Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Typhoon Lan Heads North and Strengthens

Typhoon Lan headed northward and strengthened on Thursday.  At 11:00 p.m. EDT on Thursday the center of Typhoon Lan was located at latitude 19.2°N and longitude 130.0°E which put it about 550 miles (885 km) south-southeast of Okinawa.  Lan was moving toward the north at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 956 mb.

Lan strengthened into a large powerful typhoon on Thursday.  A big circular eye developed at the core of Typhoon Lan.  The eye was not perfectly clear.  There was a small area of convection at the center of the eye and there was a clear moat around that area.  A ring of thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Multiple bands of showers and thunderstorms were revolving around the typhoon.  Lan is a very large typhoon.  Winds to typhoon force extended out up to 140 miles (225 km) from the center of circulation.  Winds to tropical storm force extended out up to 305 miles (490 km) from the center

The Hurricane Intensity Index (HII) for Typhoon Lan was 16.5.  The Hurricane Size Index (HSI) was 46.8 and the Hurricane Wind Intensity Size Index (HWISI) was 63.3.  The circulation of Typhoon Lan is almost as large as the circulation of Hurricane Sandy was when Sandy hit the U.S. in 2012.

Typhoon Lan will be moving through an environment favorable for further intensification.  Lan will move over water where the Sea Surface Temperature is near 30°C.  It will move through and area where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Lan could intensify into the equivalent of a major hurricane during the next day or two.

Typhoon Lan is moving around the western end of a subtropical ridge which is steering the typhoon toward the north.  Lan is likely to continue to move toward the north on Friday.  The typhoon will be affected by westerly winds when it moves farther north.  Those winds will cause Typhoon Lan to move more toward the north-northeast during the weekend.  On its anticipated track the center of Typhoon Lan could pass southeast of Okinawa in 24 to 36 hours.  Lan could approach Honshu within three days.

Lan Strengthens to a Typhoon East of the Philippines

Tropical Storm Lan strengthened east of the Philippines on Tuesday and the Japan Meteorological Agency designated it a typhoon.  At 5:00 p.m. EDT on Tuesday the center of Typhoon Lan was located at latitude 11.2°N and longitude 132.4°E which put it about 515 miles (830 km) east of the Philippines.  Lan was moving toward the north-northeast at 5 m.p.h. (8 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 976 mb.

The circulation of Typhoon Lan became much more well organized on Tuesday.  Several long rainbands developed in the circulation and other smaller bands formed in the periphery of the typhoon.  The circulation of Typhoon Lan was circular and symmetrical.  Thunderstorms near the core of Lan began to generate strong upper level divergence which was pumping mass away from the typhoon in all directions.  The upper level divergence allowed the surface pressure to decrease and the wind speed to increase.  Lan is a large typhoon.  Winds to tropical storm force extend out about 230 miles (370 km) from the center of circulation.

Typhoon Lan will move through an environment favorable for intensification.  Lan will move over water where the Sea Surface Temperature is near 30°C.  Typhoon Lan will move through an area where the upper level winds will be weak and there will be little vertical wind shear during the next several days.  Typhoon Lan will continue to strengthen and there could be a period of rapid intensification after a well formed eye develops at the center of circulation.

Typhoon Lan was in an area where the steering currents were weak and it moved little on Tuesday.  An upper level ridge north of Lan blocked the typhoon from moving northward.  A weakness is forecast to develop in the ridge and the models are forecasting that Typhoon Lan will move northward during the rest of this week.  On its anticipated track Typhoon Lan will remain east of the Philippines.  Lan could be southeast of Okinawa in three or four days.

Tropical Storm Lan Develops Northwest of Palau

Tropical Storm Lan developed northwest of Palau on Monday.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Lan was located at latitude 10.7°N and longitude 132.1°E which put it about 275 miles (445 km) north-northwest of Koror, Palau.  Lan was moving toward the west at 12 m.p.h. (19 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 993 mb.

A more distinct center of circulation developed within Tropical Storm Lan, but the low pressure system was still in the process of organizing.  The low level center of circulation of Lan was at the end of a long rainband that extends from the western periphery around the southern and eastern parts of the tropical storm.  That low level center appeared to be on the northern side of a much larger counterclockwise rotation.  Most of the stronger showers and thunderstorms were occurring in the long rainband.  A few new, thinner bands of showers and thunderstorms seemed to be forming inside the long rainband to west of the center of circulation.

Tropical Storm Lan will be moving through an environment that will be favorable for intensification.  Lan will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge north of Lan is producing easterly winds which were blowing toward the top of the circulation.  There was some vertical wind shear, but it was not strong enough to prevent the intensification of Tropical Storm Lan.  Tropical Storm Lan is likely to intensify more slowly while the circulation organizes.  Once the center of circulation become tighter, then Lan could intensify more quickly.  A period of rapid intensification could occur, if Lan becomes a typhoon and an eye develops.

The ridge north of Lan and the counterclockwise flow to its south are combining to steer the tropical storm toward the west.  Numerical models are indicating that a weakness will develop in the ridge north of Tropical Storm Lan.  If that happens, then the steering current could weaken for 12 to 24 hours and Tropical Storm Lan might not move much.  If the break in the ridge becomes more pronounced, then Tropical Storm Lan could start to move more toward the north.  On its anticipated track Tropical Storm Lan is expected to remain east of the Philippines, but the tropical storm could move closer to the northern Philippines if the forecast weakness in the ridge does not occur.

Typhoon Khanun Makes Landfall in Southern China

Typhoon Khanun made landfall near Zhanjiang in southern China on Sunday.  At 5:00 p.m. EDT on Sunday the center of Typhoon Khanun was located at latitude 20.9°N and longitude 109.3°E which put it about 50 miles (80 km/h) south-southeast of Beihai, China.  Khanun was moving toward the west at 17 m.p.h. (27 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 969 mb.

Typhoon Khanun brought gusty winds and locally heavy rain over coastal sections of southern China on Sunday.  Khanun has weakened since it made landfall.  An upper level ridge centered over eastern China is producing easterly winds which are blowing over the top of the circulation.  Those winds are causing strong vertical wind shear, which is pushing the upper half of the circulation to the west of low level circulation.  The circulation is pulling drier air from Asia into the western part of Typhoon Khanun and the drier air is wrapping around the southern and eastern sides of the circulation.   Interaction with land and strong vertical wind shear will continue to weaken Khanun on Monday.  Khanun will bring rain to southern China and northern Vietnam as it weakens.

Elsewhere over the western North Pacific Ocean Tropical Depression Twentyfive-W formed west of Yap.  At 5:00 p.m. EDT on Sunday the center of Tropical Depression Twentyfive-W was located at latitude 10.3°N and longitude 136.1°E which put it about 125 miles (200 km) west-northwest of Yap.  It was moving toward the north-northwest at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 999 mb.

The circulation of Tropical Depression Twentyfive-W is still organizing.  Most of the showers and thunderstorms are in a primary rainband that wraps around the eastern side of the circulation.  The depression is moving through an area favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is not much vertical wind shear.  Tropical Depression Twentyfive-W is likely to be become a tropical storm during the next 24 hours and it could become a typhoon in a couple of days.  The depression is forecast to move toward the north-northwest as it moves around the western end of a subtropical ridge over the Pacific Ocean.

Khanun Intensifies Into a Typhoon Southeast of Hong Kong

Tropical Storm Khanun intensified into a typhoon southeast of Hong Kong on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Khanun was located at latitude 20.1°N and longitude 114.2°W which put it about 170 miles (275 km) south-southeast of Hong Kong.  Khanun was moving toward the west-northwest at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 965 mb.

The circulation of Typhoon Khanun became much more well organized on Saturday.  A small circular eye formed at the center of circulation.  A tight ring of strong thunderstorms formed around the eye.  The strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Khanun.  There were many more showers and thunderstorms in the western half of the circulation.  The storms in the core of Khanun were generating upper level divergence which was pumping mass away to the west of the typhoon.  Winds to typhoon force extended out about 70 miles (110 km) from the center of circulation.  Winds to tropical storm force extended out about 250 miles (400 km) from the center.

Typhoon Khanun will move through an environment favorable for intensification for about another 12 to 18 hours.  Khanun will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge north of Typhoon Khanun is producing easterly winds which are blowing toward the top of the circulation.  The easterly winds are causing some vertical wind shear, but the shear is not strong enough to prevent intensification.  The circulation of Typhoon Khanun will interact with land in 12 to 18 hours and that interaction should halt further intensification.

The ridge north of Khanun has been steering the typhoon toward the west-northwest.  The ridge is forecast to strengthen on Sunday and it will steer Typhoon Khanun more toward the west.  On its anticipated track the center of Typhoon Khanun will pass south of Hong Kong and Macao on Sunday.  Khanun will approach the south coast of China near Zhanjiang in 12 to 18 hours.  Typhoon Khanun will bring strong gusty winds and locally heavy rain to southern China west of Hong Kong and Macao.  The heavy rain could cause flooding in some locations.  Typhoon Khanun will be weaker when it moves over the Gulf of Tongking in about 24 hours.

Tropical Storm Khanun Forms Near Luzon

Tropical Storm Khanun formed near northern Luzon on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Khanun was located near latitude 18.0°N and longitude 121.6°W which put it about 240 miles (390 km) north of Manila, Philippines.  Khanun 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 994 mb.

A center of circulation developed near the surface in an area of thunderstorms on Thursday and the Japan Meteorological Agency designated the system as Tropical Storm Khanun.  The circulation of Tropical Storm Khanun was still organizing.  The center of Khanun moved across northern Luzon and the passage over land interrupted the development of the circulation.  Despite the passage over land, a primary rainband wrapped around the western side of the circulation.  Additional bands of showers and thunderstorms developed in the western half of the circulation.  The rainbands were weaker in the eastern half of Khanun, especially in the part of the circulation still over northern Luzon.

Tropical Storm Khanun will move through an environment favorable for intensification when it moves over the South China Sea.  Khanun will move over water where the Sea Surface Temperature is near 30°C.  The tropical storm is moving under the western half of an upper level ridge.  The ridge is producing easterly winds which are blowing toward the top of the circulation.  Those winds are causing moderate vertical wind shear.  The shear will slow the rate of intensification, but it should not be strong enough to prevent Tropical Storm Khanun from intensifying.  Khanun should start to strengthen once the center move farther west of Luzon.  Tropical Storm Khanun is forecast to become a typhoon during the weekend.

Tropical Storm Khanun is moving south of a ridge which is steering the tropical storm toward the west.  A generally westward motion is expected to continue during the next several days.  On its anticipated track Tropical Storm Khanun could approach Hainan Island in about 48 hours.  Khanun is likely to be a typhoon at that time.

Tropical Storm Talim Making Landfall on Kyushu

Tropical Storm Talim made landfall on Kyushu near Yamagawa, Japan on Saturday night.  Heavy rain was already falling over parts of Kyushu and Shikoku.  At 9:00 p.m. EDT on Saturday the center of Tropical Storm Talim was located at latitude 30.8°N and longitude 130.2°E which put it about 60 miles (95 km) southwest of Kagoshima, Japan.  Talim was moving toward the east-northeast at 18 m.p.h. (30 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 975 mb.

Tropical Storm Talim was a powerful typhoon several days ago.  Talim was nearly stationary over the same part of the Pacific Ocean for nearly 48 hours.  Talim’s winds mixed cooler water to the surface and it weakened to a tropical storm.  Tropical Storm still has a well organized circulation and winds to tropical storm force extend out about 200 miles (320 km) from the center of circulation.  Drier air wrapped around the southern half of the circulation.  Most of the thunderstorms and heavy rain are occurring in the northern half of the circulation.

An upper level trough over eastern Asia is steering Tropical Storm Talim toward the east-northeast.  The trough should steer Talim more toward the northeast during the next several days.  On its anticipated track the center of Tropical Storm Talim will move over southern Kyushu, Shikoku and Honshu.  Talim will bring gusty winds and locally heavy rain when it moves across those areas.  The heavy rain could produce flash flooding in some locations.

Typhoon Doksuri Near Landfall in Vietnam, Talim Threatens Japan

Typhoon Doksuri neared a landfall in Vietnam on Thursday night while Typhoon Talim posed a threat to Japan.  At 8:00 p.m. EDT the center of Typhoon Doksuri was located at latitude 17.8°N and longitude 107.3°E which put it about 130 miles (210 km) east-southeast of Vinh, Vietnam.  Doksuri was moving toward the west-northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 135 m.p.h. (220 km/h).  The minimum surface pressure was 956 mb.

Typhoon Doksuri intensified rapidly as approached the coast of Vietnam on Thursday.  An eye appeared that the center of circulation and a ring of strong thunderstorms surrounded the eye.  The strongest winds were occurring in the ring of storms.  Winds to tropical storm force extended out over 200 miles (320 km) from the center of circulation.

Typhoon Doksuri will make landfall on the coast of Vietnam between Ky Anh and Hoa Lac in a few hours.  Doksuri will bring strong winds and heavy rain to northern Vietnam.  The heavy rain could cause flash flooding.   Winds blowing toward the coast will cause a significant storm surge of ten feet (three meters) near where the center makes landfall.  Heavy rain will fall over parts of Laos and Thailand when Doksuri moves farther inland.

Typhoon Talim weakened as it stalled southwest of Japan on Thursday.  At 8:00 p.m. EDT on Thursday the center of Typhoon Talim was located at latitude 27.8°N and longitude 124.5°E which put it about 500 miles (800 km) southwest of Nagasaki, Japan.  Talim was moving toward the north-northeast at 3 m.p.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 949 mb.

Typhoon Talim appeared to pull drier air in around the southern side of the circulation.  Little movement of Typhoon Talim may have also allowed the winds to mix cooler water to the surface.  The drier and and cooler water caused many of the thunderstorms in the southern half of the circulation.  Strong thunderstorms were still occurring in the northern half of the circulation.  An upper level trough will approach Talim from the west and the trough will start to steer Talim toward the northeast.  On its anticipated track Typhoon Talim could approach Kyushu within 48 hours.

Typhoon Talim Strengthens West of Okinawa, Doksuri Moves Closer to Vietnam

Powerful Typhoon Talim strengthened west of Okinawa on Wednesday, while Typhoon Doksuri moved closer toward Vietnam.  At 8:00 p.m. EDT on Wednesday the center of Typhoon Talim was located at latitude 26.6°N and longitude 124.6°E which put it about 210 miles (335 km) west of Okinawa.  Talim was moving toward north-northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 130 m.p.h. (215 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 937 mb.

Talim evolved into a large powerful typhoon on Wednesday.  A large circular eye with a diameter of 60 miles (95 km) developed at the center of Typhoon Talim.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in those storms.  Numerous bands of showers and thunderstorms were revolving around the core of Talim.  The thunderstorms in the core of Talim were producing upper level divergence that was pumping mass away from the typhoon.

Typhoon Talim will move over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak over the core of Talim, but there are stronger westerly winds north of the typhoon.  Talim could strengthen some more during the next 24 hours.  However, the stronger upper level winds will increase the vertical wind shear on Friday and the typhoon will start to weaken when that happens.

Typhoon Talim is moving around the western end of a subtropical ridge, which is steering the typhoon toward the north-northwest.  Typhoon Talim will move north on Thursday as it rounds the western end of the ridge.  The westerly winds north of Talim will turn the typhoon toward the northeast on Friday.  On its anticipated track Typhoon Talim could approach Kyushu in two or three days.

Tropical Storm Doksuri strengthened on Wednesday as it moved closer to Vietnam.  At 8:00 p.m. EDT on Wednesday the center of Typhoon Doksuri was located at latitude 16.2°N and longitude 112.2°E which put it about 470 miles (760 km) east-southeast of Vinh, Vietnam.  Doksuri was moving toward the west-northwest 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 978 mb.

The circulation of Doksuri became much more organized on Wednesday.  A primary rainband wrapped around the center of circulation and an eye appeared to be developing.  Additional bands of showers and thunderstorms developed and began to revolved around the core of Doksuri.  Thunderstorms round the core were generating upper level divergence which pumped mass away from the typhoon.

Typhoon Doksuri will be moving through an environment that will be favorable for intensification on Thursday.  Doksuri will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge over eastern Asia is producing easterly winds which are causing some vertical wind shear over Doksuri.  The wind shear may slow intensification, but it will not stop it.

The ridge north of Doksuri is steering the typhoon toward the west-northwest.  On its anticipated track the center of Typhoon Doksuri is forecast to pass south of Hainan Island.  Typhoon Doksuri could approach the coast of Vietnam in a little over 24 hours.  Doksuri could bring strong winds and heavy rain to northern Vietnam.  The heavy rain could cause flash floods.

Typhoon Talim Nears Ryuku Islands

Typhoon Talim neared the Ryukyu Islands late on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Typhoon Talim was located at latitude 24.4°N and longitude 126.3°E which put it about 125 miles (200 km) east of Ishigaki, Japan.  Talim was moving toward the northwest at 12 m.p.h. (19 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.

A large circular eye formed at the center of Typhoon Talim on Tuesday.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in those storms.  Additional bands of showers and thunderstorms were revolving around the core of the circulation.  The entire circulation became much more circular and symmetrical.  The thunderstorms in the core of Talim were generating upper level divergence which was pumping mass away from the center of circulation.

Typhoon Talim will move through an environment favorable for intensification for several more days.  Talim is moving over water where the Sea Surface Temperature is near 30°C.  An upper level ridge northeast of Talim is producing easterly winds that are blowing toward the top of the circulation.  Those winds are not as strong as the were 24 hours ago and the vertical wind shear has decreased.  Typhoon Talim is likely to intensify further during the next 24 to 48 hours.

Typhoon Talim is moving near the western end of a subtropical ridge which is steering the typhoon toward the northwest.  Talim is expected to turn toward the north as it rounds the western end of the ridge.  In 24 to 48 hours Talim will begin to be affected by westerly winds from the middle latitudes.  Those winds will cause Typhoon Talim to turn toward the northeast.  On its anticipated track Typhoon Talim will move across the Ryukyu Islands on Wednesday.  It looks like the center and strongest part of Typhoon Talim will move between Ishigaki and Okinawa.  Typhoon Talim will bring strong gusty winds and locally heavy rain to the southern Ryukyu Islands.  The core of Typhoon Talim is forecast to pass west of Okinawa before it turns northeast toward the larger islands of Japan.

Elsewhere in Western North Pacific, Tropical Storm Doksuri was slowly intensifying as it moved west of the Philippines.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Doksuri was located at latitude 14.6°N and longitude 116.6°E which put it about 760 miles (1225 km) east-southeast of Vinh, Vietnam.  Doksuri was moving toward the west at 15 m.p.h. (24 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 995 mb.

The circulation of Tropical Storm Doksuri became more organized on Tuesday.  Numerous bands of showers and thunderstorms formed and began to revolve around the center or circulation.  Storms near the core began to generate upper level divergence.  Tropical Storm Doksuri will be moving through a favorable environment.  Doksuri will move over warm Sea Surface Temperatures and through and area where the upper level winds are not too strong.  Tropical Storm Doksuri is likely to intensify and it could eventually strengthen into a typhoon.  Tropical Storm Doksuri is forecast to continue moving  toward the west.  On its anticipated track Doksuri could be near Hainan Island in 48 hours and it could approach the coast of Vietnam in about three days.