Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Large Powerful Typhoon Chan-hom Heading for Northeastern China

Large and powerful Typhoon Chan-hom passed south of Okinawa and headed for northeastern China on Thursday.  At 11:00 p.m. EDT on Thursday the center of Typhoon Chan-hom was located at latitude 25.9°N and longitude 125.0°E which put it about 155 miles (250 km) west-southwest of Okinawa and about 400 miles (640 km) south-southeast of Shanghai, China.  Chan-hom was moving toward the west-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there were gusts to 165 m.p.h. (265 km/h).  The minimum surface pressure was 933 mb.

Typhoon Chan-hom has a very symmetrical structure with a well formed eye and numerous rainbands.  Hurricane force winds extend out 75 miles (120 km) in all directions from the center.  Upper level divergence is well developed and it is pumping out mass in all directions.  Chan-hom is moving over water where the Sea Surface Temperature is near 28°C.  Given the favorable environment, Chan-hom is likely to remain a powerful typhoon as it approaches the coast of northeastern China.

A subtropical ridge is steering Chan-hom toward the northwest and that steering motion is expected to continue on Friday.  On its anticipated track Chan-hom will approach the coast of China in about 24 hours.  It could make landfall south of Shanghai near Taizhou.  Chan-hom is likely to bring strong winds and heavy rain to parts of northeastern China when it makes landfall.

Powerful Typhoon Nangka Moving Through Northern Marianas

Powerful Typhoon Nangka is moving through the northern Mariana Islands.  At 11:00 p.m. EDT on Wednesday the center of Typhoon Nangka was located at latitude 17.2°N and longitude 146.5°E which put it about 145 miles (240 km) north-northeast of Saipan and about 45 miles (75 km) southeast of Alamagan.  Nangka was moving toward the west-northwest at 12 m.p.h.  The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 170 m.p.h. (275 km/h).  Nangka is the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.  The minimum surface pressure was 929 mb.

Nangka has a very symmetrical structure and strong convection surrounds the eye.  It is over warm Sea Surface Temperatures and it could intensify further.  Upper level outflow from the eastern side of large Typhoon Chan-hom which is about 1200 miles (1940 km) west-northwest of Nangka could begin to create wind shear over the western side of Nangka.  Eyewall replacement cycles could also produce fluctuations in intensity.

A subtropical ridge is steering Nangka toward the west-northwest and that steering pattern is expected to continue for another two or three days.  On its anticipated track the core of Nangka will pass close to the islands of Guguan, Alamagan, Pagan and Agrihan.  It could bring very strong winds and heavy rain to those locations on Thursday.

Large Typhoon Chan-hom South-Southeast of Okinawa

Large Typhoon Chan-hom is approaching the far southern islands of Japan.  At 11:00 p.m. EDT on Wednesday the center of Typhoon Chan-hom was located at latitude 22.8°N and longitude 129.2°E which put it about 300 miles (480 km) south-southeast of Okinawa.  Chan-hom was moving toward the northwest at 14 m.p.h.  The maximum sustained wind speed was 105 m.p.h. (120 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 956 mb.

Typhoon Chan-hom has a very large circulation.  It has a 32 mile (50 km) wide eye and hurricane force winds extend out 40 miles (65 km) in all directions from the center.  The circulation is very symmetrical and upper level divergence is well developed in all directions.  Chan-hom is still over warm Sea Surface Temperatures and there is little wind shear.  Further intensification is possible, although the size of the circulation could limit the rate of intensification.

A subtropical ridge is steering Chan-hom toward the northwest and that steering pattern is expected to continue during the next several days.  On its anticipated track the center of Chan-hom could pass south of Okinawa on Thursday.  Given the large circulation it could bring winds and rain to that island.  The center could come close to Miyako-Jima and that location and other nearby islands could experience typhoon force winds and heavy rain.

Typhoon Linfa Making Landfall East of Hong Kong

The center of Typhoon Linfa is very near the coast of China.  At 11:00 p.m. EDT on Wednesday the center of Typhoon Linfa was located at latitude 22.6°N and longitude 116.4°E which put it about 165 miles east of Hong Kong.  Linfa was moving toward the west at 10 m.p.h. (16 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 974 mb.

A mid-level ridge north of Typhoon Linfa is steering it toward the west and that steering pattern is expected to continue in the short term.  On its anticipated track Linfa will move along the coast of China and it could approach Hong Kong in 12 to 18 hours.  Since half of the circulation will be over land and half of the circulation will be over water, Linfa is expected to weaken slowly on Thursday.  It could bring tropical storm force winds and heavy rain to areas near the coast.  Linfa could still be a tropical storm when it moves across Hong Kong.

Nangka Intensifies Rapidly Into a Strong Typhoon

Typhoon Nangka intensified rapidly into a strong typhoon on Monday.  At 11:00 p.m. EDT on Monday the center of Typhoon Nanga was located at latitude 13.2°N and longitude 155.0°E which put it about 670 miles (1080 km) east-southeast of Saipan.  Nangka was moving toward the west-northwest at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 110 m.p.h. (180 km/h) and there were wind gusts to 130 m.p.h. (210 km/h).  The minimum surface pressure was 952 mb.

The circulation of Typhoon Nangka is very well organized with a strong ring of thunderstorms surrounding a circular eye.  The typhoon is over an area where the Sea Surface Temperature is around 28°C to 29°C.  The upper level winds are relatively light and there appear to outflow channels to the northeast and southwest which are transporting mass away from the center of circulation.  The surface pressure is decreasing rapidly and the wind speeds are increasing quickly.  Nangka is in an environment that is very favorable for further intensification and it could become a very powerful typhoon.

A subtropical ridge is steering Nangka toward the west-northwest and that general motion is expected to continue during the next few days.  On its anticipated track Typhoon Nangka could approach the northern Mariana Islands in about 48 to 72 hours.

Chan-hom Intensifies Into a Typhoon

The circulation around Chan-hom organized rapidly on Monday and it intensified into a typhoon.  At 11:00 p.m. EDT on Monday the center of Typhoon Chan-hom was located at latitude 18.1°N and longitude 136.8°E which put it about 850 miles (1370 km) southeast of Okinawa.  Chan-hom was moving toward the west at 11 m.p.h. (18 km/h).  The maximum sustained wind speed was 85 m.p.h. (140 km/h) and there were wind gusts to 105 m.p.h. (170 km/h).  The minimum surface pressure was 967 mb.

A primary rainband wrapped completely around the center of circulation of Typhoon Chan-hom and a large eye is apparent on satellite images.  Strong thunderstorms around the eye are generating upper level divergence which is pumping out mass and allowing the surface pressure to decrease.  The typhoon is over water where the Sea Surface Temperature is around 28°C and there is plenty of energy in the upper ocean.  Upper level winds are relatively light and there is not much vertical wind shear.  The environment is very favorable for further intensification and rapid intensification is possible.  Chan-hom is expected to continue to intensify and it could become the equivalent of a major hurricane later this week.

A subtropical ridge north of Chan-hom is steering the typhoon toward the west.  The ridge is expected to steer Chan-hom toward the northwest during the next few days.  On its anticipated track Typhoon Chan-hom could approach the southern islands of Japan in about three days.  It could be a large and powerful typhoon at that time.

Tropical Storm Chan-hom Moving Away From the Marianas

Tropical Storm Chan-hom continued to move farther west of the Mariana Islands on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Chan-hom was located at latitude 16.6°N and longitude 142.0°E which put it about 1170 miles (1890 km) southeast of Okinawa.  Chan-hom was moving toward the north-northwest at 10 m.p.h. (16 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 982 mb.

The circulation around Tropical Storm Chan-hom became a little better organized on Sunday.  A primary band of thunderstorms wrapped around the southern half of the circulation.  There also appears to be some drier air wrapping into the circulation as well.  The upper level winds have decreased and some upper level divergence appears to be developing.  Chan-hom is over water there the Sea Surface Temperature is near 28°C.  With the exception of the drier air the environment is favorable for intensification Chan-hom is expected to become a typhoon.

A subtropical ridge is steering Chan-hom in a generally northwesterly direction and that steering pattern is expected to continue for the next few days.  On its anticipated track Chan-hom could approach Okinawa in three or four days.

Tropical Storm Linfa Heading for Taiwan

Tropical Storm Linfa crossed northern Luzon and turned for Taiwan on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Linfa was located at latitude 19.0°N and longitude 119.4°E which put it about 230 miles (370 km) south-southwest of Hengchun, Taiwan.  Linfa was moving toward the north-northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 45 m.p.h. (70 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 992 mb.

The circulation of Tropical Storm Linfa was relatively intact after it crossed northern Luzon and it moved back over water.  However, an upper level ridge over eastern Asia generated northeasterly winds that were strong enough to blow the top off of the circulation.  Strong upper level wind shear is making it difficult for new thunderstorms to form near the center of circulation.  Although Linfa will be moving over warm water, the wind shear will limit intensification.

Linfa has reached the western end of the subtropical ridge that has been steering the tropical storm.  It has turned toward the north and that general movement is expected to continue.  On its anticipated track Linfa could approach southern Taiwan in about two days.  It could bring locally heavy rain to parts of Taiwan.

Tropical Storm Chan-hom Bringing Wind and Rain to Guam

Tropical Storm Chan-hom is passing through the Marianas and bringing gusty winds and rain to Guam and Rota.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Chan-hom was located at latitude 14.3°N and longitude 144.8°E which put it about 10 miles (15 km) west of Rota.  Chan-hom was moving toward the west-northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 45 m.p.h. (70 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 991 mb.

Despite being over warm water Chan-hom did not intensify on Saturday.  The circulation could be pulling in some drier air which is limiting the development of thunderstorms.  More thunderstorms developed near the inner core of Chan-hom late on Saturday.  There is not much vertical wind shear over the tropical storm.  If a well organized inner core forms, then intensification will be possible.  Chan-hom could become a typhoon after it moves west of the Mariana Islands.

The subtropical ridge steering Chan-hom is expected to continue to steer it toward the northwest during the next few days.  On its anticipated track Chan-hom could approach the southern islands of Japan in about four days.

Tropical Storm Linfa Makes Landfall in Northern Luzon

Tropical Storm Linfa made landfall in northern Luzon on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Linfa was located at latitude 17.8°N and longitude 121.7°E which put it near Tuguegarao, Philippines.  Linfa was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 m.p.h.) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 989 mb.   Linfa is bringing gusty winds and locally heavy rain to parts of northern Luzon.

Linfa should continue to weaken during the next 12 to 18 hours while the center is over land.  If the circulation is intact when it moves back over water, then the tropical storm may intensify once it gets north of the Philippines.  Linfa will soon reach the western end of a subtropical ridge which has been steering it toward the west.  When Linfa reaches the end of the ridge, it will likely turn toward the north.  The tropical storm could approach Taiwan in 48 to 72 hours.