Tag Archives: HWISI

Hurricane Fiona Moves Away from the Turks and Caicos

Hurricane Fiona moved away from the Turks and Caicos on Tuesday night. At 11:00 p.m. EDT on Tuesday the center of Hurricane Fiona was located at latitude 23.2°N and longitude 71.8°W which put it about 95 miles (155 km) north of Caicos Island. Fiona was moving toward the north at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 150 m.p.h. (240 km/h). The minimum surface pressure was 947 mb.

A Tropical Storm Watch was in effect for Bermuda.

Hurricane Fiona strengthened on Tuesday night as it moved away form the Turks and Caicos. A circular eye with a diameter of 23 miles (37 km) was at the center of Fiona’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Hurricane Fiona. Storms near the core generated upper level divergence that pumped mass away from the hurricane. The removal of large quantities of mass was causing the surface pressure to decrease.

Hurricane Fiona grew larger as it strengthened. Winds to hurricane force extended out 45 miles (75 km) from the center of Fiona. Winds to tropical storm force extended out 160 miles (260 km) from the center of circulation. The Hurricane Intensity Index (HII) was 23.6. The Hurricane Size Index (HSI) was 14.8 and the Hurricane Wind Intensity Size Index (HWISI) was 38.4.

Hurricane Fiona will move through an environment favorable for intensification during the next 24 hours. Fiona will move over water where the Sea Surface Temperatures are near 29˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Hurricane Fiona is likely to intensify during the next 24 hours. Fiona could strengthen to Category 4 on the Saffir-Simpson Scale. If the inner end of a rainband wraps around the existing eye and eyewall, then an eyewall replacement cycle could cause Hurricane Fiona to weaken temporarily.

Hurricane Fiona will move around the western side of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Fiona toward the north during the next 12 hours. An upper level trough near the East Coast of the U.S. will start to steer Fiona toward the northeast on later Wednesday. On its anticipated track, Hurricane Fiona will affect Bermuda on Thursday night. Fiona could be a major hurricane when it gets to Bermuda. Hurricane Fiona could approach the Canadian Maritimes on Saturday.

Elsewhere over the Atlantic Ocean, Tropical Storm Gaston formed west of the Azores. At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Gaston was located at latitude 36.2°N and longitude 43.6°W which put it about 920 miles (1485 km) west of the Azores. Gaston was moving toward the north-northeast at 18 m.p.h. (30 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 1004 mb.

Fiona Strengthens to Major Hurricane over Turks and Caicos

Hurricane Fiona strengthened to a major hurricane over the Turks and Caicos on Tuesday morning. At 8:00 a.m. EDT on Tuesday the center of Hurricane Fiona was located at latitude 21.6°N and longitude 71.2°W which put it about 10 miles (15 km) northwest of Grand Turk. Fiona was moving toward the north-northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 135 m.p.h. (220 km/h). The minimum surface pressure was 960 mb.

A Hurricane Warning was in effect for the Turks and Caicos. Tropical Storm Warnings were in effect for the Southeastern Bahamas including the Acklins, Crooked Island, Long Cay, the Inaguas, Mayaguana and the Ragged Islands.

Hurricane Fiona strengthened on Tuesday morning and it became the first Atlantic major hurricane in 2022. A circular eye with a diameter of 18 miles (30 km) was present at the center of Fiona’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Hurricane Fiona. Storms near the core generated upper level divergence that pumped mass away from the hurricane.

Winds to hurricane force extended out 30 miles (50 km) from the center of Hurricane Fiona. Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation. The Hurricane Intensity Index (HII) was 20.6. The Hurricane Size Index (HSI) was 11.5 and the Hurricane Wind Intensity Size Index (HWISI) was 32.1. Hurricane Fiona was capable of causing regional major damage.

Hurricane Fiona will move through an environment favorable for intensification during the next 24 hours. Fiona will move over water where the Sea Surface Temperatures are near 29˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Hurricane Fiona is likey to intensify during the next 24 hours. Fiona could strengthen to Category 4 on the Saffir-Simpson Scale. If the inner end of a rainband wraps around the existing eye and eyewall, then an eyewall replacement cycle could cause Hurricane Fiona to weaken temporarily.

Hurricane Fiona will move around the western side of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Fiona toward the north during the next 24 hours. On its anticipated track Hurricane Fiona will bring strong gusty winds and locally heavy rain to the Turks and Caicos and Southeastern Bahamas on Tuesday. An upper level trough near the East Coast of the U.S. will steer Fiona toward the northeast on Wednesday. Hurricane Fiona will affect Bermuda on Thursday night. Fiona could be a major hurricane when it gets to Bermuda.

Typhoon Nanmadol Brings Strong Wind and Heavy Rain to Kyushu

Typhoon Nanmadol brought strong winds and heavy rain to Kyushu on Sunday morning. At 5:00 a.m. EDT on Sunday the center of Typhoon Nanmadol was located at latitude 31.1°N and longitude 130.6°E which put it about 40 miles (65 km) south of Kagoshima, Japan. Nanmadol was moving toward the north-northwest at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (210 km/h). The minimum surface pressure was 969 mb.

The center of Typhoon Nanmadol was moving inland over Kyushu on Sunday morning. Nanmadol was a large an powerful typhoon. Winds to typhoon force extended out 75 miles (120 km) from the center of Nanmadol. Winds to tropical storm force extended out 250 miles (400 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Nanmadol was 19.2. The Hurricane Size Index (HSI) was 30.2 and the Hurricane Wind Intensity Size Index (HWISI) was 51.1. Typhoon Nanmadol was capable of causing extensive serious damage.

Typhoon Nanmadol will move around the western end of a high pressure system over the Western North Pacific Ocean during the next 12 hours. The high pressure system will steer Nanmadol toward the north during that time. On its anticipated track the center of Typhoon Nanmadol will continue to move farther inland over Kyushu. Nanmadol will continue to produce strong gusty winds and locally heavy rain to Kyushu. Heavy rain is likely to cause flash floods in some locations. The westerly winds in the middle latitudes will Nanmadol toward the northeast later today. Typhoon Nanmadol will move over Honshu tomorrow. Nanmadol will bring strong winds and heavy rain to much of Honshu and Shikoku, when it moves northeastward.

Typhoon Nanmadol Near Yakushima

The center of Typhoon Nanmadol was near Yakushima on Saturday night. At 11:00 p.m. EDT on Saturday the center of Typhoon Nanmadol was located at latitude 30.2°N and longitude 130.8°E which put it about 90 miles (145 km) south of Kagoshima, Japan. Nanmadol was moving toward the north-northwest 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 951 mb.

The eye of Typhoon Nanmadol was just southeast of Yakushima on Saturday night. The northwestern part of the eyewall was over Yakushima. Bands on the northern side of Typhoon Nanmadol were producing gusty winds and locally heavy rain over Kyushu.

Nanmadol was a large typhoon. Winds to typhoon force extended out 70 miles (110 km) from the center of Typhoon Nanmadol. Winds to tropical storm force extended out 275 miles (445 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Nanmadol was 22.1. The Hurricane Size Index (HSI) was 29.0 and the Hurricane Wind Intensity Size Index (HWISI) was 51.1. Typhoon Nanmadol was capable of causing widespread serious damage.

Typhoon Nanmadol will move around the western end of a high pressure system over the Western North Pacific Ocean during the next 24 hours. The high pressure system will steer Nanmadol toward the north during the next 24 hours. On its anticipated track the center of Typhoon Nanmadol will reach southwestern Kyushu in a few hours. Nanmadol will bring strong gusty winds and locally heavy rain to Kyushu. Heavy rain is likely to cause flash floods in some locations. The westerly winds in the middle latitudes will Nanmadol toward the northeast in a day or so. Typhoon Nanmadol will move over Honshu early next week. Nanmadol will bring strong winds and heavy rain to Honshu and Shikoku.

Powerful Typhoon Nanmadol Is East of Okinawa

Powerful Typhoon Nanamadol was east of Okinawa on Friday night. At 11:00 p.m. EDT on Friday the center of Typhoon Nanmadol was located at latitude 26.4°N and longitude 132.7°E which put it about 330 miles (530 km) east of Okinawa. Nanmadol was moving toward the northwest at 9 m.p.h. (15 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 926 mb.

Powerful Typhoon Nanmadol was churning over the Western North Pacific Ocean east of Okinawa on Friday night. A circular eye with a diameter of 23 miles (37 km) was present at the center of Nanmadol. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Nanmadol. Storms near the core generated upper level divergence that pumped mass away from the typhoon in all directions.

The size of the circulation around Typhoon Nanmadol increased on Friday when Nanmadol intensified. Winds to typhoon force extended out 100 miles (160 km) from the center of Nanmadol. Winds to tropical storm force extended out 260 miles (420 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Nanmadol was 31.6. The Hurricane Size Index (HSI) was 28.0 and the Hurricane Wind Intensity Size Index (HWISI) was 59.6. Typhoon Nanmadol was capable of causing widespread severe damage.

Typhoon Nanmadol will move through an environment capable of supporting a powerful typhoon during the next 24 hours. Nanmadol will move over water where the Sea Surface Temperatures are near 29˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Nanmadol could maintain much of its intensity during the next 24 hours. If the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could form. That would be the start of an eyewall replacement cycle that would cause Nanmadol to weaken.

Typhoon Nanmadol will move around the southwestern part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Nanmadol toward the northwest during the next 24 hours. On its anticipated track the center of Typhoon Nanmadol will be east of Minami Daito Jima within 12 hours. Nanmadol could be east of Amami Oshima in 24 hours. Typhoon Nanmadol will bring strong, gusty winds and heavy rain to parts of the northern Ryukyu Islands during the weekend. Nanmadol could be near western Kyushu in 36 hours.

Typhoon Nanmadol Rapidly Intensifies to Equivalent of a Major Hurricane

Typhoon Nanmadol rapidly intensified to the equivalent of a major hurricane south of Japan during Thursday night. At 11:00 p.m. EDT on Thursday the center of Typhoon Nanmadol was located at latitude 24.1°N and longitude 135.4°E which put it about 535 miles (860 km) east-southeast of Okinawa. Nanmadol was moving toward the northwest at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h). The minimum surface pressure was 947 mb.

Typhoon Nanmadol rapidly intensified to the equivalent of a major hurricane over the Western North Pacific Ocean south of Japan during Thursday night. A well formed circular eye was present at the center of Nanmadol’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Nanmadol. Storms near the core generated strong upper level divergence that pumped mass away from the typhoon in all directions.

The circulation around Typhoon Nanmadol was symmetrical. Winds to typhoon force extended out 60 miles (95 km) from the center of Nanmadol. Winds to tropical storm force extended out 200 miles (320 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Nanmadol was 23.6. The Hurricane Size Index (HSI) was 20.6 and the Hurricane Wind Intensity Size Index (HWISI) was 44.2. Typhoon Nanmadol was capable of causing widespread major damage.

Typhoon Nanmadol will move through an environment favorable for intensification during the next 24 hours. Nanmadol will move over water where the Sea Surface Temperatures are near 29˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Nanmadol will intensify during the next 24 hours. If the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could form. That would be the start of an eyewall replacement cycle that would cause Nanmadol to weaken.

Typhoon Nanmadol will move around the southwestern part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Nanmadol toward then northwest during the next 36 hours. On its anticipated track the center of Typhoon Nanmadol will be east of Minami Daito Jima within 24 hours. Nanmadol could be east of Amami Oshima in 36 hours. Typhoon Nanmadol will bring strong, gusty winds and heavy rain to parts of the northern Ryukyu Islands during the weekend.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Muifa weakened over the northern Yellow Sea. At 11:00 p.m. EDT on Thursday the center of Tropical Storm Muifa was located at latitude 38.5°N and longitude 121.8°E which put it about 50 miles (80 km) northeast of Yantai, China. Muifa 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 1000 mb.

Typhoon Muifa Moves Toward Eastern China

Typhoon Muifa moved toward eastern China on Tuesday morning. At 11:00 a.m. EDT on Tuesday the center of Typhoon Muifa was located at latitude 27.2°N and longitude 123.7°E which put it about 280 miles (450 km) south-southeast of Shanghai, China. Muifa was moving toward the north-northwest at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (200 km/h). The minimum surface pressure was 964 mb.

The circulation around Typhoon Mauifa exhibited good organization on Tuesday morning. A circular eye was present at the center of Muifa. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Muifa. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The wind field around Typhoon Muifa way very symmetrical. Winds to typhoon force extended out 40 miles (65 km) from the center of Muifa. Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Muifa was 17.8. The Hurricane Size Index (HSI) was 17.1 and the Hurricane Wind Intensity Size Index (HWISI) was 34.9. Typhoon Muifa was capable of causing regional serious damage.

Typhoon Muifa will move through an environment that will be unfavorable for intensification during the next 24 hours. Muifa will move over water where the Sea Surface Temperatures are near 27˚C. An upper level trough over China will produce southwesterly winds that will blow toward the top of Muifa’s circulation. Those winds will cause the vertical wind shear to increase during the next 24 hours. The increase in wind shear and cooler water will cause Typhoon Muifa to weaken gradually.

Typhoon Muifa will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Muifa toward the north-northwest during the next 24 hours. On its anticipated track Typhoon Muifa will make landfall on the east coast of China south of Shanghai in 18 hours. The center of Muifa could make landfall near Ningbo. Typhoon Muifa will bring strong winds and locally heavy rain to the region around Shanghai. Heavy rain could cause flash floods in some locations in eastern China.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Merbok strengthened north-northwest of Wake Island and Tropical Depression 16W also strengthened southwest of Iwo To. At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Merbok was located at latitude 26.2N and longitude 162.7°E which put it about 500 miles (805 km) north-northwest of Wake Island. Merbok was moving toward the north-northwest at 10 m.p.h. (16 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 984 mb.

At 11:00 a.m. EDT on Tuesday the center of Tropical Depression 16W was located at latitude 22.6N and longitude 139.6°E which put it about 190 miles (310 km) southwest of Iwo To. The tropical depression was moving toward the northeast 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 1000 mb.

Typhoon Muifa Brings Wind and Rain to Southern Ryukyu Islands

Typhoon Muifa brought wind and rain to the southern Ryukyu Islands on Monday. At 11:00 a.m. EDT on Monday the center of Typhoon Muifa was located at latitude 25.2°N and longitude 124.0°E which put it about 55 miles (90 km) north of Ishigaki, Japan. Muifa was moving toward the north-northwest at 5 m.p.h. (8 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 967 mb.

Typhoon Muifa continued to bring wind and rain to the southern Ryukyu Islands on Monday. The center of Typhoon Muifa was moving slowly away from Ishigakijima. The strongest winds were measured in Ishigakijima after the eye passed over. A weather station on Ishigakijima measured a sustained wind speed of 68 m.p.h. (109 km/h). The same weather station measured a surface pressure of 968.3 mb when the eye of Typhoon Muifa passed over it. The weather station measured 11.71 inches (297.5 mm) of rain during the passage of Muifa. Bands in the eastern side of Muifa’s circulation also dropped heavy rain over Miyakojima.

The circulation around Typhoon Muifa remained well organized on Monday. A circular eye was present at the center of Muifa’s circulation. The eye was surrounded by a broken 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 Muifa. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

Winds to typhoon force extended out 45 miles (75 km) from the center of Typhoon Muifa. Winds to tropical storm force extended out 110 miles (175 km) from the center of Muifa. The Hurricane Intensity Index (HII) for Typhoon Muifa was 16.5. The Hurricane Size Index (HSI) was 15.4 and the Hurricane Wind Intensity Size Index (HWISI) was 31.9. Muifa was capable of causing regional serious damage.

Typhoon Muifa will move through an environment that will become unfavorable for intensification during the next 36 hours. Muifa will move over water where the Sea Surface Temperatures are near 30˚C. However, an upper level trough over China will produce southwesterly winds that will blow toward the top of Muifa’s circulation. Those winds will cause the vertical wind shear to increase during the next 36 hours. The increase in wind shear will cause Typhoon Muifa to start to weaken.

Typhoon Muifa will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Muifa slowly toward the north-northwest during the next 36 hours. The strong winds and locally heavy rain in the southern Ryukyu Islands will gradually diminish during the next 24 hours as Typhoon Muifa moves farther away. On its anticipated track Typhoon Muifa could approach the east coast of China south of Shanghai in 36 hours.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Merbok continued to strengthen northwest of Wake Island. At 11:00 a.m. EDT on Monday the center of Tropical Storm Merbok was located at latitude 22.9°N and longitude 162.8°E which put it about 350 miles (565 km) northwest of Wake Island. Merbok was moving toward the northeast at 10 m.p.h. (16 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 994 mb.

Eye of Typhoon Muifa Passes over Ishigakijima

The eye of Typhoon Muifa passed directly over Ishigakijima on Sunday night. A weather station on Ishigakijima measured a surface pressure of 968.3 mb. At 11:00 p.m. EDT on Sunday the center of Typhoon Muifa was located at latitude 24.4°N and longitude 124.2°E which put it about 5 miles (10 km) east of Ishigaki, Japan. Muifa was moving toward the north-northwest at 5 m.p.h. (8 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 967 mb.

Typhoon Muifa developed two concentric eyewalls and began an eyewall replacement cycle as it slowly approached Ishigakijima on Sunday. The inner end of rainband wrapped around the existing eye and eyewall and a larger outer eyewall surrounded them. Low level convergence became concentrated in the outer eyewall and the thunderstorms in the inner eyewall weakened. The remnants of the inner eyewall were visible on satellite images as a ring of showers and lower clouds. The outer eyewall had a diameter of 60 miles (95 km). The strongest winds were occurring in the outer eyewall. Bands of showers and thunderstorms were revolving around the core of Typhoon Muifa. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The eyewall replacement cycle caused Typhoon Muifa to weaken as it approached Ishigakijima. Winds to typhoon force extended out 35 miles (55 km) from the center of Typhoon Muifa. Winds to tropical storm force extended out 120 miles (195 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Muifa was 16.5. The Hurricane Size Index (HSI) was 13.9 and the Hurricane Wind Intensity Size Index (HWISI) was 30.4. Typhoon Muifa was capable causing regional serious damage.

Typhoon Muifa will move through an environment favorable for intensification during the next 24 hours. Muifa 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. Typhoon Muifa could intensify during the next 24 hours after the inner eyewall completely dissipates. Since Typhoon Muifa will move slowly, its winds could mix cooler water up to the surface of the ocean. Cooler water would limit potential intensification.

Typhoon Muifa will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Muifa slowly toward the north-northwest during the next 36 hours. Typhoon Muifa will continue to produce strong winds and locally heavy rain in the southern Ryukyu Islands during the next 24 hours. The strongest winds and heaviest rain are likely to affect Ishigakijima. Gusty winds and locally heavy rain could also affect Miyakojima. On its anticipated track Typhoon Muifa could approach the east coast of China near Shanghai in 60 hours.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Merbok was slowly strengthening west-northwest of Wake Island. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Merbok was located at latitude 21.6°N and longitude 161.6°E which put it about 365 miles (595 km) west-northwest of Wake Island. Merbok was moving toward the east-northeast 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 1000 mb.

Powerful Typhoon Muifa Nears Ishigakijima

Powerful Typhoon Muifa neared Ishigakijima on Sunday morning. At 5:00 a.m. EDT on Sunday the center of Typhoon Muifa was located at latitude 23.1°N and longitude 124.2°E which put it about 85 miles (135 km) south of Ishigaki, Japan. Muifa 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 942 mb.

Typhoon Muifa was the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale as it approached Ishigakijima from the south of Sunday. morning. A small circular eye was present at the center of Muifa’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. The inner end of a rainband wrapped part of the way around the eye and eyewall. A second concentric eyewall may be in the process of developing. Other bands of showers and thunderstorms were revolving around the core of Typhoon Muifa’s circulation. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

Winds to typhoon force extended out 40 miles (65 km) from the center of Typhoon Muifa. Winds to tropical storm force extended out 140 miles (225 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Muifa was 25.1. The Hurricane Size Index (HSI) was 15.1 and the Hurricane Wind Intensity Size Index (HWISI) was 40.2. Typhoon Muifa was capable causing regional severe damage.

Typhoon Muifa will move through an environment favorable for intensification during the next 24 hours. Muifa 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, two factors could prevent Typhoon Muifa from intensifying even though it will be in a favorable environment. First, if concentric eyewalls develop, then Muifa could weaken when an eyewall replacement cycle occurs. Second, Typhoon Muifa will move slowly and its winds could mix cooler water up to the surface of the ocean. Typhoon Muifa could intensify a little more during the next 12 hours, but it is likely to slowly weaken after that time.

Typhoon Muifa will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Muifa slowly toward the north-northwest during the next 36 hours. On its anticipated track, the center of Typhoon Muifa could be over Ishigakijima within 24 hours. Muifa is likely to be the equivalent of a major hurricane when it approaches the southern Ryukyu Islands. The center of Typhoon Muifa could pass directly over Ishigakijima. Ishigakijima is already reporting heavy rain. The wind speeds will increase steadily as the center of Muifa approaches. Typhoon Muifa is capable of causing severe damage. Heavy rain is likely to cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 15W was spinning west-northwest of Wake Island. At 5:00 a.m. EDT on Sunday the center of Tropical Depression 15W was located at latitude 21.4°N and longitude 160.0°E which put it about 460 miles (745 km) west-northwest of Wake Island. The tropical depression was moving toward the east-northeast at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1003 mb.