Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

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.

Banyan Rapidly Intensifies Into a Typhoon

Tropical Storm Banyan rapidly intensified into a typhoon on Saturday.  At 5:00 p.m. EDT on Saturday the center of Typhoon Banyan was located at latitude 20.8°N and longitude 164.3°E which put it about 165 miles (265 km) west-northwest of Wake Island.  Banyan was moving toward the north-northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 976 mb.

Banyan intensified rapidly from a tropical storm into a typhoon in less than 36 hours.  Banyan is a small well organized typhoon.  There is a small circular eye at the center of circulation.  The eye is surrounded by a ring of strong thunderstorms.  The strongest winds are occurring in that ring of storms.  A primary band of thunderstorms wraps around the eastern and northern sides of the core of Typhoon Banyan.  Other bands of showers and storms are revolving around the core of the typhoon.  Banyan has a small circulation.  Winds to typhoon force only extend out about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force only extend out about 100 miles (160 km) from the center.

Typhoon Banyan will continue to move through an environment that is favorable for intensification on Sunday.  Banyan will move over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Typhoon Banyan will continue to intensify during the next 24 hours and it could become the equivalent of a major hurricane.

Banyan is moving around the western end of a subtropical ridge, which is steering the typhoon toward the north-northwest.  Banyan is forecast to continue to move toward the north-northwest for another day or two.  On its anticipated track Typhoon Banyan will move away from Wake Island and the weather should improve on Sunday.

Tropical Storm Banyan Forms Near Wake Island

Tropical Storm Banyan formed quickly near Wake Island on Friday.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Banyan was located at latitude 17.9°N and longitude 167.2°E which put it about 140 miles (225 km) south-southeast of Wake Island.  Banyan was moving toward the west-northwest at 16 m.p.h. (26 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 1003 mb.

The circulation of Tropical Storm Banyan organized quickly.  It developed a distinct center of circulation.  Thunderstorms formed north and south of the center, but there were more thunderstorms south of the center.  Additional bands of showers and thunderstorms began to develop in the outer parts of the circulation.  The thunderstorms in the core of Tropical Storm Banyan were generating upper level divergence which was pumping away mass.  The circulation of Tropical Storm Banyan is relatively small.  Winds to tropical storm force only extend out about 40 miles (65 km) from the center of circulation.

Tropical Storm Banyan will move through an environment that will be favorable for intensification.  Banyan will move over water where the Sea Surface Temperature is near 30.5°C.  An upper level ridge north of Banyan is producing easterly winds which are blowing toward the top of the circulation.  Those winds are weak and there is not much vertical wind shear.  Tropical Storm Banyan is likely to intensify during the next day or two and it could intensify quickly at times.

Tropical Storm Banyan is moving near the western end of a subtropical ridge to its north.  The ridge is currently steering Banyan toward the west-northwest, but the tropical storm is expected to turn more toward the north when it reaches the end of the ridge.  On its anticipated track Tropical Storm Banyan will move over Wake Island in about 12 hours.  Banyan will cause gusty winds and heavy rain when it moves over Wake Island.

Typhoon Noru Skirts Coast of Shikoku on Way to Honshu

The eye of Typhoon Noru skirted the coast of Shikoku on Sunday as it moved closer to a landfall on Honshu.  At 11:00 p.m. EDT on Sunday the center of Typhoon Noru was located at latitude 33.6°N and longitude 134.5°W which put it about 85 miles (135 km) southwest of Osaka, Japan.  Noru was moving toward the northeast at 14 m.p.h. (22 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 970 mb.

The structure of Typhoon Noru improved on Sunday.  The circulation contracted around an eye with a diameter of approximately 20 miles (32 km).  They eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in the ring of storms.  Additional spiral bands were revolving around the core of Typhoon Noru.

An upper level trough northwest of Japan steered Typhoon Noru toward the northeast on Sunday.  The eye of Noru moved near the south coast of Shikoku.  The eye passed south of Kochi and very near Muroto, Toyo and Kainan.  Typhoon Noru brought gusty winds and heavy rain to the southern parts of Shikoku.

Typhoon Noru is expected to continue to move toward the northeast on Monday.  On its anticipated track the center of Typhoon Noru is expected to skirt the east coast of Shikoku and make landfall on Honshu near Wakayama.   After it makes landfall, Typhoon Noru is forecast to pass near Osaka and Kyoto.  Typhoon Noru will weaken as it moves across Honshu, but it will produce gusty winds and locally heavy rain.  The rain could cause floods in some locations.

Typhoon Noru Reaches Kyushu

The eye of Typhoon Noru reached the southern coast of Kyushu near Uchinoura on Saturday.  At 11:00 p.m. EDT on Saturday the center of of Typhoon Noru was located at latitude 31.0°N and longitude 131.2°E which put it about 65 miles (105 km) south-southwest of Miyazaki, Japan.  Noru was moving toward the northeast at 8 m.p.h. (13 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 970 mb.

Typhoon Noru weakened as it made a slow clockwise loop on Saturday.  The winds of the typhoon may have mixed cooler water to the surface of the ocean.  Typhoon Noru also appears to be drawing cooler, drier air into the northern half of the circulation.  There is still an eye at the center of Noru, but the strong thunderstorms are all in the southern half of the circulation.  The strongest winds are occurring in the thunderstorms at the southern edge of the eye.  There are several bands of showers and thunderstorms outside the core of Typhoon Noru.

Typhoon Noru is moving over water where the Sea Surface Temperature is near 29°C.  So, there is sufficient energy to support the circulation of a typhoon.  However, drier air in the northern half of the circulation is reducing the amount of energy that is reaching the core of the typhoon.  An upper level trough is approaching Typhoon Noru from the west and the vertical wind shear will increase when the trough gets closer to the typhoon.  Typhoon Noru could maintain its intensity for another 12 to 18 hours, but eventually the combination of drier air, more vertical shear and interaction with land will cause Noru to weaken.

Typhoon Noru was in an area where the steering currents were weak and it made a slow, tight clockwise loop on Saturday.  The upper level trough approaching from the west will start to steer Typhoon Noru toward the northeast.  Noru will move along the south coast of Kyushu.  On its anticipated path the center of Typhoon Noru could be near Kochi on the south coast of Shikoku in about 24 hours.  Noru could be near Osaka and Kyoto on Honshu in about 36 hours.

Typhoon Noru has the potential to bring strong winds, heavy rain and the potential for floods to southern Kyushu, Shikoku and parts of Honshu.

Typhoon Noru Bringing Wind and Rain to Northern Ryukyu Islands

Typhoon Noru was bringing gusty winds and heavy rain to the northern Ryukyu Islands on Friday.  At 5:00 p.m. EDT on Friday the center of Typhoon Noru was located at latitude 29.3°N and longitude 130.3°E which put it about 90 miles (140 km) south of Kagoshima, Japan.  Noru was moving toward the northwest at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 90 m.p.h. (140 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 959 mb.

The structure of Typhoon Noru has not changed much during the past 24 hours.  A large eye with a diameter of approximately 80 miles (130 km) occupies the center of the typhoon.  A broken eyewall surrounds the eye.  Strong thunderstorms surround the eastern side of the eye, while a broken ring of weaker showers and storms mark the western edge of the eye.  The strongest winds are occurring in the thunderstorms on the eastern edge of the eye.  Thunderstorms in the core of the circulation are generating upper level divergence which is pumping away mass in all directions.  A primary rainband extends from the eastern side of Typhoon Noru around the southern and western sides of the circulation.  Several other shorter bands are outside this primary rainband.  Typhoon Noru continues to exhibit a structure similar to an annular hurricane.

Although the core of Typhoon Noru is fairly large, the overall size of the storm is not as big as some typhoons.  Winds to typhoon force extend out about 40 miles in all directions from the center of circulation.  Winds to tropical storm force extend out about 160 miles (260 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Noru is 13.9.  The Hurricane Size Index (HSI) is 17.0 and the Hurricane Wind Intensity Size Index (HWISI) is 30.9.

Typhoon Noru will be in an environment favorable for intensification for about another 24 hours.  Noru will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge north of Noru is producing northerly winds which are blowing toward the top of the typhoon.  Those winds are fairly weak and there is not much vertical wind shear.  Typhoon Noru is likely to intensify during the next 24 hours and it could strengthen into the equivalent of a major hurricane again.  In a day or so, an upper level trough will approach from the west and wind shear will increase.  Typhoon Noru will weaken faster after it makes landfall in Kyushu.

Typhoon Noru is moving slowly around the western end of a subtropical ridge.  Noru is in an area where the steering currents are weak and the will remain weak for another 24 to 48 hours.  An upper level trough will approach Noru from the west in a day or so.  Southwesterly winds ahead of the trough will start to steer Typhoon Noru toward the northeast at a faster rate.  On its anticipated track Typhoon Noru could make landfall in Kyushu in less than 36 hours.

The large core and strength of Typhoon Noru make it capable of bringing strong winds and heavy rain to a large area.  Typhoon Noru will continue to bring wind and rain to the northern Ryukyu Islands for another 24 to 36 hours.  Noru could also cause wind damage, heavy rain and floods on Kyushu, Shikoku and western Honshu when it moves over those regions.

Typhoon Noru Threatens Southwestern Japan

Typhoon Noru posed an increased threat to southwestern Japan as it slowly moved closer on Thursday.  At 11:00 p.m. EDT on Thursday the center of Typhoon Noru was located at latitude 28.6°N and longitude 131.3°E which put it about 145 miles (235 km) south-southeast of Kagoshima, Japan.  Noru was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were gusts to 105 m.p.h. (170 km/h).  The minimum surface pressure was 962 mb.

Although Noru is still a powerful and dangerous typhoon, it is not quite as well organized as it was several days ago.  A very large eye with a diameter of 95 miles (150 km) is at the center of circulation.  A broken ring of thunderstorms surrounds the eye.  There are breaks on both the eastern and western sides of the eyewall.  A broad rainband wraps around the southern and eastern sides of the circulation.  Thunderstorms in the core of Noru are generating strong upper level divergence which is pumping mass away from the typhoon.  There are few showers and thunderstorms in the northwestern quadrant and there may be drier air in that part of Typhoon Noru.

Winds to typhoon force extend out about 40 miles (65 km/h) from the center of circulation.  Winds to tropical storm force extend out about 185 miles (295 km/h) from the center.  The Hurricane Intensity Index (HII) for Typhoon Noru is 12.7.  The Hurricane Size Index (HSI) is 16.4 and the Hurricane Wind Intensity Size Index (HWISI) is 29.1

Typhoon Noru will move through an environment that may be somewhat favorable for intensification.  Noru will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge northwest of Noru is producing northeasterly winds which are blowing toward the top of the typhoon.  Those winds are creating moderate vertical wind shear.  The typhoon could also pull in drier air on the northwestern side of the circulation.  Even though the environmental factors are mixed, some intensification may be possible during the next 24 to 48 hours.

Typhoon Noru is approaching the western end of a subtropical ridge which has been steering the typhoon toward the west.  Noru is forecast to slow as the steering currents weaken.  Typhoon Noru is forecast to turn slowly northward during the next 24 hours.  In about 48 hours westerly winds in the middle latitudes will begin to carry the typhoon more quickly toward the northeast.  On its anticipated track Typhoon Noru could approach the northern Ryukyu Islands on Friday.  It could bring strong winds to Amami-O-Shima.  The center could pass near Yaku-Shima and Tanega-Shima during the weekend.  In a little over two days Typhoon Noru could reach southwestern Kyushu.  Typhoon Noru has the potential to bring strong winds and heavy rain to parts of southwestern Japan during the next few days.  The heavy rain could also cause flash floods.

Typhoon Noru Turns Toward Southwestern Japan

Typhoon Noru turned toward southwestern Japan on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Typhoon Noru was located at latitude 25.6°N and longitude 136.2°E which put it about 525 miles (850 km) south-southeast of Miyazaki, Japan.  Noru was moving toward the northwest at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 942 mb.

Typhoon Noru has a very symmetrical circulation that looks similar to what are sometimes called annular hurricanes.  There is a large circular eye at the center of Typhoon Noru.  The eye has a diameter of 35 miles (55 km).  The eye is surrounded by a wide ring of strong thunderstorms.  There are few bands of showers and thunderstorms outside the core of the typhoon.  The thunderstorms in the core of Noru are generating strong upper level divergence which is pumping mass away from the typhoon.

Typhoon Noru will be moving through a favorable environment during the next several days.  Noru will move over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Typhoons and hurricanes that have an annular structure like that of Typhoon Noru tend to maintain a fairly steady intensity.  Given the favorable environment, Noru could strengthen during the next few days.

A subtropical ridge is steering Typhoon Noru slowly toward the northwest.  The ridge is forecast to strengthen and to steer Noru more toward the west-northwest during the next several days.  On its anticipated track Typhoon Noru could approach southwestern Japan in about three days.