Tag Archives: HWISI

Typhoon Yagi Brings Wind and Rain to Northern Vietnam

Typhoon Yagi brought wind and rain to northern Vietnam on Saturday.  At 5:00 a.m. EDT on Saturday the center of Typhoon Yagi was located at latitude 21.1°N and longitude 106.5°E which put the center about 65 miles (105 km) east of Hanoi, Vietnam.  Yagi was moving toward the west-northwest at 16 m.p.h. (26 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. (200 km/h).  The minimum surface pressure was 942 mb.

Typhoon Yagi was the equivalent of a major hurricane when it made landfall on the northern coast of Vietnam near Haiphong.  A small circular eye was present 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.  The strongest winds moved over the coastal regions of northern Vietnam.  Bands of showers and thunderstorms revolved around the core of Yagi’s circulation.  Storms dropped heavy rain on northern Vietnam.

‘Winds to typhoon force extended out 50 miles (80 km) from the center of Typhoon Yagi.  Winds to tropical storm force extended out 180 miles (290 km) from the center of Yagi’s circulation.

The Hurricane Intensity Index (HII) for Typhoon Yagi was 23.6.  The Hurricane Size Index (HII) was 20.6 and the Hurricane Wind Intensity Size Index (HWISI) was 44.2.  Typhoon Yagi was similar in size and intensity to Hurricane Jeanne when Jeanne hit southeast Florida in 2004.

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, Typhoon Yagi will move across northern Vietnam.  The center of Typhoon Yagi will pass near Hanoi in a few hours.

Typhoon Yagi will weaken gradually as it moves farther inland over northern Vietnam.  Yagi will bring strong winds and heavy rain to northern Vietnam during the next 24 hours.  Yagi is capable of causing major damage.  Heavy rain will cause floods in many locations.  Widespread outages of electricity are likely.

 

Typhoon Yagi Hits Hainan

Typhoon Yagi hit Hainan on Friday morning.  At 11:00 a.m. EDT on Friday the center of Typhoon Yagi was located at latitude 20.2°N and longitude 109.8°E which put the center about 25 miles (40 km) west of Haikou, China.  Yagi was moving toward the west-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 140 m.p.h. (220 km/h) and there were wind gusts to 165 m.p.h. (265 km/h).  The minimum surface pressure was 928 mb.

Typhoon Yagi brought strong winds and heavy rain to Hainan on Friday morning.  The core of Typhoon Yagi moved over the northeastern part of Hainan.  A small circular eye was present 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.  The strongest winds moved over the northern coastal regions of Hainan.  Bands of showers and thunderstorms revolved around the core of Yagi’s circulation.  Storms dropped heavy rain on Hainan and southern China.

The formation of concentric eyewalls on Thursday caused the size of Typhoon Yagi’s circulation to increase.  Winds to typhoon force extended out 70 miles (110 km) from the center of Yagi’s circulation.  Winds to tropical storm force extended out 185 miles (300 km) from the center of Typhoon Yagi.

The Hurricane Intensity Index (HII) for Typhoon Yagi was 28.3.  The Hurricane Size Index (HII) was 24.9 and the Hurricane Wind Intensity Size Index (HWISI) was 53.2.  Typhoon Yagi was similar in size to Hurricane Jeanne when Jeanne hit southeast Florida in 2004.  Yagi was stronger than Jeanne was.

Typhoon Yagi will move through an environment that will be somewhat favorable for intensification during the next 12 hours.  The center of Yagi’s circulation will move over water where the Sea Surface Temperatures are near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  However, Typhoon Yagi may not intensify during the next 12 hours because the core of Yagi’s circulation was somewhat disrupted as it moved across Hainan.

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 reach northeastern Vietnam in 12 hours.  Typhoon Yagi could still be the equivalent of a major hurricane when it reaches VIetnam.

Typhoon Yagi will continue to produce strong winds and heavy rain in parts of Hainan during the  next few hours.  Yagi will be capable of causing major damage in Hainan.  Heavy rain is likely to cause floods in some locations. Typhoon Yagi will also produce strong winds and heavy rain in parts of southern China.  Yagi will produce strong winds and heavy rain in southwestern Guangdong and Guangxi.  Typhoon Yagi will bring strong winds and heavy rain to northeastern Vietnam during the weekend.  Yagi is likely to cause floods in northeastern Vietnam.  Typhoon Yagi could also cause a storm surge of up to 10 feet (3 meters) along the coast of northeastern Vietnam.

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.

 

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.

 

Hurricane Ernesto Approaches Bermuda

Hurricane Ernesto was approaching Bermuda on Friday afternoon.  At 5:00 p.m. EDT on Friday the center of Hurricane Ernesto was located at latitude 30.6°N and longitude 65.6°W which put the center about 125 miles (200 km) south-southwest of Bermuda.   Ernesto was moving toward the northeast at 13 m.p.h. (20 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 969 mb.

A Hurricane Warning was in effect for Bermuda.

A circular eye with a diameter of 60 miles (95 km) was present at the center of Ernesto’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 Ernesto’s circulation.  Storms near the center generated upper level divergence that pumped mass away from the hurricane.  The removal of mass in the upper levels was balanced by the inflow of mass in the lower levels.

The size of the circulation around Hurricane Ernesto was large.  Winds to hurricane force extended out 70 miles (110 km) from the center of Ernesto’s circulation.  Winds to tropical storm force extended out 275 miles (445 km) from the center of Hurricane Ernesto.

The Hurricane Intensity Index (HII) was 16.5.  The Hurricane Size Index (HSI) was 24.8 and the Hurricane Wind Intensity Size Index (HWISI) was 41.3.  Hurricane Ernesto is similar in size to Hurricane Gustav when Gustav hit Louisiana in 2008.  Ernesto is not quite as strong as Gustav  was.

Hurricane Ernesto will move through an environment that will become less favorable for intensification during the next 24 hours.  Ernesto will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the southern portion of an upper level trough off the east coast of the U.S.  The upper level trough will produce southwesterly winds that will blow toward the top of Ernesto’s circulation.  Those winds will cause moderate vertical wind shear.  The wind shear will inhibit intensification but Hurricane Ernesto is likely to maintain its intensity during the next 24 hours.

Hurricane Ernesto will move around the western side of a subtropical high pressure system over the Atlantic Ocean.  The high pressure system will steer Ernesto toward the north during the next 24 hours.  On its anticipated track, the center of Hurricane Ernesto will move near Bermuda early on Saturday morning.

Hurricane Ernesto will bring strong winds and heavy rain to Bermuda.  The strong winds will be capable of causing serious damage.  Heavy rain could cause flash floods.

 

Typhoon Ampil Passes East of Tokyo

Typhoon Ampil passed east of Tokyo on Friday morning.  At 11:00 a.m. EDT on Friday the center of Typhoon Ampil was located at latitude 35.4°N and longitude 142.5°E which put the center about 130 miles (210 km) east of Tokyo, Japan.  Ampil was moving toward the northeast at 14 m.p.h. (22 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 944 mb.

Typhoon Ampil was the equivalent of a major hurricane when it passed east of Tokyo on Friday morning.  Bands in the western part of Ampil’s circulation brought gusty winds and locally heavy rain to coastal parts of central Honshu.  The airport at Narita reported a sustained wind speed of 32 m.p.h. (52 km/h) and a wind gust of 52 m.p.h. (83 km/h).

A large circular eye was present at the center of Typhoon Ampil.  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 Ampil’s circulation.  Storms near the core generated upper level divergence that pumped mass away from the typhoon.  The removal of mass in the upper levels of the atmosphere was almost in balance with the inflow of mass in the lower atmosphere.

The circulation around Typhoon Ampil was large. Winds to typhoon force extended out 50 miles (80 km) from the center of Ampil’s circulation.  Winds to tropical storm force extended out 150 miles (240 km) from the center of Typhoon Ampil.

The Hurricane Intensity Index (HII) for Typhoon Ampil was 22.1.  The Hurricane Size Index (HSI) was 17.0 and the Hurricane Wind Intensity Size Index (HWISI) was 39.1.  Typhoon Ampil was similar in intensity to Hurricane Delta when Delta hit Louisiana in 2020.  Ampil is larger than Delta was.

Typhoon Ampil will move through an environment that will become less favorable for intensification during the next 24 hours.  Ampil will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the upper level westerly winds in the middle latitudes.  Those westerly winds will cause the vertical wind shear to increase.  The increase in vertical wind shear will cause Typhoon Ampil to start to weaken during the next 24 hours.

The westerly winds in the middle latitudes will steer Typhoon Ampil toward the east during the next 24 hours.  On its anticipated track, Typhoon Ampil will move away from Japan.