Typhoon Yagi Passes South of Hong Kong

Powerful Typhoon Yagi passed south of Hong Kong on Thursday.  At 5:00 p.m. EDT on Thursday the center of Typhoon Yagi was located at latitude 19.3°N and longitude 112.5°E which put the center about 230 miles (370 km) south-southwest of Hong Kong.  Yagi was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h).  The minimum surface pressure was 923 mb.

The inner end of a rainband wrapped around the original eye and eyewall at the core of Typhoon Yagi and concentric eyewalls formed.  The formation of concentric eyewalls ended the intensification of Typhoon Yagi, but Yagi was still the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.

A circular eye with a diameter of 23 miles (37 km) was 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.  A second outer ring of thunderstorms surrounded the inner eyewall.  Bands of showers and thunderstorms were revolving around the core of Typhoon Yagi.  Storms near the core of Yagi generated upper level divergence that pumped mass away from the typhoon.

The formation of concentric eyewalls caused the size of Typhoon Yagi’s circulation to increase.  Winds to typhoon force extended out 90 miles (145 km) from the center of Yagi’s circulation.  Winds to tropical storm force extended out 205 miles (330 km) from the center of Typhoon Yagi.

The Hurricane Intensity Index (HII) for Typhoon Yagi was 31.6.  The Hurricane Size Index (HII) was 24.8 and the Hurricane Wind Intensity Size Index (HWISI) was 56.4.  Typhoon Yagi was similar in intensity to Hurricane Laura when Laura hit southwest Louisiana in 2020.  Yagi is bigger than Laura was.

Typhoon Yagi will move through an environment that will be favorable for intensification during the next 12 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.  Even though Typhoon Yagi will move through a favorable environment, the concentric eyewalls may prevent Yagi from intensifying.  If the inner eyewalls weakens, then Typhoon Yagi could weaken as well.  If the inner eyewall remains intact, then Typhoon Yagi could intensify during the next few hours.

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 during the next 24 hours.  On its anticipated track, the center of Typhoon Yagi will reach northeastern Hainan in 12 hours.  Typhoon Yagi is likely to be the equivalent of a major hurricane when it reaches Hainan.

Typhoon Yagi will bring strong winds and heavy rain to Hainan.  Yagi will be capable of causing major damage in Hainan.  Heavy rain is likely to cause floods in some locations.  Typhoon Yagi could also cause a storm surge of up to 14 feet (4.3 meters) along the coast of northeastern Hainan.  Yagi will also bring strong winds and heavy rain to southwestern Guangdong and Guangxi.

 

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 Cyclone Asna Weakens East of Oman

Tropical Cyclone Asna weakened over the northern Arabian Sea east of Oman on Sunday.  At 5:00 p.m. EDT on Sunday the center of Tropical Cyclone Asna was located at latitude 21.4°N and longitude 61.4°E which put the center about 185 miles (300 km) east-northeast of Masirah Island.  Asna was moving toward the southwest at 6 m.p.h. (10 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.

Tropical Cyclone Asna moved into a large mass of dry air over the Arabian Sea east of Oman on Sunday.  The dry air caused the thunderstorms in Asna’s circulation to dissipate.  Tropical Cyclone Asna still had a well defined low level circulation on Sunday afternoon, but the circulation was very shallow.  Bands of showers and lower clouds were revolving around the center of Asna’s circulation.  However, there were no thunderstorms and there wasn’t any upper level divergence.

Tropical Cyclone Asna will move through an environment unfavorable for intensification during the next 24 hours.  Asna will move over water where the Sea Surface Temperatures are near 28°C.  However, it will remain within the large mass of dry air.  The dry air will prevent the formation of new thunderstorms.  Tropical Cyclone Asna will weaken during the next 24 hours as the low level circulation gradually dissipates.

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 Cyclone Asna Spins South of Pakistan

Tropical Cyclone Asna was spinning over the Arabian Sea south of Pakistan on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Asna was located at latitude 23.2°N and longitude 62.9°E which put the center about 275 miles (445 km) west-southwest of Karachi, Pakistan.  Asna was moving toward the west 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 989 mb.

Tropical Cyclone Asna strengthened on Saturday as it moved across the northern Arabian Sea south of Pakistan.  The inner end of a rainband wrapped around the western and southern side of the center of Tropical Cyclone Asna.  Thunderstorms were occurring in bands in the northern and western parts of Asna’s circulation.  Bands in the southeastern part of Asna consisted primarily of showers and lower clouds.  Storms near the center of Asna’s circulation generated upper level divergence that pumped mass away to the west of the tropical cyclone.

Winds to tropical storm force extended out 100 miles (160 km) from the center of Tropical Cyclone Asna.

Tropical Cyclone Asna will move through an environment somewhat favorable for intensification during the next 24 hours.  Asna 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.  There is a large mass of drier air over Southwest Asia.  The circulation around the northern side of Asna could draw drier air into the tropical cyclone.  Tropical Cyclone Asna could strengthen a little more during the next 24 hours, if Asna does not pull too much drier air into its circulation.

Tropical Cyclone Asna will move around the southeastern part of a high pressure system over Southwest Asia.  The high pressure system will steer Asna toward the west during the next 24 hours.  On its anticipated track, Tropical Cyclone Asna will move toward Oman.

 

Tropical Cyclone Asna Forms Over Northern Arabian Sea

Tropical Cyclone Asna formed over the northern Arabian Sea south of Pakistan on Friday.  At 11:00 a.m. EDT on Friday the center of Tropical Cyclone Asna was located at latitude 23.9°N and longitude 66.4°E which put the center about 65 miles (105 km) south of Karachi, Pakistan. Asna was moving toward the west at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 990 mb.

A low pressure system over the Arabian Sea south of Pakistan strengthened on Friday and the India Meteorological Department designated the system as Tropical Cyclone Asna.  There was a distinct low level center of circulation in Tropical Cyclone Asna.  Thunderstorms were occurring in bands in the southern half of Asna’c circulation.  Bands in the northern part of Tropical Cyclone Asna consisted primarily of showers and lower clouds.  Storms near the center of Asna’s circulation generated upper level divergence that pumped mass away to the southwest of the tropical cyclone.

Winds to tropical storm force extended out 100 miles (160 km) from the center of Tropical Cyclone Asna.

Tropical Cyclone Asna will move through an environment somewhat favorable for intensification during the next 24 hours.  Asna 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.  There is a large mass of drier air over Southwest Asia.  The circulation around the northern side of Asna could draw drier air into the tropical cyclone.  Tropical Cyclone Asna could strengthen during the next 24 hours, if it does not pull too much drier air into its circulation.

Tropical Cyclone Asna will move around the southeastern part of a high pressure system over Southwest Asia.  The high pressure system will steer Asna toward the west during the next 24 hours.  On its anticipated track, Tropical Cyclone Asna will move parallel to the coast of Pakistan.

Bands in the northern side of Tropical Cyclone Asna could bring gusty winds and locally heavy rain to southern Pakistan.  Heavy rain could cause floods in some locations.

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.

Gilma Weakens East of Hawaii

Former Tropical Storm Gilma weakened east of Hawaii on Thursday.  At 5:00 p.m. EDT on Thursday the center of Tropical Depression Gilma was located at latitude 20.3°N and longitude 151.7°W which put the center about 225 miles (360 km) east of Hilo, Hawaii.  Gilma was moving toward the west-northwest at 12 m.p.h. (19 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 1010 mb.

An upper level low west of California was producing strong southwesterly winds that blew toward the top of former Tropical Storm Gilma.  Those winds caused strong vertical wind shear.  The strong wind shear blew the middle and upper parts of Gilma;s circulation to the northeast of the lower portion of the circulation.

The lower portion of the circulation around Tropical Depression Gilma consisted primarily of bands of showers and low clouds.  Thunderstorms were still being produced in the middle level circulation which was northeast of the low level center of Gilma.

Tropical Depression Gilma will move through an environment that will be unfavorable for intensification during the next 24 hours.  Gilma will move over water where the Sea Surface Temperatures are near 24°C.  The upper level low west of California will continue to produce southwesterly winds that will blow toward the top of Gilma’s circulation.  Those winds will cause strong vertical wind shear.  Tropical Depression Gilma is likely to continue to weaken during the next 24 hours.

Tropical Depression Gilma will move around the southern side of a subtropical high pressure system over the Eastern and Central North Pacific Ocean.  The high pressure system will steer Gilma toward the west-northwest during the next 24 hours.  On its anticipated track, Tropical Depression Gilma pass just north of Hawaii on Friday.

The circulation in the western side of Tropical Depression Gilma could enhance the northeasterly trade winds.  Stronger trade winds could cause more rain to fall on the northeastern slopes of the Hawaiian Islands.

Elsewhere, Tropical Storm Hone was spinning southeast of Midway Island.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Hone was located at latitude 21.4°N and longitude 172.4°W which put the center about 565 miles (910 km) southeast of Midway Island.  Hone was moving toward the west-northwest at 7 m.p.h. (11 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 1006 mb.