Tag Archives: South China Sea

Tropical Storm Talas Makes Landfall in Vietnam

Tropical Storm Talas made landfall on the coast of Vietnam on Sunday.  Talas was bringing gusty winds and heavy rainfall to parts of Vietnam, Laos and Thailand.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Talas was located at latitude18.6°N and longitude 105.5°E which put the center near Vinh, Vietnam.  Talas was moving toward the west 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 984 mb.

Tropical Storm Talas strengthened before it made landfall in Vietnam.  A primary band wrapped around the western and southern sides of the center of circulation.  Thunderstorms formed near the center of Talas as the tropical storm approached the coast of Vietnam.  The strongest winds in Tropical Storm Talas were occurring in thunderstorms over the South China Sea.  Tropical Storm Talas will weaken as it moves farther inland.

Tropical Storm Talas was bringing gusty winds and heavy rain to parts of Vietnam, Laos and Thailand.  Locally heavy rain could cause flooding, which will be the greatest risk as Tropical Storm Talas moves farther inland.

Tropical Storm Talas Forms East of Vietnam

Tropical Storm Talas formed east of Vietnam on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Talas was located at latitude 17.3°N and longitude 110.1°E which put it about 170 miles (270 km) east-northeast of Da Nang, Vietnam.  Talas was moving toward the west at 11 m.p.h. (17 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 996 mb.

A large area of showers and thunderstorms persisted over the South China Sea for the past several days.  A distinct center of circulation began to develop in the northern part of the area of thunderstorms.  The Japan Meteorological Agency classified the system as Tropical Storm Talas on Saturday.

The circulation of Tropical Storm Talas is still organizing.  The center of rotation was near the northwestern edge of the area of thunderstorms.  Additional thunderstorms were beginning to form near the center of circulation.  Several bands of showers and thunderstorms were southwest of the center.  Bands of lighter showers were occurring in the remainder of Tropical Storm Talas.  Thunderstorms forming near the center of circulation were beginning to generate strong upper level divergence which was pumping out mass.

Tropical Storm Talas has about 24 hours to strengthen.  Talas will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge north of Talas is producing easterly winds which are blowing toward the top of the tropical storm.  There is some vertical wind shear, but the shear appears to have diminished during the past few hours.  Since Tropical Storm Talas will be moving through an environment of very warm water and reduced vertical wind shear, it will likely strengthen during the next 24 hours.

A subtropical ridge north of Talas is steering the tropical storm toward the west and motion a little to the north of due west is forecast.  On its anticipated track the center of Tropical Storm Talas will pass south of Hainan Island.  Tropical Storm Talas will approach the coast of Vietnam near Vinh in about 24 hours.  Tropical Storm Talas will bring gusty winds and locally heavy rain to Central Vietnam when it makes landfall.

Tropical Depression 01W Redevelops East of Vietnam

More thunderstorms developed on Saturday around the circulation previously designated Tropical Depression 01W earlier this week when it moved through the southern Philippines.  At 10:00 p.m. EST the center of Tropical Depression 01W was located at latitude 9.4°N and longitude 109.1°E which put it about 220 miles (355 km) east-southeast of Ho Chi Minh City, Vietnam.  The depression was moving toward the west at 6 m.p.h. (10 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 1002 mb.

After persisting mainly as a low level circulation during the past few days as it moved westward across the South China Sea, more thunderstorms developed in the depression on Saturday.  Most of the thunderstorms developed in bands north and west of the center of circulation.  There were bands of low clouds and showers in the southeastern portion of the circulation. The depression has a well defined low level center of circulation.  Thunderstorms were starting to generate some upper level divergence which was pumping mass away to the northwest of the depression.

The depression will be moving through an environment that is marginal for intensification.  It will be moving over water where the Sea Surface Temperature is near 26°C to 27°C.  So, there will be enough energy in the upper ocean to support intensification.  An upper level ridge to the east of the depression is generating southeasterly winds which are blowing across the top of the circulation.  The moderate vertical wind shear will inhibit intensification.  If the shear does not increase, the depression could maintain its intensity or strengthen slightly during the next 24 hours.

A ridge north of the depression is steering it toward the west and that general motion is expected to continue for another day or two.  On its anticipated track the depression will move toward the southernmost part of Vietnam.  The depression could bring locally heavy rain to southern Vietnam.  The rain could be heavy enough to cause flooding in some areas.

Typhoon Nock-ten Moves South of Manila

Typhoon Nock-ten moved across southern Luzon and weakened on Sunday.  At 10:00 p.m. EST on Sunday the center of Typhoon Nock-ten was located at latitude 13.8°N and longitude 120.9°E which put it near Batangas and about 75 miles (120 km/h) south-southeast of Manila, Philippines.  Nock-ten was moving toward the west at 18 m.p.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 956 mb.

Typhoon Nock-ten weakened when the center moved over parts of southern Luzon.  Increased friction slowed the wind and areas of higher terrain temporarily disrupted the lower level circulation.  In addition easterly winds in the upper levels appeared to increase.  The increased vertical wind shear contributed to making the circulation more asymmetrical.  More of the thunderstorms formed in the western half of the circulation and there were fewer storms east of the center of circulation.

Typhoon Nock-ten will remain in a favorable environment for another day or so.  When Nock-ten moves west of Luzon into the South China Sea, it will move over water where the Sea Surface Temperature is near 29°C.  Typhoon Nock-ten could maintain its intensity or weaken slowly during the next 24 hours.  After that time Typhoon Nock-ten will move into an environment where the upper level winds are stronger.  Increased vertical wind shear will weaken the circulation.

A subtropical ridge to the north of Nock-ten is steering the typhoon toward the west and that general motion is expected to continue for another day or two.  The center of Typhoon Nock-ten passed near Catanduanes Island.  The center then moved near Tabaco, Ligao, Burias Island, San Francisco, and Marinduque Island.  The center is near Batangas.  It will move across Lake Taal and Lubang Island before it passes into the South China Sea.  Typhoon Nock-ten will continue to produce gusty winds and locally heavy rain as the center passes south of Manila.

Tropical Storm Kujira Makes Landfall on Hainan Island

Tropical Storm Kujira made landfall on the east coast of Hainan Island on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Kujira was located at latitude 19.9°N and longitude 109.1°E which put it about 100 miles (160 km) south of Beihai, China.  Kujira was moving toward the northwest at 10 m.p.h. (16 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 992 mb.

Passing across Hainan Island weakened Tropical Storm Kujira on Monday.  In addition, an upper level ridge over southern Asia continues to generate vertical wind shear over the tropical storm.  However, it will move over warm water when the center moves northwest of Hainan Island.  So, Kujira could maintain tropical storm intensity until it makes another landfall in China in about 18 to 24 hours.  The primary risk will be locally heavy rainfall.

Tropical Storm Kujira Nearing Hainan Island

Tropical Storm Kujira moved slowly northward on Sunday.  At 11:00 p.m. EDT on Sunday night the center of Tropical Storm Kujira was located at latitude 18.0°N and longitude 111.2°E which put it about 150 miles (240 km) south-southeast of Xuwen, China.  Kujira 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 65 m.p.h. (105 km/h).  The minimum surface pressure was 994 mb.

Although Kujira is moving over water where the Sea Surface Temperature is near 30°C, vertical wind shear is inhibiting intensification.  An upper level ridge over southern Asia is producing northeasterly winds over the top of Kujira.  As a result of the vertical shear, most of the stronger thunderstorms are occurring southwest of the center of circulation.  As Kujira moves farther north, some of the circulation will move over Hainan Island, which will further limit the potential for intensification.

Kujira is moving around the western end of a subtropical ridge which is steering the tropical storm toward the north.  The steering pattern is expected to remain in place for the early part of the week.  Kujira could be very close to the east coast of Hainan Island in about 12 hours.  It will move near or just east of Hainan and Kujira could make landfall in China in 24 to 36 hours.  Although it will bring some wind, the primary risk will be locally heavy rainfall.

Tropical Storm Kujira Forms South of Hainan Island

A surface circulation organized within a larger area of thunderstorms east of Vietnam on Saturday and the system was designated as Tropical Storm Kujira.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Kujira was located at latitude 15.7°N and longitude 111.4°E which put it about 210 miles (340 km) east of Da Nang, Vietnam.  Kujira was moving north-northwest at 3 m.p.h. (5 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 998 mb.

Tropical Storm Kujira is moving over water where the Sea Surface Temperature is near 30°C.  However an upper level ridge over southern Asia is generating northeasterly winds over the top of Kujira.  Those northeasterly winds are producing moderate vertical wind shear, which is causing most of the stronger thunderstorms to be located in the western half of the circulation.  Some spiral bands are beginning to form and a band is wrapping around the southern side of the center of circulation.  It appears that Kujira is becoming more well organized and intensification is likely, although the wind shear could slow that process.

Kujira is in an area where the steering currents are weak.  The tropical storm is near the western end of a subtropical ridge and the highest probability is that it will move north toward Hainan Island and southern China.  Some numerical models project a landfall on Hainan Island, but others have Kujira passing east of the island before making landfall on the coast of China.  In either scenario Kujira could approach Hainan Island in 24 to 36 hours.

Convection Redevelops in Remnants of Jangmi

Upper level wind shear decreased over the remnants of Jangmi on Thursday and thunderstorms redeveloped on the western side of the circulation.  At 11:00 p.m. EST on Thursday the center of circulation of the remnants of Jangmi was located at latitude 5.8°N and longitude 112.0°E which put it about 360 miles northeast of Kuching, Malaysia on the island of Borneo and about 600 miles east of Kuala Terengganu, Malaysia.  The center of circulation was moving just slightly south of due west at 8 m.p.h.  The maximum sustained wind speed was 35 m.p.h. with gusts to 45 m.p.h.  The minimum surface pressure was 1007 mb.

The subtropical ridge that was pushing strong southeasterly winds in the upper levels over the top of the remnants of Jangmi weakened slightly on Thursday.  As the upper level winds slowed down, it allowed more thunderstorms to develop around the western half of the circulation.  The increase of convection also increased the vertical extent of the circulation and created the potential for Jangmi to redevelop as a tropical cyclone.  The circulation is over Sea Surface Temperatures near 28°C, which provide sufficient energy to support a tropical cyclone.

As the circulation has grown taller, it has been steered more toward the west.  That pushed the center of circulation north of the northern tip of Borneo and kept it over the South China Sea.  Guidance suggests that the remnants of Jangmi will continue to move in a generally westerly direction which would take it toward Malaysia.

 

Jangmi Weakens over Sulu Sea

Increased vertical wind shear blew the tops off of thunderstorms and Tropical Storm Jangmi weakened to a tropical depression,  At 11:00 p.m. EST on Tuesday the center of Tropical Depression Jangmi was located at latitude 8.0°N and longitude 120.8°E which put it about 150 miles north of Jolo, Philippines and about 300 miles east-northeast of Kudat, Malaysia on the northern end of Borneo.  Jangmi was moving toward the west-southwest at 7 m.p.h.  The maximum sustained wind speed was 30 m.p.h. and there were gusts to 40 m.p.h.

A subtropical ridge north of Jangmi intensified southeasterly winds in the upper levels and increased the wind shear over the top of the tropical storm.  The stronger upper level winds blew away the upper portions of thunderstorms and the circulation contained mainly shallower convection during the most recent 12 hours.  Recent satellite images show the redevelopment of some thunderstorms southwest of the center of circulation, but some wind shear continues.  Jangmi is over Sea Surface Temperatures that are warm enough to support some intensification, but that will not happen if the wind shear continues.  If Jangmi continues to move southwestward, interaction with the island of Borneo could weaken the circulation and possibly cause it to dissipate entirely.  If the center passes just west of Borneo, then some intensification may be possible, unless the wind shear remains too strong.

Since the circulation of Jangmi consisted mainly of shallower convection, it was steered toward the southwest by northeasterly winds in the lower levels of the atmosphere.  Even though a few thunderstorms have redeveloped, most of the convection is still shallow and Jangmi is likely to continue to be steered in a generally west-southwesterly direction.  The projected track could bring Jangmi or its remnants near the northern end of Borneo in 24-48 hours.

 

 

Tropical Storm Jangmi Moving across the Sulu Sea

Tropical Storm Jangmi moved across Mindanao and the center passed near Cebu.  It has now moved back over the open waters of the Sulu Sea.  At 11:00 p.m. EST on Monday the center of Tropical Storm Jangmi was located at latitude 10.4°N and longitude 121.0°E which put it about 320 miles south of Manila, about 200 miles east-northeast of Puerto Princesa and about 1300 miles east-northeast of Singapore.  Jangmi was moving toward the west at 11 m.p.h.  The maximum sustained wind speed was 45 m.p.h. and there were gusts to 60 m.p.h.

Thunderstorms are beginning to redevelop near the center of circulation now that it has moved back over water.  The low level center appears to be relatively intact after its passage over some of the islands in the southern Philippines.  Easterly winds in the upper levels are generating some wind shear, but there is well developed upper level outflow on the northern side of Jangmi.  It will be moving over warm Sea Surface Temperatures and some intensification is possible as it moves westward.

Jangmi is being steered to the west by a subtropical ridge located to its north.  The general westward motion is expected to continue in the short term.  Eventually, northeasterly winds are expected to push Jangmi in a more west-southwesterly direction over the next few days.  The projected track is expected to take the center across Palawan near Puerto Princesa in about 24 hours.  The west-southwesterly motion is expected to continue and it could take Jangmi in the general direction of Malaysia.

Jangmi could bring some locally heavy rainfall to parts of Palawan and some flooding and landslides are possible.