Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Typhoon Sanvu Brings Wind and Rain to Chichi Jima

Typhoon Sanvu is bringing a prolonged period of gusty winds and heavy rain to Chichi JIma, Japan.  Sanvu strengthened during the past several days while it meandered around Chichi Jima.  At 11:00 a.m. EDT on Thursday the center to Typhoon Sanvu was located at latitude 28.1°N and longitude 142.0°E which put it about 60 miles (95 km) north-northwest of Chichi Jima, Japan.  Sanvu was moving toward the north at 8 m.p.h. (13 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. (170 km/h).  The minimum surface pressure was 967 mb.

The organization of Typhoon Sanvu has been slowly improving.  An eye developed at the center of Sanvu as the typhoon moved slowly over Chichi Jima.  A broken ring of thunderstorms surrounds the eye.  The strongest winds are occurring in the ring of storms.  A primary band of thunderstorms wraps around the western and southern sides of the center of circulation.  Other bands of showers and thunderstorms are developing outside the core of Typhoon Sanvu.  Most of the bands are developing in the southern half of the circulation.  Thunderstorms in the core of Sanvu are producing upper level divergence which is pumping mass away to the north of the typhoon.

Typhoon Sanvu will move through an environment favorable for intensification for several more days.  It will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge east of Sanvu is producing southerly winds which are blowing toward the top of the circulation, but there is not much vertical wind shear.  Typhoon Sanvu is likely to continue to strengthen for another 24 to 48 hours.  Eventually, Sanvu will move over colder water and the wind shear will increase.  It will start to weaken when that happens.

Sanvu is moving around the western end of a subtropical ridge which steering the typhoon toward the north.  When Typhoon Sanvu moves farther north, it will be steered by an upper level trough over Japan.  Southwesterly winds will steer Sanvu toward the northeast at a faster speed in a day or two.  On its anticipated track Typhoon Sanvu would stay east of Tokyo, but it could affect the northernmost islands of Japan in four or five days.  Conditions in Chichi Jima should improve slowly as Typhoon Sanvu moves farther away.

Tropical Storm Sanvu Forms Over Northern Marianas

Tropical Storm Sanvu formed over the northern Marianas on Monday.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Sanvu was located at latitude 20.4°N and longitude 146.4°E which put it about 100 miles (160 km) north-northeast of Agrihan.  Sanvu was moving toward the north-northeast at 3 m.p.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 994 mb.

Tropical Storm Sanvu developed when a distinct center of circulation formed within a much larger area of low pressure over the northern Marianas.  The circulation of Sanvu is still in the early stages of consolidation around the center.  Most of the showers and thunderstorms were forming in bands in the southern half of the circulation.  The bands in the northern half of the circulation were weaker.  The showers and thunderstorms south of the center were beginning to generate some upper level divergence which was pumping mass away to the south of the tropical storm.

Tropical Storm Sanvu will be moving through an environment that is somewhat favorable for intensification.  Sanvu will move over water where the Sea Surface Temperature is near 30.5°C.  Sanvu is under the axis of a narrow upper level ridge and the winds over the southern half of the circulation are fairly weak.  There is little vertical wind shear over that part of the tropical storm.  An upper level trough north of the ridge is producing stronger winds over that half of the circulation.  The stronger winds may be responsible for the lack of strong rainbands in the northern half of Sanvu.  The trough is forecast to move east and the shear in that region should decrease.  When the shear decreases Sanvu could intensify at a faster rate and it is forecast to become a typhoon in two or three days.

The trough is currently steering Tropical Storm Sanvu slowly toward the north-northeast.  When the trough moves away to the east a ridge if forecast to steer Sanvu more toward the north.  On its anticipated track Tropical Storm Sanvu will gradually move away from the northern Marianas and the weather should improve in that region.

Tropical Storm Pakhar Makes Landfall Near Macau

Tropical Storm Pakhar sped across the South China Sea and made landfall on the coast of China near Macau.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Pakhar was located at latitude 22.3°N and longitude 112.7°E which put it about 60 miles (95 km) southwest of Hong Kong.  Pakhar was moving toward the northwest at 27 m.p.h. (43 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 987 mb.

Tropical Storm Pakhar will bring gusty winds and locally heavy rain as it quickly moves inland over southern China.  The wind and rain will hinder the efforts in the area to recover from Typhoon Hato.  Fortunately, Tropical Storm Pakhar is a fairly small storm.  Winds to tropical storm force only extend out about 80 miles (130 km) from the center of circulation.  The small size of Pakhar and its rapid rate of movement will limit the impact of the tropical storm.  Tropical Storm Pakhar should spin down fairly quickly as it rapidly moves inland.

Tropical Storm Pakhar Forms East of Luzon

Tropical Storm Pakhar formed east of Luzon on Thursday.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Pakhar was located at latitude 15.2°N and longitude 124.7°E which put it about 280 miles (455 km) east of Manila, Philippines.  Pakhar was moving toward the west at 13 m.p.h. (21 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 center of circulation developed on the eastern edge of a cluster of thunderstorms east of Luzon on Thursday and the Japan Meteorological Agency designated the system as Tropical Storm Pakhar.  The circulation of Pakhar is still in the early organizational stages.  Most of the showers and thunderstorms are occurring west of the center of circulation.  An upper level ridge north of Pakhar is producing easterly winds which are blowing across the circulation.  Those easterly winds are probably responsible for the asymmetrical distribution of thunderstorms on the western side of the tropical storm.

Tropical Storm Pakhar will move through an environment that will be somewhat favorable for intensification during the next 12 to 18 hours.  Pakhar will move over water where the Sea Surface Temperature (SST) is near 30°C.  The easterly winds in the upper levels are causing moderate vertical wind shear and the shear will inhibit intensification.  Tropical Storm Pakhar will weaken when it moves across Luzon.  After Pakhar moves out over the South China Sea, it will move back over water where the SST is near 30°C.  The forecast suggests that there could be less vertical wind shear at that time and Pakhar has a chance to intensify into a typhoon when it moves away from the Philippines.

Pakhar is being steered westward by a subtropical ridge north of the tropical storm.  Pakhar is forecast to turn more toward the northwest when it crosses Luzon.  On its anticipated track Tropical Storm Pakhar will reach the coast of Luzon near Baler in 12 to 18 hours.  Pakhar is forecast to continue moving toward the northwest and it could make another landfall in China west of Hong Kong in about three days.  However, there is more uncertainty about the future track of Pakhar after the tropical storm exits Luzon.

Tropical Storm Pakhar could bring heavy rain to Luzon and cause flooding in some locations.  If Tropical Storm Pakhar intensifies over the South China Sea and makes landfall west of Hong Kong as a typhoon, it could seriously affect the efforts to recover from damage caused by Typhoon Hato which hit that same area a few days ago.

Typhoon Hato Brings Wind and Rain to Hong Kong

Typhoon Hato brought wind and rain to Hong Kong as the eye moved just south of the city.  At 11:00 p.m. EDT on Tuesday the center of Typhoon Hato was located at latitude 21.8°N and longitude 113.8°E which put it about 60 miles (95 km) south-southeast of Hong Kong.  Hato was moving toward the west-northwest at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 130 m.p.h. (210 km/h).  The minimum surface pressure was 963 mb.

Typhoon Hato intensified rapidly as it approached Hong Kong.  A circular eye with a diameter of 50 miles (80 km) developed at the center of Hato.  The eye was surrounded by a thick ring of strong thunderstorms and the strongest winds were occurring in that ring.  Additional bands of showers and thunderstorms were revolving around the core of Hato.  The size of the circulation around Typhoon Hato also increased significantly.  Winds to typhoon force extended out about 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out about 175 miles (280 km) from the center.

The Hurricane Intensity Index (HII) was 17.8.  The Hurricane Size Index (HSI) was 16.9 and the Hurricane Wind Intensity Size Index (HWISI) was 38.7.  Those indices indicate that Typhoon Hato is capable of producing serious regional wind damage.  Typhoon Hato could cause a storm surge of 6 to 9 feet (2 to 3 meters) along the coast.  Hato will also drop heavy rain over parts of China and flash floods could occur in some areas.

Typhoon Hato is being steered toward the west-northwest by a subtropical ridge northeast of the typhoon and that general motion is forecast to continue.  On its anticipated track the center of Typhoon Hato will make landfall west of Hong Kong in a few hours.  Hato will continue to move inland over southeastern China.   Typhoon Hato will weaken as it moves inland, but it could drop locally heavy rain over parts of Zizhiqu, Huangzu and Guangxi provinces.

Strengthening Typhoon Hato Nears China

Typhoon Hato strengthened to a typhoon as it moved closer to a landfall on the coast of China.  At 11:00 a.m. EDT on Tuesday the center of Typhoon Hato was located at latitude 20.9°N and longitude 116.6°E which put it about 225 miles (365 km) east-southeast of Hong Kong.  Hato was moving toward the west-northwest at 15 m.p.h. (24 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. (150 km/h).  The minimum surface pressure was 978 mb.

The organization of Typhoon Hato improved significantly in recent hours.  A circular eye developed at the center of circulation.  A ring of strong thunderstorms formed around the eye.  The strongest winds were occurring in the ring of storms around the eye.  Additional bands of showers and thunderstorms developed south and east of the center.   There were fewer showers and thunderstorms north and west of the center of circulation.  Thunderstorms in the core of Hato were generating strong upper level divergence which was pumping mass away to the south and east of the typhoon.  Hato is a fairly small typhoon.  Winds to typhoon force extend out about 20 miles (32 km) from the center of circulation.  Winds to tropical storm force extend out about 145 miles (230 km) from the center.

The Hurricane Intensity Index (HII) for Typhoon Hato is 10.4.  The Hurricane Size Index (HSI) is 8.3 and the Hurricane Wind Intensity Size Index (HWISI) is 18.7.

Typhoon Hato will move through an environment favorable for intensification until it makes landfall in China.  Hato will move over water where the Sea Surface Temperature is near 31°C.  An upper level ridge over China is producing easterly winds which are blowing toward the top of the circulation.  The strongest winds are north of Typhoon Hato and the vertical wind shear is moderate.  The shear could slow the rate of intensification, but it is not likely to prevent further intensification.

Typhoon Hato is being steered to the west-northwest by a subtropical ridge to the north of the typhoon and that general motion is expected to continue.  On its anticipated track Typhoon Hato will make landfall near Hong Kong in 12 to 18 hours.  Typhoon Hato will bring strong gusty winds and locally heavy rain to parts of eastern China.  Heavy rain could produce flash floods in some locations.  Hato will also generate a storm surge along the coast.

Tropical Storm Hato Forms Southeast of Taiwan

Tropical Storm Hato formed southeast of Taiwan on Sunday.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Hato was located at latitude 19.6°N and longitude 126.1°E which put it about 390 miles (630 km) east-southeast of Taitung, Taiwan.  Hato was moving toward the west-northwest at 15 m.p.h. (22 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 1001 mb.

A low level center of circulation developed near the western edge of a cluster of thunderstorms southeast of Taiwan and the Japan Meteorological Agency designated the system as Tropical Storm Hato.  The structure of Tropical Storm Hato is very asymmetrical.  Most of the showers and thunderstorms are forming in the western half of the circulation.  There are some very tall strong thunderstorms west of the center of circulation.  An upper level ridge north of Hato is producing easterly winds which  are blowing toward the top of the tropical storm.  Those winds are limiting upper level divergence toward the east and they are probably the reason for the asymmetrical distribution of thunderstorms.

Tropical Storm Hato will move through an environment that will be somewhat favorable for intensification.  Tropical Storm Hato is moving over water where the Sea Surface Temperature is near 31°C.  The upper level ridge is creating moderate vertical wind shear, which is inhibiting intensification.  Tropical Storm Hato is likely to intensify, but it will do so more slowly because of the vertical shear.  Hato does have a chance to strengthen into a typhoon.

Hato is being steered toward the west-northwest by a subtropical ridge north of the tropical storm.  A general west-northwesterly motion is expected to continue for several more days.  On its anticipated track Tropical Storm Hato could reach the islands in the Luzon Strait or southern Taiwan in less than 36 hours.  Hato could make landfall on the east coast of China in less than three days.  Tropical Storm Hato will bring gusty winds and locally heavy rain when it passes near southern Taiwan and the islands in the Luzon Strait.

Banyan Rapidly Intensifies Into a Typhoon

Tropical Storm Banyan rapidly intensified into a typhoon on Saturday.  At 5:00 p.m. EDT on Saturday the center of Typhoon Banyan was located at latitude 20.8°N and longitude 164.3°E which put it about 165 miles (265 km) west-northwest of Wake Island.  Banyan was moving toward the north-northwest at 7 m.p.h. (11 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 976 mb.

Banyan intensified rapidly from a tropical storm into a typhoon in less than 36 hours.  Banyan is a small well organized typhoon.  There is a small circular eye at the center of circulation.  The eye is surrounded by a ring of strong thunderstorms.  The strongest winds are occurring in that ring of storms.  A primary band of thunderstorms wraps around the eastern and northern sides of the core of Typhoon Banyan.  Other bands of showers and storms are revolving around the core of the typhoon.  Banyan has a small circulation.  Winds to typhoon force only extend out about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force only extend out about 100 miles (160 km) from the center.

Typhoon Banyan will continue to move through an environment that is favorable for intensification on Sunday.  Banyan will move over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Typhoon Banyan will continue to intensify during the next 24 hours and it could become the equivalent of a major hurricane.

Banyan is moving around the western end of a subtropical ridge, which is steering the typhoon toward the north-northwest.  Banyan is forecast to continue to move toward the north-northwest for another day or two.  On its anticipated track Typhoon Banyan will move away from Wake Island and the weather should improve on Sunday.

Tropical Storm Banyan Forms Near Wake Island

Tropical Storm Banyan formed quickly near Wake Island on Friday.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Banyan was located at latitude 17.9°N and longitude 167.2°E which put it about 140 miles (225 km) south-southeast of Wake Island.  Banyan was moving toward the west-northwest at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1003 mb.

The circulation of Tropical Storm Banyan organized quickly.  It developed a distinct center of circulation.  Thunderstorms formed north and south of the center, but there were more thunderstorms south of the center.  Additional bands of showers and thunderstorms began to develop in the outer parts of the circulation.  The thunderstorms in the core of Tropical Storm Banyan were generating upper level divergence which was pumping away mass.  The circulation of Tropical Storm Banyan is relatively small.  Winds to tropical storm force only extend out about 40 miles (65 km) from the center of circulation.

Tropical Storm Banyan will move through an environment that will be favorable for intensification.  Banyan will move over water where the Sea Surface Temperature is near 30.5°C.  An upper level ridge north of Banyan is producing easterly winds which are blowing toward the top of the circulation.  Those winds are weak and there is not much vertical wind shear.  Tropical Storm Banyan is likely to intensify during the next day or two and it could intensify quickly at times.

Tropical Storm Banyan is moving near the western end of a subtropical ridge to its north.  The ridge is currently steering Banyan toward the west-northwest, but the tropical storm is expected to turn more toward the north when it reaches the end of the ridge.  On its anticipated track Tropical Storm Banyan will move over Wake Island in about 12 hours.  Banyan will cause gusty winds and heavy rain when it moves over Wake Island.

Typhoon Noru Skirts Coast of Shikoku on Way to Honshu

The eye of Typhoon Noru skirted the coast of Shikoku on Sunday as it moved closer to a landfall on Honshu.  At 11:00 p.m. EDT on Sunday the center of Typhoon Noru was located at latitude 33.6°N and longitude 134.5°W which put it about 85 miles (135 km) southwest of Osaka, Japan.  Noru was moving toward the northeast at 14 m.p.h. (22 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 970 mb.

The structure of Typhoon Noru improved on Sunday.  The circulation contracted around an eye with a diameter of approximately 20 miles (32 km).  They eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in the ring of storms.  Additional spiral bands were revolving around the core of Typhoon Noru.

An upper level trough northwest of Japan steered Typhoon Noru toward the northeast on Sunday.  The eye of Noru moved near the south coast of Shikoku.  The eye passed south of Kochi and very near Muroto, Toyo and Kainan.  Typhoon Noru brought gusty winds and heavy rain to the southern parts of Shikoku.

Typhoon Noru is expected to continue to move toward the northeast on Monday.  On its anticipated track the center of Typhoon Noru is expected to skirt the east coast of Shikoku and make landfall on Honshu near Wakayama.   After it makes landfall, Typhoon Noru is forecast to pass near Osaka and Kyoto.  Typhoon Noru will weaken as it moves across Honshu, but it will produce gusty winds and locally heavy rain.  The rain could cause floods in some locations.