Cyclone Hettie (2009)
Encyclopedia
Tropical Cyclone Hettie was the first named tropical cyclone in the South Pacific since Cyclone Gene
of 2008
. Late on January 24, the Regional Specialized Meteorological Centre
in Nadi, Fiji, reported that a weak tropical disturbance had formed within a monsoon trough, to the north of the Fijian dependency of Rotuma
. The next day after the disturbance had made landfall on Rotuma, it was designated as Tropical Depression 08F. A Tropical Cyclone Formation Alert
was released by the Joint Typhoon Warning Center
(JTWC), early on January 27. The depression was not upgraded to a tropical cyclone until the next day when it was named as Hettie by RSMC Nadi whilst the JTWC designated Hettie as Tropical Cyclone 11P. As Hettie moved towards the southeast it did not intensify any further and was downgraded to a depression the next day. Over the next couple of days it moved slowly towards the southeast and slowly weakened before being downgraded to an area of low pressure late on January 31. There was very little damage from Cyclone Hettie on Rotuma and in Tonga
with 55.8 mm of rainfall falling on Rotuma during January 24 and January 25. There was also no deaths reported within Fiji
or within Tonga.
in Nadi, Fiji, reported that a weak tropical disturbance had formed to the north of the Fijian dependency of Rotuma
. At this time the disturbance was located within a Monsoonal Trough, and in an environment of low vertical wind shear. Early on January 25, the tropical disturbance made landfall on Rotuma with winds of 35 km/h (25 mph). Later that day RSMC Nadi reported that the disturbance had organised enough to be classified as Tropical Depression 08F. During the afternoon of January 26 the Joint Typhoon Warning Center
(JTWC) reported that the low level circulation center, was located within an area of moderate vertical wind shear. They also reported that animated infrared imagery had shown that deep convection was flaring on the eastern boundary of the low level circulation center.
Early the next day, RSMC Nadi reported that there was a moderate to high chance of the tropical depression intensifying into a tropical cyclone within 24 hours. This was because good outflow channels existed to the north and south of the depression which were aiding the development of the depression. Later that morning the JTWC issued a Tropical Cyclone Formation Alert
on the depression, as animated multispectral imagery had indicated that the depression had a well-defined but wide low-level circulation center. They also reported that the convection was sheared to the east of the low level circulation center and predicted that an upper level trough that was to the west of the system could allow convection to build over the low level circulation center.
During the morning of January 28, RSMC Nadi reported that Tropical Depression 08F had intensified into Tropical Cyclone Hettie, they also reported that there was a possibility that Hettie could intensify further. However this did not occur and thus Hettie was a minimal Category One Tropical Cyclone on the Australian Tropical Cyclone Intensity Scale, at its peak, with winds of 65 km/h (40 mph). Later that day the JTWC designated Hettie as Tropical Cyclone 11P, and reported that Hettie had peak one-minute sustained winds of 65 km/h (40 mph). Early on January 29, the JTWC released their last advisory on Cyclone Hettie, whilst RSMC Nadi downgraded Cyclone Hettie to Tropical Depression 08F ex Hettie. Later that day RSMC Nadi reported that the depression had reached its secondary peak winds of 65 km/h (40 mph) to 75 km/h (45 mph). However they did not re-upgrade it to a Category One Cyclone as gales did not extend more than halfway around the center of the depression, thus they continued to call Hettie a depression. Over the next couple of days the depression moved towards the northwest and weakened before RSMC Nadi released their final Tropical Disturbance Summary late on January 31, as the depression had lost all its tropical characteristics and lied under an upper-level trough of low pressure.
for central and southern parts of Tonga. However later that day RSMC Nadi cancelled the issuance of the Special Weather Bulletins for Tonga as it was now moving to the southwest, and was no longer expected to recurve towards Tonga. On January 29, the Tongan National Disaster Office reported that there had been no reports of any major damage or deaths within Tonga from Hettie. Between January 24 and 25, 55.8 mm (2.19 inches) of rain fell on Rotuma. Despite the center of the disturbance passing directly over the island, there were no reports of damage.
Cyclone Gene
Severe Tropical Cyclone Gene was the deadliest storm as well as the most damaging tropical cyclone of the 2007–08 South Pacific cyclone season east of 160ºE...
of 2008
2007–08 South Pacific cyclone season
The 2007–08 South Pacific cyclone season was one of the least active tropical cyclone seasons on record, with only four tropical cyclones occurring within the South Pacific Ocean to the east of 160°E. The season officially ran from November 1, 2007 until April 30, 2008, although the first cyclone,...
. Late on January 24, the Regional Specialized Meteorological Centre
Regional 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 weak tropical disturbance had formed within a monsoon trough, to the north of the Fijian dependency of Rotuma
Rotuma
Rotuma is a Fijian dependency, consisting of Rotuma Island and nearby islets. The island group is home to a small but unique indigenous ethnic group which constitutes a recognizable minority within the population of Fiji, known as "Rotumans"...
. The next day after the disturbance had made landfall on Rotuma, it was designated as Tropical Depression 08F. A Tropical Cyclone Formation Alert
Tropical Cyclone Formation Alert
A Tropical Cyclone Formation Alert is a bulletin released by the U.S. Navy-operated Joint Typhoon Warning Center in Honolulu, Hawaii or the Naval Maritime Forecast Center in Norfolk, Virginia, warning of the possibility of a tropical cyclone forming from a tropical disturbance that has been...
was released by 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...
(JTWC), early on January 27. The depression was not upgraded to a tropical cyclone until the next day when it was named as Hettie by RSMC Nadi whilst the JTWC designated Hettie as Tropical Cyclone 11P. As Hettie moved towards the southeast it did not intensify any further and was downgraded to a depression the next day. Over the next couple of days it moved slowly towards the southeast and slowly weakened before being downgraded to an area of low pressure late on January 31. There was very little damage from Cyclone Hettie on Rotuma and in 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...
with 55.8 mm of rainfall falling on Rotuma during January 24 and January 25. There was also no deaths reported within 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...
or within Tonga.
Meteorological history
On January 24, 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 weak tropical disturbance had formed to the north of the Fijian dependency of Rotuma
Rotuma
Rotuma is a Fijian dependency, consisting of Rotuma Island and nearby islets. The island group is home to a small but unique indigenous ethnic group which constitutes a recognizable minority within the population of Fiji, known as "Rotumans"...
. At this time the disturbance was located within a Monsoonal Trough, and in an environment of low vertical wind shear. Early on January 25, the tropical disturbance made landfall on Rotuma with winds of 35 km/h (25 mph). Later that day RSMC Nadi reported that the disturbance had organised enough to be classified as Tropical Depression 08F. During the afternoon of January 26 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...
(JTWC) reported that the low level circulation center, was located within an area of moderate vertical wind shear. They also reported that animated infrared imagery had shown that deep convection was flaring on the eastern boundary of the low level circulation center.
Early the next day, RSMC Nadi reported that there was a moderate to high chance of the tropical depression intensifying into a tropical cyclone within 24 hours. This was because good outflow channels existed to the north and south of the depression which were aiding the development of the depression. Later that morning the JTWC issued a Tropical Cyclone Formation Alert
Tropical Cyclone Formation Alert
A Tropical Cyclone Formation Alert is a bulletin released by the U.S. Navy-operated Joint Typhoon Warning Center in Honolulu, Hawaii or the Naval Maritime Forecast Center in Norfolk, Virginia, warning of the possibility of a tropical cyclone forming from a tropical disturbance that has been...
on the depression, as animated multispectral imagery had indicated that the depression had a well-defined but wide low-level circulation center. They also reported that the convection was sheared to the east of the low level circulation center and predicted that an upper level trough that was to the west of the system could allow convection to build over the low level circulation center.
During the morning of January 28, RSMC Nadi reported that Tropical Depression 08F had intensified into Tropical Cyclone Hettie, they also reported that there was a possibility that Hettie could intensify further. However this did not occur and thus Hettie was a minimal Category One Tropical Cyclone on the Australian Tropical Cyclone Intensity Scale, at its peak, with winds of 65 km/h (40 mph). Later that day the JTWC designated Hettie as Tropical Cyclone 11P, and reported that Hettie had peak one-minute sustained winds of 65 km/h (40 mph). Early on January 29, the JTWC released their last advisory on Cyclone Hettie, whilst RSMC Nadi downgraded Cyclone Hettie to Tropical Depression 08F ex Hettie. Later that day RSMC Nadi reported that the depression had reached its secondary peak winds of 65 km/h (40 mph) to 75 km/h (45 mph). However they did not re-upgrade it to a Category One Cyclone as gales did not extend more than halfway around the center of the depression, thus they continued to call Hettie a depression. Over the next couple of days the depression moved towards the northwest and weakened before RSMC Nadi released their final Tropical Disturbance Summary late on January 31, as the depression had lost all its tropical characteristics and lied under an upper-level trough of low pressure.
Preparations and impact
Early on January 27, RSMC Nadi started to issue Special Weather Bulletins for Tonga, within them they issued a tropical cyclone gale alertGale warning
A gale warning is a warning issued by weather services in maritime locations about the existence of winds of gale force or above or the imminent occurrence of gales at sea...
for central and southern parts of Tonga. However later that day RSMC Nadi cancelled the issuance of the Special Weather Bulletins for Tonga as it was now moving to the southwest, and was no longer expected to recurve towards Tonga. On January 29, the Tongan National Disaster Office reported that there had been no reports of any major damage or deaths within Tonga from Hettie. Between January 24 and 25, 55.8 mm (2.19 inches) of rain fell on Rotuma. Despite the center of the disturbance passing directly over the island, there were no reports of damage.
See also
- 2008–09 South Pacific cyclone season
- Timeline of the 2008–09 South Pacific cyclone seasonTimeline of the 2008–09 South Pacific cyclone seasonThe 2008–09 South Pacific cyclone season was a below-average season with only six tropical cyclones occurring within the South Pacific between 160°E and 120°W...