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Tropical Storm Haishen (2008)
Encyclopedia
Tropical Storm Haishen was the twentieth officially recognized tropical storm of the 2008 Pacific typhoon season
. The tropical depression that was to become Tropical Storm Haishen formed late on November 14, as a minor tropical depression to the south of the Ogasawara Islands
, however the Japan Meteorological Agency
(JMA) did not start issuing advisories on it until early the next day. As the JMA were starting to issue advisories on the minor tropical depression, the Joint Typhoon Warning Center
(JTWC) reported that it was not expected to become a significant tropical cyclone within 24 hours as they anaylised the depression as subtropical
. During that afternoon the JMA upgraded the depression to a full tropical depression while the JTWC issued a Tropical Cyclone Formation Alert
on the developing depression as it had become Tropical. That evening, the JMA reported that the depression had become a tropical storm and named it as Haishen while the JTWC designated Haishen as Tropical Depression 25W. Early on November 16, the JTWC upgraded the depression to a tropical storm and then both the JMA and the JTWC declared it had reached its peak intensity with winds of 75 km/h (45 mph). At this time, the JTWC reported that there were signs in satellite imagery that Haishen had started its extratropical transition and then issued their final advisory 12 hours later. The JMA continued to issue advisories on Haishen for another 24 hours, when they declared that Haishen had become an extratropical low
. The extratropical low then raced across the Pacific Ocean and crossed the International Dateline later that day. There were no casualties or Impact reported from Haishen as it remained out to sea throughout its life.
(JMA) reported that a minor tropical depression had formed 490 km (304.5 mi) to the southeast of Iwo To. The JMA then started issuing advisories on the depression early the next day while the Joint Typhoon Warning Center
(JTWC) reported that Tropical Cyclone formation was unlikely within the next 24 hours. This was because multispectral satellite imagery had shown that deep convection was developing along the eastern portion of a transitioning Tropical upper tropospheric trough
. A QuickScat pass had also shown that a circulation which had previously been confined to the middle of the depression had spawned the development of a low level circulation center
. They also reported that the depression currently had a subtropical
cold core
but was transitioning into a tropical warm core
circulation and that a trough of low pressure
had introduced increasing vertical wind shear.
Later that day the JMA designated the low as a full tropical depression while later that afternoon, the JTWC reported that deep convection was now persisting along the eastern portion of a low level circulation center, and that the core was now a fully warm tropical core. Despite the low level circulation center progressing rapidly into an area of increasing vertical wind shear, the JTWC issued a Tropical Cyclone Formation Alert
on the system. During that evening the JMA upgraded the depression to a tropical storm and named it Haishen whilst, at the same time the JTWC designated Haishen as Tropical Depression 25W while it was located 900 km (559.2 mi) to the east of Iwo To.
Early on November 16, the JTWC upgraded the Haishen to a Tropical Storm and at the same time Haishen had reached both its 1-minute and 10-minute peak intensity with winds of 75 km/h (45 mph). At this time the JTWC reported that vertical wind shear had increased over the previous 12 hours, which had kept most of the deep convection confined to the eastern portion of the low level circulation center. They also reported that Haishen was traveling along the north portion of a subtropical ridge to the southeast of the system. Microwave imagery had shown that dry air was starting to wrap around the western part of the low level circulation center, they also noted that prefrontal features had appeared on satellite imagery which suggested that extratropical transition had started. The JTWC then issued their final warning later that day as they thought that Haishen was rapidly taking on extratropical characteristics and had lost most of its deep convection, frontal features had also become more pronounced within the last twelve hours. However, the JMA kept issuing advisories on Haishen for another 24 hours before declaring Haishen as extratropical. The extratropical low of Haishen accelerated towards the International Dateline and crossed into the central Pacific later that day. As an extratropical low, the system reintensified to storm intensity but weakened into a 65 km/h (40 mph) gale early on November 21.
The name Haishen was submitted to the World Meteorological Organisation's Typhoon Committee by the People's Republic of China
and was one of the original names submitted for use from January 1, 2000. The name Haishen is Chinese
for the God of the sea and was last used in the 2002 Pacific typhoon season
.
2008 Pacific typhoon season
The 2008 Pacific typhoon season has no official bounds; it runs year-round in 2008, but most tropical cyclones tend to form in the northwestern Pacific Ocean between May and November...
. The tropical depression that was to become Tropical Storm Haishen formed late on November 14, as a minor tropical depression to the south of the Ogasawara Islands
Ogasawara Islands
The Bonin Islands, known in Japan as the are an archipelago of over 30 subtropical and tropical islands, some directly south of Tokyo, Japan. Administratively, they are part of Ogasawara Municipality of Ogasawara Subprefecture, Tokyo...
, however the Japan Meteorological Agency
Japan Meteorological Agency
The or JMA, is the Japanese government's weather service. Charged with gathering and reporting weather data and forecasts in Japan, it is a semi-autonomous part of the Ministry of Land, Infrastructure and Transport...
(JMA) did not start issuing advisories on it until early the next day. As the JMA were starting to issue advisories on the minor tropical depression, 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 it was not expected to become a significant tropical cyclone within 24 hours as they anaylised the depression as subtropical
Subtropical cyclone
A subtropical cyclone is a weather system that has some characteristics of a tropical and an extratropical cyclone. As early as the 1950s, meteorologists were unclear whether they should be characterized as tropical or extratropical cyclones. They were officially recognized by the National...
. During that afternoon the JMA upgraded the depression to a full tropical depression while 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 developing depression as it had become Tropical. That evening, the JMA reported that the depression had become a tropical storm and named it as Haishen while the JTWC designated Haishen as Tropical Depression 25W. Early on November 16, the JTWC upgraded the depression to a tropical storm and then both the JMA and the JTWC declared it had reached its peak intensity with winds of 75 km/h (45 mph). At this time, the JTWC reported that there were signs in satellite imagery that Haishen had started its extratropical transition and then issued their final advisory 12 hours later. The JMA continued to issue advisories on Haishen for another 24 hours, when they declared that Haishen had become an extratropical low
Extratropical cyclone
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of cyclones defined as synoptic scale low pressure weather systems that occur in the middle latitudes of the Earth having neither tropical nor polar characteristics, and are connected with fronts and...
. The extratropical low then raced across the Pacific Ocean and crossed the International Dateline later that day. There were no casualties or Impact reported from Haishen as it remained out to sea throughout its life.
Meteorological history
Late on November 14, 2008, The Japan Meteorological AgencyJapan Meteorological Agency
The or JMA, is the Japanese government's weather service. Charged with gathering and reporting weather data and forecasts in Japan, it is a semi-autonomous part of the Ministry of Land, Infrastructure and Transport...
(JMA) reported that a minor tropical depression had formed 490 km (304.5 mi) to the southeast of Iwo To. The JMA then started issuing advisories on the depression early the next day 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...
(JTWC) reported that Tropical Cyclone formation was unlikely within the next 24 hours. This was because multispectral satellite imagery had shown that deep convection was developing along the eastern portion of a transitioning Tropical upper tropospheric trough
Tropical Upper Tropospheric Trough
A tropical upper tropospheric trough , also known as the mid-oceanic trough, is a trough situated in upper-level tropics. Its formation is usually caused by the intrusion of energy and wind from the mid-latitudes into the tropics. It can also develop from the inverted trough adjacent to an upper...
. A QuickScat pass had also shown that a circulation which had previously been confined to the middle of the depression had spawned the development of a low level circulation center
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...
. They also reported that the depression currently had a subtropical
Subtropical cyclone
A subtropical cyclone is a weather system that has some characteristics of a tropical and an extratropical cyclone. As early as the 1950s, meteorologists were unclear whether they should be characterized as tropical or extratropical cyclones. They were officially recognized by the National...
cold core
Polar cyclone
Polar cyclones are low-pressure areas which strengthen in the winter and weaken in the summer...
but was transitioning into a tropical warm core
Polar cyclone
Polar cyclones are low-pressure areas which strengthen in the winter and weaken in the summer...
circulation and that a trough of low pressure
Low pressure area
A low-pressure area, or "low", is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as...
had introduced increasing vertical wind shear.
Later that day the JMA designated the low as a full tropical depression while later that afternoon, the JTWC reported that deep convection was now persisting along the eastern portion of a low level circulation center, and that the core was now a fully warm tropical core. Despite the low level circulation center progressing rapidly into an area of increasing vertical wind shear, 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 system. During that evening the JMA upgraded the depression to a tropical storm and named it Haishen whilst, at the same time the JTWC designated Haishen as Tropical Depression 25W while it was located 900 km (559.2 mi) to the east of Iwo To.
Early on November 16, the JTWC upgraded the Haishen to a Tropical Storm and at the same time Haishen had reached both its 1-minute and 10-minute peak intensity with winds of 75 km/h (45 mph). At this time the JTWC reported that vertical wind shear had increased over the previous 12 hours, which had kept most of the deep convection confined to the eastern portion of the low level circulation center. They also reported that Haishen was traveling along the north portion of a subtropical ridge to the southeast of the system. Microwave imagery had shown that dry air was starting to wrap around the western part of the low level circulation center, they also noted that prefrontal features had appeared on satellite imagery which suggested that extratropical transition had started. The JTWC then issued their final warning later that day as they thought that Haishen was rapidly taking on extratropical characteristics and had lost most of its deep convection, frontal features had also become more pronounced within the last twelve hours. However, the JMA kept issuing advisories on Haishen for another 24 hours before declaring Haishen as extratropical. The extratropical low of Haishen accelerated towards the International Dateline and crossed into the central Pacific later that day. As an extratropical low, the system reintensified to storm intensity but weakened into a 65 km/h (40 mph) gale early on November 21.
Preparations, impact and naming
As Haishen remained out over open waters for the duration of its existence, there was no impact on any land-masses.The name Haishen was submitted to the World Meteorological Organisation's Typhoon Committee by the People's Republic of China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
and was one of the original names submitted for use from January 1, 2000. The name Haishen is Chinese
Chinese language
The Chinese language is a language or language family consisting of varieties which are mutually intelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the branches of Sino-Tibetan family of languages...
for the God of the sea and was last used in the 2002 Pacific typhoon season
2002 Pacific typhoon season
A Tropical Cyclone Formation Alert was issued on July 19 for a Tropical Disturbance that was located east of the international Date Line. The Next day the Disturbance crossed the international date line and was classified as a Tropical Depression by the JMA. The JMA then upgraded the depression to...
.
See also
2008 Pacific typhoon season2008 Pacific typhoon season
The 2008 Pacific typhoon season has no official bounds; it runs year-round in 2008, but most tropical cyclones tend to form in the northwestern Pacific Ocean between May and November...
- Timeline of the 2008 Pacific typhoon seasonTimeline of the 2008 Pacific typhoon seasonThis timeline documents all the storm formations, strengthening, weakening, landfalls, extratropical transitions, as well as dissipation during the 2008 Pacific typhoon season. The 2008 Pacific typhoon season officially started on January 1, 2008 and ended on January 1, 2009. The first tropical...