation: 14F, JTWC Designation: 15P) formed on March 31 as a tropical depression within a monsoon trough to the northwest of Fiji. Over the next few days, the depression moved towards the southeast through the Fijian archipelago until late on April 3, when the Regional Specialized Meteorological Center in Nadi reported that the depression had intensified into a category one cyclone, and named it Lin. The JTWC did not start issuing warnings on Lin until the next day as it was approaching its 10-minute peak windspeeds of 110 km/h (70 mph) and 1-minute peak windspeeds of 100 km/h (65 mph). Cyclone Lin then reached its peak windspeeds early on April 5 as it passed directly over Tonga. Later that day as it approached the edge of RSMC Nadi's area of responsibility Lin started to go through an extratropical transition with the JTWC issuing their last advisory on it. As it crossed into TCWC Wellington's area of responsibility the cyclone was declared extratropical, however TCWC Wellington kept issuing warnings on Lin until late on April 8.
In Tonga initial reports, suggested that only vegetation had been impacted. However, it was later reported that power lines had been knocked down by high winds and the heavy rains triggered minor flooding in Nuku'alofa. Power stations in Tongatapu were also forced to close to protect the system. No one was injured by the storm but there were reports of significant crop losses. The Tongan Meteorological Service also reported that about $2,000 2009 TOP, ($1,000 2009 USD) worth of damage had been done to property owned by the service.
Contents |
Late on March 31 2009, the Regional Specialized Meteorological Centre in Nadi, Fiji reported that a tropical depression had formed within a monsoonal trough of low pressure which was located to the northwest of Fiji and had a moderate level of vertical windshear.[1] The Depression at this stage was weak with its low level circulation center exposed with deep convection detached to the east.[1] Over the next few days the depression moved towards the southeast through the Fiji archipelago until late on April 2 when Nadi started to issue full advisories on the depression as convective banding was evident to the north of the system, however the depression was poorly organized at this time and was now located in an area of low shear.[2]
Late on April 3, RSMC Nadi reported that the depression had intensified into a category one tropical cyclone, on the Australian tropical cyclone intensity scale and named it as Lin whilst the cyclone was relocated to about 135 km (84 mi) to the south-west of Niuafo'ou.[3] Early the next day the JTWC started to issue warnings on Lin, designating it as Tropical Cyclone 25P, as Lin's low level circulation center had rapidly consolidated itself during the last 12 hours.[4] Later that morning RSMC Nadi reported that Lin had continued to intensify and had become a category 2 tropical cyclone, before early on April 5, Lin reached its 10-minute peak windspeeds of 110 km/h (70 mph) and 1-minute peak windspeeds of 100 km/h (65 mph) with the eye of Lin passing very close to the west of Tongatapu. At this stage Barometer and wind observations from the Meteorological service in Tonga suggested that the cyclone had a double eye wall.[5][6] Lin then started to weaken as deep convection becoming sheared to the southeast of Lin.[5] Outflow also became restricted with dry air being entrapped within the low level circulation center.[5] Later that day the JTWC issued their final warning on Lin as it had started its extratropical transition.[7] RSMC Nadi then passed primary warning responsibility of Lin to TCWC Wellington who immediately downgraded Lin to an extratropical cyclone.[8] TCWC Wellington then issued warnings on extratropical cyclone Lin until early on April 8 when they released their final advisory as it was moving towards Australia.[8]
The Regional Specialized Meteorological Center in Nadi, Fiji uses the Australian Tropical Cyclone Intensity Scale which is based on 10-minute sustained winds and three second gusts for its tropical cyclone tracking information, while the Joint Typhoon Warning Center uses 1-minute sustained winds.[9] The conversion factor between the two is 1.14.[10] RSMC Nadi's peak intensity for Lin was 110 km/h, (70 mph) 10-minute sustained, or 130 km/h (80 mph) 1-minute sustained.[5][10] The JTWC's peak intensity for Lin was 95 km/h (60 mph) 1-minute sustained, or 85 km/h (50 mph) 10-minute sustained.[10]
Late on April 2, RSMC Nadi reported that a tropical cyclone alert had been issued for Wallis and Futuna and for the whole of Tonga this came as the tropical depression was located about 500 km (310 mi) to the west of Nukualofa.[11][6] Early the next day RSMC Nadi reported that a tropical cyclone alert had been declared for Vanua Levu, the Lau islands, Taveuni, as well as other nearby islands, while later that morning Wallis and Futuna were placed under a tropical cyclone warning.[12][13] Later that day RSMC Nadi reported that Northern Tonga had now been placed under a tropical cyclone warning, while the tropical cyclone alert for Vanua Levu and the cyclone warning for Wallis had been canceled.[6][14][15] Later that day as the depression had been relocated and had been named as Cyclone Lin, RSMC Nadi canceled the tropical cyclone alert for Taveuni, and other nearby islands as well as the tropical cyclone warning for Futuna. RSMC Nadi also reported at this time that a tropical cyclone gale warning had been declared for the Lau group and the whole of Tonga.[16][6][17] During the next morning the tropical cyclone warnings for the Lau group and the Niuas in Tonga were canceled, while the gale warnings for Tonga were upgraded to storm warnings.[18][6] Over the next 24 hours the remaining warnings for Tonga were gradually canceled, with the last warning being issued at 1100 UTC on April 5.[6]
On April 4, Lin passed directly over Tonga with winds up to 110 km/h (70 mph) and heavy rains. Initial reports of damage stated that only vegetation had been impacted.[19] However, later reports stated that power lines had been knocked down by high winds and the heavy rains triggered minor flooding in Nuku'alofa. Some houses lost their rain gutters from the storm.[20] Due to strong winds, officials were forced to shut down power stations in Tongatapu to protect the system. Most of the power lines in Tonga were either downed or damaged by the storm and numerous trees fell across the island. Several roads were also blocked by downed trees and billboards were broken.[21] No one was injured by the storm but there were reports of significant crop losses.[22]
The Tongan Meteorological Service reported that some of its property and equipment had been damaged. The property damage had an approximate value of about $2,000 (2009 TOP, $1,000 2009 USD). This included a Stevenson screen, office guttering, a HF radio antennae, signal processor, and satellite receiver.[6] They also reported that the National weather forecasting center in Fua’amotu had experienced power failure on April 4 at 1600 UTC; for this reason the center operated using a small portable generator until early the next day when they stopped issuing warnings as Lin was no longer a threat to Tonga. Power was eventually restored later that day.[6]