Cyclone Lin (2009)
Encyclopedia
Tropical Cyclone Lin 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.
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
. The Depression at this stage was weak with its low level circulation center
exposed with deep convection
detached to the east. 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.
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 (83.9 mi) to the south-west of Niuafo'ou
. 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. 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. Lin then started to weaken as deep convection becoming sheared to the southeast of Lin. Outflow also became restricted with dry air being entrapped within the low level circulation center. Later that day the JTWC issued their final warning on Lin as it had started its extratropical transition. RSMC Nadi then passed primary warning responsibility of Lin to TCWC Wellington who immediately downgraded Lin to an extratropical cyclone. 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
.
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. The conversion factor between the two is 1.14. 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. 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.
and for the whole of Tonga
this came as the tropical depression was located about 500 km (310.7 mi) to the west of Nukualofa. 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. 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. 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. 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. 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.
. Some houses lost their rain gutter
s from the storm. 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. No one was injured by the storm but there were reports of significant crop losses.
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. 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.
Monsoon trough
The monsoon trough is that portion of the Intertropical Convergence Zone which extends into or through a monsoon circulation, as depicted by a line on a weather map showing the locations of minimum sea level pressure, and as such, is a convergence zone between the wind patterns of the southern and...
to the northwest of Fiji
Fiji
Fiji , officially the Republic of Fiji , is an island nation in Melanesia in the South Pacific Ocean about northeast of New Zealand's North Island...
. Over the next few days, the depression moved towards the southeast through the Fijian archipelago
Fiji
Fiji , officially the Republic of Fiji , is an island nation in Melanesia in the South Pacific Ocean about northeast of New Zealand's North Island...
until late on April 3, when the Regional Specialized Meteorological Center
Regional Specialized Meteorological Center
A Regional Specialized Meteorological Centre is responsible for the distribution of information, advisories, and warnings regarding the specific program they have a part of, agreed by consensus at the World Meteorological Organization as part of the World Weather Watch.-Tropical...
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
Tonga
Tonga, officially the Kingdom of Tonga , is a state and an archipelago in the South Pacific Ocean, comprising 176 islands scattered over of ocean in the South Pacific...
. 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
Meteorological Service of New Zealand Limited
Meteorological Service of New Zealand Limited was established as a State-Owned Enterprise in 1992. It employs about 215 staff and its headquarters are in Wellington, New Zealand...
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.
Meteorological history
Late on March 31 2009, the Regional Specialized Meteorological CentreRegional Specialized Meteorological Centre
A Regional Specialized Meteorological Centre is responsible for the distribution of information, advisories, and warnings regarding the specific program they have a part of, agreed by consensus at the World Meteorological Organization as part of the World Weather Watch.-Tropical...
in Nadi, Fiji reported that a tropical depression had formed within a monsoonal
Monsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...
trough of low pressure
Trough (meteorology)
A trough is an elongated region of relatively low atmospheric pressure, often associated with fronts.Unlike fronts, there is not a universal symbol for a trough on a weather chart. The weather charts in some countries or regions mark troughs by a line. In the United States, a trough may be marked...
which was located to the northwest of Fiji
Fiji
Fiji , officially the Republic of Fiji , is an island nation in Melanesia in the South Pacific Ocean about northeast of New Zealand's North Island...
and had a moderate level of vertical windshear
WindShear
The Windshear Full Scale Rolling Road Wind Tunnel is an automotive wind tunnel in Concord, North Carolina.In January 2008 Wind Shear, a division of US machine tool builder Haas Automat-80.7ion, completed construction on one of the most advanced automotive wind tunnels in the world. The full-scale...
. The Depression at this stage was weak with its low level circulation center
Eye (cyclone)
The eye is a region of mostly calm weather found at the center of strong tropical cyclones. The eye of a storm is a roughly circular area and typically 30–65 km in diameter. It is surrounded by the eyewall, a ring of towering thunderstorms where the second most severe weather of a cyclone...
exposed with deep convection
Atmospheric convection
Atmospheric convection is the result of a parcel-environment instability, or temperature difference, layer in the atmosphere. Different lapse rates within dry and moist air lead to instability. Mixing of air during the day which expands the height of the planetary boundary layer leads to...
detached to the east. 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
Banding
Banding is a medical procedure which uses elastic bands for constriction. Banding may be used to tie off blood vessels in order to stop bleeding, as in the treatment of bleeding esophageal varices. The band restricts blood flow to the ligated tissue, so that it eventually dies and sloughs away...
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.
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 (83.9 mi) to the south-west of Niuafo'ou
Niuafo'ou
Niuafoou is the most northerly island in the kingdom of Tonga. It is a volcanic rim island of 15 km² and with a population of 650 in 2006.-Geography:...
. 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. 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
Barometer
A barometer is a scientific instrument used in meteorology to measure atmospheric pressure. Pressure tendency can forecast short term changes in the weather...
and wind observations from the Meteorological service in Tonga suggested that the cyclone had a double eye wall. Lin then started to weaken as deep convection becoming sheared to the southeast of Lin. Outflow also became restricted with dry air being entrapped within the low level circulation center. Later that day the JTWC issued their final warning on Lin as it had started its extratropical transition. RSMC Nadi then passed primary warning responsibility of Lin to TCWC Wellington who immediately downgraded Lin to an extratropical cyclone. 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
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
Differences among warning centers
The Regional Specialized Meteorological CenterRegional Specialized Meteorological Center
A Regional Specialized Meteorological Centre is responsible for the distribution of information, advisories, and warnings regarding the specific program they have a part of, agreed by consensus at the World Meteorological Organization as part of the World Weather Watch.-Tropical...
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
Joint Typhoon Warning Center
The Joint Typhoon Warning Center is a joint United States Navy – United States Air Force task force located at the Naval Maritime Forecast Center in Pearl Harbor, Hawaii...
uses 1-minute sustained winds. The conversion factor between the two is 1.14. 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. 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.
Preparations
Late on April 2, RSMC Nadi reported that a tropical cyclone alert had been issued for Wallis and FutunaWallis and Futuna
Wallis and Futuna, officially the Territory of the Wallis and Futuna Islands , is a Polynesian French island territory in the South Pacific between Tuvalu to the northwest, Rotuma of Fiji to the west, the main part of Fiji to the southwest, Tonga to the southeast,...
and for the whole of Tonga
Tonga
Tonga, officially the Kingdom of Tonga , is a state and an archipelago in the South Pacific Ocean, comprising 176 islands scattered over of ocean in the South Pacific...
this came as the tropical depression was located about 500 km (310.7 mi) to the west of Nukualofa. Early the next day RSMC Nadi reported that a tropical cyclone alert had been declared for Vanua Levu
Vanua Levu
Vanua Levu , formerly known as Sandalwood Island, is the second largest island of Fiji. Located 64 kilometres to the north of the larger Viti Levu, the island has an area of 5,587.1 km² and a population of some 130,000.- Geography :...
, the Lau islands
Lau Islands
The Lau Islands of Fiji are situated in the southern Pacific Ocean, just east of the Koro Sea. Of this chain of about one hundred islands and islets, about thirty are inhabited...
, Taveuni
Taveuni
Taveuni is the third-largest island in Fiji, after Vanua Levu and Viti Levu, with a total land area of 435 square kilometers . The cigar-shaped island, a massive shield volcano which rises from the floor of the Pacific Ocean, is situated 6.5 kilometers to the east of Vanua Levu, across the...
, as well as other nearby islands, while later that morning Wallis and Futuna were placed under a tropical cyclone warning. 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
Vanua Levu
Vanua Levu , formerly known as Sandalwood Island, is the second largest island of Fiji. Located 64 kilometres to the north of the larger Viti Levu, the island has an area of 5,587.1 km² and a population of some 130,000.- Geography :...
and the cyclone warning for Wallis had been canceled. 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
Taveuni
Taveuni is the third-largest island in Fiji, after Vanua Levu and Viti Levu, with a total land area of 435 square kilometers . The cigar-shaped island, a massive shield volcano which rises from the floor of the Pacific Ocean, is situated 6.5 kilometers to the east of Vanua Levu, across the...
, 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. 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. 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.
Impact
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. However, later reports stated that power lines had been knocked down by high winds and the heavy rains triggered minor flooding in Nuku'alofaNuku'alofa
Nukualofa is the capital of the Kingdom of Tonga. It is located on the north coast of the island of Tongatapu, in the southern most island group of Tonga.-Mythological origins:...
. Some houses lost their rain gutter
Rain gutter
A rain gutter is a narrow channel, or trough, forming the component of a roof system which collects and diverts rainwater shed by the roof....
s from the storm. 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. No one was injured by the storm but there were reports of significant crop losses.
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
Stevenson screen
A Stevenson screen or instrument shelter is an enclosure to shield meteorological instruments against precipitation and direct heat radiation from outside sources, while still allowing air to circulate freely around them. It forms part of a standard weather station...
, office guttering, a HF radio antennae, signal processor, and satellite receiver. 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.
See also
- 2008-09 South Pacific cyclone season2008-09 South Pacific cyclone seasonThe 2008–09 South Pacific cyclone season began on December 1, 2008 with the formation of Tropical Disturbance 01F. This was 30 days after the season had officially begun on November 1, 2008. The season officially ended on April 30, 2009. Tropical cyclones that were between 160°E and 120°W and north...
- Timeline of the 2008-09 South Pacific cyclone season