Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Typhoon Damrey Makes Landfall in Vietnam

Typhoon Damrey made landfall in Vietnam late on Friday.  At 5:00 p.m. EDT on Friday the center of Typhoon Damrey was located at latitude 12.9°N and longitude 109.7°E which put it about 100 miles (160 km) east-northeast of Nha Trang, Vietnam.  Damrey was moving toward the west at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/hr) and there were wind gusts to 125 m.p.h. (205 km/h).  The minimum surface pressure was 960 mb.

Typhoon Damrey strengthened until it made landfall on the coast of Vietnam.  A small eye formed at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring that ring.  Multiple bands of showers and thunderstorms were revolving around the core of Typhoon Damrey.  Winds to typhoon force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out 150 miles (240 km) from the center.

A ridge north of Damrey steered the typhoon steadily westward across the South China Sea.  The center of Typhoon Damrey made landfall on the coast of Vietnam north of Nha Trang.  The ridge is forecast to continue to steer Damrey toward the west.  Typhoon Damrey will move across southern Vietnam, southern Laos, Cambodia and Thailand during the next several days.

Typhoon Damrey brought strong winds and heavy rain to the coast of Vietnam.  Damrey was capable of causing serious wind damage.  Typhoon Damrey was also capable of generating a storm surge of 9 to 12 feet (3 to 4 meters) where the winds blew the water toward the coast.  Damrey will weaken as it moves inland over Southeast Asia, but it will drop locally heavy rain.  The locally heavy rain could produce serious floods in parts of Vietnam, Laos, Cambodia and Thailand.

Typhoon Damrey Strengthens As It Approaches Vietnam

Typhoon Damrey strengthened as it approached Vietnam on Thursday.  At 11:00 p.m. EDT on Thursday the center of Typhoon Damrey was located at latitude 12.6°N and longitude 113.1°E which put it about 185 miles (300 km) east-northeast of Nha Trang, Vietnam.  Damrey 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 979 mb.

The circulation of Tropical Storm Damrey became much more well organized on Thursday and it strengthened in a typhoon.  A small circular eye developed at the center of Typhoon Damrey.  A broken ring of thunderstorms surrounded the eye.  Numerous bands of showers and thunderstorms were revolving around the core of the symmetrical circulation of Typhoon Damrey.  The storms generated well developed upper level divergence which pumped mass away from the typhoon and allowed the surface pressure to decrease.

Typhoon Damrey will move through an environment favorable for intensification for about another 18 hours.  Damrey will move over water where the Sea Surface Temperature is near 28°C.  An upper level ridge to the north of Damrey is producing easterly winds which are blowing toward the top of the circulation.  However, there are also easterly winds in the lower and middle of the troposphere.  So, there is not a lot of vertical wind shear.  Typhoon Damrey will continue to intensify on Friday and there could be a period of more rapid intensification.  Typhoon Damrey will begin to weaken after the center makes landfall in Vietnam.

The ridge to the north of Damrey is steering the typhoon toward the west and that general motion is expected to continue for several more days.  On its anticipated track the center of Typhoon Damrey will reach the coast of Vietnam in 18 to 24 hours.  The center could make landfall between Cam Ranh and Quy Nhon.

Typhoon Damrey will bring strong winds to southern Vietnam.  Damrey cold produce a storm surface of 6 to 12 feet (2 to 4 meters) near where the center makes landfall on the coast.  Typhoon Damrey will also drop very heavy rain over parts of southern Vietnam, southern Laos, Cambodia and Thailand.  The heavy rain could cause flooding in those areas.

Tropical Storm Damrey Forms West of the Philippines

Tropical Storm Damrey formed west of the Philippines on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Damrey was located at latitude 12.8°N and longitude 116.4°E which put it about 615 miles (990 km) east-southeast of Da Nang, Vietnam.  Damrey was moving toward the west-northwest 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.

An area of low pressure slowly organized as it moved through the Philippines during the past several days.  A center of circulation developed and bands of showers and thunderstorms formed and started to revolve around the core of the low pressure system.  The Japan Meteorological Agency designated the system as Tropical Storm Damrey.

The circulation of Tropical Storm Damrey is still organizing.  More thunderstorms formed near the center of circulation.  A primary rainband wrapped around the western and southern sides of the center.  Additional bands of showers and thunderstorms formed outside the core of the circulation.  Storms in the core of Damrey began to generate upper level divergence which pumped mass away from the tropical storm and allowed the surface pressure to decrease.

Tropical Storm Damrey will be moving through an environment that will be favorable for intensification.  Damrey will move over water where the Sea Surface Temperature will be near 28°C.  An upper level ridge north of Tropical Storm Damrey is producing easterly winds which are blowing toward the top of the circulation.  Those winds are causing some vertical wind shear, but the shear is not strong enough to prevent intensification.  Tropical Storm Damrey will continue to intensify and it could become a typhoon in 24 to 36 hours.

The upper level ridge north of Damrey is steering the tropical storm toward the west-northwest and a general westerly motion is forecast.  On its anticipated track Tropical Storm Damrey will move toward Vietnam.  Damrey could approach the coast of Vietnam in less than 48 hours.  Damrey could be a typhoon when it gets to Vietnam.

Tropical Storm Saola Speeding Toward Tokyo

Tropical Storm Saola sped toward Tokyo, Japan on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Saola was located at latitude 32.4°N and longitude 134.4°E which put it about 370 miles (595 km) west-southwest of Tokyo.  Saola was moving toward the northeast at 24 m.p.h. (39 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 979 mb.

Tropical Storm Saola was weakening and making a transition to an extratropical cyclone.  A primary band of showers and thunderstorms wrapped around the eastern side of the circulation.  There were other thinner bands of showers revolving around the core of the circulation.  Strong westerly winds in the upper levels were causing significant vertical wind shear which was tilting the upper part of the circulation toward the northeast.  Cooler drier air appeared to be flowing toward the western part of the circulation.

Westerly winds in the middle latitudes were steering Tropical Storm Saola quickly toward the northeast.  The center of Saola will pass south of Shikoku.  On its anticipated track the center of Tropical Storm Saola will pass near Tokyo in about 12 hours.  Tropical Storm Saola will bring gusty winds and locally heavy rain to Shikoku and central Honshu.  The heavy rain could cause flash floods in some locations.

Typhoon Saola Near Okinawa

The core of Typhoon Saola moved near Okinawa on Friday night.  At 11:00 p.m. EDT on Friday the center of Typhoon Saola was near latitude 26.2°N and longitude 128.2°E which put it about 70 miles (110 km) south of Okinawa.  Saola was moving toward the north 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 979 mb.

The circulation of Typhoon Saola became more well organized on Friday.   The primary rainband wrapped most of the way around the center of circulation.  A large eye was surrounded by a broken ring of showers and thunderstorms.  Low clouds and showers were scattered throughout the large eye.  Several other bands of showers and storms were revolving around the core of Typhoon Saola.  The rainbands were weaker on the northwestern side of Typhoon Saola and there appeared to be cooler, drier air on that side of the typhoon.  Winds to typhoon force extended out about 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out about 200 miles (320 km) from the center.

Typhoon Saola could be near its maximum intensity.  Saola will move over water where the Sea Surface Temperature is near 29°C.  However Typhoon Saola is near the upper level westerly winds in the middle latitudes and the vertical wind shear will increase on Saturday.  Typhoon Saola could strengthen a little more during the next six to twelve hours, but it will start to weaken when the vertical wind shear increases.

Typhoon Saola is moving around the western end of a ridge which is steering Saola toward the north.  When Typhoon Saola reaches the westerly winds of the middle latitudes, those winds will turn Saola toward the east-northeast.  On its anticipated track Typhoon Saola will bring strong winds and heavy rain to Okinawa and the Ryukyu Islands.  The center of Typhoon Saola will be near southern Kyushu in about 12 hours and the center could pass near Tokyo in about 24 hours.

Tropical Storm Saola Strengthens, Moves Toward Okinawa

Tropical Storm strengthened on Thursday as it moved closer to Okinawa.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Saola was located at latitude 22.2°N and longitude 129.4°E which put it about 350 miles (570 km) south-southeast of Okinawa.  Saola was moving toward the north-northwest at 17 m.p.h. (27 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 987 mb.

The circulation of Tropical Storm Saola exhibited more organization in recent hours.  For much of the past several days many of the showers and thunderstorms were in a single primary rainband that wrapped around the outer part of the circulation.  There were few showers or storms near and to the north of the center of circulation.  A broken ring of showers and thunderstorms began to develop around the center during the past few hours.  The ring could represent the initial formation of an eyewall.  Additional bands of showers and thunderstorms also began to form outside the core of Tropical Storm Saola.

Tropical Storm Saola will be moving through an environment that will be favorable for intensification during the next 24 hours.  Saola will move over water where the Sea Surface Temperature is near 29°C.  The winds will be similar in all levels of the atmosphere and there will be little vertical wind shear.  Tropical Storm Saola will intensify on Friday and it could become a typhoon.  After about 24 hours Tropical Storm Saola will reach the upper level westerly winds in the middle latitudes and the vertical wind shear will increase.  More wind shear will start to weaken Saola.

Tropical Storm Saola was moving the western end of a ridge which is steering the tropical storm toward the north-northwest and that general motion is expected to continue for about another 24 hours.  On its anticipated track Tropical Storm Saola will approach Okinawa in about 24 hours.  When Saola nears Okinawa, it will encounter the westerly winds in the middle latitudes.  Those winds will turn Saola toward the northeast.  Tropical Storm Saola will bring gusty winds and locally heavy rain to Okinawa and the Ryukyu Islands.

Tropical Storm Saola Develops West of Guam

Tropical Storm Saola developed west of Guam on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Saola was located at latitude 14.8°N and longitude 134.8°E which put it about 375 miles (605 km) northwest of Yap.  Saola was moving toward the west-northwest at 24 m.p.h. (39 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 997 mb.

The core of the circulation of Tropical Storm Saola became more well organized on Tuesday.  The center of circulation strengthened and more thunderstorms developed close to the center  Bands of showers and thunderstorms formed outside the core of Tropical Storm Saola.  Many of the showers and storms formed southwest of the center.  There were fewer showers and storms northeast of the center.  The storms near the core of Saola began to produce upper level divergence which was pumping mass away from the tropical storm.

Tropical Storm Saola will move through an environment that will be somewhat favorable for intensification.  Saola will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge north of Tropical Storm Saola is producing easterly winds which are blowing toward the top of the circulation.  Those winds are causing moderate vertical wind shear which is inhibiting the intensification of Tropical Storm Saola.  The upper level winds are forecast to weaken which would cause the wind shear to decrease.  The decreased wind shear should allow Tropical Storm Saola to intensify during the next several days and it could eventually strengthen into a typhoon.

The upper level ridge has been steering Tropical Storm Saola toward the west-northwest.  An upper level trough east of Asia is forecast to weaken the ridge.  When the ridge weakens,Tropical Storm Saola will turn more the north.  On its anticipated track Tropical Storm Saola will remain east of the Philippines and Taiwan.  Tropical Storm Saola could approach Okinawa in about 72 hours.  Saola could be a typhoon when it approaches Okinawa.

Typhoon Lan Brings Wind and Rain to Japan

Typhoon Lan brought wind and rain to parts of Japan on Sunday.  At 5:00 p.m. EDT on Sunday the center of Typhoon Lan was located at latitude 35.2°N and longitude 139.1°E which put it about 50 miles southwest of Tokyo, Japan.  Lan was moving toward the northeast at 37 m.p.h. (60 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (155 km/h).  The minimum surface pressure was 960 mb.

Typhoon Lan weakened significantly before it reached Japan.  Lan moved over cooler water south of Japan.  Strong upper level westerly winds caused strong vertical wind shear.  The circulation of Lan pulled drier air into the western half of the circulation.  The combination of cooler water, strong shear and drier air caused the significant weakening.  In addition the shear was strong enough to push the heavier rain to the northeast of the center of Typhoon Lan.

Lan was still a typhoon when it made landfall in Honshu despite the unfavorable environment.  A weather station at the Tokyo International Airport reported a wind speed of 56 m.p.h. (90 km/h).  Some areas in eastern Honshu experienced periods of heavy rain and gusty winds.  The drier air will limit the rainfall after the center of the typhoon passes a given location.

The strong westerly winds will steer Typhoon Lan rapidly toward the northeast.  Lan will move east of Honshu in a few hours.  The strong vertical wind shear and cooler, drier air will cause Typhoon Lan to transition to a strong extratropical cyclone east of Japan.

While Typhoon Lan races across eastern Japan, Tropical Depression 27W organized southeast of Guam.  At 5:00 p.m. EDT on Sunday the center of Tropical Depression 27W was located at latitude 9.3°N and longitude 147.4°E which put it about 360 miles (580 km) southeast of Guam.  It was moving toward west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gust to 45 m.p.h.  The minimum surface pressure was 1004 mb.

Tropical Depression 27W will move through an environment that will be somewhat favorable for development during the next several days.  It will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge centered northeast of the Marianas is producing easterly winds which are blowing over the top of the depression.  Those winds are causing moderate vertical wind shear.  The shear is inhibiting the organization of the circulation and it is slowing the development of the depression.  The shear is forecast to decrease during the next several days and the depression could strengthen into a tropical storm if a distinct low level center forms.

Tropical Depression 27W is near the southwestern end of the ridge to its northeast.  The ridge is currently steering the depression toward the west.  It is forecast to move around the end of the ridge and turn more toward the north during the next few days.  On its anticipated track the depression could be near Guam in about 24 hours.  It could be a tropical storm at that time.

Powerful Typhoon Lan Speeds Toward Japan

Powerful Typhoon Lan sped toward Japan on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Lan was located at latitude 28.9°N and longitude 134.5°E, which put it about 575 miles (925 km) southwest of Tokyo, Japan.  Lan was moving toward the north-northeast at 27 m.p.h. (43 km/h).  The maximum sustained wind speed was 145 m.p.h. (230 km/h) and there were wind gusts to 170 m.p.h. (275 km/h).  The minimum surface pressure was 928 mb.

Lan is a large and powerful typhoon.  There is an eye at the center of circulation, but the eye has become less clear during the past few hours.  A ring of strong thunderstorms surrounds the eye and the strongest winds are occurring in that ring of storms.  Additional bands of showers and thunderstorms are revolving around the core of Typhoon Lan.  The outer bands in the western half of the circulation consist primarily of low clouds and showers.  Winds to typhoon force extend out about 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extend out about 335 miles (540 km) from the center.

The Hurricane Intensity Index (HII) for Typhoon Lan was 29.9.  The Hurricane Size Index (HSI) was 20.6 and the Hurricane Wind Intensity Size Index (HWISI) was 50.5.

Typhoon Lan has reached its maximum intensity and it will weaken during the next several days.  Lan is moving over water where the Sea Surface Temperature is near 28°C, but it will move over colder water when it moves farther north.  Westerly winds in the upper levels are starting to increase the vertical wind shear.  Typhoon Lan also appears to be drawing cooler and drier air into the western side of the circulation.  Cooler water, more vertical wind shear and drier air will cause steady weakening of Typhoon Lan.

Typhoon Lan is moving around the western end of a ridge which is steering the typhoon rapidly toward the north-northeast.  Westerly winds in the upper levels will carry Lan quickly toward Japan.  On its anticipated track Typhoon Lan will approach Honshu and the area near Tokyo in 12 to 18 hours.  Lan will still be a strong typhoon when it gets to Japan.  Typhoon will bring strong winds and drop locally heavy rain over the area around Tokyo.  Heavy rain could cause flash floods.

Typhoon Lan Intensifies Into Equivalent of a Major Hurricane

Typhoon Lan intensified into the equivalent of a major hurricane on Friday.  At 11:00 a.m. EDT on Friday the center of Typhoon Lan was located at latitude 20.9°N and longitude 130.3°E which put it about 450 miles (720 km) south-southeast of Okinawa.  Lan was moving toward the north at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h).  The minimum surface pressure was 942 mb.

Typhoon Lan has a large and powerful circulation.  There is a large circular eye at the center of circulation.  The eye has a diameter of 60 miles (96 km) and it is surrounded by a ring of strong thunderstorms.  The strongest winds are occurring in that ring of storms.  Multiple bands of showers and thunderstorms are revolving around the core of the circulation.  Typhoon Lan is generating strong upper level divergence which is pumping mass away to the northeast of the typhoon.  Winds to typhoon force extend out about 100 miles (160 km) from the center of circulation.  Winds to tropical storm force extend out about 330 miles (530 km) from the center.

The Hurricane Intensity Index (HII) for Typhoon Lan is 20.6.  The Hurricane Size Index (HSI) is 37.2 and the Hurricane Wind Intensity Size Index (HWISI) is 57.8.  Those indices indicate that Typhoon Lan is capable of causing widespread major damage.

Typhoon Lan will move through an environment that will be favorable for further intensification during the next 24 hours.  Lan will move over water where the Sea Surface Temperature is near 31°C.  An upper level ridge centered east of Lan is producing southerly winds which are blowing toward the top of the circulation.  There are also southerly winds in the lower levels of the atmosphere and thus there is not much vertical wind shear.  The southerly winds in the upper levels are actually enhancing the upper level divergence to the northeast of Typhoon Lan.  Warm water and little vertical wind shear will allow Typhoon Lan to strengthen during the next day or so.  When Lan moves farther north, it will reach the upper level westerly winds in the middle latitudes.  The vertical wind shear will increase at that time, and Typhoon Lan will start to weaken.

Typhoon Lan is moving around the western end of a subtropical ridge which is steering the typhoon toward the north.  As Typhoon Lan moves farther toward the north, it will begin to move toward the north-northeast.  When Lan reaches the upper level westerlies on Sunday, it will turn more toward the northeast.  On its anticipated track the center of Typhoon Lan will pass east of Okinawa and the Ryuku Islands on Saturday.  Typhoon Lan will approach Honshu in about 48 hours.

Typhoon Lan will still be a large powerful typhoon when it approaches Honshu.  Lan will be capable of producing strong gusty winds and very heavy rainfall.  Flash floods could occur when Typhoon Lan moves across Japan.