Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Dujuan Weakens to a Tropical Depression

Former Tropical Storm Dujuan weakened to a tropical depression on Saturday. At 10:00 a.m. EST on Saturday the center of Tropical Depression Dujuan was located at latitude 8.4°N and longitude 129.6°E which put it about 210 miles (335 km) east of Hinatuan, Philippines. Dujuan was moving toward the west-northwest at 5 m.p.h. (8 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 1003 mb.

Strong easterly winds in the upper troposphere blew the top off of former Tropical Storm Dujuan on Friday night. The circulation in the lower levels gradually weakened and Dujuan was classified as a tropical depression on Saturday. The low level circulation consisted almost entirely of showers and lower clouds during much of Saturday. A few thunderstorms developed northeast of the center of Tropical Depression Dujuan on Saturday night, but it was not clear that the thunderstorms would persist.

Tropical Depression Dujuan will move through an environment unfavorable for intensification during the next 48 hours. Dujuan will move over water where the Sea Surface Temperature is near 28°C. So, there will be enough energy in the upper ocean to support intensification. However, Tropical Depression Dujuan will move under the southern part of an upper level ridge over the Western North Pacific Ocean. The ridge will continue to produce strong easterly winds which will blow toward the top of Dujuan. In addition, a surface high pressure system over eastern Asia will produce strong northeasterly winds in the lower levels. Those winds will transport drier air over the Philippines. The combination of vertical wind shear and drier air will likely prevent intensification of Tropical Depression Dujuan.

Tropical Depression Dujuan will move south of a high pressure system over the Western North Pacific Ocean. The high will steer Dujuan toward the west-northwest during the next several days. On its anticipated track Tropical Depression Dujuan could approach northern Mindano, southern Samar and Cebu in 18 hours. Dujuan will bring gusty winds and locally heavy rain to parts of the central Philippines.

Tropical Storm Dujuan Moves Toward Mindanao

Tropical Storm Dujuan moved toward Mindanao on Friday. At 10:00 a.m. EST on Friday the center of Tropical Storm Dujuan was located at latitude 6.2°N and longitude 130.1°E which put it about 320 miles (515 km) east of Davao, Philippines. Dujuan was moving toward the west at 9 m.p.h. (11 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 994 mb.

The distribution of thunderstorms around Tropical Storm Dujuan was asymmetrical. The strongest thunderstorms were occurring in bands in the northwestern quadrant of Dujuan. Bands in the rest of the tropical storm consisted primarily of showers and lower clouds. Storms northwest of the center of circulation generated upper level divergence which pumped mass away to the northwest of the tropical storm. Winds to tropical storm force extended out 200 miles (320 km) from the center of Dujuan.

Tropical Storm Dujuan will move through an environment unfavorable for intensification during the next 48 hours. Dujuan will move over water where the Sea Surface Temperature is near 29°C. So, there will be enough energy in the upper ocean to support intensification. However, Tropical Storm Dujuan will move under the southern part of an upper level ridge over the Western North Pacific Ocean. The ridge will produce strong easterly winds which will blow toward the top of Dujuan. Those winds are causing the asymmetrical distribution of thunderstorms and they will create strong vertical wind shear. In addition, a surface high pressure system over eastern Asia will produce strong northeasterly winds in the lower levels. Those winds will transport drier air over the Philippines. The combination of vertical wind shear and drier air will likely prevent further intensification of Tropical Storm Dujuan. Dujuan is likely to weaken gradually during the next 36 hours.

Tropical Storm Dujuan will move south of a high pressure system over the Western North Pacific Ocean. The high will steer Dujuan toward the west-northwest during the next several days. On its anticipated track Tropical Storm Dujuan could approach northeastern Mindano in 36 hours. Dujuan could be a tropical storm when it reaches Mindanao. It will bring gusty winds and locally heavy rain to Mindano and other parts of the southern Philippines.

Tropical Storm Dujuan Develops East of Mindanao

Tropical Storm Dujuan developed east of Mindanao on Thursday. At 10:00 a.m. EST on Thursday the center of Tropical Cyclone Dujuan was located at latitude 7.3°N and longitude 131.6°E which put it about 430 miles (695 km) east of Davao, Philippines. Dujuan was moving toward the west-northwest at 4 m.p.h. (6 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.

The circulation around an area of low pressure east of the Philippines strengthened on Thursday morning and the Japan Meteorological Agency designated the system as Tropical Storm Dujuan. The distribution of thunderstorms around Tropical Storm Dujuan was asymmetrical. The strongest thunderstorms were occurring in bands in the western half of Dujuan. Bands in the eastern half of the tropical storm consisted primarily of showers and lower clouds. Storms west of the center of circulation began to generate upper level divergence which pumped mass away to the west of the tropical storm. Winds to tropical storm force extended out 100 miles (160 km) from the center of Dujuan.

Tropical Storm Dujuan will move through an environment somewhat favorable for intensification during the next 36 hours. Dujuan will move over water where the Sea Surface Temperature is near 29°C. It will move under the southern part of an upper level ridge over the Western North Pacific Ocean. The ridge will produce easterly winds which will blow toward the top of Tropical Storm Dujuan. Those winds will create moderate vertical wind shear and they are causing the asymmetrical distribution of thunderstorms. The wind shear will inhibit intensification, but it will not be strong enough to prevent Dujuan from strengthening. Tropical Storm Dujuan is likely to intensify gradually during the next 36 hours.

Tropical Storm Dujuan will move south of a high pressure system over the Western North Pacific Ocean. The high will steer Dujuan toward the west-northwest during the next several days. On its anticipated track Tropical Storm Dujuan could approach northeastern Mindano in 48 hours. Dujuan could bring gusty winds and locally heavy rain to Mindano and other parts of the southern Philippines.

Tropical Storm Krovanh Develops over South China Sea

Tropical Storm Krovanh developed over the South China Sea on Sunday. At 4:00 p.m. EST on Sunday the center of Tropical Storm Krovanh was located at latitude 9.7°N and longitude 113.9°E which put it about 515 miles (830 km) east of Ho Chi Minh City, Vietnam. Krovanh was moving toward the west-southwest at 7 m.p.h. (11 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.

The circulation around Tropical Storm Krovanh was very asymmetrical. A high pressure system over eastern Asia was contributing to a strong pressure gradient northwest of Krovanh. The pressure gradient between the high pressure system and Krovanh was producing strong northeasterly winds in the northwestern quadrant of the tropical storm. Winds to tropical storm force extended out 300 miles (485 km) in the northwestern quadrant of Tropical Storm Krovanh. However, winds in the southeastern quadrant of Krovanh were blowing at less than tropical storm force.

Tropical Storm Krovanh will move through an environment that is only marginally favorable for intensification. Krovanh will move over water where the Sea Surface Temperature is near 27°C. So, there will be enough energy in the upper ocean to support intensification. However, the northeasterly winds on the northwestern side of Tropical Storm Krovanh will transport drier air into the circulation. The drier air will inhibit the development of thunderstorms. Krovanh will move under the southern part of an upper level ridge over the Western North Pacific Ocean. The ridge will produce strong easterly winds which will blow toward the top of the tropical storm. Those winds will cause moderate vertical wind shear, which will also inhibit intensification. Tropical Storm Krovanh could intensify a little during the next 24 hours, but the dry air and wind shear are likely to cause it to weaken next week.

Tropical Storm Krovanh will move around the southern side of the high pressure system over eastern Asia. The high will steer Krovanh toward the west-southwest during the next several days. On its anticipated track Tropical Storm Krovanh could be near the southernmost part of Vietnam in about three days.

Typhoon Vamco Brings Wind and Rain to Vietnam

Typhoon Vamco brought wind and rain to Vietnam on Saturday night. At 10:00 p.m. EST on Saturday the center of Typhoon Vamco was located at latitude 17.3°N and longitude 107.5°E which put it about 40 miles (65 km) east of Vinh Linh, Vietnam. Vamco was moving toward the northwest at 8 m.p.h. (13 km/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 979 mb.

The center of Typhoon Vamco was about to make landfall on the coast of Vietnam between Vinh Linh and Dong Hoi on Saturday night. Bands on the western side of Vamco were already bringing wind and rain to Vietnam. A flow of drier air from eastern Asia into the western part of the circulation around Vamco caused the typhoon to weaken as it approached Vietnam. Even though it was weaker, Typhoon Vamco was still capable of causing serious damage. Winds to typhoon force extended out 30 miles (50 km) from the center of Vamco. Winds to tropical storm force extended out 130 miles (210 km from the center.

Typhoon Vamco will bring strong winds to the coast of central Vietnam during the next few hours. Wind blowing water toward the coast will cause a storm surge north of Vinh Linh. The winds blwoing around Vamco will weaken when it moves inland. However, Typhoon Vamco will drop heavy rain over parts of central Vietnam, southern Laos and northeastern Thailand. Heavy rain will fall on saturated ground and significant flooding is likely to occur.

Typhoon Vamco Strengthens to Equivalent of Major Hurricane

Typhoon Vamco strengthened to the equivalent of a major hurricane east of Vietnam on Friday. At 4:00 p.m. EST on Friday the center of Typhoon Vamco was located at latitude 15.7°N and longitude 111.9°E which put it about 275 miles (440 km) east of Da Nang, Vietnam. Vamco was moving toward the west at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h). The minimum surface pressure was 954 mb.

Typhoon Vamco rapidly intensified into the equivalent of a major hurricane over the East China east of Vietnam on Friday. The circulation contracted around a small clear eye. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Vamco. Storms near the core were generating strong upper level divergence which was pumping mass away fro the typhoon. The removal of mass allowed the pressure to decrease rapidly which contributed to the rabid intensification.

Winds to typhoon force extended out 40 miles (65 km) from the center of Typhoon Vamco. Winds to tropical storm force extended out 200 miles (320 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Vamco was 25.1. The Hurricane Size Index (HSI) was 16.7 and the Hurricane Wind Intensity Size Index (HWISI) was 41.8. Vamco was capable of causing significant damage.

Typhoon Vamco will move through an environment that will become less favorable for intensification during the next day or so. Vamco will move over water where the Sea Surface Temperature is near 28°C. So, there will be enough energy in the upper ocean to support an intense typhoon. However, northeasterly winds will transport drier air over eastern Asia toward the western side of Typhoon Vamco. Vamco is likely to start to weaken when the drier air is pulled into the core of the circulation.

Typhoon Vamco will move south of a high pressure system over the eastern Asia. The high will steer Vamco toward the west during the next several days. On its anticipated track Typhoon Vamco will approach the coast of Vietnam north of Da Nang in about 24 hours. Vamco is likely to still be a typhoon when it reaches Vietnam. Typhoon Vamco will drop heavy rain over Vietnam, Laos and northeastern Thailand. The rain will fall on saturated surfaces and floods will occur in those areas.

Typhoon Vamco Moves Toward Vietnam

Typhoon Vamco moved toward Vietnam on Thursday. At 10:00 p.m. EST on Thursday the center of Typhoon Vamco was located at latitude 15.5°N and longitude 115.0°E which put it about 480 miles (775 km) east of Da Nang, Vietnam. Vamco was moving toward the west-northwest at 9 m.p.h. (15 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. (165 km/h). The minimum surface pressure was 972 mb.

One day after causing widespread damage on Luzon, Typhoon Vamco moved across the South China Sea toward Vietnam. An eye was present at the center of Vamco, but there were clouds in the eye. The eye was surrounded by a broken ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Vamco. The size of the circulation around Vamco increased after it crossed Luzon. Winds to typhoon force extended out 75 miles (120 km) from the center of circulation. Winds to tropical storm force extended out 230 miles (370 km) from the center.

Typhoon Vamco will move through an environment that could allow it to maintain its intensity for another 24 to 36 hours. Vamco will move over water where the Sea Surface Temperature is near 28°C. It will move under the southern portion of an upper level ridge over eastern Asia. The ridge will produce easterly winds which will blow toward the top of the Typhoon Vamco. Those winds will cause some vertical wind shear, but the shear will not be too strong. Northeasterly winds will transport drier air toward the western side of Typhoon Vamco when it moves closer to land in 24 to 36 hours. Vamco could start to weaken if the drier air is pulled into the core of the typhoon.

Typhoon Vamco will move south of a high pressure system over the eastern Asia. The high will steer Vamco toward the west-northwest during the next several days. On its anticipated track Typhoon Vamco will approach the center coast of Vietnam in about 36 hours.

Typhoon Vamco Makes Landfall Northeast of Manila

Typhoon Vamco made landfall on Luzon northeast of Manila on Wednesday. At 4:00 p.m. EST on Wednesday the center of Typhoon Vamco was located at latitude 15.0°N and longitude 120.6°E which put it about 35 miles (55 km) northeast of Manila, Philippines. Vamco was moving toward the west at 17 m.p.h. (28 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. (210 km/h). The minimum surface pressure was 956 mb.

Typhoon Vamco was strengthening when it made landfall on Luzon. Vamco was nearly the equivalent of a major hurricane at the time of landfall. The circulation around Typhoon Vamco also increased in size prior to landfall. Winds to typhoon force extended out 100 miles (160 km) on the northern side of Vamco. Winds to force extended out 40 miles (65 km) on the southern side of the typhoon. Winds to tropical storm force extended out 350 miles in the northern half of the circulation. Winds to tropical storm force extended out 150 miles in the southern half of Vamco. The Hurricane Intensity Index (HII) for Typhoon Vamco was 19.2. The Hurricane Size Index (HSI) was 28.4 and the Hurricane Wind intensity Size Index (HWISI) was 47.6. Typhoon Vamco was capable of causing widespread serious damage to Luzon.

The center of Typhoon Vamco passed over the Polillo Islands before it reached Luzon. The center of Vamco will pass just north Manila, but it will be close enough to cause strong winds. The center will pass near San Fernando and Olongapo before it moves over the South China Sea. Typhoon Vamco will drop very heavy rain over Luzon and significant floods could occur. There will also be widespread power outages.

Typhoon Vamco will weaken as it passes over Luzon, but Vamco could still be a typhoon when it reaches the South China Sea. A high pressure system over eastern Asia will steer Typhoon Vamco toward the west. On its anticipated track Vamco could approach Vietnam in two or three days.

Vamco Rapidly Intensifies to Typhoon East of Luzon

Former Tropical Storm Vamco rapidly intensified into a typhoon east of Luzon on Tuesday. At 10:00 p.m. EST on Tuesday the center of Typhoon Vamco was located at latitude 14.9°N and longitude 124.0°E which put it about 230 miles (375 km) east of Manila, Philippines. Vamco was moving toward the west at 16 m.p.h. (26 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. (165 km/h). The minimum surface pressure was 973 mb.

Typhoon Vamco intensified rapidly on Tuesday. A circular eye was visible on satellite images. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Vamco. Storms near the center were generating upper level divergence which was pumping mass away from the typhoon. Winds to typhoon force extended out 30 miles (50 km) from the center of Vamco. Winds to tropical storm force extended out 175 miles (280 km) from the center of circulation.

Typhoon Vamco will move through an environment that will be favorable for intensification during the next 12 hours. Vamco will move over water where the Sea Surface Temperature is near 28°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Vamco will continue to intensify rapidly and it could strengthen to the equivalent of a major hurricane.

Typhoon Vamco will move south of a high pressure system over the Western North Pacific Ocean. The high will steer Vamco toward the west during the next several days. On its anticipated track Typhoon Vamco will make landfall on the east coast of Luzon in about 12 hours. The center of Vamco will pass north of Manila and the core of Typhoon Vamco could come close to San Francisco.

Typhoon Vamco will bring strong winds and heavy rain to Luzon. Vamco will be capable of causing major damage. The heavy rain will cause flash floods in part of Luzon. Typhoon Vamco could cause a storm surge of up to 10 feet (3 meters) on the east coast of Luzon. Vamco will weaken when the center passes over Luzon, but it is likely to still be a typhoon when it passes north of Manila. Typhoon Vamco is also likely to cause widespread power outages on Luzon.

Elsewhere over the Western North Pacific Ocean, Tropical Depression Etau was dropping heavy rain over Cambodia. At 10:00 p.m. EST on Tuesday the center of Tropical Depression Etau was located at latitude 12.5°N and longitude 105.5°E which put it about 100 miles (160 km) northeast of Phnom Penh, Cambodia. Etau was moving toward the west at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 25 m.p.h. (40 km/h) and there were wind gusts to 30 m.p.h. (50 km/h). The minimum surface pressure was 1006 mb.

Tropical Storm Etau Nears Vietnam, Vamco Threatens Philippines

Tropical Storm Etau neared Vietnam on Monday and newly formed Tropical Storm Vamco threatened the Philippines. At 4:00 a.m. EST on Monday the center of Tropical Storm Etau was located at latitude 12.8°N and longitude 111.6°E which put it about 170 miles (280 km) east of Tuy Hoa, Vietnam. Etau was moving toward the west at 15 m.p.h. (24 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 995 mb.

The distribution of thunderstorms around Tropical Storm Etau was asymmetrical. Etau was moving under the southern part of an upper level ridge over eastern Asia. The ridge was producing easterly winds which were blowing toward the top of Etau. Those winds were causing moderate vertical wind shear. The shear was causing the stronger thunderstorms to occur in bands on the western side of Tropical Storm Etau. The bands in the eastern side of Etau consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 150 miles (240 km) in the northern half of Tropical Storm Etau. Winds to tropical storm force only extended out 50 miles in the southern half of Etau.

Tropical Storm Etau will move south of a high pressure system over eastern Asia. The high will steer Etau toward the west during the next two days. On its anticipated track the center of Etau will make landfall in Vietnam near Tuy Hoa in about 12 hours.

Tropical Storm Etau will move through an environment that should allow it to maintain its intensity until it makes landfall in Vietnam. Etau will move over water where the Sea Surface Temperature is near 28°C. The upper level ridge over eastern Asia will continue to cause moderate vertical wind shear which will limit intensification.

Since the stronger thunderstorms are in the western half of Tropical Storm Etau, heavy rain will fall over central Vietnam before the center of Etau makes landfall. Etau will drop locally heavy rain over central Vietnam, northern Cambodia, southern Laos and northeastern Thailand. The ground is already saturated in that region and flash floods are likely.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Vamco developed east of the Philippines. At 4:00 a.m. EST on Monday the center of Tropical Storm Vamco was located at latitude 12.8°N and longitude 130.6°E which put it about 370 miles (605 km) east of Laoang, Philippines. Vamco was moving toward the northwest at 13 m.p.h. (20 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. Tropical Storm Vamco is forecast to move toward Luzon and to strengthen into a typhoon.