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Typhoon Hato Brings Wind and Rain to Hong Kong

Typhoon Hato brought wind and rain to Hong Kong as the eye moved just south of the city.  At 11:00 p.m. EDT on Tuesday the center of Typhoon Hato was located at latitude 21.8°N and longitude 113.8°E which put it about 60 miles (95 km) south-southeast of Hong Kong.  Hato was moving toward the west-northwest at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 130 m.p.h. (210 km/h).  The minimum surface pressure was 963 mb.

Typhoon Hato intensified rapidly as it approached Hong Kong.  A circular eye with a diameter of 50 miles (80 km) developed at the center of Hato.  The eye was surrounded by a thick ring of strong thunderstorms and the strongest winds were occurring in that ring.  Additional bands of showers and thunderstorms were revolving around the core of Hato.  The size of the circulation around Typhoon Hato also increased significantly.  Winds to typhoon force extended out about 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out about 175 miles (280 km) from the center.

The Hurricane Intensity Index (HII) was 17.8.  The Hurricane Size Index (HSI) was 16.9 and the Hurricane Wind Intensity Size Index (HWISI) was 38.7.  Those indices indicate that Typhoon Hato is capable of producing serious regional wind damage.  Typhoon Hato could cause a storm surge of 6 to 9 feet (2 to 3 meters) along the coast.  Hato will also drop heavy rain over parts of China and flash floods could occur in some areas.

Typhoon Hato is being steered toward the west-northwest by a subtropical ridge northeast of the typhoon and that general motion is forecast to continue.  On its anticipated track the center of Typhoon Hato will make landfall west of Hong Kong in a few hours.  Hato will continue to move inland over southeastern China.   Typhoon Hato will weaken as it moves inland, but it could drop locally heavy rain over parts of Zizhiqu, Huangzu and Guangxi provinces.

Strengthening Typhoon Hato Nears China

Typhoon Hato strengthened to a typhoon as it moved closer to a landfall on the coast of China.  At 11:00 a.m. EDT on Tuesday the center of Typhoon Hato was located at latitude 20.9°N and longitude 116.6°E which put it about 225 miles (365 km) east-southeast of Hong Kong.  Hato was moving toward the west-northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (150 km/h).  The minimum surface pressure was 978 mb.

The organization of Typhoon Hato improved significantly in recent hours.  A circular eye developed at the center of circulation.  A ring of strong thunderstorms formed around the eye.  The strongest winds were occurring in the ring of storms around the eye.  Additional bands of showers and thunderstorms developed south and east of the center.   There were fewer showers and thunderstorms north and west of the center of circulation.  Thunderstorms in the core of Hato were generating strong upper level divergence which was pumping mass away to the south and east of the typhoon.  Hato is a fairly small typhoon.  Winds to typhoon force extend out about 20 miles (32 km) from the center of circulation.  Winds to tropical storm force extend out about 145 miles (230 km) from the center.

The Hurricane Intensity Index (HII) for Typhoon Hato is 10.4.  The Hurricane Size Index (HSI) is 8.3 and the Hurricane Wind Intensity Size Index (HWISI) is 18.7.

Typhoon Hato will move through an environment favorable for intensification until it makes landfall in China.  Hato will move over water where the Sea Surface Temperature is near 31°C.  An upper level ridge over China is producing easterly winds which are blowing toward the top of the circulation.  The strongest winds are north of Typhoon Hato and the vertical wind shear is moderate.  The shear could slow the rate of intensification, but it is not likely to prevent further intensification.

Typhoon Hato is being steered to the west-northwest by a subtropical ridge to the north of the typhoon and that general motion is expected to continue.  On its anticipated track Typhoon Hato will make landfall near Hong Kong in 12 to 18 hours.  Typhoon Hato will bring strong gusty winds and locally heavy rain to parts of eastern China.  Heavy rain could produce flash floods in some locations.  Hato will also generate a storm surge along the coast.

Tropical Storm Hato Forms Southeast of Taiwan

Tropical Storm Hato formed southeast of Taiwan on Sunday.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Hato was located at latitude 19.6°N and longitude 126.1°E which put it about 390 miles (630 km) east-southeast of Taitung, Taiwan.  Hato was moving toward the west-northwest at 15 m.p.h. (22 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1001 mb.

A low level center of circulation developed near the western edge of a cluster of thunderstorms southeast of Taiwan and the Japan Meteorological Agency designated the system as Tropical Storm Hato.  The structure of Tropical Storm Hato is very asymmetrical.  Most of the showers and thunderstorms are forming in the western half of the circulation.  There are some very tall strong thunderstorms west of the center of circulation.  An upper level ridge north of Hato is producing easterly winds which  are blowing toward the top of the tropical storm.  Those winds are limiting upper level divergence toward the east and they are probably the reason for the asymmetrical distribution of thunderstorms.

Tropical Storm Hato will move through an environment that will be somewhat favorable for intensification.  Tropical Storm Hato is moving over water where the Sea Surface Temperature is near 31°C.  The upper level ridge is creating moderate vertical wind shear, which is inhibiting intensification.  Tropical Storm Hato is likely to intensify, but it will do so more slowly because of the vertical shear.  Hato does have a chance to strengthen into a typhoon.

Hato is being steered toward the west-northwest by a subtropical ridge north of the tropical storm.  A general west-northwesterly motion is expected to continue for several more days.  On its anticipated track Tropical Storm Hato could reach the islands in the Luzon Strait or southern Taiwan in less than 36 hours.  Hato could make landfall on the east coast of China in less than three days.  Tropical Storm Hato will bring gusty winds and locally heavy rain when it passes near southern Taiwan and the islands in the Luzon Strait.

Tropical Storm Namtheun Bringing Wind and Rain to Southwest Kyushu

Tropical Storm Namtheun brought wind and rain to southwestern Kyushu on Saturday as the center moved just west of the coast.  At 8:00 p.m. EDT on Saturday the center of Tropical Storm Namtheun was located at latitude 31.4°N and longitude 129.6°E which put it about 85 miles (135 km) south of Nagasaki, Japan.  Namtheun was moving toward the north-northwest at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 985 mb.

Tropical Storm Namtheun has a small, but well organized circulation.  There is the remnant of the eye that existed when Namtheun was a typhoon.  A broken ring of thunderstorms surrounds the remnant eye.  Several spiral rainbands are rotating around just outside the small core of Namtheun.  Winds to tropical storm force extend out about 60 miles (95 km) from the center of circulation.

Tropical Storm Namtheun is moving through an environment that is marginally favorable for a tropical storm.  It is moving over water where the Sea Surface Temperature (SST) is near 29°C.  A large upper level trough is producing southerly winds which are blowing across the top of Tropical Storm Namtheun.  Those winds are generating moderate vertical wind shear and they are inhibiting the upper level divergence to the south of the tropical storm.  The marginally favorable environment could allow Tropical Storm Namtheun to maintain its intensity for another 12 to 24 hours.  After that time it will move over cooler SSTs and start to weaken faster.

The upper level trough is steering Tropical Storm Namtheun toward the north and that general motion is expected to continue for another 12 hours or so.  After that time, southwesterly winds are expected to turn Tropical Storm Namtheun more toward the northeast.  On its anticipated track Tropical Storm Namtheun will move close to Nagasaki, Fukuoka, Kitakyushu and the southwestern portion of Honshu.

Tropical Storm Namtheun’s small size should keep the wind damage minimal.  It could cause locally heavy rainfall and the potential for flooding, but the areal extent of any floods should be limited.

Typhoon Namtheun Heads for Southern Japan

Typhoon Namtheun spun up quickly on Thursday and moved steadily toward Kyushu in southern Japan.  At 11:00 p.m. EDT on Thursday the center of Typhoon Namtheun was located at latitude 26.6°N and longitude 130.8°E which put it about 335 miles (540 km) south of Kagoshima, Japan.  Namtheun was moving toward the north at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 975 mb.

Typhoon Namtheun developed quickly from a low pressure system along a surface trough.  Namtheun has a small but very well organized circulation.  It has a tiny pinhole eye surrounded by a ring of strong thunderstorms.  Several other rainbands are spiraling around the ring of strong thunderstorms.  The thunderstorms are generating upper level divergence which is pumping out mass in all directions.  The upper level divergence is slightly less to the west of the center of circulation.

Typhoon Namtheun is in an environment favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  Although there is a large upper level trough over eastern Asia which contains strong southwesterly winds, Typhoon Namtheun developed east of those strong winds.  It is in an area where the upper level winds are weaker and there is little vertical wind shear.  Namtheun is likely to intensify more during the next day or two.  However, Namtheun’s small circulation means that it will respond very rapidly to positive or negative changes in its surrounding environment.

A ridge to the east of Namtheun is steering the typhoon toward the north and that general motion is expected to continue for several more days.  On its anticipated track Typhoon Namtheun could be very near the southern tip of Kyushu within 48 hours.  It could bring strong winds and heavy rain to parts of southern Japan.