Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Typhoon Yagi Rapidly Intensifies to Equivalent of a Major Hurricane

Typhoon Yagi rapidly intensified to the equivalent of a major hurricane over the South China Sea on Wednesday.  At 11:00 a.m. EDT on Wednesday the center of Typhoon Yagi was located at latitude 19.2°N and longitude 116.6°E which put the center about 275 miles (445 km) southeast of Hong Kong.  Yagi was moving toward the west at 6 m.p.h. (10 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 968 mb.

Typhoon Yagi rapidly intensified to the equivalent of a majoro hurricane on Wednesday.  A circular eye was visible at the center of Yagi’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 Yagi.  Storms near the core generated upper level divergence that pumped large amounts of mass away from the typhoon.  The removal of large amounts of mass caused the surface pressure to decrease rapidly.

The circulation around Typhoon Yagi increased in size as Yagi intensified rapidly.  Winds to typhoon force extended out 60 miles (95 km) from the center of Yagi’s circulation.  Winds to tropical storm force extended out 140 miles (220 km) from the center of Typhoon Yagi.

The Hurricane Intensity Index (HII) for Typhoon Yagi was 23.6.  The Hurricane Size Index (HSI) was 16.2 and the Hurricane Wind Intensity Size Index (HWISI) was 39.8.  Typhoon Yagi was similar in intensity to Hurricane Dennis when Dennis hit Florida in 2005.  Yagi is larger than Dennis was.

Typhoon Yagi will move through an environment that will be very favorable for intensification during the next 24 hours.  Yagi will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the middle of an upper level ridge over the South China Sea. The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear.  Typhoon Yagi will intensify during the next 24 hours.  Yagi could continue to intensify rapidly during the next few hours.  If the inner end of rainband wraps around the eye and eyewall in the core of Yagi’s circulation, then an eyewall replacement cycle could cause Typhoon Yagi to weaken.

Typhoon Yagi will move around the southern part of a high pressure system over China.  The high pressure system will steer Yagi toward the west-northwest during the next 24 hours. On its anticipated track, the center of Typhoon Yagi will be south of Hong Kong in 24 hours.  Yagi will approach Hainan and the coast of southern China in 36 hours.  Typhoon Yagi is likely to be the equivalent of a major hurricane when it approaches Hainan and the coast of southern China.

Typhoon Yagi will bring strong winds and heavy rain to southern China later this week.  Yagi will bring strong winds and heavy rain to Guangdong, Guangxi and Hainan.  Heavy rain is likely to cause floods in some locations.

 

Yagi Strengthens to a Typhoon Southeast of Hong Kong

Former Tropical Storm Yagi strengthened to a typhoon southeast of Hong Kong on Tuesday evening.  At 11:00 p.m. EDT on Tuesday the center of Typhoon Yagi was located at latitude 19.1°N and longitude 117.5°E which put the center about 315 miles (510 km) southeast of Hong Kong.  Yagi was moving toward the west-northwest at 9 m.p.h. (15 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 Yagi intensified rapidly to a typhoon after it moved over the South China Sea.  A circular eye formed at the center of Yagi’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 Yagi.  Storms near the core generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The circulation around Typhoon Yagi was symmetrical.  Winds to typhoon force extended out 35 miles (55 km) from the center of Yagi’s circulation.  Winds to tropical storm force extended out 110 miles (185 km) from the center of Typhoon Yagi.

Typhoon Yagi will move through an environment that will be very favorable for intensification during the next 24 hours.  Yagi will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the middle of an upper level ridge over the South China Sea. The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear.  Typhoon Yagi will intensify during then next 24 hours.  Yagi could intensify rapidly to the equivalent of a major hurricane.

Typhoon Yagi will move around the southern part of a high pressure system over China.  The high pressure system will steer Yagi toward the west-northwest during the next 24 hours.  On its anticipated track, the center of Typhoon Yagi will be south of Hong Kong in 36 hours.  Yagi will approach Hainan and the coast of southern China in 48 hours.  Typhoon Yagi could be the equivalent of a major hurricane when it approaches Hainan and the coast of southern China.

 

 

Tropical Storm Yagi Drops Heavy Rain on Northern Luzon

Tropical Storm Yagi dropped heavy rain on parts of northern Luzon on Monday.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Yagi was located at latitude 17.5°N and longitude 121.7°E which put the center about 25 miles (40 km) south of Tuguegarao, Philippines.  Yagi was moving toward the north-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 996 mb.

The center of Tropical Storm Yagi moved across northern Luzon on Monday.  Storms near the center of Yagi’s circulation dropped heavy rain on parts of northern Luzon.  There were reports that heavy rain caused floods and landslides in some locations.  There were also reports that the floods and landslides caused an unknown number of deaths.

The circulation around Tropical Storm Yagi weakened gradually as Yagi move across northern Luzon.  Thunderstorms were still occurring near the center of Yagi’s circulation.  Thunderstorms were also occurring in bands revolving around the center of circulation.  Storms near the center of Yagi 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 Tropical Storm Yagi.

Tropical Storm Yagi will move around the western part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Yagi toward the northwest during the next 24 hours.  On its anticipated track, the center of Tropical Storm Yagi will move over the South China Sea in 12 hours.  A second high pressure system that is over China will steer Yagi toward the west on Tuesday.

Tropical Storm Yagi will continue to weaken gradually during the next few hours while it moves across northern Luzon.  Yagi will move into an environment that will be favorable for intensification when it moves over the South China Sea.  Yagi will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the middle of an upper level ridge over the South China Sea.  The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear.  Tropical Storm Yagi is likely to intensify after it moves over the South China Sea.  Yagi is likely to strengthen to a typhoon by the middle of the week.

Tropical Storm Yagi will continue to drop heavy rain over northern Luzon during the next few hours.  Heavy rain is likely to cause additional floods and landslides.

Tropical Storm Yagi Forms Near the Northern Philippines

Tropical Storm Yagi formed near the northern Philippines on Sunday.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Yagi was located at latitude 13.9°N and longitude 124.4°E which put the center about 40 miles (65 km) northeast of Virac, Philippines.  Yagi was moving toward the northwest at 13 m.p.h. (20 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.

A low pressure system near the northern Philippines strengthened on Sunday morning and the Japan Meteorological Agency designated the system as Tropical Storm Yagi.  The center of Yagi’s circulation was near Catanduanes Island.  Thunderstorms were forming near the center of Tropical Storm Yagi.  However, the distribution of thunderstorms in Yagi was asymmetrical.  Thunderstorms were forming in bands in the western half of Yagi’s circulation.  Bands in the eastern half of Tropical Storm Yagi consisted primarily of showers and lower clouds.  Storms near the center of Yagi began to generate upper level divergence that pumped mass away from the tropical storm.

Tropical Storm Yagi will move through an environment that will be mostly favorable for intensification during the next 24 hours.  Yagi 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 upper level ridge will produce easterly winds that will blow toward the top of Yagi’s circulation.  Those winds will cause moderate vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be enough to prevent Yagi from strengthening.  Tropical Storm Yagi is likely to intensify during the next 24 hours.

Tropical Storm Yagi will move around the western part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Yagi toward the north-northwest during the next 24 hours.  On its anticipated track, the center of Tropical Storm Yagi will move near the east coast of Luzon.  A second high pressure system that is over China will steer Yagi toward the west early next week.

Bands in the western side of Tropical Storm Yagi will drop heavy rain over parts of Luzon.  Heavy rain is likely to cause widespread flooding.

Tropical Storm Shanshan Drops Heavy Rain on Japan

Tropical Storm Shanshan dropped heavy on parts of southwestern Japan on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Shanshan was located at latitude 33.8°N and longitude 131.6°E which put the center about 20 miles (30 km) west of Matsuyama, Japan.  Shanshan was moving toward the east-northeast at 3 m.p.h. (5 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 990 mb.

Former Typhoon Shanshan weakened to a tropical storm as it moved across Kyushu on Thursday.  Bands in the eastern side of Tropical Storm Shanshan dropped heavy rain on parts of Kyushu, Shikoku and southwestern Honshu.  The heaviest rain fell in locations where southerly winds pushed air up the slopes of mountains.  A weather station in Yosuhara reported 16.37 inches (416 mm) of rain.  A weather station in Hongawa reported 13.05 inches (331.5 mm) of rain.  Heavy rainfall caused flash floods in some locations.

Tropical Storm Shanshan weakened on Thursday as the center moved over land.  Bands of showers and thunderstorms were revolving around the center of Shanshan’s circulation.  The heaviest rain was falling in bands in the eastern side of Tropical Storm Shanshan.  Winds to tropical storm force extended out 100 miles (160 km) from the center of Shanshan.

An upper level trough over northeastern Asia will steer Tropical Storm Shanshan toward the east-northeast during the next 24 hours.  On its anticipated track, the center Tropical Storm Shanshan will move across Shikoku during the next 24 hours.

Tropical Storm Shanshan will continue to drop heavy rain on parts of southwestern Japan on Friday.  Heavy rain will fall in parts of Shikoku and southwestern Honshu.  The heaviest rain will fall where southerly winds push air up the slopes of mountains.  Heavy rain is likely to cause additional flash floods.

Typhoon Shanshan Brings Wind and Rain to Kyushu

Typhoon Shanshan brought wind and rain to Kyushu on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Typhoon Shanshan was located at latitude 31.6°N and longitude 130.2°E which put the center about 35 miles (55 km) west of Kagoshima, Japan.  Shanshan was moving toward the north at 8 m.p.h. (13 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 957 mb.

Typhoon Shanshan brought wind and rain to Kyushu on Wednesday.  The eastern side of the eyewall of Shanshan moved over Makurazaki, Japan.  A weather station in Makurazaki reported a sustained wind speed of 69 m.p.h. (111 km/h).  The weather station also reported 8.42 inches (214 mm) of rain.  A weather station in Kaseda reported 10.95 inches (278 mm) of rain.  A weather station in Ibusuki reported 9.33 inches (237 mm) of rain.

Typhoon Shanshan was weakening gradually when it reached the west coast of Kyushu.  An upper level trough over northeastern Asia was producing southwest winds that were blowing toward the top of Shanshan’s circulation.  Those winds caused more vertical wind shear.  The increase in wind shear caused Typhoon Shanshan to start to weaken.

An eye was no longer visible at the center of Typhoon Shanshan on conventional satellite images.  The former eye was still being detected by radars operated by the Japan Meteorological Agency.  There were breaks in the ring of thunderstorms that surrounded the former eye.  The strongest winds were still occurring in that broken ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Shanshan.

The circulation around Typhoon Shanshan was still symmetrical.  Winds to typhoon force extended out 30 miles (50 km) from the center of Shanshan’s circulation.  Winds to tropical storm force extended out 125 miles (200 km) from the center of Typhoon Shanshan.

The Hurricane Intensity Index (HII) for Typhoon Shanshan was 16.5.  The Hurricane Size Index (HSI) was 11.8 and the Hurricane Wind Intensity Size Index (HWISI) was 28.3.  Typhoon Shanshan was similar in intensity to Hurricane Idalia when Idalia hit Florida in 2023.  Shanshan was bigger than Idalia was.

Typhoon Shanshan will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Shanshan toward the north during the next 12 hours.  The upper level trough over northeastern Asia will steer Shanshan toward the northeast on Thursday.  On its anticipated track, the center Typhoon Shanshan will move near the west coast of Kyushu during the next 12 hours.  Shanshan will move inland over Kyushu on Thursday.

Typhoon Shanshan will weaken gradually as it moves inland over Kyushu.  Even though Shanshan will weaken it will still produce strong winds and drop heavy rain over much of Kyushu.  Heavy rain is likely to cause flash floods in some locations,

Typhoon Shanshan Strengthens to Equivalent of a Cat. 4 Hurricane

Typhoon Shanshan strengthened to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale over the northern Ryukyu Islands on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Typhoon Shanshan was located at latitude 29.2°N and longitude 130.0°E which put the center about 90 miles (145 km) south-southwest of Kamiyaku, Japan.  Shanshan was moving toward the north-northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 932 mb.

Typhoon Shanshan intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Tuesday.  A circular eye with a diameter of 30 miles (50 km) was at the center of Shanshan’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 Shanshan.  Storms near the core generated strong upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The circulation around Typhoon Shanshan was symmetrical.  Winds to typhoon force extended out 30 miles (50 km) from the center of Shanshan’s circulation.  Winds to tropical storm force extended out 145 miles (230 km) from the center of Typhoon Shanshan.

The Hurricane Intensity Index (HII) for Typhoon Shanshan was 25.1.  The Hurricane Size Index (HSI) was 12.1 and the Hurricane Wind Intensity Size Index (HWISI) was 37.2.  Typhoon Shanshan was similar in size and intensity to Hurricane Harvey when Harvey hit Texas in 2017.

Typhoon Shanshan will move through an environment that will be favorable for intensification during the next 24 hours.  Shanshan will move over water where the Sea Surface Temperatures are near 29°C.  It will through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Shanshan could intensify during the next 24 hours.

Typhoon Shanshan will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Shanshan toward the north-northwest during the next 24 hours.  On its anticipated track, Typhoon Shanshan will toward western Kyushu.  Shanshan could approach western Kyushu in 36 hours.

Typhoon Shanshan will continue to produce strong winds and heavy rain in the northern Ryukyu Islands.  The eastern side of the eyewall of Shanshan will move near Yakushima.  Shanshan will be capable of causing severe damage.  Heavy rain is likely to cause flash floods in some locations.  Typhoon Shanshan will also cause a storm surge in the northern Ryukyu Islands where the wind blows the water toward the shore.

 

Typhoon Shanshan Intensifies to the Equivalent of a Major Hurricane

Typhoon Shanshan intensified to the equivalent of a major hurricane near the northern Ryukyu Islands on Monday evening.  At 11:00 p.m. EDT on Monday the center of Typhoon Shanshan was located at latitude 28.3°N and longitude 130.6°E which put the center about 75 miles (120 km) east of Naze, Japan.  Shanshan was moving toward the northwest 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 943 mb.

Typhoon Shanshan intensified to the equivalent of a major hurricane on Monday evening as it moved slowly near the northern Ryukyu Islands.  A small circular eye with a diameter of 12 miles (19 km) was at the center of Shanshan’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 Shanshan.  Storms near the core generated strong upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The circulation around Typhoon Shanshan was symmetrical.  Winds to typhoon force extended out 40 miles (65 km) from the center of Shanshan’s circulation.  Winds to tropical storm force extended out 125 miles (200 km) from the center of Typhoon Shanshan.

The Hurricane Intensity Index (HII) for Typhoon Shanshan was 22.1.  The Hurricane Size Index (HSI) was 13.7 and the Hurricane Wind Intensity Size Index (HWISI) was 35.8.  Typhoon Shanshan was similar in size to Hurricane Delta when Delta hit southwest Louisiana in 2020.  Shanshan was stronger than Delta was.

Typhoon Shanshan will move through an environment that will be favorable for intensification during the next 24 hours. Shanshan will move over water where the Sea Surface Temperatures are near 29°C.  It will through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Shanshan is likely to continue to intensify during the next 24 hours.

Typhoon Shanshan will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Shanshan slowly toward the northwest during the next 24 hours.  On its anticipated track, Typhoon Shanshan will move over the northern Ryukyu Islands.  Shanshan could approach southwestern Japan in 48 hours. Shanshan could be a strong typhoon when it approaches Kyushu.

Typhoon Shanshan will bring strong winds and heavy rain to the northern Ryukyu Islands.  Shanshan will be capable of causing major damage.  Heavy rain is likely to cause flash floods in some locations.  Typhoon Shanshan will also cause a storm surge on the northern Ryukyu Islands where the wind blows the water toward the shore.

Typhoon Shanshan Continues to Strengthen

Typhoon Shanshan continues to strengthen over the Western North Pacific Ocean south of Japan on Sunday.  At 11:00 p.m. EDT on Sunday the center of Typhoon Shanshan was located at latitude 27.3°N and longitude 133.5°E which put the center about 350 miles (565 km) south-southeast of Kagoshima, Japan.  Shanshan was moving toward the west-northwest at 12 m.p.h. (19 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 968 mb.

Typhoon Shanshan strengthened gradually on Sunday as it moved over the Western North Pacific Ocean south of Japan.  A large circular eye was present at the center of Shanshan’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 Shanshan.  Storms near the core of Shanshan’s circulation generated more upper level divergence that pumped mass away from the typhoon.  The removal of more mass caused the surface pressure to decrease.

The size of the circulation around typhoon Shanshan increased slightly on Sunday.  Winds to typhoon force extended out 35 miles (55 km) from the center of Shanshan’s circulation.  Winds to tropical storm force extended out 145 miles (230 km) from the center of Typhoon Shanshan.

The Hurricane Intensity Index (HII) for Typhoon Shanshan was 13.9.  The Hurricane Size Index (HSI) was 11.7 and the Hurricane Wind Intensity Size Index (HWISI) was 25.6.

Typhoon Shanshan will move through an environment that will be favorable for intensification during the next 24 hours.  Shanshan will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the northern periphery of an upper level low south of Japan.  The upper level low will produce easterly winds that will blow toward the top of Shanshan’s circulation.  Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification.  Typhoon Shanshan will intensify during the next 24 hours.

Typhoon Shanshan will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Shanshan toward the northwest during the next 24 hours.  On its anticipated track, Typhoon Shanshan will move closer to Kyushu and Shikoku.  Shanshan could approach southwestern Japan in 48 hours.  Shanshan could be a strong typhoon when it approaches Japan.

 

Typhoon Shanshan Passes West of Iwo To

The center of Typhoon Shanshan passed west of Iwo To on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Typhoon Shanshan was located at latitude 25.4°N and longitude 138.4°E which put the center about 150 miles (240 km) west of Iwo To.  Shanshan was moving toward the 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. (145 km/h).  The minimum surface pressure was 974 mb.

Typhoon Shanshan maintained its intensity on Saturday as it moved over the Western North Pacific Ocean west of Iwo To.  Shanshan moved under the eastern side of an upper level low south of Japan.  The upper level low produced southerly winds that blew toward the top of Shanshan’s circulation.  Those winds caused moderate vertical wind shear, and the wind shear prevented intensification of Typhoon Shanshan.

The vertical wind shear also affected the structure of Typhoon Shanshan.  A small circular eye was present at the center of Shanshan’s circulation.  The eye was surrounded by a broken ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Thunderstorms were occurring in bands in the northern side of Typhoon Shanshan.  Bands in the southern part of Shanshan’s circulation consisted primarily of showers and lower clouds.  Storms near the center of Shanshan generated upper level divergence that pumped mass away to the north of the typhoon.  The removal of mass in the upper levels was balanced by the inflow of mass in the lower levels of the atmosphere.  The balance of the outflow and inflow of mass caused the surface pressure to remain steady on Saturday.

Winds to typhoon force extended out 35 miles (55 km) from the center of Typhoon Shanshan.  Winds to tropical storm force extended out 125 miles (200 km) from the center of Shanshan’s circulation.

Typhoon Shanshan will move through an environment that will become more favorable for intensification during the next 24 hours.  Shanshan will move over water where the Sea Surface Temperatures are near 29°C.  It will move farther away from the upper level low south of Japan.  The upper level low will still produce southerly winds that will blow toward the top of Shanshan’s circulation.  However, there will be less vertical wind shear on Sunday.  Typhoon Shanshan is likely to intensify during the next 24 hours.

Typhoon Shanshan will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Shanshan toward the northwest during the next 24 hours.  On its anticipated track, Typhoon Shanshan will move closer to Kyushu and Shikoku.  Shanshan could approach southwestern Japan in 48 hours.  Shanshan could be a strong typhoon when it approaches Japan.