Tag Archives: Taiwan

Tropical Storm Jebi Forms West of the Northern Marianas

Tropical Storm Jebi formed west of the Northern Marianas on Friday.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Jebi was located at latitude 18.7°N and longitude 144.6°E which put the center about 60 miles (95 km) west-northwest of Agrihan. Jebi was moving toward the north-northwest at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 45 m.p.h. (65 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1001 mb.

A low pressure system west of the Northern Marianas strengthened on Friday and the Japan Meteorological Agency designated the system as Tropical Storm Jebi.  The circulation around Tropical Storm Jebi was poorly organized.  Thunderstorms were occurring in the southeastern quadrant of Jebi’s circulation.  There were no thunderstorms near the center of Tropical Storm Jebi.  Bands in the other parts of Jebi’s circulation consisted primarily of showers and lower clouds.

Tropical Storm Jebi will move through an environment somewhat favorable for intensification during the next 24 hours.  Jebi will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the southeastern part of an upper level ridge south of Japan.  The upper level ridge will produce northeasterly winds that will blow toward the top of Jebi’s circulation.  Those winds will cause moderate vertical wind shear.  The wind shear will inhibit intensification.  Tropical Storm Jebi could intensify a little during the next 24 hours, if the wind shear does not get any stronger.

Tropical Storm Jebi will move around the western side of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Jebi toward the northwest during the next 24 hours.  On its anticipated track, Tropical Storm Jebi will move slowly away from the Northern Marianas.  Jebi could approach Iwo To in 36 hours.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 20W formed south-southeast of Taiwan.  At 11:00 a.m. EDT on Friday the center of Tropical Depression 20W was located at latitude 19.6°N and longitude 125.8°E which put the center about 430 miles (690 km) south-southeast of Taipei, Taiwan.  The tropical depression was moving toward the southwest at 7 m.p.h. (11 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 1001 mb.

Typhoon Gaemi Batters Taiwan

Typhoon Gaemi battered Taiwan on Wednesday.  At 11:00 a.m. EDT on Wednesday the center of Typhoon Gaemi was located at latitude 24.0°N and longitude 121.4°E which put the center about 100 miles (160 km) south of Taipei, Taiwan.  Gaemi was moving toward the northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 928 mb.

The inner end of a rainband wrapped around the existing eye and eyewall of Typhoon Gaemi as it approached the east coast of Taiwan.  Concentric eyewalls formed in the core of Gaemi’s circulation.  The diameter of the inner eye was 7 miles (11 km).  The inner eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Gaemi.

The inner eye of Typhoon Gaemi began to make a counterclockwise loop inside the outer eyewall as Gaemi neared the east coast of Taiwan.  Mountains in Taiwan also deflected winds blowing around the western side of Typhoon Gaemi.  The deflection of the winds by the mountains also contributed to the counterclockwise loop of the inner eye.  The inner eye made landfall near Yilan City after it completed the counterclockwise loop.

The circulation around Typhoon Gaemi was large.  Winds to typhoon force extended out 105 miles (165 km) from the center of Gaemi’s circulation.  Winds to tropical storm force extended out 315 miles (510 km) from the center of Typhoon Gaemi.

Typhoon Gaemi was the equivalent of a major hurricane at the time of landfall.  The Hurricane Intensity Index (HII) was 23.6.  The Hurricane Size Index (HSI) was 35.2 and the Hurricane Wind Intensity Size Index (HWISI) was 58.8.  Typhoon Gaemi was as strong as Hurricane Katrina was when Katrina made landfall on the coast of the Gulf of Mexico in 2005.  Gaemi was larger than Katrina was when Katrina made landfall.

Typhoon Gamei was producing strong winds in Taiwan.  Gaemi was also dropping very heavy rain over parts of Taiwan.  Prolonged heavy rain is likely to cause flash floods in many locations.  Typhoon Gaemi was also causing a storm surge of up to 13 feet (4 meters) along the coast of northern Taiwan where the wind was blowing water toward the coast.

Typhoon Gaemi will move toward the northwest during the next 24 hours.  Gaemi will continue to produce strong winds and heavy rain in Taiwan for another 12 to 24 hours.  The center of Typhoon Gaemi will move over the Taiwan Strait in a few hours.  Gaemi will make another landfall on the east coast of China in about 18 hours.

Typhoon Gaemi Strengthens to Equivalent of a Major Hurricane

Typhoon Gaemi strengthened to the equivalent of a major hurricane east of Taiwan on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Typhoon Gaemi was located at latitude 23.1°N and longitude 123.2°E which put the center about 200 miles (325 km) southeast of Taipei, Taiwan.  Gaemi was moving toward the northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there were wind gusts to 165 m.p.h. (265 km/h).  The minimum surface pressure was 948 mb.

Typhoon Gaemi rapidly intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale east of Taiwan on Tuesday.  A small circular eye with a diameter of 6 miles (10 km) formed at the center of Gaemi’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storm.  Bands of showers and thunderstorms were revolving around the core of Typhoon Gaemi.  Storms near the core generated strong upper level divergence that pumped mass away from the typhoon.  The removal of large amounts of mass caused the surface pressure to decrease rapidly.

The circulation around Typhoon Gaemi was large.  Winds to typhoon force extended out 100 miles (160 km) from the center of Gaemi’s circulation.  Winds to tropical storm force extended out 345 miles (555 km) from the center of Typhoon Gaemi.

The Hurricane Intensity Index (HII) for Typhoon Gaemi was 28.3.  The Hurricane Size Index (HSI) was 31.0 and the Hurricane Wind Intensity Size Index (HWISI) was 59.3.  Typhoon Gaemi was similar in size to Hurricane Wilma when Wilma hit South Florida in 2005.  Gaemi is stronger than Wilma was when it hit South Florida.

Typhoon Gaemi will move through an environment favorable for intensification during the next 12 hours.  Gaemi will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the axis of an upper level ridge over the Western North Pacific Ocean.  The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear.  Typhoon Gaemi could continue to intensify during the next 12 hours.

Typhoon Gaemi will move around the western part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Typhoon Gaemi toward the northwest during the next 24 hours.  On its anticipated track, Typhoon Gaemi will approach the coast of northeastern Taiwan in 12 hours.

Typhoon Gaemi will bring very strong winds and torrential rain to Taiwan.  Gaemi will be capable of causing extensive severe damage.  Heavy rain is likely to cause widespread flash floods.  Typhoon Gaemi will also be capable of causing a storm surge of up to 13 feet (4 meters) along the east coast of Taiwan.

Typhoon Gaemi will also bring strong winds and heavy rain to the southern Ryukyu Islands.  The strongest part Gaemi’s circulation will pass southwest of the Ryukyu Islands, but the typhoon is likely to some wind damage.  Heavy rain could cause flash floods in some locations.

Typhoon Gaemi will move toward the east coast of China after is crosses northern Taiwan.  Gaemi could approach the coast of China in less than 36 hours.  Typhoon Gaemi will weaken when it moves over Taiwan, but Gaemi could still be a typhoon when it reaches China.

Elsewhere, former Tropical Storm Prapiroon weakened to a tropical depression over northern Vietnam.  At 11:00 a.m. EDT on Tuesday the center of Tropical Depression Prapiroon was located at latitude 22.0°N and longitude 107.0°E which put the center about 25 miles (40 km) northeast of Lang Son, Vietnam.  Prapiroon was moving toward the north-northwest at 5 m.p.h. (8 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 994 mb.

Gaemi Intensifies to Typhoon Southeast of Taiwan

Former Tropical Storm Gaemi intensified to a typhoon over the Western North Pacific Ocean southeast of Taiwan on Monday.  At 5:00 p.m. EDT on Monday the center of Typhoo Gaemi was located at latitude 18.8°N and longitude 124.7°E which put the center about 405 miles (655 km) southeast of Hualien, Taiwan.  Gaemi was moving toward the west at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 977 mb.

Former Tropical Storm Gaemi exhibited more organization on Monday as it strengthened to a typhoon.  The inner end of a rainband wrapped around the center of Gaemi’s circulation.  An eye appeared to be forming at the center of Typhoon Gaemi.  A ring of showers and thunderstorms surrounded the developing eye.  The ring was thickest in the southeastern side of the eye and thinnest in the northwestern side.  Other bands of thunderstorms were occurring southern and eastern parts of Gaemi’s circulation.  Bands in the northern and western parts of Typhoon Gaemi consisted primarily of showers and lower clouds.

Winds to typhoon force extended out 45 miles (75 km) from the center of Typhoon Gaemi.  Winds to tropical storm force extended out 155 miles (250 km) from the center of Gaemi’s circulation.

Typhoon Gaemi will move through an environment favorable for intensification during the next 24 hours.  Gaemi will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the axis of an upper level ridge over the Western North Pacific Ocean.  The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear.  Typhoon Gaemi will continue to intensify during the next 24 hours.

Typhoon Gaemi will move around the western part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Typhoon Gaemi toward the northwest during the next 24 hours.  On its anticipated track, Typhoon Gaemi will approach the east coast of Taiwan in 36 hours.

Typhoon Gaemi will bring strong winds and heavy rain to Taiwan during the middle of the week.  Heavy rain is likely to cause flash floods.

Elsewhere, Tropical Storm Prapiroon brought wind and rain to northern Vietnam.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Prapiroon was located at latitude 21.2°N and longitude 107.9°E which put the center about 40 miles (65 km) east of Cam Pha, Vietnam.  Prapiroon was moving toward the northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 985 mb.

Tropical Storm Prapiroon Brings Wind and Rain to Hainan

Tropical Storm Prapiroon brought wind and rain to Hainan on Sunday.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Prapiroon was located at latitude 19.1°N and longitude 109.9°E which put the center about 65 miles (105 km) south-southwest of Haikou, China.  Prapiroon was moving toward the northwest at 13 m.p.h. (21 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 992 mb.

Tropical Storm Prapiroon intensified on Sunday before the center moved over Hainan.  Microwave satellite images indicated that an eye was in the process of forming at the center of Prapiroon’s circulation as the tropical storm made landfall in Hainan.  The formative eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Tropical Storm Prapiroon.

Winds to tropical storm force extended out 70 miles (110 km) from the center of Tropical Storm Prapiroon.

The center of Tropical Storm Prapiroon made landfall on the south coast of Hainan near Lingshui.  The core of Prapiroon’s circulation moved across the center of Hainan.  Storms near the center of Tropical Storm Prapiroon brought heavy rain and strong winds to much of Hainan.  Bands in the northern part of Hainan’s circulation were also bringing gusty winds and heavy rain to parts of southern China.

Tropical Storm Prapiroon will move around the southern side of a high pressure system over southern China.  The high pressure system will steer Prapiroon toward the northwest during the next 24 hours.  On its anticipated track Tropical Storm Prapiroon will move over the Gulf of Tonkin on Monday.  The center of Prapiroon’s circulation could approach the southern coast of China in 24 hours.

Tropical Storm Prapiroon will continue to cause strong winds and locally heavy rain in Hainan during the next few hours.  Heavy rain could cause flash floods in some locations.  Prapiroon will also bring gusty winds and heavy rain to parts of southern China and northeastern Vietnam.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Gaemi strengthened east of Luzon.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Gaemi was located at latitude 17.2°N and longitude 125.7°E which put the center about 525 miles (845 km) south of Ishigakijima, Japan.  Gaemi was moving toward the north-northwest at 3 m.p.h. (5 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 992 mb.

Tropical Storm Prapiroon Forms Over South China Sea

Tropical Storm Prapiroon formed over the South China Sea on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Prapiroon was located at latitude 16.3°N and longitude 111.2°E which put the center about 260 miles (460 km) south-southeast of Haikou, China.  Prapiroon was moving toward the west at 5 m.p.h. (8 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 998 mb.

Former Tropical Depression 04W strengthened on Saturday night and the Japan Meteorological Agency designated the system as Tropical Storm Prapiroon.  The circulation around Tropical Storm Prapiroon was exhibiting a little more organization.  There were not a lot of thunderstorms near the center of Prapiroon’s circulation.  Thunderstorms were occurring in bands revolving around the center of Tropical Storm Prapiroon.

Although the circulation around Tropical Storm Prapiroon was large, the area of stronger winds was relatively small.  Winds to tropical storm force extended out 60 miles (95 km) from the center of Prapiroon’s circulation.

Tropical Storm Prapiroon will move through an environment somewhat favorable for intensification during the next 24 hours.  Prapiroon will move over water where the Sea Surface Temperatures are near 30°C.   It will move under the southeastern part of an upper level ridge over China.  The upper level ridge will produce northeasterly winds that will blow toward the top of Prapiroon’s circulation.  Those winds will cause moderate vertical wind shear.  The wind shear will inhibit intensification but the shear may not be strong enough to prevent some strengthening.  Tropical Storm Prapiroon could intensify a little during the next 24 hours.

Tropical Storm Prapiroon will move around the southern part of a high pressure system over eastern China.  The high pressure system will steer Prapiroon toward the northeast during the next 24 hours.  On its anticipated track Tropical Storm Prapiroon will move toward Hainan.

Tropical Storm Prapiroon will bring gusty winds and heavy rain to Hainan during the next 24 hours.  Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Gaemi strengthened gradually east of the Philippines.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Gaemi was located at latitude 17.0°N and longitude 125.5°E which put the center about 485 miles (780 km) south of Ishigakijima, Japan.  Gaemi was moving toward the west-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 996 mb.

Tropical Storm Gaemi Forms East of the Philippines

Tropical Storm Gaemi formed over the Western North Pacific Ocean east of the Philippines early on Saturday.   At 5:00 a.m. EDT on Saturday the center of Tropical Storm Gaemi was located at latitude 16.1°N and longitude 128.2°E which put the center about 520 miles (840 km) south-southeast of Ishigakijima, Japan.  Gaemi was moving toward the northwest at 14 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 1002 mb.

A low pressure system over the Western North Pacific Ocean east of the Philippines strengthened early on Saturday and the Japan Meteorological Agency designated the system as Tropical Storm Gaemi.  The circulation around Tropical Storm Gaemi was starting to exhibit more organization.  More thunderstorms were forming near the center of Gaemi’s circulation.  Thunderstorms were also developing in bands revolving around the center of Tropical Storm Gaemi.  Storms near the center of Gaemi started to generate upper level divergence that pumped mass away from the tropical storm.

Tropical Storm Gaemi will move through an environment favorable for intensification during the next 24 hours.  Gaemi will move over water where the Sea Surface Temperatures are near 30°C.   It will move under the western part of an upper level ridge over the Western North Pacific Ocean.  The upper level ridge will produce southeasterly winds that will blow toward the top of Gaemi’s circulation.  Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification.  Tropical Storm Gaemi is likely to intensify gradually during the next 24 hours.  Gaemi could strengthen to a typhoon by early next week.

Tropical Storm Gaemi will move around the western part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Gaemi toward the northwest during the next 24 hours.  On its anticipated track, Tropical Storm Gaemi will move toward the southern Ryukyu Islands.  Gaemi could be a typhoon when it approaches the southern Ryukyu Islands early next week.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 04W formed over the South China Sea.  At 5:00 a.m. EDT on Saturday the center of Tropical Depression 04W was located at latitude 16.1°N and longitude 113.8°E which put the center about 360 miles (580 km) southeast of Haikou, China.   The tropical depression was moving toward the northwest at 7 m.p.h. (11 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 999 mb.

Typhoon Koinu Brings Wind and Rain to Taiwan

Typhoon Koinu brought wind and rain to Taiwan on Wednesday night. At 11:00 p.m. EDT on Wednesday the center of Typhoon Koinu was located at latitude 22.1°N and longitude 120.6°E which put it about 10 miles (15 km) west of Hengchun, Taiwan. Koinu was moving toward the west-northwest at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h). The minimum surface pressure was 945 mb.

Typhoon Koinu brought strong winds and heavy rain to southern Taiwan on Wednesday night. The eye of Koinu passed over the southern tip of Taiwan. The northern half of the eyewall moved across southern Taiwan. Typhoon Koinu was the equivalent of a major hurricane when it moved across Taiwan. Winds to typhoon force extended out 70 miles (110 km) from the center of Koinu’s circulation. Winds to tropical storm force extended out 230 miles (370 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Koinu was 23.6. The Hurricane Size Index (HSI) was 21.6 and the Hurricane Wind Intensity Size Index (HWISI) was 45.2. Typhoon Koinu was stronger than Hurricane Rita was when Rita hit southwest Louisiana in 2005. Koinu was a little smaller than Rita was.

Easterly winds blowing around the northern side of Typhoon Koinu will rise up the eastern slopes of mountains in Taiwan. The enhanced rising motion will produce very heavy rainfall on those eastern slopes. The heavy rain is likely to cause flash floods in some locations.

Typhoon Koinu will move will move around the southern part of a high pressure system over eastern Asia and the Western North Pacific Ocean. The high pressure system will steer Koinu toward the west during the next 24 hours. On its anticipated track the center Typhoon Koinu will move over the South China Sea on Thursday.

The core of Typhoon Koinu was partially disrupted when the eye and northern part of the eyewall moved across southern Taiwan. The disruption of the inner core of Koinu’s circulation is likely to cause Typhoon Koinu to weaken during the next 24 hours even though Koinu will move through an environment favorable for intensification. Koinu will move over water where the Sea Surface Temperatures are near 28°C. It will move under the southern part of an upper level ridge over China. The ridge will produce easterly winds that will blow toward the top of Koinu’s circulation. Those winds will cause some little vertical wind shear, but the wind shear will not be too strong. Typhoon Koinu is likely to weaken gradually during the next 24 hours because of the disruption of its inner core.

Typhoon Koinu Approaches Taiwan

Typhoon Koinu approached Taiwan from east on Tuesday night. At 11:00 p.m. EDT on Tuesday the center of Typhoon Koinu was located at latitude 22.1°N and longitude 123.3°E which put it about 175 miles (280 km) east of Hengchun, Taiwan. Koinu was moving toward the west-northwest at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h). The minimum surface pressure was 953 mb.

Typhoon Koinu was the equivalent of a major hurricane as it approached Taiwan on Tuesday night. A circular eye with a diameter of 30 miles (50 km) was at the center of Koinu’s circulation. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Koinu. Storms near the core generated strong upper level divergence that pumped large quantities of mass away from the typhoon.

The size of the circulation around Typhoon Koinu increased on Tuesday. Winds to typhoon force extended out 90 miles (145 km) from the center of Koinu’s circulation. Winds to tropical storm force extended out 200 miles (320 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Koinu was 20.6. The Hurricane Size Index (HSI) was 29.2 and the Hurricane Wind Intensity Size Index (HWISI) was 49.8. Typhoon Koinu was similar in size and intensity to Hurricane Frances when Frances hit southeast Florida in 2004.

Typhoon Koinu will move through an environment favorable for intensification during the next 12 hours. Koinu will move over water where the Sea Surface Temperatures are near 28°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Koinu is likely to intensify during the next 12 hours.

Typhoon Koinu will move around the southern part of a high pressure system over eastern Asia and the Western North Pacific Ocean. The high pressure system will steer Koinu toward the west during the next 24 hours. On its anticipated track the center Typhoon Koinu will reach the coast of southeast Taiwan in less than 24 hours. Typhoon Koinu is likely to be the equivalent of a major hurricane when it approaches Taiwan. Koinu will bring strong, gusty winds and locally heavy rain to Taiwan. Heavy rain will cause flash floods in some locations. Typhoon Koinu could also cause widespread outages of electricity.

Typhoon Koinu Rapidly Intensifies to Equivalent of a Major Hurricane

Typhoon Koinu rapidly intensified to the equivalent of a major hurricane over the Western North Pacific Ocean east-southeast of Taiwan on Sunday night. At 5:00 a.m. EDT on Monday the center of Typhoon Koinu was located at latitude 19.9°N and longitude 126.4°E which put it about 405 miles (650 km) east-southeast of Hengchun, Taiwan. Koinu was moving toward the northwest at 9 m.p.h. (15 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 953 mb.

Typhoon Koinu rapidly intensified to the equivalent of a major hurricane during the past 24 hours. A circular eye with a diameter of 10 miles (16 km) was at the center of Koinu’s circulation. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the center of Typhoon Koinu. Storms near the center generated upper level divergence that pumped mass away from the typhoon.

The size of the circulation around Typhoon Koinu increased when Koinu rapidly intensified. Winds to typhoon force extended out 50 miles (80 km) from the center of Koinu’s circulation. Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Koinu was 22.1. The Hurricane Size Index (HSI) was 17.3 and the Hurricane Wind Intensity Size Index (HWISI) was 39.4.

Typhoon Koinu will move through an environment favorable for intensification during the next 24 hours. Koinu will move over water where the Sea Surface Temperatures are near 30°C. It will move under the southern part of an upper level ridge over the Western North Pacific Ocean and eastern Asia. The upper level ridge will produce easterly winds that will blow toward the top of Koinu’s circulation. Those winds will cause some vertical wind shear, but the wind shear will not be strong enough to prevent intensification. Typhoon Koinu is likely to intensify during the next 24 hours.

Typhoon Koinu will move around the southern part of a high pressure system over eastern Asia. The high pressure system will steer Koinu toward the northwest during the next 24 hours. On its anticipated track Typhoon Koinu will move closer to Taiwan. Koinu will approach southern Taiwan in 48 hours. Typhoon Koinu is likely to be the equivalent of a major hurricane when it approaches Taiwan. Koinu will bring strong, gusty winds and locally heavy rain to Taiwan. Heavy rain will cause flash floods in some locations.