Tag Archives: HWISI

Tropical Cyclone Belna Makes Landfall in Western Madagascar

Tropical Cyclone Belna made landfall in the west coast of Madagascar near Soalala on Monday.  At 9:00 a.m. EST on Monday the center of Tropical Cyclone Belna was located at latitude 16.0°S and longitude 45.0°E which put it about 20 miles (30 km) west-southwest of Soalala, Madagascar.  Belna was moving toward the south-southwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 974 mb.

Tropical Cyclone Belna made landfall near Soalala, Madagascar on Monday as the equivalent of a hurricane/typhoon.  There was a small circular eye at the center of Belna.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  The circulation around Tropical Cyclone Belna was relatively small.  Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 80 miles (130 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Belna was 13.9.  The Hurricane Size Index (HSI) was 7.1 and the Hurricane Wind Intensity Size Index (HWISI) was 21.0.  Belna was capable of causing localized serious damage.

Tropical Cyclone Belna will move around the western end of a subtropical high pressure system over the South Indian Ocean during the next 24 hours.  The high will steer Belna toward the south-southwest during that time period.  On it anticipated track Tropical Cyclone Belna will move across west central Madagascar.  Belna will weaken when it moves farther inland but it will bring gusty winds and heavy rain to the southwestern part of the district of Mahajanga.  Locally heavy rain could cause flash floods, especially in areas of steeper terrain.  Some rivers could rise very rapidly.

Tropical Cyclone Ambali Rapidly Intensifies to Threshold of Cat. 5

Tropical Cyclone Ambali rapidly intensified to the threshold of a Category 5 hurricane on the Saffir-Simpson Scale on Thursday.  At 10:00 p.m. EST on Thursday the center of Tropical Cyclone Ambali was located at latitude 10.8°S and longitude 62.1°E which put it about 740 miles (1190 km) north-northeast of Port Louis, Mauritius.  Ambali was moving toward the south-southwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 932 mb.

Tropical Cyclone Ambali rapidly intensified from a minimal tropical storm to the threshold of a Cat. 5 hurricane in less than 36 hours over the Southwest Indian Ocean.  Nearly perfect environmental conditions including warm water and little vertical wind shear allowed Ambali to strengthen very rapidly.  A small circular eye formed at the center of the tropical cyclone.  The eye was surrounded by 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 Ambali.

The circulation around Tropical Cyclone Ambali was small which also contributed to the rapid intensification.  Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 100 miles (160 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Ambali was 33.3.  The Hurricane Size Index (HSI) was 7.9 and the Hurricane Wind Intensity Size Index (HWISI) was 41.2.

Tropical Cyclone Ambali may be near its maximum intensity, although it could strengthen a little more during the next six to twelve hours.  Ambali will move over water where the Sea Surface Temperature is near 28°C.  It will remain in an area where the upper level winds are weak during the next six to twelve hours and there will be little vertical wind shear during that time.  Tropical Cyclone Ambali will approach an area where there are strong upper level westerly winds during the weekend.  Ambali will weaken when the wind shear increases.

Tropical Cyclone Ambali will move around the western part of a subtropical high pressure over the South Indian Ocean.  The high will steer Ambali toward the south-southwest during the next several days.  On its anticipated track Tropical Cyclone Ambali will move toward Mauritius.

Elsewhere over the Southwest Indian Ocean, Tropical Cyclone Belna was intensifying north of Madagascar.  At 10:00 p.m. EST on Thursday the center of Tropical Cyclone Belna was located at latitude 7.5°S and longitude 49.0°E which put it about 300 miles (485 km) north of Madagsacar.  Belna was moving toward the southwest at 8 m.p.h. (13 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 982 mb.

The circulation around Tropical Cyclone Belna exhibited much greater organization on Thursday.  An eye appeared to be forming at the center of circulation on microwave 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 about the core of Belna.  Storms near the core were generating upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out 100 miles (160 km) from the center of circulation.

Tropical Cyclone Belna will move through an environment favorable for intensification during the next 24 to 48 hours.  Belna will move over water where the Sea Surface Temperature is near 28.5°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Belna is likely to strengthen into the equivalent of a hurricane/typhoon on Friday.  Belna could intensify rapidly once an eye and eyewall are full formed.  It could strengthen into the equivalent of a major hurricane during the weekend.

Tropical Cyclone Belna will move around the western end of a ridge of high pressure over the South Indian Ocean.  The high will steer Belna toward the south-southwest during the next few days.  On its anticipated track Tropical Cyclone Blena could approach the coast of northwestern Madagascar in three or four days.  Belna could be the equivalent of a hurricane/typhoon when it approaches Madagascar.

Major Typhoon Kammuri Makes Landfall on Southeastern Luzon

Major Typhoon Kammuri made landfall on southeastern Luzon near Sorsogon and Legaspi on Monday.  At noon EST on Monday the center of Typhoon Kammuri was located at latitude 13.2°N and longitude 123.6°E which put it about 10 miles (15 km) west of Legaspi, Philippines and about 230 miles (370 km) east-southeast of Manila.  Kamuri was moving toward the west at 11 m.p.h. (17 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 950 mb.

Typhoon Kammuri rapidly intensified into the equivalent of a major hurricane during the 12 hours prior to landfall on Monday.  A large eye with a diameter to 50 miles (80 km) developed at the center of Kammuri.  A thick 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 the typhoon.  Storms near the core generated strong upper level divergence which pumped mass away from the typhoon in all directions.  The removal of large amounts of mass allowed the surface pressure to decrease more quickly.

Typhoon Kammuri also grew larger as it got stronger.  Winds to typhoon force extended out about 50 miles (80 km) in most portions of Kammuri, but those strong winds extended out 90 miles (145 km) in the northwestern part of the circulation.  Winds to tropical storm force extended out 175 miles (280 km) in most parts of the circulation, but they extended out 300 miles (480 km) to the northwest of the center of Kammuri.  The Hurricane Intensity Index (HII) for Typhoon Kammuri was 25.1.  The Hurricane Size Index (HSI) was 25.4 and the Hurricane Wind Intensity Size Index (HWISI) was 50.5.  Typhoon Kammuri was capable of causing widespread major damage to southern Luzon.

Typhoon Kammuri will move south of a ridge of high pressure over the Western North Pacific Ocean.  The ridge will steer Kammuri toward the west-northwest during the next 36 to 48 hours.  On its anticipated track Typhoon Kammuri will move across southeastern Luzon and over the Sibuyan Sea during the next few hours.  The center of Kammuri is forecast to pass south of Manila in 18 to 24 hours.

Typhoon Kammuri will weaken slowly as it moves across southeastern Luzon.  Kammuri will bring strong winds and heavy rain to southern Luzon.  Typhoon Kammuri will also have a big impact on Burias, Marinduque Island and Mindoro.  Kammuri could produce winds to near typhoon force around Manila.  Typhoon Kammuri is likely to cause major damage around Legaspi.  Locally heavy rain could produce flash floods in numerous locations.  Kammuri could cause serious damage around Manila.

Typhoon Kammuri Strengthens As It Nears Southeast Luzon

Typhoon Kammuri strengthened as it neared southeast Luzon on Sunday night.  At 10:00 p.m. EST on Sunday the center of Typhoon Kammuri was located at latitude 13.0°N and longitude 126.0°E which put it about 385 miles (625 km) east- southeast of Manila, Philippines and about 160 miles (260 km) east of Legaspi.  Kammuri was moving toward the west at 15 m.p.h. (24 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 959 mb.

Typhoon Kammuri strengthened on Sunday.  An ellipitical eye with a mean radius of 30 miles (50 km) cleared out at the center of circulation.  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 Kammuri.  Storms near the core were generating upper level divergence which was pumping mass away from the typhoon.  The removal of mass allowed the surface pressure to decrease.

The wind field around Typhoon Kammuri became more symmetrical on Sunday.  Winds to typhoon force extended out 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out 180 miles (290 km) from the center.  The Hurricane Intensity Index (HII) was 17.8.  The Hurricane Size Index (HSI) was 19.3 and the Hurricane Wind Intensity Size Index (HWISI) was 37.1.  Typhoon Kammuri was capable of causing serious damage.

Typhoon Kammuri will move through an environment favorable for intensification during the next 12 hours.  Kammuri 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 Kammuri could strengthen into the equivalent of a major hurricane before it reaches southeastern Luzon.  Kammuri will start to weaken after the center moves over land.

Typhoon Kammuri will move south of a high pressure system over the Western North Pacific Ocean.  The high will steer Kammuri toward the west during the next several days.  On its anticipated track the center of Typhoon Kammuri will pass between Samar and Catanduanes Island before making landfall near Sorsogon on southeast Luzon.  The center of Kammuri will pass near Legaspi, Tabaco and Ligao.

Typhoon Kammuri will be capable of causing major damage in the Philippines.  Kammuri will bring strong winds to southeast Luzon.  Typhoon Kammuri could also produce winds to near typhoon force in Virac on Catanduanes Island.  Kammuri could produce a storm surge of up to 10 feet (3 meters) in locations where the wind blows water toward the coast.  Typhoon Kammuri will drop locally heavy rain over southern Luzon.  Flash floods could occur, especially in areas of steeper slopes.

Typhoon Kammuri Moves Closer to the Philippines

Typhoon Kammuri moved closer to the Philippines on Saturday.  At 10:00 p.m. EST on Saturday the center of Typhoon Kammuri was located at latitude 13.2°N and longitude 130.5°E which put it about 685 miles (1100 km) east of Manila, Philippines.  Kammuri was moving toward the west at 19 m.p.h. (29 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 110 m.p.h. (175 km/h).  The minimum surface pressure was 970 mb.

Typhoon Kammuri appeared to be getting better organized on Saturday night.  Visible satellite images of Kammuri  suggested that an eye was clearing out at the center of the typhoon.  The inner end of a rainband wrapped around much of the developing eye.  There was still a gap on the northwestern side of the eyewall, but the gap was getting smaller.  Bands of showers and thunderstorms were revolving around the more organized core of Typhoon Kammuri.  Storms near the core were generating upper level divergence which was pumping mass away from the typhoon.

Winds to typhoon force extended out 50 miles from the center of circulation in the northern half of Typhoon Kammuri and out 25 miles in the southern side of the typhoon.  Winds to tropical storm force extended out 220 miles (355 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Kammuri was 13.9.  The Hurricane Size Index (HSI) was 17.0 and the Hurricane Wind Intensity Size Index (HWISI) was 30.9.

Typhoon Kammuri will move through an environment favorable for intensification during the next 36 hours.  Kammuri 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 Kammuri will intensify and it could strengthen into the equivalent of a major hurricane.  Intensification could be more rapid once an eye and eyewall are full formed.

Typhoon Kammuri will move south of a high pressure system that extends from eastern Asia to the Western North Pacific Ocean.  The high will steer Kammuri toward the west during the next three days.  On its anticipated track Typhoon Kammuri could approach Catanduanes Islands and southeastern Luzon in about 36 hours.  Kammuri could be the equivalent of a major hurricane at that time.

Typhoon Kammuri Churns West Over Philippine Sea

Typhoon Kammuri churned westward over the Philippine Sea on Friday night.  At 10:00 p.m. EST on Friday the center of Typhoon Kammuri was located at latitude 13.9°N and longitude 135.7°E which put it about 1015 miles (1640 km) east of Manila, Philippines.  Kammuri was moving toward the west at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 110 m.p.h. (175 km/h).  The minimum surface pressure was 970 mb.

Typhoon Kammuri exhibited few changes on Friday.  The eye and eyewall were still not fully formed.  The tops of strong thunderstorms near the eye were obscuring the center of circulation on conventional satellite images.  Many of the stronger thunderstorms were occurring in bands in the western half of the circulation.  Bands in the eastern half of Kammuri consisted of showers and lower clouds.  Storms near the center of circulation were generating strong upper level divergence which was pumping mass away from the typhoon.

The circulation around Typhoon Kammuri did increase in size on Friday.  Winds to typhoon force extended out 50 miles (80 km).  Winds to tropical storm force extended out 230 miles (370 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Kammuri was 13.9.  The Hurricane Size Index (HSI) was 18.8 and the Hurricane Wind Intensity Size Index (HWISI) was 32.7.

Typhoon Kammuri will move through an environment favorable for intensification during the next two to three days.  Kammuri will move over water where the Sea Surface Temperature is near 29°C.  It will move through an environment where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Kammuri will intensify and it could strengthen into the equivalent of a major hurricane.  A period of more rapid intensification could occur once an eye and eyewall are fully formed.

Typhoon Kammuri will move south of a high pressure system over the Western North Pacific Ocean.  The high will steer Kammuri toward the west.  On its anticipated track Typhoon Kammuri could approach Luzon in about 72 hours.  Kammuri could be the equivalent of a major hurricane when it approaches Luzon.

Typhoon Fengshen Strengthens into Equivalent of a Major Hurricane

Typhoon Fengshen strengthened into the equivalent of a major hurricane on Friday.  At 4:00 p.m. EST on Friday the center of Typhoon Fengshen was located at latitude 23.0°N and longitude 142.9°E which put it about 175 miles (285 km) south-southeast of Io To.  Fengshen was moving toward the north at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 949 mb.

Typhoon Fengshen strengthened quickly into the equivalent of a major hurricane on Friday.  An eye with a diameter of 25 miles (40 km) developed at the center of Fengshen.  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 Fengshen.  Storms near the core were generating strong upper level divergence which was pumping mass away to the northeast of the typhoon.

The circulation around Typhoon Fengshen increased in size on Friday.  Winds to typhoon force extended out 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out 140 miles (225) km from the center.  The Hurricane Intensity Index (HII) for Typhoon Fengshen was 23.6.  The Hurricane Size Index (HSI) was 11.2 and the Hurricane Wind Intensity Size Index (HWISI) was 34.8.

Typhoon Fengshen may have reached its peak intensity.  Fengshen will move over water where the Sea Surface Temperature is near 28°C.  So, there will be suffiicient energy in the upper levels of the Western Pacific to support intensification.  However, a large upper level trough southwest of Japan will move toward Fengshen.  The trough will produce strong southwesterly winds which will blow toward the top of the typhoon.  Those winds will cause moderate to strong vertical wind shear and the shear will cause Typhoon Fengshen to being to weaken.

A ridge of high pressure east of Typhoon Fengshen and the upper level trough southwest of Japan will interact to steer the typhoon toward the northeast during the weekend.  On its anticipated track the core of Typhoon Fengshen which contains the strongest winds will pass southeast of Iwo To.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Kalmaegi moved very slowly toward northern Luzon.  At 4:00 p.m. EST on Friday the center of Tropical Storm Kalmaegi was located at latitude 16.0°N and longitude 125.9°E which put it about 345 miles (555 km) southeast of Aparri, Philippines.  Kalmaegi was moving toward the west at 2 m.p.h. (3 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 1002 mb.

Tropical Cyclone Bulbul Moving Toward Kolkata

Tropical Cyclone Bulbul moved toward Kolkata, India on Friday.  At 4:00 p.m. EDT on Friday the center of Tropical Cyclone Bulbul was located at latitude 19.7°N and longitude 87.8°E which put it about 225 miles (360 km) south of Kolkata, India.  Bulbul was moving toward the north at 8 m.p.h. (13 k/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 861 mb.

It appeared that Tropical Cyclone Bulbul may have pulled drier air from India around the southern and eastern sides of its circulation.  Rainbands in those parts of the tropical cyclone consisted primarily of showers and lower clouds.  Microwave satellite images provided some evidence of an eye at the center of circulation.  A ring of thunderstorms around the eye exhibited weaker sections on the eastern side of the eye.  The strongest winds were occurring in the ring of storms.  Other strong bands of thunderstorms were present in the western half of the circulation.

Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of Tropical Cyclone Bulbul.  Winds to tropical storm force extended out 140 miles (220 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Bulbul was 16.5.  The Hurricane Size index (HSI) was 13.2 and the Hurricane Wind Intensity Size Index (HWISI) was 29.7.  Bulbul was capable of causing serious damage.

Tropical Cyclone Bulbul may be near its maximum intensity.  Bulbul will move over water where the Sea Surface Temperature is near 29°C.  So, there is sufficient energy in the upper Bay of Bengal to support further intensification.  However, the introduction of drier air into the southern and eastern parts of the circulation will inhibit the development of thunderstorms in those portions of the tropical cyclone.  Bulbul will move under the western end of an upper level ridge over southeast Asia.  The ridge will produce some vertical wind shear which will also inhibit further intensification.  Tropical Cyclone Bulbul could weaken when it nears the coast around the northern Bay of Bengal.

Tropical Cyclone Bulbul will move around the western end of the ridge over southeast Asia.  The ridge will steer Bulbul toward the north for another 18 to 24 hours.  On its anticipated track Tropical Cyclone Bulbul could approach the coast of India south of Kolkata in about 18 hours.  Bulbul will turn more toward the east when it moves around the northwestern part of the ridge in a day or so.

Tropical Cyclone Bulbul could be the equivalent of a hurricane/typhoon when it makes landfall in West Bengal south of Kolkata.  Bulbul will bring gusty winds to the coast of West Bengal and Bangladesh.  Tropical Cyclone Bulbul will be capable of generating a storm surge of up to 6 to 9 feet ( 2 to 3 meters) along portions of the coast around the northern Bay of Bengal.  That area is particularly prone to storm surges.  Bulbul will drop locally heavy rain over parts of West Bengal and Bangladesh when it moves inland.  Locally heavy rain could cause flash floods in some locations.

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.