Tag Archives: Vietnam

Typhoon Nida Brushes Luzon and Heads for Hong Kong

Typhoon Nida brought wind and rain to northern Luzon on Sunday as it continued to move toward Hong Kong on the coast of China.  At 11:00 p.m. EDT on Sunday the center of Typhoon Nida was located at latitude 20.4°N and longitude 118.3°E which put it about 340 miles (545 km) east-southeast of Hong Kong.  Nida was moving toward the west-northwest 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. (145 km/h).  The minimum surface pressure was 974 mb.

The Hurricane Intensity Index (HII) for Typhoon Nida is 10.4.  The Hurricane Size Index (HSI) is 13.1 and the Hurricane Wind Intensity Size Index (HWISI) is 23.5.  These indices suggest that Typhoon Nida will be capable of causing minor wind damage on a regional scale.

The structure of Typhoon Nida changed significantly on Sunday.  The primary rainband wrapped around the core of the circulation and a very large eye was created at the center.  The diameter of the eye is approximately 50 miles (80 km).  The strongest winds are occurring in the ring of thunderstorms that surrounds the eye.  Other spiral bands of thunderstorms are rotating around the large eye.  The thunderstorms were generating upper level divergence which pumped out mass and allowed the surface pressure to decrease.

Typhoon Nida is in an environment that would favor intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  Easterly winds are blowing in the upper levels, but there is not much vertical wind shear.  The large size of the eye of Nida is the major factor inhibiting intensification.  It takes more energy to increase the wind speed in a large typhoon than it does in a smaller storm.  If the eye contracts, then Typhoon Nida could intensify more before it makes landfall.

A subtropical ridge north of Nida is steering the typhoon toward the west-northwest and that general motion is expected to continue for another day or so.  On its anticipated track Typhoon Nida will be very near Hong Kong in about 24 hours.

As mentioned above, the large size of Typhoon Nida means that it will be capable of causing wind damage on a regional scale.  In addition, Typhoon Nida will be capable of creating a significant storm surge when it moves into the coast of China.  A large slow moving typhoon like Nida will also produce heavy rain and flooding as it moves inland.

Tropical Storm Mirinae Bringing Wind and Heavy Rain to Vietnam

Tropical Storm Mirinae is bringing wind and heavy rain as it moves inland over northern Vietnam.  At 5:00 p.m. EDT on Wednesday the center of Tropical Storm MIrinae was located at latitude 20.4°N and longitude 105.6°E which put it about 45 miles (70 km) south of Hanoi, Vietnam.  Mirinae was moving toward the west-northwest at 10 m.p.h. (16 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 993 mb.

As it moved over the Gulf of Tongking, Tropical Storm Mirinae intensified rapidly during the final few hours before it made landfall on the coast of northern Vietnam.  Microwave and infrared satellite imagery indicates that an eye developed in the center of circulation and a circular ring of strong thunderstorms surrounded the eye.  Tropical Storm Mirinae may have been near typhoon intensity at the time it made landfall.

Tropical Storm Mirinae has weakened somewhat as it moved inland over northern Vietnam.  However, it does still exhibit a very well organized, circular structure.  The upper level divergence has been more impressive than it has been at any time during the existence of Mirinae.  The strongest winds are occurring near the core of the tropical storm and in rainbands over the open water of the Gulf of Tongking.  Mirinae will gradually weaken further as the circulation spins down over land.

Tropical Storm Mirinae will produce very heavy rain as it moves across northern Vietnam toward northern Laos.  The rapid intensification and improved structure of Mirinae mean that the rain will be heavier and will continue for a longer period.  Heavy, persistent rainfall will create the potential for serious flash flooding.

Tropical Storm Mirinae Moving Over Hainan Island

A defined center of circulation developed within a cluster of thunderstorms that moved west of the Philippines on Tuesday and the system was designated Tropical Storm Mirinae.  Tropical Storm Mirinae is now moving over Hainan Island and it is bringing heavy rain to the southern portion of the island.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Mirinae was located at latitude 19.3°N and 109.4°E which put it about 60 miles (95 km) south-southwest of Haikou, China.  Mirinae 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. (90 km/h).  The minimum surface pressure was 996 mb.

An upper level ridge over Asia is producing northeasterly winds which are blowing over the top of Tropical Storm Mirinae.  The moderate vertical wind shear is causing most of the strong thunderstorms to be located in the southern half of the tropical storm.  Those thunderstorms are generating upper level divergence to the south of the center of circulation, but the northeasterly winds are inhibiting the motion of air trying to diverge to the north of Mirinae.

Tropical Storm MIrinae is in an environment that is not overly favorable for intensification.  It is moving over Hainan Island and increased surface friction will slow the circulation.  The moderate vertical wind shear is also a negative factor.  However, when the center of circulation moves west of Hainan Island, it will move over water where the Sea Surface Temperature is near 30°C.  So, some re-intensifcation could occur before Tropical Storm MIrinae makes landfall in Asia.

A subtropical ridge northeast of MIrinae is steering the tropical storm toward the west-northwest and that general motion is expected to continue for another day or so.  On its anticipated track Tropical Storm Mirinae will move over the Gulf of Tongking in a few hours.  The center of Tropical Storm Mirinae could reach the coast of northern Vietnam in about 24 hours.

MIrinae is a minimal tropical storm and it is not likely to intensify a great deal.  Heavy rain and floods are the primary risks associated with Tropical Storm Mirinae.  The heaviest rain is likely to fall near and south of the center of circulation.

Typhoon Mujigae Making Landfall in China

Strong Typhoon Mujigae is making landfall on the coast of China near Zhanjiang.  At 11:00 p.m. EDT on Saturday the center of Typhoon Jiang was located at latitude 20.8°N and longitude 111.1°E which put it about 55 miles (90 km) southeast of Zhanjiang.  Mujigae was moving toward the northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (215 km/h).  The minimum surface pressure was 949 mb.

The northwestern side of the eyewall is beginning to affect the coast of China.  Mujigae will bring strong winds and heavy rain as it moves inland over southern China.  The typhoon will begin to weaken as soon as the center moves over land and it will gradually spin down over southern China.

Tropical Storms Mujigae and Choi-Wan Form Over NW Pacific

Two new tropical storms with the names of Mujigae and Choi-Wan have formed over the western North Pacific Ocean.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Mujigae was located at latitude 17.4°N and longitude 117.3°E which put it about 275 miles (445 km) northwest of Manila, Philippines.  Mujigae was moving toward the west-northwest at 17 m.p.h.  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 990 mb.

At 11:00 a.m. EDT on Friday the center of Tropical Storm Choi-Wan was located at latitude 19.2°N and longitude 166.4°E which put it about 15 miles (20 km) south-southeast of Wake Island.  Choi-Wan was moving toward the west-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 50 m.p.h. (80 km/h).  The minimum surface pressure was 996 mb.

Tropical Storm Mujigae organized quickly after the system move west of the Philippines.  A primary curved rainband wrapped around the western and southern sides of the center of circulation.  A possible eye is apparent intermittently on infrared satellite imagery.  Upper level divergence is beginning to occur both north and south of the center.  Mujigae is moving over water where the Sea Surface Temperature is near 28°C and there is not enough vertical wind shear to prevent intensification.  A period of rapid intensification is possible and Mujigae could become a typhoon in 12 to 24 hours.

A subtropical ridge is steering Mujigae toward the west-northwest and that general motion is expected to continue for the next several days.  On its anticipated track, Mujigae could be approaching the southern coast of China in 36 hours.  It could bring strong winds and heavy rain when it makes landfall.

Tropical Storm Choi-Wan is still in the organizational stage.  It has a large broad circulation without a well developed inner core.  Winds to tropical storm force are occurring in clusters of thunderstorms.  Choi-Wan is over Sea Surface Temperatures near 29°C, but there is moderate vertical wind shear over the northern part of the tropical storm.  The wind shear is expected to decrease in a day or two and Choi-Wan is forecast to become a typhoon.

Choi-Wan is between two subtropical ridges and the steering currents are relatively weak.  In a day or two the western ridge is expected to steer Choi-Wan toward the northwest.  Choi-Wan will cause squally weather on Wake Island for 24 to 48 hours.

Tropical Storm Vamco Forms East of Vietnam

A large area of low pressure east of Vietnam developed enough organization on Sunday to be classified as Tropical Storm Vamco.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Vamco was located at latitude 14.8°N and longitude 110.0°E which put it about 160 miles (260 km) east-southeast of Da Nang, Vietnam.  Vamco was moving toward the west 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 1000 mb.

Although there is a large area of low pressure, the circulation around Tropical Storm Vamco is not well organized.  Most of the thunderstorms are located in a large rainband about 100 miles (160 km) from the center of circulation that wraps around the northern and western parts of the storm.  There are not many thunderstorms located near the center of the circulation.  Vamco is located over water where the Sea Surface Temperature is near 30°C.  However, an upper level ridge is generating northeasterly winds over the top of the storm and the vertical wind shear is inhibiting development.  Some intensification is possible in the short term, but the lack of a well formed inner core and proximity to land will limit strengthening.

A subtropical ridge north of Vamco is steering the tropical storm toward the west and that steering pattern is expected to continue.  On its anticipated track the center of Vamco will reach the central coast of Vietnam in about 18 hours.  The primary impacts will be locally heavy rainfall and the potential for flooding.

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.

Hagupit a Tropical Storm for One More Day

Thunderstorms continue to develop intermittently near the center of Hagupit and it is producing enough deep convection to maintain its status as a tropical storm.  At 10:00 p.m. EST on Wednesday the center of Tropical Storm Hagupit was located at latitude 13.2°N and longitude 113.1°E which put it about 275 miles east-northeast of Cam Ranh, Vietnam and about 460 miles east-northeast of Ho Chi Minh City.  Hagupit was moving toward the west-southwest at 9 m.p.h.  The maximum sustained wind speed was 40 m.p.h.  and there were gusts to 50 m.p.h.

Although Hagupit is moving over warm Sea Surface Temperatures, the rest of the environmental factors are unfavorable for intensification.  Northeasterly winds over the South China Sea are transporting cooler and drier air, which is wrapping around the western and southern parts of Hagupit’s circulation.  There is also significant vertical wind shear, which is tilting the circulation.  The tight low level center of circulation is producing enough convergence to continue generating some new thunderstorms near the center, but the convection is becoming more intermittent.  Hagupit is likely to slowly weaken during the next 24 hours as a result of the mainly hostile environment around it.

The northeasterly winds are likely to push Hagupit toward the west-southwest or southwest during the next 24 hours.  The projected track would bring Hagupit to the coast of Vietnam near Cam Ranh in about 24 hours.  It is likely to have minimal impact when it makes landfall.  There could be a period of gustier winds and an increase in rainfall, but Hagupit could dissipate fairly quickly as it moves inland.