Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Tropical Storm Nakri Brings Wind, Rain to Vietnam and Cambodia

Tropical Storm Nakri brought wind and rain to Vietnam and Cambodia on Sunday.  At 4:00 p.m. EST on Sunday the center of Tropical Storm Nakri was located at latitude 13.0°N and longitude 108.9°E which put it about 20 miles (35 km) west of Tuy Hoa, Vietnam.  Nakri was moving toward the west 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 992 mb.

The center of Tropical Storm Nakri made landfall on the coast of Vietnam near Tuy Hoa on Sunday.  The maximum sustained wind speed at the time of landfall was 65 m.p.h. (105 km/h).  Nakri moved slowly toward the west after it made landfall.  Tropical Storm Nakri has been weakening slowly since the center moved over land.  The heaviest rain was falling in bands in the western half of the circulation.  Heavy rain was falling over portions of southern Vietnam and northeastern Cambodia.  The strongest winds were occurring in the eastern half of Nakri which was still over the South China Sea.  Winds to tropical storm force extended out 60 miles (95 km) from the center of circulation.

Tropical Storm Nakri will move south of a ridge over high pressure over the South China Sea and southeast Asia.  The ridge will steer Nakri toward the west-northwest during the next 24 to 36 hours.  Tropical Storm Nakri will continue to weaken as it moves farther inland.  On its anticipated track Nakri will drop locally heavy rain over parts of southern Vietnam, northern Cambodia, southern Laos and eastern Thailand.  Heavy rain could cause flash floods in some locations.

Nakri Strengthens to a Typhoon and Moves Toward Vietnam

Former Tropical Storm Nakri strengthened into a typhoon and started to move toward Vietnam on Friday.  At 4:00 p.m. EST on Friday the center of Typhoon Nakri was located at latitude 12.9°N and longitude 114.9°E which put it about 395 miles (635 km) east of Quy Nhon, Vietnam.  Nakri was moving toward the west at 13 m.p.h. (20 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 977 mb.

The distribution of thunderstorms around Typhoon Nakri was asymmetrical.  A broken ring of showers and thunderstorms surrounded the center of Nakri.  The strongest thunderstorms were in the southern portion of the ring.  Most of the strongest rainbands were in the southern half of the typhoon, although there was one strong rainband along the northern periphery of the circulation.  Many of the other bands on the eastern and northern sides of Typhoon Nakri consisted primarily of showers and lower clouds.  It appeared that sinking, drier air was limiting the development of thunderstorms in the northern half of the circulation.

In spite of the effects of the drier air, the size of the circulation around Typhoon Nakri increased on Friday.  Winds to typhoon force extended out 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out 175 miles (280 km) from the center.

Typhoon Nakri will be moving through an environment marginally favorable for intensification during the next 12 to 24 hours.  Nakri will move over water where the Sea Surface Temperature is near 28°C.  It will move around the southern side of an upper level ridge over southeast Asia and the South China Sea.  The ridge will produce easterly winds which will blow toward the top of the circulation.  Those winds will cause moderate vertical wind shear which will inhibit intensification.  Drier air to the north of Typhoon Nakri will also inhibit intensification.  Nakri is likely to maintain its intensity during the next day or so, but it could start to weaken if the wind shear increases or more drier air sinks over the circulation.

The ridge over southeast Asia and the South China Sea will steer Typhoon Nakri toward the west during the next two to three days.  On its anticipated track Typhoon Nakri could approach the coast of Vietnam in about 48 hours.  Typhoon Nakri could bring gusty winds and a storm surge for the central coast of Vietnam.  Nakri could drop locally heavy rainfall when it moves inland and flash floods could occur in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Halong was speeding away from Miami Tori Shima, Japan.  At 4:00 p.m. EDT on Friday the center of Tropical Storm Halong was located at latitude 30.9°N and longitude 161.1°E which put it about 580 miles (935 km) northeast of Minami Tori Shima, Japan.  Halong was moving toward the northeast at 14 m.p.h. (22 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 983 mb.

Tropical Storm Nakri Stalls West of the Philippines

Tropical Storm Nakri stalled west of the Philippines on Thursday.  At 10:00 p.m. EST on Thursday the center of Tropical Storm Nakri was located at latitude 12.8°N and longitude 116.8°E which put it about 290 miles (465 km) west-southwest of Manila, Philippines.  Nakri was moving toward the south at 2 m.p.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 980 mb.

Tropical Storm Nakri meandered slowly west of the Philippines on Thursday.  The structure of Nakri did not change a lot during the day.  There was a distinct low level center center of circulation.  Thunderstorms were forming on the south side of the center and the strongest winds were occurring in those thunderstorms.  Thunderstorms were also developing in bands in the southern half of Tropical Storm Nakri.  Bands in the northern half of the circulation consisted primarily of showers and lower clouds.  Storms south of the center generated upper level divergence that pumped mass away to the west of the tropical storm.  Winds to tropical storm force extended out 175 miles (280 km) from the center of circulation.

Tropical Storm Nakri will move through an environment favorable for intensification during the next 24 to 36 hours.  Nakri mixed cooler water to the surface during the period when it meandered west of the Philippines, but it will move over water where the Sea Surface Temperature is near 29°C when it starts moving.  Tropical Storm Nakri will move southeast of an upper level ridge over southeast Asia.  The ridge will produce easterly winds which will cause moderate vertical wind shear.  The wind shear will inhibit intensification, but it will not be strong enough to prevent Tropical Storm Nakri from strengthening.  Nakri will likely become a typhoon on Friday or Saturday.

Tropical Storm Nakri has been in an area where the steering winds have been weak and it has moved little during the past 24 hours.  The ridge over southeast Asia will strengthen and it will steer Nakri toward the east during the next 72 hours.  On its anticipated track Tropical Storm Nakri could approach the coast of Vietnam in less than 72 hours.  Nakri is likely to be a typhoon when it approaches the coast of Vietnam.

Elsewhere over the Western North Pacific Ocean, Typhoon Halong was passing north of Minami Tori Shima, Japan.  At 10:00 p.m. EST on Thursday the center of Typhoon Halong was located at latitude 27.2°N and longitude 154.4°E which put it about 175 miles (280 km) north of Minami Tori Shima, Japan.  Halong was moving toward the northeast at 16 m.p.h. (26 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 Halong Intensifies into Equivalent of Cat. 5 Hurricane

Typhoon Halong intensified into the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Tuesday.  At 4:00 p.m. EST on Tuesday the center of Typhoon Halong was located at latitude 20.4°N and longitude 150.6°E which put it about 345 miles (560 km) southwest of Minami Tori Shima, Japan.  Halong was moving toward the north-northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 180 m.p.h. (290 km/h) and there were wind gusts to 220 m.p.h. (355 km/h).  The minimum surface pressure was 900 mb.

Typhoon Halong intensified into one of the strongest tropical cyclones of 2019 over the Western North Pacific Ocean on Tuesday.  There was a circular eye with a diameter of 15 miles (24 km) at the center of Halong.  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 Halong.  Storm near the core were generating strong upper level divergence which was pumping mass away to the northeast of the typhoon.

The circulation around Typhoon along was compact and symmetrical.  Winds to typhoon force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Halong was 42.2.  The Hurricane Size Index (HSI) was 9.4 and the Hurricane Wind Intensity Size Index (HWISI) was 51.6.

Typhoon Halong has probably reached its peak intensity.  Halong will move over water where the Sea Surface Temperature is near 29°C.  However, an upper level trough near Japan will approach Typhoon Halong from the northwest.  The trough will produce strong southwesterly winds which will start to increase the vertical wind shear.  More wind shear will cause Halong to weaken.

The upper level trough will start to steer Typhoon Halong toward the northeast in 12 to 24 hours.  On its anticipated track Typhoon Halong will pass northwest of Minami Tori Shima on Thursday.  Even though it will weaken, Halong will bring strong, gusty winds and heavy rain.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Nakri developed over the South China Sea between the Philippines and Vietnam on Tuesday.  At 4:00 p.m. EST on Tuesday the center of Tropical Storm Nakri was located at latitude 13.8°N and longitude 116.0°E which put it about 380 miles (615 km) west of Manila, Philippines.  Nakri was moving toward the northeast at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 998 mb.

Although Tropical Storm Nakri is currently moving toward the northeast, it is forecast to move back toward the west later this week.  Nakri will move through an environment favorable for intensification.  It will move over water where the Sea Surface Temperature is near 28°C.  Tropical Storm Nakri could strengthen into a typhoon before it reaches the coast of Vietnam.

Typhoon Halong Strengthens to Equivalent of a Major Hurricane

Typhoon Halong strengthened to the equivalent of a major hurricane northeast of the Northern Marianas on Monday.  At 4:00 p.m. EST on Monday the center of Typhoon Halong was located at latitude 18.9°N and longitude 152.1°E which put it about 390 miles (630 km) south of Minami Tori Shima, Japan.  Halong was moving toward the northwest at 7 m.p.h. (11 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 952 mb.

Typhoon Halong continued to strengthen on Monday and it reached the equivalent of a major hurricane.  A small, well formed circular eye was evident on infrared 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 Typhoon Halong.  Storms near the core were generating strong upper level divergence which was pumping mass away from the typhoon.

The circulation around Typhoon Halong increased in size on Monday.  Winds to typhoon force extended out 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out 160 miles (260 km) from the center.  The Hurricane intensity Index (HII) for Typhoon Halong was 22.0.  The Hurricane Size Index (HSI) was 14.3 and the Hurricane Wind Intensity Size Index was 36.3.  Halong was capable of causing major damage.

Typhoon Halong will remain in an environment favorable for intensification for another 24 hours.  Halong will move over water where the Sea Surface Temperature is near 29°C.  It will move under the northwestern portion of an upper level ridge where the winds are weaker and there will be little vertical wind shear.  An upper level trough southwest of Japan will approach Typhoon Halong in 24 hours.  The trough will produce stronger southwesterly winds which will cause more vertical wind shear.  Halong will start to weaken when the wind shear increases.

Typhoon Halong will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean during the next 36 to 48 hours.  The ridge will steer Halong toward the north-northwest.  Halong will move toward the northeast later this week after if moves around the western end of the high pressure system.  On its anticipated track Typhoon Halong could approach Minami Tori Shima in less than 72 hours.

Halong Strengthens into a Typhoon East of the Northern Marianas

Former Tropical Storm Halong strengthened into a typhoon east of the Northern Marianas on Sunday.  At 4:00 p.m. EDT on Sunday the center of Typhoon Halong was located at latitude 17.0°N and longitude 153.3°E which put it about 520 miles (840 km) east-northeast of Saipan.  Halong was moving toward the northwest at 12 m.p.h. (19 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.

The circulation around former Tropical Storm Halong exhibited much better organization on Sunday.  An eye with a diameter of approximately 12 miles (19 km) formed at the center of Halong.  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 Halong.  The strongest rainbands were north and east of the center of circulation.  Bands in the western half of Halong consisted primarily of showers and lower clouds.  Typhoon Halong may have been pulling sinking, drier air into the western half of the circulation, which may be why the bands were weaker in that part of the typhoon.  Storms around the core of Halong were generating strong upper level divergence which was pumping mass away from the typhoon.  Winds to typhoon force extended out 10 miles (15 km) from the center of circulation.  Winds to tropical storm force extended out 175 miles (280 km) from the center.

Typhoon Halong will move through an environment favorable for intensification during the next 36 to 48 hours.  Halong will move over water where the Sea Surface Temperature is near 29°C.  It will move under the western part of an upper level ridge where the winds are weak.  So, there will not be a lot of vertical wind shear.  Typhoon Halong will continue to intensify and it could strengthen into the equivalent of a major hurricane.

Typhoon Halong will move around the western end of a ridge of high pressure over the Western North Pacific Ocean.  The ridge will steer Halong toward the northwest during the next 24 hours.  After that time Typhoon Halong will move more toward the north while it moves around the western end of the ridge.  Halong will move northeastward after it moves around the end of the ridge.  On its anticipated track Typhoon Halong is forecast to remain northeast of the Northern Marianas.  Halong is expected to pass between Iwo To and Wake Island later next week.

Tropical Storm Halong Develops East of the Marianas

Tropical Storm Halong developed east of the Marianas on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Halong was located at latitude 13.3°N and longitude 156.7°E which put it about 820 miles (1325 km) east of Guam.  Halong 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 minimum surface pressure was 1000 mb.

A distinct low level center of circulation formed in an area of thunderstorms east of the Marianas on Saturday.  When more thunderstorms formed near the center of circulation, the Japan Meteorological Agency designated the system as Tropical Storm Halong.  The circulation around Halong appeared to be organizing quickly.  New thunderstorms were forming close to the center of circulation.  Bands of showers and thunderstorms were also organizing quickly and the bands were starting to revolve around the center of Tropical Storm Halong.  Storms near the center were generating upper level divergence which was pumping mass away from the tropical storm in all directions.  Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation.

Tropical Storm Halong will move through an environment favorable for intensification during the next two to three days.  Halong will move over water where the Sea Surface Temperature is near 29°C.  It will move under the western end of an upper level ridge over the Western North Pacific Ocean.  The winds will be blowing from the south at all levels and so there will be little vertical wind shear.  Tropical Storm Halong will continue to intensify and it could strengthen rapidly.  Halong is likely to strengthen into a typhoon within 36 hours.

The ridge over the Western North Pacific will steer Tropical Storm Halong toward the northwest during the next several days.  On its anticipated track Halong will be northeast of the Marianas by the end of the weekend.

Tropical Storm Matmo Makes Landfall in Vietnam

Tropical Storm Matmo made landfall on the southern coast of Vietnam near Quy Nhon on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Matmo was located at latitude 13.7°N and longitude 108.2°E which put it about 50 miles (80 km) west of Quy Nhon, Vietnam.  Matmo was moving toward the west at 13 m.p.h. (20 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 944 mb.

Tropical Storm Matmo organized quickly as it approached the coast of southern Vietnam on Wednesday.  The inner end of a band of showers and thunderstorms wrapped about 75% around the center of circulation and an eye appeared to be forming.  Thunderstorms near the center of Matmo were generating upper level divergence which was pumping mass away from the tropical storm.  The removal of mass allowed the pressure to decrease which caused the wind speed to increase.  The maximum sustained wind speed at the time when Tropical Storm Matmo made landfall was 60-65 m.p.h. (95-105 km/h).

Tropical Storm Matmo began to weaken after the center moved over land.  The strongest winds were occurring in bands of showers and thunderstorms in the eastern half of Matmo over the South China Sea.  Wind speeds in the parts of the circulation what were over land were less.  Tropical Storm Matmo will continue to move westward during the next several days.  Matmo will drop heavy rain over parts of southern Vietnam, Cambodia, southern Laos, and Thailand.  Heavy rain could cause floods in some locations.

Tropical Storm Matmo Forms East of Vietnam

Tropical Storm Matmo formed over the South China Sea east of Vietnam on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Matmo was located at latitude 12.7°N and longitude 112.2°E which put it about 60 miles (260 km) east of Dai Lanh, Vietnam.  Matmo was moving toward the west at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 998 mb.

More thunderstorms developed near the center of a low pressure system over the South China Sea east of Vietnam on Tuesday and the Japan Meteorological Agency designated the system as Tropical Storm Matmo.  The circulation around Tropical Storm Matmo was still organizing.  Thunderstorms were forming around the center of circulation.  Bands of showers and thunderstorms were developing in the northern and western parts of the tropical storm.  Bands in the eastern and southern parts of the circulation consisted primarily of showers and lower clouds.  Storms near the center of circulation were beginning to generate upper level divergence.

Tropical Storm Matmo will move through an environment favorable for intensification during the next 12 to 18 hours.  Matmo will move over water where the Sea Surface Temperature is near 29°C.  It will move under the west part of an upper level ridge where the winds are weaker and where there is less vertical wind shear.  Tropical Storm Matmo could strengthen during the next 12 hours.  Matmo will near the coast of Vietnam in about 12 hours and it will start to weaken when the center moves over land.

Tropical Storm Matmo will move south of a ridge of high pressure over the Western North Pacific Ocean.  The ridge will steer Matmo toward the west.  On its anticipated track Tropical Storm Matmo could make landfall on the coast of Vietnam between Dai Lanh and Quy Nhon in 12 to 18 hours.  Matmo will bring gusty winds to the coastal regions of southern Vietnam.  Tropical Storm Matmo could also drop heavy rain over parts of southern Vietnam, Cambodia, southern Laos and eastern Thailand.  Heavy rain could cause floods in some locations.

Typhoon Bualoi Brings Wind and Rain to Ogasawara Islands

Typhoon Bualoi brought wind and rain to the Ogasawara Islands on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Typhoon Bualoi was located at latitude 27.6°N and longitude 142.2°E which put it about 30 miles (50 km) north of Chichijima, Japan.  Bualoi was moving toward the north at 19 m.p.h. (31 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 963 mb.

Typhoon Bualoi moved over the Ogasawara Islands on Wednesday.  The core of Bulaoi and the strongest winds moved just to the east of Iwo To.  The international airport on Iwo To reported winds to near typhoon force.  The center of Typhoon Bualoi passed very close to Hahajima and Chichijima.  Bualoi produced gusty winds on Iwo To, Hahajima and Chichijima.  The typhoon also dropped locally heavy rain over some of the Ogasawara Islands.

Typhoon Bualoi weakened slowly on Wednesday.  There was a circular eye at the center of 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 occurring in the northern half of Bualoi.  Bands in the southern half of the typhoon consisted primarily of showers and lower clouds.  An upper level trough west of Japan produced southwesterly winds which were blowing toward the top of the circulation.  Those winds were causing vertical wind shear and they were the probable reason for the weaker bands in the southern half of the circulation.

Typhoon Bualoi will continue to weaken.  Bualoi will move over water where the Sea Surface Temperature is near 28°C.  However, the upper level trough west of Japan will continue to cause wind shear which will weaken the typhoon.  In addition, the circulation around Typhoon Bualoi will pull drier air around the southern side of the typhoon.  The drier air will make Bualoi start to weaken more quickly.

The upper level trough west of Japan will turn Typhoon Bualoi toward the northeast on Thursday.  On its anticipated track Typhoon Bualoi will move away from the Ogasawara Islands during the next 24 hours.  The wind speeds should gradually decrease and rainfall will end quickly as Bualoi moves away from those islands.  Typhoon Bualoi is forecast to pass well to the southeast of Honshu.