Tag Archives: Laos

Tropical Storm Bolaven Forms Over the South China Sea

Tropical Storm Bolaven formed over the South China Sea near the Spratly Islands on Tuesday.  At 10:00 p.m. EDT on Tuesday the center of Tropical Storm Bolaven was located at latitude 10.4°N and longitude 115.1°E which put it about 620 miles (1000 km) east of Ho Chi Minh City, Vietnam.  Bolaven was moving toward the west-northwest at 21 m.p.h. (33 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 1002 mb.

A low level center of circulation developed on the eastern side of a cluster of thunderstorms that moved across the southern Philippines on Monday.  The center exhibited greater organization on Tuesday and the Japan Meteorological Agency designated the system as Tropical Storm Bolaven.  The structure of Tropical Storm Bolaven is asymmetrical.  The strongest thunderstorms are occurring northwest of the center of circulation.  Thin bands of low clouds and showers were revolving around the center of circulation in the other quadrants of Tropical Storm Bolaven.

Tropical Storm Bolaven is moving around the southern side of an upper level ridge centered east of the Philippines.  The ridge is generating strong southeasterly winds which are blowing across the top of the circulation.  Those winds are causing moderate vertical wind shear.  The wind shear is probably the reason why most of the stronger storms are occurring northwest of the center of circulation.  Although Bolaven will move over water where the Sea Surface Temperature is near 28°C, the vertical wind shear will likely prevent intensification.  In fact if the shear increases, then Bolaven could weaken to a tropical depression.

The ridge north of Bolaven is steering the tropical storm toward the west-northwest and that general motion is expected to continue for several more days.  On its anticipated track Tropical Storm Bolaven could reach the coast of South Vietnam in 24 to 36 hours.  Bolaven will bring gusty winds and locally heavy rain to parts of southern Vietnam.

Tropical Depression Tembin Passes Near Southern Tip of Vietnam

The center of Tropical Depression Tembin passed near the southern tip of Vietnam on Monday night.  At 10:00 p.m. EST on Monday the center of Tropical Depression Tembin was located at latitude 8.5°N and longitude 104.6°E which put it about 200 miles (320 km) southwest of Ho Chi Minh City, Vietnam.  Tembin was moving toward the west at 14 m.p.h. (22 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 1005 mb.

An upper level ridge north of Tropical Depression Tembin continued to produce strong easterly winds which were blowing across the top of the circulation.  Those winds were causing strong vertical wind shear.  The shear was strong enough to prevent thunderstorm from developing in most parts of the circulation of Tropical Depression Tembin.  A few thunderstorms formed in the extreme northwestern portion of the circulation, but most of the circulation consisted of bands of low clouds and showers.  The strong shear and lack of tall thunderstorms caused the wind speeds at the surface to decrease and Tembin weakened to a tropical depression.

Tropical Depression Tembin will remain in an environment that is unfavorable for intensification.  Tembin will move over water where the Sea Surface Temperature is near 29°C.  So, there is enough energy in the upper ocean to support intensification.  However, the upper ridge will continue to produce strong easterly winds.  The vertical wind shear is likely to cause the circulation of Tropical Depression Tembin to spin down.

The ridge north of Tembin has been steering the tropical depression toward the west and a general westerly motion is expected to continue for another day or two.  On its anticipated track Tropical Depression Tembin will move across the Gulf of Thailand.   The center of Tropical Depression Tembin could reach the coast of Thailand near Sichon in about 36 hours.

Typhoon Tembin Nears Southern Vietnam

Typhoon Tembin moved nearer to southern Vietnam on Sunday.  At 10:00 p.m. EST on Sunday the center of Typhoon Tembin was located at latitude 8.0°N and longitude 109.3°E which put it about 290 miles (470 km) southeast of Ho Chi Minh City, Vietnam.  Tembin was moving toward the west at 13 m.p.h. (21 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.

Typhoon Tembin weakened during the past 12 hours as it moved over the South China Sea.  An upper level ridge north of Tembin generated stronger easterly winds on Sunday which increased the vertical wind shear.  The strong upper level winds weakened the rainbands in the eastern half of the circulation of Typhoon Tembin.  Those winds also tilted the upper portion of the circulation toward the west.  The low level circulation of Typhoon Tembin remained well organized, but the storms around the center weakened.  The strongest thunderstorms were occurring in bands west of the core of Tembin.  Winds to typhoon force extended out about 40 miles (65 km) from the center in the northern half of the circulation and about 25 miles (40 km) in the southern half.  Winds to tropical storm force extended out about 155 miles (250 km) from the center.

Typhoon Tembin is likely to continue to weaken on Monday.  Typhoon Tembin will move over water where the Sea Surface Temperature is near 29°C.  However, the upper level ridge is likely to continue to generate strong easterly winds and the significant vertical wind shear will make it difficult for tall thunderstorms to develop around much of the circulation.  The wind shear will probably weaken Tembin to a tropical storm on Monday.

The ridge north of Tembin is steering the typhoon toward the west and a general westerly motion is expected to continue for several more days.  On its anticipated track the center of Typhoon Tembin will pass near the southern tip of Vietnam in about 24 hours.  Tembin will likely move into the Gulf of Thailand as a tropical storm or tropical depression.

The heavy rain with Typhoon Tembin is occurring in bands west of the core of the typhoon.  So, the heavy rain will begin to fall before the center of circulation reaches places.  The heaviest rain will fall over the Mouths of the Mekong River and the part of Vietnam south of that area.  The rain could be heavy enough to cause floods in some locations.  Gusty winds could produce isolated damage as well in the southern part of Vietnam.

Tembin Strengthens to a Typhoon Over South China Sea

Tropical Storm Tembin strengthened into a typhoon on Saturday as it moved over the South China Sea.  At 10:00 p.m. EST on Saturday the center of Typhoon Tembin was located at latitude 8.2°N and longitude 113.6°E which put it about 540 miles (880 km) east of Ho Chi Minh City, Vietnam.  Tembin was moving toward the west 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 105 m.p.h. (170 km/h).  The minimum surface pressure was 976 mb.

Typhoon Tembin became much better organized on Saturday.  A primary rainband wrapped around the center of circulation and an eye became apparent on microwave satellite imagery.  Several other rainbands strengthened outside the core of Typhoon Tembin.  Storms near the core of the circulation generated strong upper level divergence which pumped mass away to the west and northeast of the typhoon.  The removal of mass allowed the surface pressure to decrease and the wind speed to increase.  Winds to typhoon force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out about 155 miles (250 km) from the center.

Typhoon Tembin will move through an environment favorable for intensification during the next 24 hours.  Tembin will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge north of Tempin is producing easterly winds which are blowing toward the typhoon.  However, the easterly winds are blowing at most levels of the atmosphere and there is not a lot of vertical wind shear.  Typhoon Tembin is likely to continue to intensify on Sunday.

The subtropical ridge north of Tembin is steering the typhoon quickly toward the west.  A general motion toward the west is expected to continue.  On its anticipated track Typhoon Tembin could approach the southern part of Vietnam in about 36 hours.  Tembin has the potential to bring strong winds, heavy rain and a storm surge to the southern coast of Vietnam.

Tropical Storm Tembin Strengthens Over the Sulu Sea

Tropical Storm Tembin moved west of Mindanao and it strengthened over the Sulu Sea on Friday.  At 4:00 p.m. EST on Friday the center of Tropical Storm Tembin was located at latitude 8.0°N and longitude 120.8°E which put it about 200 miles (320 km) southeast of Puerto Princesa, Philippines.  Tembin was moving toward the west at 8 m.p.h. (13 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 992 mb.

Tropical Storm Tembin weakened when the center moved across Mindanao.  The center is back over water in the Sulu Sea and the circulation of Tembin is strengthening again.  There is a distinct low level center of circulation, but the distribution of thunderstorms is asymmetrical.  Most of the strong thunderstorms are occurring in bands in the western half of the circulation.  Bands in the eastern half of the circulation consist primarily of low clouds and showers.  The storms west of the center are generating upper level divergence which is pumping mass away to the west of the tropical storm.  The removal of mass has caused the surface pressure to decrease and the wind speeds have started to increase.

Tropical Storm Tembin will be moving through an environment that is favorable for intensification.  Tembin will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge north of Tropical Storm Tembin is producing easterly winds which are blowing toward the top of the circulation.   Those winds are causing vertical wind shear, which is probably the reason for the asymmetrical distribution of thunderstorms.  However, the shear is not strong enough to prevent Tropical Storm Tembin from intensifying.  Tembin could strengthen into a typhoon during the next day or two while is moves over the South China Sea.

The subtropical ridge north of Tembin is steering the tropical storm toward the west.  A general motion toward the west-northwest west is forecast for the next two or three days.  On its anticipated track Tropical Storm Tembin will move across Palawan in about 18 hours.  Tembin could reach the southern coast of Vietnam in about three days.  Tembin will bring gusty winds and heavy rain to Palawan.  Tembin could be a typhoon when it approaches southern Vietnam.

Elsewhere over the western North Pacific Ocean Tropical Depression Kai-tak is approaching the east coast of Malaysia.  At 4:00 p.m. EST on Friday the center of Tropical Depression Kai-tak was located at latitude 4.0°N and longitude 104.4°E which put it about 175 miles (285 km) north-northeast of Singapore.  Kai-tak was moving toward the southwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1005 mb.  Tropical Depression Kai-tak will drop locally heavy rain over portions of Malaysia, which could cause floods and mudslides.

Tropical Storm Tembin Drops Heavy Rain on Mindanao

Tropical Storm Tembin dropped heavy rain on Mindanao on Thursday.  At 4:00 p.m. EST on Thursday the center of Tropical Storm Tembin was located at latitude 7.9°N and longitude 126.1°E which put it near Monkayo, Philippines.  Tembin was moving toward the west-southwest at 12 m.p.h. (19 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 990 mb.

Tropical Storm Tembin intensified on Thursday before it made landfall on Mindanao.  More thunderstorms developed near the core of the circulation and those storms generated stronger upper level divergence which pumped mass away from the tropical storm.  The removal of mass allowed the surface pressure to decrease and the wind speed to increase.  Although the circulation became much better organized, the distribution of thunderstorms was still asymmetrical.  There were far fewer thunderstorms forming in the eastern half of the circulation.

The center of Tropical Storm Tembin will be moving across Mindanao for another day or so.  The mountains on the island will disrupt the lower levels of the circulation and increased friction will slow the wind speed.  Tropical Storm Tembin will weaken while the center is over Mindanao.  However, the middle and upper parts of the circulation are likely to remain intact, and Tropical Storm Tembin will move through a favorable environment when it reaches the Sulu Sea.  Tembin will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge north of Tropical Storm Tembin is producing easterly winds which are blowing toward the top of the circulation.  The winds in the middle and lower levels are also blowing from the east and the vertical wind shear will not be strong enough to prevent intensification of Tropical Storm Tembin once the center gets back over water.  Temping could strengthen into a typhoon when it reaches the South China Sea.

The ridge north of Tembin is steering the tropical storm toward the west-southwest.  A general motion toward the west is expected during the next two to three days.  On its anticipated track Tropical Storm Tembin will move east to west over Mindanao during the next 24 hours.  Afterwards, Tropical Storm Tembin will move across the Sulu Sea toward Palawan.  Tembin could be near Palawan in about 48 hours and it could be over the South China Sea shortly thereafter.

Tropical Storm Tembin represents a serious hazard for Mindanao and nearby locations in the southern Philippines.  Tembin is dropping heavy rain and it has the potential to cause serious floods.  Water levels could rise quickly and flash floods could develop.  Saturated soils could result in mudslides in areas of steeper terrain.

Farther to the west, Tropical Storm Kai-tak continued to move across the South China Sea.  At 4:00 p.m. EST on Thursday the center of Tropical Storm Kai-tak was located at latitude 5.7°N and longitude 106.9°E which put it about 250 miles (400 km) east of Kuala Terengganu, Malaysia.  Kai-tak was moving toward the west-southwest at 5 m.p.h. (8 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.

Tropical Storm Kirogi Brings Rain to Southern Vietnam

Tropical Storm Kirogi brought locally heavy rain to southern Vietnam on Saturday night.  At 10:00 p.m. EST on Saturday night the center of Tropical Storm Kirogi was located at latitude 10.4°N and longitude 109.8°E which put it about 220 miles (355 km) east of Ho Chi Minh City, Vietnam.  Kirogi 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 1001 mb.

Kirogi is a small tropical storm.  Winds to tropical storm force extend out about 90 miles (145 km) from the center of circulation.  The circulation is compact and circular.  Most of the strong storms are in the western half of the circulation.  There are numerous bands of lighter showers in eastern half of the circulation.  An upper level ridge north of Kirogi is producing easterly winds which are blowing toward the top of the circulation.  The vertical wind shear is causing the asymmetrical distribution of the stronger storms.

The ridge is steering Tropical Storm Kirogi toward the west.  The center of Tropical Storm Kirogi will make landfall on the coast of Vietnam near Ham Thuan Nam in a few hours.  Kirogi will continue moving west toward Ho Chi Minh City and then over southeastern Cambodia.  Tropical Storm Kirogi will drop locally heavy rain along the coast from Nha Trang to the Mouths of the Mekong River.  Kirogi will also be capable of producing heavy heavy over parts of the southern Cambodia.  The rainfall could be heavy enough to cause flooding in some locations.

Tropical Storm Kirogi Forms West of the Philippines

Tropical Storm Kirogi formed west of the Philippines on Friday.  At 4:00 p.m. EST on Friday the center of Tropical Storm Kirogi was located at latitude 10.9°N and longitude 115.7°E which put it about 465 miles (745 km) east of Nha Trang, Vietnam.  Kirogi was moving toward the west-northwest at 18 m.p.h. (30 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 low level center of circulation developed near the eastern edge of an area of showers and thunderstorms west of the Philippines on Friday and the Japan Meteorological Agency designated the system as Tropical Storm Kirogi.  The distribution of showers and thunderstorms in Kirogi was asymmetrical.  A primary rainband wrapped around the western side of the center of circulations and most of the stronger storms were west of the center.  There were only bands of low clouds and showers east of the center of Kirogi.  An upper level ridge north of Kirogi was producing easterly winds which were blowing across the top of the tropical storm.  The vertical wind shear created by those winds was causing the asymmetrical distribution of showers and thunderstorms.

Tropical Storm Kirogi will move through an environment that will be somewhat favorable for intensification.  Kirogi will move over water where the Sea Surface Temperature is near 29°C.  The upper level ridge will continue to cause vertical wind shear.  The shear may be strong enough to slow intensification, but it may not strong enough to prevent Tropical Storm Kirogi from strengthening.  The forecast is for Tropical Storm Kirogi to intensify during the next 24 to 36 hours.

The ridge is steering Tropical Storm Kirogi toward the west-northwest and a general westerly motion is expected to continue.  On its anticipated track Tropical Storm Kirogi will move across the South China Sea toward Vietnam.  Kirogi could reach the coast of Vietnam near Nha Trang in about 36 hours.  Kirogi will bring gusty winds and locally heavy rain when it reaches the coast.  The locally heavy rain could cause flash floods.  There could also be a storm surge of 3 to 6 feet (1 to 2 meters) where the wind blows water toward the coast of Vietnam.

Remnants of Tropical Storm Haikui Make Landfall in Vietnam

The remnants of Tropical Storm Haikui made landfall near Da Nang, Vietnam late on Monday.  At 10:00 p.m. EDT on Monday the center of Tropical Depression Haikui were located at latitude 17.0°N and longitude 108.2°E which put it about 20 miles (30 km/h) north of Da Nang, Vietnam.  Haikui was moving toward the west at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 25 m.p.h. (40 km/h) and there were wind gusts to 35 m.p.h. (55 km/h).  The minimum surface pressure was 1003 mb.

The remnants of Tropical Storm Haikui consists of primarily of a low level counterclockwise circulation.  There are several thin bands of low clouds and showers.  Stronger thunderstorms were forming near the core of the circulation.  It appeared that winds blowing toward the coast were converging due to increased friction caused by the land.  The convergence was causing stronger rising motion which was contributing to the development of strong thunderstorms near and to the west of the center of circulation.

The remnants of Tropical Storm Haikui will move inland before significant intensification can occur.  The remnants of Haikui could drop locally heavy rainfall over portions of Vietnam, southern Laos and northeastern Thailand.  Locally heavy rainfall could cause flooding in some places.

Tropical Storm Haikui Weakens Southeast of Hainan Island

Tropical Storm Haikui weakened as it moved southeast of Hainan Island on Saturday.  At 10:00 p.m. EST on Saturday the center of Tropical Storm Haikui was located at latitude 17.6°N and longitude 112.6°E which put it about 290 miles (470 km) east of Da Nang, Vietnam.  Haikui was moving toward the west-southwest at 6 m.p.h. (10 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 999 mb.

A combination of drier air and strong vertical wind shear weakened Tropical Storm Haikui on Saturday.  Strong northeasterly winds transported colder drier air from eastern Asia into the circulation of Tropical Storm Haikui.  The drier air reached the core of the circulation and it prevented the formation of new thunderstorms around the center of circulation.  Strong westerly winds in the upper levels were blowing over the top of the circulation.  The combination of northeasterly winds in the lower levels and westerly winds in the upper levels produced strong vertical wind shear.  The wind shear blew the upper portion of the circulation to the east of the low level core of Tropical Storm Haikui.  The core of Tropical Storm Haikui consists of a circular rotation of showers and low clouds.  The only thunderstorms are occurring in a rainband on the northeastern periphery of the circulation.

The strong wind vertical wind shear and drier air should continue to weaken Tropical Storm Haikui.  Haikui is likely to weaken to a tropical depression on Sunday.  Since the circulation exists primarily in the lower levels, it will be steered by the winds closer to the surface of the Earth.  The northeasterly winds in the lower levels will steer Tropical Storm Haikui toward the west- southwest.  On its anticipated track Tropical Storm Haikui will pass south of Hainan Island.  Haikui or its remnants could reach the coast of Vietnam in 36 to 48 hours.