Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Large Typhoon Maysak Churns Toward South Korea

Large, powerful Typhoon Maysak churned toward South Korea on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Typhoon Maysak was located at latitude 30.1°N and longitude 126.9°E which put it about 405 miles (655 km) south-southwest of Busan, South Korea.  Maysak was moving toward the north-northeast at 13 m.p.h. (20 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 Maysak neared the completion of an eyewall replacement cycle on Tuesday which resulted in an increase in the size of the circulation.  The original inner eyewall had not quite dissipated, but low level convergence was focused on the much larger outer eyewall.  Winds to typhoon force extended out 90 miles (145 km) from the center of circulation.  Winds to tropical storm force extended out 240 miles (390 km) from the center of Maysak.

Typhoon Maysak was a large, dangerous tropical cyclone.  The Hurricane Intensity Index (HII) was 25.1.  The Hurricane Size Index (HSI) was 27.5 and the Hurricane Wind Intensity Size Index (HWISI) was 52.6.  Typhoon Maysak was capable of causing widespread major damage.

Since Typhoon Maysak was near the end of an eyewall replacement cycle, it will likely weaken slowly during the next 18 hours.  Maysak will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough over eastern Asia will approach Typhoon Maysak on Wednesday.  The trough will produce southwesterly winds which will blow toward the top of the circulation.  Those winds will cause more vertical wind shear and the shear will cause Typhoon Maysak to weaken more quickly.

Typhoon Maysak will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Maysak toward the north during the next 24 hours.  On its anticipated track the core of Typhoon Maysak is likely to pass west of Kyushu.  Maysak could reach South Korea in about 18 hours.  Typhoon Maysak could be the equivalent of a large, major hurricane when it gets to South Korea.  Maysak will produce very strong winds over South Korea.  It will also drop heavy rain and flash floods could occur.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Haishen strengthened south of Iwo To.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Haishen was located at latitude 20.1°N and longitude 142.8°E which put it about 340 miles (545 km) south-southeast of Iwo To.  Haishen was moving toward the west-southwest at 8 m.p.h. (13 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 1000 mb.  Tropical Storm Haishen is forecast to strengthen into a typhoon and it could move toward western Japan later this week.

Typhoon Maysak Brings Wind and Rain to the Ryukyu Islands

Typhoon Maysak brought winds and rain to the Ryukyu Islands on Monday.  At 11:00 p.m. EDT on Monday the center of Typhoon Maysak was located at latitude 27.5°N and longitude 126.5°E which put it about 110 miles (175 km) west-northwest of Kadena AFB, Okinawa.  Maysak was moving toward the north-northwest at 13 m.p.h. (20 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.

The eye and eyewall of Typhoon Maysak passed west of Okinawa on Monday.  Rainbands on the eastern side of Maysak passed over Okinawa and some of the other southern Ryukyu Islands.  A weather station at Naha reported a sustained wind speed of 58 m.p.h. (93 km/h).  A station at Kitahari (Kumejima Airport), which was closer to the center of Typhoon Maysak reported a sustained wind speed of 89 m.p.h. (144 km/h).

Satellite and radar images suggest that concentric eyewalls may have formed at the core of Typhoon Maysak.  The inner eye had a diameter of 8 miles (13 km).  A much larger outer eye with a diameter of approximately 100 miles (160 km) surrounded the inner eye.  Bands of showers and thunderstorms were revolving around the large core of Maysak.  Storms near the core were generating upper level divergence which was pumping mass away from the typhoon.

The circulation around Typhoon Maysak was large.  Winds to typhoon force extended out 70 miles (110 km) from the center of circulation.  Winds to tropical storm force extended out 200 miles (320 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Maysak was 25.1.  The Hurricane Size Index (HSI) was 25.5 and the Hurricane Wind Intensity Size Index (HWISI).  Maysak was capable of causing widespread major damage.

Typhoon Maysak will move through an environment capable of supporting a strong typhoon during the next 24 hours, but it has likely reached its peak intensity.  The formation of concentric eyewalls normally results in a weaker, but larger tropical cyclone.  The wind speed will decrease when the inner eyewall dissipates.  When that occurs, the maximum wind speeds will occur in the larger outer eyewall.  Since Maysak will move over water where the Sea Surface Temperature is near 29°C, it will remain a typhoon for another 24 to 36 hours.

Typhoon Maysak will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Maysak toward the north during the next 36 hours.  On its anticipated track the center of Typhoon Maysak will pass west of Kyushu.  Typhoon Maysak could reach South Korea in 36 hours

Elsewhere over the Western North Pacific Ocean, Tropical Depression 11W was passing southeast of Iwo To.  At 11:00 p.m. EDT on Monday the center of Tropical Depression 11W was located at latitude 21.7°N and longitude 144.2°E which put it about 290 miles (470 km) southeast of Iwo To.  The depression was moving toward the west-southwest at 8 m.p.h. (13 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 1006 mb.

Typhoon Maysak Strengthens to Equivalent of Major Hurricane Near Okinawa

Typhoon Maysak strengthened to the equivalent of a major hurricane near Okinawa on Monday.  At 11:00 a.m. EDT on Monday the center of Typhoon Maysak was located at latitude 25.5°N and longitude 127.0°E which put it about 110 miles (180 km) south-southwest of Kadena AFB, Okinawa.  Maysak was moving toward the north-northwest at 12 m.p.h. (19 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 936 mb.

Typhoon Maysak strengthened to the equivalent of a major hurricane on Monday as it approached Okinawa.  A circular eye with a diameter of 30 miles (50 km) was at the center of Maysak.  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 Maysak.  Storms near the core were generating upper level divergence which was pumping mass away from the typhoon.

Typhoon Maysak had a large circulation.  Winds to typhoon force extended out 70 miles (110 km) from the center of Maysak.  Winds to tropical storm force extended out 200 miles (320 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Maysak was 23.6.  The Hurricane Size Index (HSI) was 24.1 and the Hurricane Wind Intensity Size Index (HWISI) was 47.7.  Typhoon Maysak was capable of causing widespread major damage.

Typhoon Maysak will move through an environment favorable for intensification during the next 12 to 24 hours.  Maysak will move over water where the Sea Surface Temperature is 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 Maysak could strengthen further and it could intensify into the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.

Typhoon Maysak will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Maysak toward the north during the next several days.  On its anticipated track the center of Typhoon Maysak will pass west of Okinawa during the next few hours.  Maysak will bring strong winds and heavy rain to Okinawa.  Typhoon Maysak could approach South Korea in about 48 hours.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 11W formed east-southeast of Iwo To.  At 11:00 a.m. EDT on Monday the center of Tropical Depression 11W was located at latitude 25.5°N and longitude 127.0°E which put it about 315 miles (515 km) east-southeast of Iwo To.  the depression was moving toward the southwest at 14 m.p.h. (22 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 1008 mb.

Maysak Intensifies into a Typhoon East of Luzon

Former Tropical Storm Maysak intensified into a typhoon on Saturday.  At 5:00 p.m. EDT on Saturday the center of Typhoon Maysak was located at latitude 17.2°N and longitude 128.7°E which put it about 335 miles (540 km) east of Luzon.  Maysak was moving toward the west-northwest at 4 m.p.h. (6 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 976 mb.

The circulation around Typhoon Maysak exhibited greater organization on Saturday.  The inner end of a rainband wrapped partially around the center of circulation and an eye could be forming at the center of Maysak.  Bands of showers and thunderstorms were revolving around the core of Maysak.  Storms near the core were generating upper level divergence which was pumping mass away from the core.  Winds to typhoon force extended out 30 miles (50 km) from the center of circulation.  Winds to tropical storm force extended out 185 miles (295 km) from the center.

Typhoon Maysak will move through an environment favorable for intensification during the next 36 to 48 hours.  Maysak will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds will be weak and there will be little vertical wind shear.  Typhoon Maysak will continue to strengthen and it could intensify rapidly when an eye and eyewall are fully formed.  Maysak could strengthen into the equivalent of a major hurricane within 24 to 36 hours.

Typhoon Maysak will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Maysak toward the north during the next several days.  On its anticipated track Typhoon Maysak will move toward the southern Ryukyu Islands.  Maysak could pass near Okinawa in about 48 hours.  Typhoon Maysak is likely to be the equivalent of a major hurricane when it passes near Okinawa.

Tropical Storm Maysak Forms East of Luzon

Tropical Storm Maysak formed east of Luzon on Friday.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Maysak was located at latitude 16.4°N and longitude 129.4°E which put it about 435 miles (700 km) east of Luzon.  Maysak was moving toward the west-southwest 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 997 mb.

More thunderstorms developed near the center of a low pressure system east of Luzon on Friday and the Japan Meteorological Agency designated the system as Tropical Storm Maysak.  Thunderstorms were also forming in bands revolving around the center of Maysak.  Storm nears the center were generating upper level divergence which was pumping mass away from the tropical storm.  Winds to tropical storm force extended out 140 miles (225 km) from the center of circulation.

Tropical Storm Maysak will move through an environment favorable for intensification during the next 48 hours.  Maysak will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Maysak will intensify quickly and it could strengthen into a typhoon within 24 hours.  Once an inner core with an eye and an eyewall is established Maysak could rapidly intensify into the equivalent of a major hurricane.

Tropical Storm Maysak will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Maysak toward the north-northwest.  On its anticipated track Tropical Storm Maysak could approach the Ryukyu Islands within 72 hours.  Maysak could be the equivalent of a major hurricane by that time.

Typhoon Bavi Passes East of Shanghai

Typhoon Bavi passed east of Shanghai on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Typhoon Bavi was located at latitude 31.9°N and longitude 124.7°E which put it about 200 miles (320 km) east-northeast of Shanghai, China.  Bavi was moving toward the north-northwest at 9 m.p.h. (15 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 958 mb.

The circulation around Typhoon Bavi was well organized on Tuesday.  A circular eye with a diameter of 18 miles (30 km) was at the center of Bavi.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Bavi.  Storm near the core generated upper level divergence which pumped mass away to the north of the typhoon.

The circulation around Typhoon Bavi was moderately large.  Winds to typhoon force extended out 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out 150 miles (240 km) from the center.  The Hurricane Intensity Index (HII) for Bavi was 19.2.  The Hurricane Size Index (HSI) was 16.0 and the Hurricane Wind Intensity Size Index (HWISI) was 35.2.  Typhoon Bavi was capable of causing regional serious damage.

Typhoon Bavi will move through an environment favorable for intensification during the next 12 hours.  Bavi will move over water where the Sea Surface Temperature is 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 Bavi could strengthen into the equivalent of a major hurricane during the next 12 hours.  In 12 hours Bavi will start to move over cooler water, which could end the chance for intensification.  In 24 hours Typhoon Bavi will approach the eastern part of an upper level trough over China.  The trough will produce strong southwesterly winds which will cause strong vertical wind shear.  The strong shear will cause Bavi to weaken more quickly.

Typhoon Bavi will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Bavi toward the north during the next 36 hours.  On its anticipated track Typhoon Bavi could approach the west coast of North Korea in about 24 hours.  Bavi will bring strong winds and locally heavy rain to North Korea and parts of northeastern China.

Typhoon Bavi Passes West of Okinawa

Typhoon Bavi passed west of Okinawa on Sunday.  At 5:00 p.m. EDT on Sunday the center of Typhoon Bavi was located at latitude 27.2°N and longitude 125.6°E which put it about 595 miles (965 km) south-southwest of Chinhae, South Korea.  Bavi was moving toward the east-northeast at 4 m.p.h. (6 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 979 mb.

A circular eye developed at the center of Typhoon Bavi.  The eye was surrounded by a ring of strong thunderstorms.  Bands of showers and thunderstorms were revolving around the core of Bavi.  Storms near the core were generating upper level divergence which was pumping mass away from the typhoon.  Winds to typhoon force extended out 45 miles from the center of circulation.  Winds to tropical storm force extended out 140 miles (225 km) from the center.

Typhoon Bavi will move through an environment favorable for intensification during the next 24 to 36 hours.  Bavi will move over water where the Sea Surface Temperature is 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 Bavi will intensify during the next 36 hours and it could strengthen to the equivalent of a major hurricane.

Typhoon Bavi will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Bavi toward the north during the next several days.  On its anticipated track Typhoon Bavi will pass west of the northern Ryukyu Islands.  Bavi could be southeast of South Korea in about 72 hours.

Tropical Storm Bavi Forms East of Taiwan

Tropical Storm Bavi formed east of Taiwan on Friday night.  At 11:00 p.m. on Friday the center of Tropical Storm Bavi was located at latitude 23.9°N and longitude 122.8°E which put it about 85 miles (135 km) southeast of Taipei, Taiwan.  Bavi was moving toward the north-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.

The circulation around a low pressure system east of Taiwan strengthened on Friday night and the Japan Meteorological Agency designated the system as Tropical Storm Bavi.  The circulation around Bavi was asymmetrical.  Many of the thunderstorms were occurring in bands in the eastern half of the tropical storm.  Bands in the western half of the circulation consisted primarily of showers and lower clouds.  Storms near the center of circulation were generating upper level divergence which was pumping mass away to the east of the tropical storm.  Winds to tropical storm force extended out 80 miles (130 km) to the east of the center of circulation.  The winds on the western side of Tropical Storm Bavi were blowing at less than tropical storm force.

Tropical Storm Bavi will move through an environment favorable for intensification during the next several days.  Bavi will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Bavi will intensify and it could strengthen into a typhoon by the end of the weekend.

Tropical Storm Bavi will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Bavi toward the north-northeast during the next few days.  On its anticipated track the center of Tropical Storm Bavi will pass west of the Ryukyu Islands including Okinawa.  Bavi could approach South Korea in about four days.  The eastern side of Bavi will bring gusty winds and locally heavy rain to the Ryukyu Islands.

Tropical Storm Higos Makes Landfall Near Macau

Tropical Storm Higos made landfall near Macau on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Higos was located at latitude 22.6°N and longitude 112.5°E which put it about 75 miles (120 km) west of Hong Kong.  Higos was moving toward the northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 992 mb.

Tropical Storm Higos made landfall on the coast of China just to the west of Macau on Tuesday night.  Higos intensified on Tuesday and an eye was beginning to form at the time of landfall.  A partial eyewall was on the southern side of the developing eye and the strongest winds were occurring in the partial eyewall.  Bands of thunderstorms were revolving around the core of Tropical Storm Higos.  Winds to tropical storm force extended out 80 miles (130 km) from the center of circulation.

Tropical Storm Higos will weaken steadily as it moves inland over southern China.  Higos will bring gusty winds and it will drop locally heavy rainfall over parts of southern China.  Locally heavy rain could cause flash floods in some locations.

Tropical Storm Higos Forms Southeast of Hong Kong

Tropical Storm Higos formed southeast of Hong Kong on Monday night.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Higos was located at latitude 20.5°N and longitude 116.0°E which put it about 205 miles (335 km) southeast of Hong Kong.  Higos was moving toward the west-northwest at 15 m.p.h. (24 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.

More thunderstorms developed near the center of a low pressure system southeast of Hong Kong on Monday night and the Japan Meteorological Agency designated the system as Tropical Storm Higos.  The circulation around Tropical Storm Higos was organizing quickly.  Thunderstorms were developing around the center of circulation.  Bands of showers and thunderstorms were revolving around the center of Higos.  Storms near the center of circulation were generating upper level divergence which pumped mass away from the tropical storm.  Winds to tropical storm force extended out 100 miles (160 km) from the center of circulation.

Tropical Storm Higos will move through an environment favorable for intensification during the next 18 to 24 hours.  Higos will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Higos will continue to intensify and there is a chance it could strengthen into a typhoon before it makes landfall on the coast of China.

Tropical Storm Higos will move around the southern side of a high pressure system over the Western North Pacific Ocean.  The high will steer Higos toward the west-northwest during the next 48 hours.  On its anticipated track Tropical Storm Higos will make landfall on the coast of China west of Macau near Yangjiang.  Higos will bring gusty winds and locally heavy rain to parts of southern China.  Locally heavy rain could cause flash floods in some locations.