Monthly Archives: October 2023

Tropical Storm Max Approaches Mexico

Tropical Storm Max was approaching the coast of Mexico near Zihuatanejo on Monday morning. At 11:00 a.m. EDT on Monday the center of Tropical Storm Max was located at latitude 17.1°N and longitude 101.2°W which put it about 50 miles (80 km) south-southeast of Zihuantenajo, Mexico. Max was moving toward the north-northeast at 5 m.p.h. (8 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 996 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Acapulco to Punta San Telmo, Mexico.

Tropical Storm Max intensified as it neared the coast of southwest Mexico near Zihuatanejo on Monday morning. A rainband wrapped around the southern part of the center of Max’s circulation. Bands of showers and thunderstorms were revolving around the center of Tropical Storm Max. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 60 miles (95 km) from the center of Max’s circulation.

Tropical Storm Max will move around the western side of a high pressure system over the Caribbean Sea and Mexico. The high pressure system will steer max toward the north-northeast during the next 24 hours. On its anticipated track, Tropical Storm Max will make landfall on the coast of Mexico near Zihuatenajo in a few hours.

Tropical Storm Max will move through an environment favorable for intensification until it makes landfall. Max 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 that extends from Mexico to the Eastern North Pacific Ocean. The ridge will produce easterly winds that will blow toward the top of Max’s circulation. Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification. Tropical Storm Max could intensify a little more before it makes landfall in Mexico.

Tropical Storm Max will bring gusty winds to the coast of southwest Mexico. Max will also drop heavy rain of parts of Guerrero and Michoacan. Heavy rain is likely to cause flash floods in some locations. Tropical Storm Max could cause a storm surge of up to 6 feet (1.8 meters) along the coast near Zihuatanejo.

Elsewhere over the Eastern North Pacific Ocean, Tropical Storm Lidia started to move northeast toward the west coast of Mexico. At 11:00 a.m. EDT on Monday the center of Tropical Storm Lidia was located at latitude 18.5°N and longitude 111.8°W which put it about 350 miles (525 km) south-southwest of Cabo San Lucas, Mexico. Lidia was moving toward the northeast at 6 m.p.h. (10 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 Lidia is forecast to intensify to a hurricane as it moves toward the west coast of Mexico. A Hurricane Warning is in effect for the portion of the coast from Playa Perula to Escuinapa, Mexico. A Hurricane Warning is also in effect for Las Islas Marias. A Tropical Storm Warning is in effect for the portion of the coast from Escuinapa to Bahia Tempehuaya, Mexico. A Tropical Storm Warning is also in effect for the portion of the coast from Manzanillo to Playa Perula, Mexico.

Tropical Storm Bolaven Moves Toward the Marianas

Tropical Storm Bolaven moved toward the Marianas on Sunday night. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Bolaven was located at latitude 11.1°N and longitude 149.9°E which put it about 410 miles (660 km) east-southeast of Guam. Bolaven was moving toward the west-northwest at 10 m.p.h. (16 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.

A Typhoon Watch was in effect for Guam, Rota, Tinian and Saipan. A Tropical Storm Warning was also in effect for Guam.

Tropical Storm Bolaven strengthened on Sunday. The inner end of a rainband wrapped around the center of Bolaven’s circulation. Bands of showers and thunderstorms revolved around the center of circulation. Storms near the center generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 70 miles (100 km) from the center of Bolaven.

Tropical Storm Bolaven will move through an environment favorable for intensification during the next 24 hours. Bolaven 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. The ridge will produce easterly winds that will blow toward the top of Bolaven’s circulation. Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification. Tropical Storm Bolaven is likely to intensify to a typhoon during the next 24 hours.

Tropical Storm Bolaven will move around the southwestern part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Bolaven toward the northwest during the next 24 hours. On its anticipated track Tropical Storm Bolaven will move closer to the Marianas. Bolaven could reach the Marianas in less than 36 hours. Bolaven will very likely be a typhoon when it reaches the Marianas.

Elsewhere over the Western North Pacific Ocean, former Typhoon Koinu made landfall on the coast of China west of Hong Kong on Sunday. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Koinu was located at latitude 21.5°N and longitude 112.9°E which put it about 75 miles (120 km) west-southeast of Hong Kong. Koinu was moving toward the west at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h). The minimum surface pressure was 988 mb.

Tropical Storm Max Forms Near Southwest Mexico

Tropical Storm Max formed over the Eastern North Pacific Ocean near the coast of southwest Mexico on Sunday night. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Max was located at latitude 16.3°N and longitude 101.9°W which put it about 100 miles (160 km) south-southwest of Zihuantenajo, Mexico. Max was moving toward the north-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 1001 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Acapulco to Punta San Telmo, Mexico.

A low pressure system over the Eastern North Pacific Ocean near the southwest coast of Mexico strengthened during Sunday evening and the U.S. National Hurricane Center designated the system as Tropical Storm Max. More thunderstorms formed near the center of Tropical Storm Max on Sunday evening. Bands of showers and thunderstorms were revolving around the center of Max’s circulation. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical storm. Wind to tropical storm force extended out 105 miles (165 km) from the center of Max.

Tropical Storm Max will move around the western side of a high pressure system over the Caribbean Sea and Mexico. The high pressure system will steer max toward the north during the next 24 hours. On its anticipated track, Tropical Storm Max will make landfall on the coast of Mexico west of Zihuatenajo on Monday evening.

Tropical Storm Max will move through an environment favorable for intensification during the next 18 hours. Max 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 that extends from Mexico to the Eastern North Pacific Ocean. The ridge will produce easterly winds that will blow toward the top of Max’s circulation. Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification. Tropical Storm Max is likely to intensify before it makes landfall in Mexico.

Tropical Storm Max will bring gusty winds to the coast of southwest Mexico. Max will also drop heavy rain of parts of Guerrero and Michoacan. Heavy rain is likely to cause flash floods in some locations.

Elsewhere over the Eastern North Pacific Ocean, Tropical Storm Lidia continued to meander south of Baja California. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Lidia was located at latitude 18.2°N and longitude 112.6°W which put it about 370 miles (595 km) south-southwest of Cabo San Lucas, Mexico. Lidia was moving toward the north at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h). The minimum surface pressure was 990 mb.

Tropical Storm Lidia is forecast to start to move toward the northeast on Monday and to strengthen to a hurricane. A Hurricane Watch is in effect for Las Islas Marias and the portion of the coast from Playa Perula to Mazatlan, Mexico. Tropical Storm Watches are in effect for the portions of the coast from Manzanillo to Playa Perula and from Bahia Tempehuaya to Mazatlan, Mexico.

Typhoon Koinu Lingers Near Hong Kong

Typhoon Koinu lingered over the Western North Pacific Ocean near Hong Kong on Saturday. At 11:00 p.m. EDT on Saturday the center of Typhoon Koinu was located at latitude 21.4°N and longitude 114.4°E which put it about 65 miles (105 km) south-southeast of Hong Kong. Koinu was moving toward the west-northwest at 4 m.p.h. (6 km/h). The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h). The minimum surface pressure was 968 mb.

Typhoon Koinu weakened gradually on Saturday as it lingered near Hong Kong. Since Koinu moved very slowly, the strong winds in the lower atmosphere mixed cooler water to the surface of the ocean. Koinu was unable to extract as much energy from the cooler water and the typhoon weakened. Thunderstorms in Typhoon Koinu did not rise quite as high into the atmosphere.

Even though Typhoon Koinu weakened on Saturday, it still exhibited a well organized circulation. A very small eye was present at the center of Koinu’s circulation. The inner end of a rainband wrapped around the existing eye and eyewall, and concentric eyewalls could be developing. Bands of showers and thunderstorms revolved around the small core of Typhoon Koinu. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The size of the circulation around Typhoon Koinu decreased as Koinu gradually weakened. Winds to typhoon force extended out 25 miles (40 km) from the center of Koinu’s circulation. Winds to tropical storm force extended out 90 miles (145 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Koinu was 16.5. The Hurricane Size Index (HSI) was 8.6. and the Hurricane Wind Intensity Size Index (HWISI) was 25.1.

Typhoon Koinu will move through an environment somewhat unfavorable for intensification during the next 24 hours. Koinu will move over water where the Sea Surface Temperatures are near 27°C. It will move under axis of an upper level ridge over China. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. However, strong winds in the lower atmosphere will continue to mix cooler water to the surface of the ocean. In addition, the circulation around the northern side of Typhoon Koinu could draw in some drier air from China. Typhoon Koinu is likely to continue to weaken gradually during the next 24 hours due to the mix of cooler water to the surface of the ocean.

Typhoon Koinu will move will move around the southern part of a high pressure system over eastern Asia. The high pressure system will steer Koinu slowly toward the west during the next 24 hours. On its anticipated track the center Typhoon Koinu will move south of Hong Kong on Sunday.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 15W strengthened to Tropical Storm Bolaven east-southeast of Guam. At 11:00 p.m. EDT on Saturday the center of Tropical Storm Bolaven was located at latitude 9.6°N and longitude 152.9°E which put it about 630 miles (1020 km) east-southeast of Guam. Bolaven was moving toward the west-northwest 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 1000 mb. Typhoon Watches were in effect for Guam, Rota, Tinian and Saipan.

Tropical Storm Lidia Meanders South of Baja California

Tropical Storm Lidia meandered over the Eastern North Pacific Ocean south of Baja California on Saturday. At 11:00 a.m. EDT on Saturday the center of Tropical Storm Lidia was located at latitude 16.2°N and longitude 112.2°W which put it about 485 miles (780 km) south-southwest of Cabo San Lucas, Mexico. Lidia was moving toward the west-northwest at 5 m.p.h. (8 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 995 mb.

Tropical Storm Lidia meandered slowly south of Baja California on Saturday. The distribution of thunderstorms in Tropical Storm Lidia continued to be asymmetrical on Saturday. Many of the thunderstorms were occurring in a bands in the southern and western parts of Lidia’s circulation. Bands in the northern and eastern parts of Tropical Storm Lidia consisted primarily of showers and lower clouds. Storms near the center of Lidia’s circulation generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 105 miles (165 km) from the center of Lidia’s circulation.

Tropical Storm Lidia will move through an environment that will be marginally favorable for intensification during the next 24 hours. Lidia will move over water where the Sea Surface Temperatures are near 29°C. It will move under the southern part of an upper level ridge that extends from Mexico to the Eastern North Pacific Ocean. The ridge will produce easterly winds that will blow toward the top of Lidia’s circulation. Those winds will continue to cause moderate vertical wind shear. The wind shear is likely to inhibit intensification of Tropical Storm Lidia during the next 24 hours.

Tropical Storm Lidia will be in an area where the steering currents are weak during the next 24 hours. On its anticipated track, Tropical Storm Lidia is likely to continue to meander the south of Baja California on Sunday. An upper level trough west of California will move closer to Lidia on Monday. The upper level trough is likely to steer Lidia toward the northeast early next week. Lidia could approach the west coast of Mexico by Tuesday. Tropical Storm Lidia could strengthen to a hurricane as it approaches the coast of Mexico.

Typhoon Koinu Moves Southeast of Hong Kong

Typhoon Koinu moved southeast of Hong Kong on Friday night. At 11:00 p.m. EDT on Friday the center of Typhoon Koinu was located at latitude 21.1°N and longitude 115.3°E which put it about 115 miles (185 km) southeast of Hong Kong. Koinu was moving toward the west-southwest at 4 m.p.h. (6 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 952 mb.

Typhoon Koinu intensified back to the equivalent of a major hurricane over the South China Sea southeast of Hong Kong on Friday. A circular eye with a diameter of 12 miles (19 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 revolved around the core of Typhoon Koinu. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

Wins to typhoon force extended out 40 miles (65 km) from the center of Typhoon Koinu. Winds to tropical storm force extended out 285 miles (460 km) in the northeast quadrant of Koinu’s circulation. Winds to tropical storm force extended out 130 miles (210 km) in the other parts of Typhoon Koinu. The Hurricane Intensity Index (HII) for Typhoon Koinu was 22.1. The Hurricane Size Index (HSI) was 14.9 and the Hurricane Wind Intensity Size Index (HWISI) was 37.0. Typhoon Koinu was similar in size and intensity to Hurricane Harvey when Harvey hit Texas in 2017.

Typhoon Koinu will move through an environment somewhat favorable for a strong typhoon during the next 24 hours. 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 vertical wind shear. The wind shear will inhibit intensification. The circulation around the northern side of Typhoon Koinu could draw in some drier air from China. Typhoon Koinu could maintain its intensity during the next 24 hours if the drier air does not reach the inner core of the circulation. Koinu is likely to weaken if the drier penetrates to the core of the circulation.

Typhoon Koinu will move will move around the southern part of a high pressure system over eastern Asia. The high pressure system will steer Koinu slowly toward the west-southwest during the next 24 hours. On its anticipated track the center Typhoon Koinu will move south of Hong Kong on Saturday.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 15W formed east-southeast of Guam. At 11:00 p.m. EDT on Friday the center of Tropical Depression 15W was located at latitude 9.9°N and longitude 154.2°E which put it about 700 miles (1130 km) east-southeast of Guam. The tropical depression was moving toward the west-northwest at 13 m.p.h. (21 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 1003 mb.

Tropical Storm Philippe Brings Gusty Winds to Bermuda

Tropical Storm Philippe brought gusty winds to Bermuda on Friday morning. At 11:00 a.m. EDT on Friday the center of Tropical Storm Philippe was located at latitude 30.7°N and longitude 64.6°W which put it about 110 miles (185 km) south of Bermuda. Philippe was moving toward the north-northeast 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 around Tropical Storm Philippe brought gusty winds to Bermuda on Friday morning. A weather station at L.F. Wade International Airport (TXKF) reported a sustained wind speed of 30 m.p.h. (50 km/h) and a gust of 56 m.p.h. (91 km/h). A weather station at an elevated location near the Bermuda National Museum reported a sustained wind speed of 46 m.p.h. (74 km/h) and a wind gust of 57 m.p.h. (91 km/h). Philippe produce intermittent rain showers in Bermuda, but the heaviest rain passed to the east of Bermuda.

Tropical Storm Philippe made a transition to an extratropical cyclone on Friday morning. The circulation former Tropical Storm Philippe combined with a frontal system near Bermuda. A warm front extended to the east of the center of circulation and a cold front trailed south of the center. Winds to tropical storm force extended out 175 miles (280 km) in the eastern side of former Tropical Storm Philippe. The winds in the western side of the extratropical cyclone were blowing at less than tropical storm force.

Former Tropical Storm Philippe will move between a high pressure system over the Atlantic Ocean and an upper level trough over the Great Lakes. The high pressure system and the upper level trough will steer the extratropical cyclone toward the north during the next 48 hours. On its anticipated track, former Tropical Storm Philippe will affect the Northeast U.S. and the Canadian Maritimes during the weekend. The extratropical cyclone could produce locally heavy rain in some places. Heavy rain could cause flash floods in some locations. Gusty winds could knock down trees and localized outages of electricity are possible.

Typhoon Koinu Moves Toward Hong Kong

Typhoon Koinu moved toward Hong Kong on Thursday. At 11:00 p.m. EDT on Thursday the center of Typhoon Koinu was located at latitude 21.5°N and longitude 117.4°E which put it about 225 miles (365 km) east of Hong Kong. Koinu 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 wind gusts to 105 m.p.h. (165 km/h). The minimum surface pressure was 967 mb.

Typhoon Koinu moved over the South China Sea toward Hong Kong on Thursday. Koinu was weaker and smaller after passing over southern Taiwan on Wednesday. The circulation around Typhoon Koinu started to exhibit more organization again on Thursday evening. A circular eye with a diameter of 18 miles (30 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 revolved around the core of Typhoon Koinu. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

Wins to typhoon force extended out 35 miles (55 km) from the center of Typhoon Koinu. Winds to tropical storm force extended out 285 miles (460 km) in the northeast quadrant of Koinu’s circulation. Winds to tropical storm force extended out 130 miles (210 km) in the other parts of Typhoon Koinu.

Typhoon Koinu will move through an environment somewhat favorable for intensification during the next 24 hours. 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 vertical wind shear. The wind shear will inhibit intensification but the shear may not be strong enough to prevent intensification. The circulation around the northern side of Typhoon Koinu could start to draw in some drier air from China. Typhoon Koinu could intensify during the next 24 hours if the drier air does not reach the inner core of the circulation.

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 closer to Hong Kong on Friday.

Tropical Storm Lidia Moves South of Baja California

Tropical Storm Lidia moved south of Baja California on Wednesday. At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Lidia was located at latitude 15.6°N and longitude 109.4°W which put it about 505 miles (815 km) south of Cabo San Lucas, Mexico. Lidia was moving toward the northwest at 7 m.p.h. (11 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 1001 mb.

Tropical Storm Lidia strengthened gradually over the Eastern North Pacific Ocean south of Baja California on Wednesday. Even though Tropical Storm Lidia was a little stronger, the distribution of thunderstorms continued to be asymmetrical. Many of the thunderstorms were occurring in a bands in the western part of Lidia’s circulation. Bands in the eastern side of Tropical Storm Lidia consisted primarily of showers and lower clouds. More thunderstorms formed near the center of Lidia’s circulation on Wednesday evening. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 70 miles (110 km) from the center of Lidia’s circulation.

Tropical Storm Lidia will move through an environment that will be a little more favorable for intensification during the next 24 hours. Lidia will move over water where the Sea Surface Temperatures are near 29°C. It will move under the southern part of an upper level ridge that extends from Mexico to the Eastern North Pacific Ocean. The ridge will produce easterly winds that will blow toward the top of Lidia’s circulation. Those winds will weaken a little on Thursday and there will be a little less vertical vertical wind shear. The reduction of wind shear could allow Tropical Storm Lidia intensify a little faster during the next 24 hours.

Tropical Storm Lidia will move around the western part of a high pressure system over Mexico. The high pressure system will steer Lidia toward the west-northwest during the next 24 hours. On its anticipated track, Tropical Storm Lidia will remain far to the south of Baja California on Thursday.

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.