Tag Archives: WP15

Tropical Storm Jongdari Forms Southwest of Iwo To

Tropical Storm Jongdari formed southwest of Iwo To on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Jongdari was located at latitude 20.9°N and longitude 136.9°E which put it about 410 miles (665 km) southwest of Iwo To.  Jongdari was moving toward the north at 10 m.p.h. (16 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 996 mb.

A distinct low level center of circulation developed within former Tropical Depression 15W on Tuesday afternoon and the Japan Meteorological Agency designated the system as Tropical Storm Jongdari.  The circulation of Jongdari was asymmetrical.  Most of the stronger thunderstorms were forming in bands north of the center.  Bands south of the center consisted primarily of showers and lower clouds.  Stronger storms near the center were beginning to generate upper level divergence which was pumping mass away from the core of the circulation.

Tropical Storm Jongdari will move through an environment favorable for intensification during the next several days.  Jongdari will move over water where the Sea Surface Temperature is near 28°C.  So, there will be sufficient energy in the upper ocean to support intensification.  It will move under the middle of an upper level ridge where the winds are weaker and there will be little vertical wind shear.  Intensification could be slow at first while the circulation becomes more organized, but Jongdari could strengthen more quickly when the inner core becomes more well developed.  Tropical Storm Jongari could strengthen to a typhoon with 48 hours.  It could eventually intensify into the equivalent of a major hurricane.

Tropical Storm Jongari will move around the western end of a subtropical ridge which will steer Jongari toward the northeast during the next two or three days.  When Jongari moves farther north, it will be affected by a second ridge located farther to the north.  The second ridge is forecast to strengthen and push Jongari more toward the northwest.  On its anticipated track Jongari could reach Iwo To in about 48 hours.  It could be a typhoon at that time.  Jongari could approach Tokyo in about four days and it is likely to be a typhoon when it reaches Honshu.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Wokung was churning well southeast of Japan.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Wokung was located at latitude 32.3°N and longitude 158.0°E which put it about 1250 miles (2015 km) east-southeast of Tokyo, Japan.  Wokung was moving toward the north-northwest at 11 m.p.h. (17 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 984 mb.

Tropical Storm Wukong Forms Southeast of Japan

Tropical Storm Wukong formed southeast of Japan on Monday.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Wukong was located at latitude 29.0°N and longitude 159.0°E which put it about 1370 miles (2210 km) east-southeast of Tokyo, Japan.  Wukong was moving toward the north at 24 m.p.h. (39 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and the were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 984 mb.

A cluster of thunderstorms developed southeast of Japan during the weekend and a low level center of circulation formed near the southwestern edge of the cluster of storms.  However, strong upper level winds blowing from the southwest kept blowing the top of the circulation northeast of the low level center and the system was unable to develop.  The upper level winds slowed on Monday and a band of showers and thunderstorms wrapped around the northern and western sides of the center of circulation.  The Japan Meteorological Agency designated the system as Tropical Storm Wukong.

The circulation of Tropical Storm Wukong organized quickly after the upper level winds weakened.   As mentioned above, a primary rainband wrapped around the northern and western sides of the center of circulation.  Storms in the primary rainband generated upper level divergence which was pumping mass away to the north of the tropical storm.  Several other bands of showers and thunderstorms developed in the eastern half of the circulation.  Bands south and west of the center consisted primarily of showers and lower clouds.

Tropical Storm Wukong will move through an environment favorable for intensification during the next day or so.  Wukong will move over water where the Sea Surface Temperature is near 27°C.  Wukong is moving along the eastern portion of an upper level trough.  The trough is producing southwesterly winds which are blowing toward the top of the circulation.  However, those winds weakened on Monday and they will not cause enough vertical wind shear to prevent further intensification.  Tropical Storm Wukong could strengthen into a typhoon during the next 24 to 36 hours.  Eventually, Wukong will move over cooler water and it will begin to weaken.

Tropical Storm Wukong is moving between an upper level trough to the west and an upper level ridge to the east.  The trough and ridge were combining to steer Wukong toward the north and a general northerly motion is expected to continue.  On its anticipated track Tropical Storm Wukong will stay west of the larger islands of Japan.  Wukong could approach the Kuril Islands in about three days.

Elsewhere over the Western North Pacific former Tropical Storm Ampil weakened to a tropical depression over land southeast of Beijing, China, Tropical Storm Son-tinh meandered near the coast of southeastern China and Tropical Depression 15W organized southwest of Iwo To, Japan.  At 5:00 p.m. EDT on Monday the center of Tropical Depression Ampil was located at latitude 38.8°N and longitude 117.6°E which put it about 110 miles (175 km) southeast of Beijing, China.  Ampil was moving toward the north-northwest at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 35 m.p.h. (55k km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 998 mb.  Tropical Depression Ampil was still dropping locally heavy rain over parts of eastern China.

At 5:00 p.m. EDT on Monday the center of Tropical Storm Son-tinh was located at latitude 21.2°N and longitude 109.0°E which put it about 40 miles (65 km) southeast of Beihai, China.  Son-tinh was moving toward the west-northwest at 6 m.p.h. (10 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 996 mb.  Tropical Storm Son-tinh was dropping locally heavy rain over parts of southeastern China and Hainan Island.

At 5:00 p.m. EDT on Monday the center of Tropical Depression 15W was located at latitude 17.6°N and longitude 136.3°E which put it about 585 miles (945 km) southwest of Iwo To, Japan.  It was moving toward the north-northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 998 mb.  The circulation of Tropical Depression 15W became more organized on Monday and it could eventually strengthen into a typhoon when it moves toward Iwo To later this week.

Tropical Storm Ampil Nears Landfall Southeast of Shanghai

Tropical Storm Ampil neared landfall on the coast of China southeast of Shanghai on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Ampil was located at latitude 31.0°N and longitude 122.3°E which put it about 60 miles (95 km) southeast of Shanghai, China.  Ampil was moving toward the west-northwest at 14 m.p.h. (22km/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 990 mb.

Tropical Storm Ampil moved steadily toward the coast of China on Saturday with little change of structure or intensity.  Drier air continued to circulate around the tropical storm and it limited the development of taller thunderstorms in much of Ampil.  The strongest thunderstorms were occurring in the inner portion of a band northwest of center of circulation.  The strongest winds were associated with those storms.  Bands around the rest of Tropical Storm Ampil consisted of showers and lower clouds.  Winds to tropical storm force extended out about 165 miles (270 km) from the center.

Tropical Storm Ampil will make landfall on the coast of China southeast of Shanghai in a few hours.  Ampil will cause gusty winds and the strong band of thunderstorms will drop locally heavy rain.  The heavy rain could cause flash floods in parts of eastern China.

Elsewhere the tropics became more active over the Western North Pacific Ocean on Saturday.  The remnants of former Tropical Storm Son-tinh were reorganizing west of Hainan Island over the Gulf of Tongking, Tropical Depression 13W moved east of Taiwan, and Tropical Depression 14W formed northwest of Wake Island and Tropical Depression 15W formed west of Guam.

At 11:00 p.m. EDT on Saturday the center of Tropical Depression Son-tinh was located at latitude 19.2°N and longitude 108.2°E which put it about 45 miles (75 km) west of Dongfeng, China.  Son-tinh was moving toward the east-southeast at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 999 mb.

Former Tropical Storm Son-tinh completed a slow clockwise loop over Laos and Vietnam which during the past several days and it emerged back over the Gulf of Tongking on Saturday.  There was a distinct low level center of circulation.  Bands of showers and thunderstorms were circulating around the enter.  The rainbands were dropping heavy rain over Hainan Island and creating the potential for flash floods.

At 11:00 p.m. EDT on Saturday the center of Tropical Depression 13W was located at latitude 21.6°N and longitude 122.9°E which put it about 165 miles (265 km) south-southeast of Hualien, Taiwan.  It was moving toward the northwest at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 998 mb.

At 11:00 p.m. EDT on Saturday the center of Tropical Depression 14W was located at latitude 22.5°N and longitude 159.4°E which put it about 370 miles (600 km) east-southeast of Minami Tori Shima.  It was moving toward the north at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 998 mb.

At 11:00 p.m. EDT on Saturday the center of Tropical Depression 15W was located at latitude 13.2°N and longitude 138.1°E which put it about 225 miles (365 km) north-northwest of Ulithi.  It was moving toward the northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 998 mb.

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.