Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Tropical Storm Kujira Forms West of Wake Island

Tropical Storm Kujira formed west of Wake Island on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Kujira was located at latitude 21.1°N and longitude 158.5°E which put it about 515 miles (830 km) west of Wake Island.  Kujira was moving toward the northwest at 9 m.p.h. (15 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 maximum sustained wind speed was 1002 mb.

Tropical Storm Kujira was moving around the eastern side of an upper level low.  The upper low was causing vertical wind shear which was causing the distribution of thunderstorms to be asymmetrical.  There were few thunderstorms near the center of the circulation.  Many of the thunderstorms were occurring in bands east and south of the center of Kujira.  Bands in the western half of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 200 miles (320 km) in the southeastern quadrant of Tropical Storm Kujjira.  The winds in the other parts of the circulation were blowing at less than tropical storm force.

Tropical Storm Kujira will move through an environment favorable for intensification after it moves away from the upper level low.  When Kujira moves away from the upper low, the vertical wind shear will decrease.  Tropical Storm Kujira will move over water where the Sea Surface Temperature is near 28°C.  Kujira will intensify when the wind shear decreases.   It could strengthen into a typhoon in two or three days.

The upper level low will pull Tropical Storm Kujira toward the northwest during the next 12 to 24 hours.  Then Kujira will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Tropical Storm Kujira toward the north for 24 to 36 hours.  Kujira will eventually be steered toward the northeast when it reaches the westerly winds in the middle latitudes.  On its anticipated track Tropical Storm Kujira will pass well to the east of Japan.

Tropical Storm Dolphin Passes Southeast of Japan

Tropical Storm Dolphin passed southeast of Japan on Wednesday.  At 11:00 a.m. EDT on Wednesday the center of Tropical Storm Dolphin was located at latitude 32.9°N and longitude 141.4°E which put it about 200 miles (320 km) south-southeast of Tokyo, Japan.  Dolphin was moving toward the northeast at 19 m.p.h. (31 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 986 mb.

An upper level trough over eastern Asia steered Tropical Storm Dolphin quickly toward the northeast on Wednesday.  The trough carried Dolphin southeast of Tokyo.  Winds to tropical storm force extended out 175 miles from the center of Dolphin.  The northern periphery of tropical storm Dolphin was bringing gustier winds to parts of the coast of Honshu.  Most of the rain falling in Tropical Storm Dolphin fell southeast of Honshu.

The upper level trough will carry Tropical Storm Dolphin east of Japan.  Although Dolphin is currently over water where the Sea Surface Temperature is near 28°C, the tropical storm will soon move over cooler water.  The upper level trough and the cooler water will cause Tropical Storm Dolphin to make a transition to an extratropical cyclone during the next several days.

Tropical Storm Dolphin Forms South of Japan

Tropical Storm Dolphin formed south of Japan on Monday.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Dolphin was located at latitude 26.0°N and longitude 135.0°E which put it about 365 miles (590 km) southwest of Tokyo, Japan.  Dolphin was moving toward the north-northeast at 5 m.p.h. (8 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 996 mb.

A distinct low level center of circulation developed near the southern side of an area of thunderstorms south of Japan on Monday and the Japan Meteorological Agency designated the system as Tropical Storm Dolphin.  The circulation around Tropical Storm Dolphin was still organizing.  The strongest thunderstorms were occurring in bands in the northern half of the circulation.  Bands in the southern half of Dolphin consisted primarily of showers and lower clouds.  Storms near the center of circulation generated upper level divergence which pumped mass away to the northeast of the tropical storm.  Winds to tropical storm force extended out 125 miles (200 km) from the center.

Tropical Storm Dolphin will move through an environment somewhat favorable for intensification during the next 36 hours.  Dolphin will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough approaching Japan from the west will produce southwesterly winds which will blow toward the top of Tropical Storm Dolphin.  Those winds will cause moderate vertical wind shear and they will inhibit intensification of Dolphin.  The shear will limit intensification, but Tropical Storm Dolphin is likely to get stronger during the next 36 hours.

Tropical Storm Dolphin will move around the northwestern part of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Dolphin toward the north-northeast during the next 24 to 36 hours.  Tropical Storm Dolphin will reach the westerly winds in the middle latitudes after that period and those winds will steer Dolphin more toward the northeast during the middle of the week.  On its anticipated track Tropical Storm Dolphin could approach the coast of Honshu near Tokyo in about 72 hours.

Tropical Storm Noul Brings Wind and Rain to Central Vietnam

Tropical Storm Noul brought wind and rain to central Vietnam on Thursday night.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Noul was located at latitude 16.7°N and longitude 107.2°E which put it about 45 miles (75 km) north-northwest of Da Nang, Vietnam.  Noul was moving toward the west at 22 m.p.h. (35 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.

The distribution of thunderstorms and rain around Tropical Storm Noul was asymmetrical.  The strongest thunderstorms and the heaviest rain were on the western side of Noul.  Tropical Storm Noul was moving under the southern part of a large upper level ridge over Asia and the Western North Pacific Ocean.  The ridge was producing strong easterly winds which were blowing toward the top of Noul.  Those winds were causing moderate vertical wind shear and they were also the cause of the asymmetrical distribution of rainfall.  Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation.

The upper level ridge will steer Tropical Storm Noul quickly toward the west.  Noul will across central Vietnam and southern Laos on Friday.  Tropical Storm Noul will drop locally heavy rain over parts of central Vietnam, southern Laos and northeastern Thailand.  Flash floods could occur in some locations.

Tropical Storm Noul Moves Toward Vietnam

Tropical Storm Noul moved toward Vietnam on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Noul was located at latitude 14.8°N and longitude 113.8°E which put it about 420 miles (675 km) east-southeast of Da Nang, Vietnam.  Noul was moving toward the northwest at 12 m.p.h. (19 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.

Tropical Storm Noul moved under the southern portion of a large upper level ridge over Asia and the Western North Pacific Ocean.  The ridge produced strong easterly winds which blew toward the top of Noul’s circulation.  Those winds caused moderate vertical wind shear and they contributed to an asymmetrical distribution of thunderstorms in Tropical Storm Noul.  The strongest thunderstorms were occurring in the western half of Noul.  Bands in the eastern half of the circulation consisted primarily of showers and lower clouds.  Storms near the center of circulation generated upper level divergence which pumped mass away to the west of the tropical storm.  Winds to tropical storm force extended out 140 miles (220 km) from the center of circulation.

Tropical Storm Noul will move through an environment marginally favorable for intensification during the next 24 hours.  Noul will move over water where the Sea Surface Temperature is near 30.5°C.  The upper level ridge will continue to cause moderate vertical wind shear.  The shear will inhibit intensification.  Tropical Storm Noul could strengthen if the wind shear decreases.

The upper level ridge will steer Tropical Storm Noul toward the west-north west during the next day or so.  On its anticipated track Noul will approach the coast of central Vietnam in about 24 hours.  Tropical Storm Noul will bring gusty winds and rain to central Vietnam on Friday.

Tropical Storm Noul Forms West of the Philippines

Tropical Storm Noul formed over the South China Sea west of the Philippines on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Noul was located at latitude 12.9°N and longitude 118.0°E which put it about 215 miles (345 km) southwest of Manila, Philippines.  Noul was moving toward the west-northwest at 11 m.p.h. (17 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 Tropical Storm Noul was still organizing on Tuesday afternoon.  More thunderstorms were developing near the center of circulation.  Bands of showers and thunderstorms were revolving around the center of Noul.  Storms near the center started to generate upper level divergence which pumped mass away to the west of the tropical storm.  Winds to tropical storm force extended out 100 miles (160 km) from the center of circulation.

Tropical Storm Noul will move through an environment favorable for intensification during the next 48 hours.  Noul will move over water where the Sea Surface Temperature is near 30.5°C.  It will move south of an upper level ridge over the South China Sea.  The ridge will produce easterly winds which will blow toward the top of Tropical Storm Noul.  Those winds will cause moderate vertical wind shear, but they will not be strong enough to prevent Noul from intensifying.  Tropical Storm Noul could strengthen into a typhoon within 48 hours.

Tropical Storm Noul will move south of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Noul toward the west-northwest during the next several days.  On its anticipated track Noul could approach the coast of Vietnam in about 60 hours.  It is likely to be a typhoon when it nears Vietnam.

Typhoon Haishen Drops Heavy Rain over South Korea

Typhoon Haishen dropped heavy rain over South Korea on Sunday night. Haishen weakened to a tropical storm after it made landfall on South Korea.   At 11:00 p.m. EDT on Sunday the center of Tropical Storm Haishen was located at latitude 36.6°N and longitude 128.8°E which put it about 30 miles north-northwest of Busan, South Korea.  Haishen was moving toward the north at 27 m.p.h. (43 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 969 mb.

The center of Typhoon Haishen passed just to the west of Kyushu earlier on Sunday.  A weather station at Makurazaki, Japan reported a wind speed of 65 m.p.h. (105 km/h) and a pressure of 966.6 mb.

Typhoon Haishen began dropping heavy rain over parts of South Korea hours before the center made landfall west of Busan.  Heavy rain was falling on some of the same places that also received heavy rain from Typhoon Maysak a few days ago.  The additional rain will cause flash floods in some locations.  Tropical Storm Haishen will continue to weak as it moves rapidly toward the north.

Typhoon Haishen Brings Wind and Rain to Northern Ryukyu Islands

Typhoon Haishen brought wind and rain to the northern Ryukyu Islands on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Haishen was located at latitude 28.3°N and longitude 130.4°E which put it about 170 miles (280 km) east-northeast of Okinawa.  Haishen was moving toward the north-northwest at 15 m.p.h. (24 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 945 mb.

The center of Typhoon Haishen passed west of Minami-Daito Jima on Saturday.  A weather station there measured a wind speed of 72 m.p.h. (116 km/h) and a pressure of 943.6 mb.

The circulation around around Typhoon Haishen developed concentric eyewalls on Saturday.  The smaller original eyewall started to weaken as low level convergence became more concentrated into the much larger outer eyewall.  The strongest winds were originally found in the inner eyewall, but those wind speeds decreased.  The stronger winds were blowing in the larger outer eyewall on Saturday night.

The concentric eyewall structure produced an increase in the size of the circulation around Typhoon Haishen.  Winds to typhoon force extended out 100 miles (160 km) from the center of circulation.  Winds to tropical storm force extended out 325 miles (530 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Haishen was 19.2.  The Hurricane Size Index (HSI) was 37.2 and the Hurricane Wind Intensity Size Index (HWISI) was 56.4.  Typhoon Haishen was capable of causing widespread serious damage.

Typhoon Haishen will move into a less favorable environment during the next 24 hours.  Haishen will move over water where the Sea Surface Temperature is near 28°C.  Drier air over Asia will get pulled into the circulation.  Wind shear will increase when Typhoon Haishen moves farther north because it will get closer to the upper level westerly winds in the middle latitudes.  The effects of the concentric eyewalls, drier air and more wind shear will cause Typhoon Haishen to gradually weaken.

Typhoon Haishen will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Haishen toward the north.  On its anticipated track the center of Typhoon Haishen will pass near the western part of Kyushu in about 12 hours.  Haishen will reach South Korea in about 24 hours.  Typhoon Haishen will bring strong winds and heavy rain to parts of Kyushu and South Korea.  Heavy rain could cause flash floods, especially in places that received heavy rain from Typhoon Maysak a few days ago.

Typhoon Haishen Intensifies to Equivalent of Major Hurricane

Typhoon Haishen intensified to the equivalent of a major hurricane over the Western North Pacific Ocean on Thursday.  At 5:00 p.m. EDT on Thursday the center of Typhoon Haishen was located at latitude 21.4°N and longitude 135.4°E which put it about 405 miles (650 km) southeast of Minamidaitojima, Japan.  Haishen was moving toward the west-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 938 mb.

Typhoon Haishen intensified rapidly on Thursday.  A circular eye became more visible on conventional satellite images.  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 Haishen.  Storms near the core generated strong upper level divergence which pumped mass away from the typhoon.

The circulation around Typhoon Haishen increased in size on Thursday.  Winds to typhoon force extended out 65 miles (105 km) from the center of circulation.  Winds to tropical storm force extended out 215 miles (315 km) from the center.  The Hurricane Intensity Index (HII) was 29.9.  The Hurricane Size Index (HSI) was 23.5 and the Hurricane Wind Intensity Size Index (HWISI) was 53.4.  Typhoon Haishen was capable of causing widespread significant damage.

Typhoon Haishen will move through an environment favorable for intensification during the next 24 hours.  Haishen 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 Haishen could strengthen to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.

Typhoon Haishen will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Typhoon Haishen toward the northwest during the next 36 hours.  Haishen will move more toward the north when it reaches the western end of the high pressure system.  On its anticipated track Typhoon Haishen could reach Minamidaitojima in about 36 hours.  Haishen could approach the northern Ryukyu Islands in about 48 hours.  Typhoon Haishen could hit South Korea in a little over three days.

Typhoon Maysak Brings Wind and Rain to South Korea

Typhoon Maysak brought wind and rain to South Korea on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Typhoon Maysak was located at latitude 36.9°N and longitude 128.9°E which put it about 30 miles (50 km) north-northwest of Busan, South Korea.  Maysak was moving toward the north-northeast at 30 m.p.h. (50 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (165 km/h).  The minimum surface pressure was 950 mb.

The center of Typhoon Maysak made landfall on the south coast of South Korea west of Busan on Wednesday.  The large circulation around Maysak brought gusty winds and heavy rain to much of the Korean Peninsula.  Winds to typhoon force extended out 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out 200 miles (320 km) from the center.  The heavy rain was falling on ground that was saturated by previous tropical cyclones and other weather systems.  The rain will likely cause widespread flash flooding.

Typhoon Maysak was being steered quickly toward the north by an upper level trough over eastern Asia.  On its anticipated track the center of Maysak will move along the east coast of the Korean Peninsula.  Typhoon Maysak will weaken and it will made a transition to an extratropical cyclone during the next 24 hours.

Elsewhere over the Western North Pacific Ocean, Typhoon Haishen strengthened south of Iwo To.  At 5:00 p.m. EDT on Wednesday the center of Typhoon Haishen was located at latitude 20.3°N and longitude 138.8°E which put it about 350 miles (560 km) south-southwest of Iwo To.  Haishen was moving toward the west-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (165 km/h).  The minimum surface pressure was 979 mb.

Typhoon Haishen will move through an environment favorable for intensification during the next 36 to 48 hours.  Haishen 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 Haishen will continue to intensify and it is likely to strengthen into the equivalent of a major hurricane.

Typhoon Haishen will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Haishen toward the northwest during the next several days.  On its anticipated track Typhoon Haishen could approach the northern Ryukyu Islands in about 72 hours.  Haishen could eventually bring wind and rain to the same areas in Kyushu and South Korea affected by Typhoon Maysak.