Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Hinnamnor Rapidly Intensifies to a Typhoon Near Chichi Jima

Former Tropical Storm Hinnamnor rapidly intensified to a typhoon near Chichi Jima on Monday morning. At 5:00 a.m. EDT on Monday the center of Typhoon Hinnamnor was located at latitude 27.4°N and longitude 142.2°E which put it about 30 miles (50 km) north of Chichi Jima. Hinnamnor was moving toward the west at 22 m.p.h. (35 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 967 mb.

Former Tropical Storm Hinnamnor rapidly intensified to a typhoon in a favorable environment over the Western North Pacific Ocean near Chichi Jima. A small circular eye formed at the center of Hinnamnor’s circulation. 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 Hinnamnor. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The circulation around Typhoon Hinnamnor was small. Winds to typhoon force extended out 25 miles (40 km) from the center of Hinnamnor. Winds to tropical storm force extended out 85 miles (135 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Hinnamnor was 12.7. The Hurricane Size Index (HSI) was 7.8 and the Hurricane Wind Intensity Size Index (HWISI) was 20.5.

Typhoon Hinnamnor will move through an area favorable for intensification during the next 24 hours. Hinnamnor will move over water where the Sea Surface Temperatures are 30˚C. It will move through region where the winds at all levels of the troposphere are blowing from the east. Since the winds at different levels are blowing from the same direction, there will be little vertical wind shear. Typhoon Hinnamnor is likely to continue to intensify rapidly during the next 24 hours. Hinnamnor could strengthen to the equivalent of a major hurricane.

Typhoon Hinnamnor will move around the southwestern part of a high pressure system that extends over Japan. The high pressure system will steer Hinnamnor toward the west during the 48 hours. On its anticipated track Typhoon Hinnamnor could approach the Ryukyu Islands in 48 hours. Hinnamnor will continue to produce strong gusty winds and locally heavy rain on Chichi Jima during the next few hours until it moves farther away. Typhoon Hinnamnor could be the equivalent of a major hurricane when it approaches the Ryukyu Islands.

Tropical Storm Hinnamnor Forms East of Iwo To

Tropical Storm Hinnamnor formed east of Iwo To on Sunday morning. At 5:00 a.m. EDT on Sunday the center of Tropical Storm Hinnamnor was located at latitude 26.2°N and longitude 148.8°E which put it about 510 miles (825 km) east-northeast of Iwo To. Hinnamnor was moving toward the north-northwest at 14 m.p.h. (22 km/h). The maximum sustained wind speed was 40 m.p.h. (64 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 997 mb.

The circulation around a low pressure system east of Iwo To strengthened on Sunday morning and the Japan Meteorological Agency designated the system as Tropical Storm Hinnamnor. The circulation around Hinnamnor was still organizing. The inner end of a rainband wrapped around the western and southern sides of the center of circulation. Other bands of showers and thunderstorms were revolving around the center of Tropical Storm Hinnamnor. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 140 miles (225 km) on the eastern side of Hinnamnor’s circulation. Winds to tropical storm force extended out 75 miles (120 km) on the western side of the circulation.

Tropical Storm Hinnamnor will move through an area favorable for intensification during the next 24 hours. Hinnamnor will move over water where the Sea Surface Temperatures are 30˚C. It will move through region between an upper level trough over Japan, a small upper level low northwest of the Marianas, and a larger upper level low east of the Marianas. The upper level winds are weak in the region between the upper level trough, and the two upper level lows. Tropical Storm Hinnamnor will be in a region where there is little vertical wind shear during the next 24 hours and it is likely to intensify.

Tropical Storm Hinnamnor will move around the southwestern part of a high pressure system that extends over Japan. The high pressure system will steer Hinnamnor toward the west during the several days. On its anticipated track the center of Tropical Storm Hinnamnor could be north of Iwo To in 36 hours.

Tropical Storm Ma-on Makes Landfall in Southeast China

Tropical Storm Ma-on made landfall in southeast China on Thursday morning. At 5:00 a.m. EDT on Thursday the center of Tropical Storm Ma-on was located at latitude 22.0°N and longitude 109.2°E which put it about 80 miles (130 km) east of Qinzhou. Ma-on was moving toward the west-northwest at 20 m.p.h. (32 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.

Tropical Storm Ma-on made landfall on the coast of southeastern China between Dianbai and Zhanjiang on Thursday morning. The center of Ma-on made landfall near Wuchuan. Ma-on was a strong tropical storm at the time of landfall. The maximum sustained wind speed was 65 m.p.h. (105 km/h). The distribution of thunderstorms and heavy rain in Tropical Storm Ma-on was asymmetrical. Many of the thunderstorms with heavy rain were occurring in the southern half of Ma-on’s circulation. The strongest winds were occurring over the South China Sea. Winds to tropical storm force extended out 130 miles (210 km) from the center of Tropical Storm Ma-on.

Tropical Storm Ma-on will move around the southwestern part of a high pressure system over the Western North Pacific during the next 36 hours. The high pressure system will steer Ma-on toward the west-northwest. On its anticipated track Tropical Storm Ma-on will move inland over southeastern China and northern Vietnam. Ma-on will drop locally heavy rain over parts of southeastern China and northern Vietnam. Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Tokage was weakening as it sped away from Japan. At 5:00 a.m. EDT on Thursday the center of Tropical Storm Tokage was located at latitude 41.3°N and longitude 153.9°E which put it about 610 miles (985 km) east of Misawa, Japan. Tokage was moving toward the northeast at 25 m.p.h. (40 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 987 mb.

Tropical Storm Ma-on Moves over South China Sea

Tropical Storm Ma-on moved over the South China Sea southeast of Hong Kong on Wednesday morning. At 5:00 a.m. EDT on Wednesday the center of Tropical Storm Ma-on was located at latitude 20.0°N and longitude 116.1°E which put it about 245 miles (395 km) southeast of Hong Kong. Ma-on was moving toward the west-northwest at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 984 mb.

Tropical Storm Ma-on maintained its intensity as it moved over the South China Sea southeast of Hong Kong on Wednesday morning. The inner end of a rainband wrapped around the southern and eastern sides of the center of Ma-on’s circulation. However, the distribution of thunderstorms in the rest of Tropical Storm Ma-on was asymmetrical. The strongest thunderstorms were occurring in bands in the southern and western parts of Ma-on. Bands in the eastern and northern parts of the circulation consisted primarily of showers and lower clouds. An upper level ridge over China was producing east-northeasterly winds that were blowing toward the top of Tropical Storm Ma-on. Those winds were causing moderate vertical wind shear and the wind shear was causing the asymmetrical distribution of thunderstorms.

Tropical Storm Ma-on will move through an environment somewhat favorable for intensification during the next 24 hours. Ma-on will move over water where the Sea Surface Temperatures are 29˚C. The upper level ridge over China will continue to cause vertical wind shear. If the vertical wind shear does not increase, then Tropical Storm Ma-on could strengthen during the next 24 hours. There is a chance Ma-on could strengthen to a typhoon.

Tropical Storm Ma-on will move around the southwestern part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Ma-on toward the west-northwest during the next 36 hours. On its anticipated track Tropical Storm Ma-on could be south of Hong Kong in 12 hours. The center of Ma-on could make landfall on the south coast of China near Yangjiang and Dianbai in 24 hours. Tropical Storm Ma-on will bring gusty winds and locally heavy rain to southern China. Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Typhoon Tokage was passing east of Japan. At 5:00 a.m. EDT on Wednesday the center of Typhoon Tokage was located at latitude 35.8°N and longitude 149.4°E which put it about 475 miles (770 km) east of Tokyo, Japan. Tokage was moving toward the north-northeast at 13 m.p.h. (20 km/h). The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (200 km/h). The minimum surface pressure was 961 mb.

Tropical Storm Ma-on Brings Wind and Rain to Northern Luzon

Tropical Storm Ma-on brought wind and rain to northern Luzon on Tuesday morning. At 5:00 a.m. EDT on Tuesday the center of Tropical Storm Ma-on was located at latitude 18.0°N and longitude 121.2°E which put it about 50 miles (80 km) southeast of Claveria, Philippines. Ma-on was moving toward the northwest at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 985 mb.

Tropical Storm Ma-on brought gusty winds and locally heavy rain to parts of northern Luzon on Tuesday morning. The center of Ma-on made landfall on the northeastern coast of Luzon east of Tuguegarao during Monday night. Tropical Storm Ma-on moved northwest across northern Luzon. Ma-on intensified before it made landfall and it was almost a typhoon at the time of landfall. Winds to tropical storm force extended out 120 miles (195 km) from the center of Ma-on’s circulation.

Tropical Storm Ma-on will move through an environment favorable for intensification when it moves over the South China Sea. Ma-on will move over water where the Sea Surface Temperatures are 29˚C. It will move under the southern part of an upper level ridge over China. The ridge will produce easterly winds that will blow toward the top of Ma-on’s circulation. Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification. Tropical Storm Ma-on is likely to strengthen to a typhoon during the next 36 hours.

Tropical Storm Ma-on will move around the southwestern part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Ma-on toward the west-northwest during the next 36 hours. On its anticipated track Tropical Storm Ma-on will move away from northern Luzon later on Tuesday. Ma-on will continue to bring gusty winds and locally heavy rain to northern Luzon until it moves farther away. Heavy rain could cause flash floods in some locations. Ma-on could be south of Hong Kong in 36 hours.

Elsewhere over the Western North Pacific Ocean, former Tropical Storm Tokage intensified to a typhoon southeast of Japan. At 5:00 a.m. EDT on Tuesday the center of Typhoon Tokage was located at latitude 30.8°N and longitude 149.6°E which put it about 670 miles (1080 km) southeast of Tokyo, Japan. Tokage was moving toward the north-northwest at 19 m.p.h. (30 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.

Tropical Storm Ma-on Develops near Northern Luzon

Tropical Storm Ma-on developed near northern Luzon on Sunday night. At 5:00 a.m. EDT on Monday the center of Tropical Storm Ma-on was located at latitude 16.3°N and longitude 123.4°E which put it about 100 miles (160 km) southeast of Tuguegarao, Philippines. Ma-on was moving toward the west at 11 m.p.h. (17 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.

Former Tropical Depression 10W strengthened to Tropical Storm Ma-on just to the east of northern Luzon on Sunday night. The distribution of thunderstorms in Ma-on continued to be asymmetrical. Most of the thunderstorms were in bands in the southern half of Ma-on’s circulation. The bands in the northern half of the circulation consisted primarily of showers and lower clouds. A strong upper level ridge over China was producing strong northerly winds that were blowing toward the top of Tropical Storm Ma-on. Those winds were causing moderate vertical wind shear and the wind shear was causing the asymmetrical distribution of thunderstorms.

Tropical Storm Ma-on will move through an environment favorable for intensification during the next 12 hours. Ma-on will move over water where the Sea Surface Temperatures are 30˚C. The upper level ridge over China will continue to produce northerly winds that will blow toward the top of Ma-on’s circulation. However, Tropical Storm Ma-on could strengthen during the next 12 hours. Ma-on will weaken when the center passes over northern Luzon, but it could strengthen again over the South China Sea later this week.

Tropical Storm Ma-on will move around the southwestern part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Ma-on toward the west-northwest during the next 24 hours. On its anticipated track Tropical Storm Ma-on will hit northern Luzon in 12 hours. Ma-on will bring gusty winds and locally heavy rain to northern Luzon. Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Tokage formed southeast of Japan. At 5:00 a.m. EDT on Monday the center of Tropical Storm Tokage was located at latitude 25.5°N and longitude 151.6°E which put it about 1010 miles (1635 km) southeast of Tokyo, Japan. Tokage was moving toward the north at 11 m.p.h. (17 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 998 mb.

Tropical Depression Forms East of Luzon

A tropical depression formed over the Western North Pacific Ocean east of Luzon on Sunday morning. At 5:00 a.m. EDT on Sunday the center of the tropical depression was located at latitude 17.4°N and longitude 127.3°E which put it about 350 miles (565 km) east of Luzon. The tropical depression was moving toward the west 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 1000 mb.

A distinct low level center of circulation formed in an area of lower pressure east of Luzon on Sunday morning and the Japan Meteorological Agency classified the system as a tropical depression. The distribution of thunderstorms in the tropical depression was asymmetrical. Most of the thunderstorms were in bands in the western half of the tropical depression. The bands in the eastern half of the circulation consisted primarily of showers and lower clouds. A strong upper level ridge over China was producing strong northeasterly winds that were blowing toward the top of the tropical depression. Those winds were causing moderate vertical wind shear and the wind shear was causing the asymmetrical distribution of thunderstorms.

The tropical depression will move through an environment favorable for intensification during the next 24 hours. The tropical depression will move over water where the Sea Surface Temperatures are 30˚C. The upper level ridge over China will continue to produce northeasterly winds that will blow toward the top of the tropical depression. However, the upper level winds are forecast to weaken. The vertical wind shear could decrease during the next 24 hours. The tropical depression is forecast to strengthen to a tropical storm.

The tropical depression will move around the southwestern part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer the tropical depression toward the west during the next 24 hours. On its anticipated track the tropical depression could approach northeastern Luzon in 24 hours. It is likely to be a tropical storm when it approaches Luzon. The weather system will bring gusty winds and locally heavy rain to northern Luzon. Heavy rain could cause flash floods in some locations.

Tropical Storm Meari Brings Rain to Tokyo

Tropical Storm Meari brought rain to Tokyo on Saturday morning. At 5:00 a.m. EDT on Saturday the center of Tropical Storm Meari was located at latitude 35.4°N and longitude 139.2°E which put it about 90 miles (145 km) southwest of Tokyo, Japan. Meari was moving toward the northeast at 15 m.p.h. (24 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 998 mb.

Tropical Storm Meari brought rain to the region around Tokyo on Saturday morning. The heaviest rain was falling in bands in the eastern and southern parts of Meari’s circulation. Much of the heavier rain was falling south and east of Tokyo. Bands in the northern and western parts of the circulation consisted primarily of showers and lower clouds. The strongest winds were occurring along the coast of Honshu southeast of Tokyo.

Tropical Storm Meari was moving under the southern part of an upper level trough centered northwest of Japan. The upper level trough was producing southwesterly winds that were steering Meari toward the northeast. On its anticipated track Tropical Storm Meari will move east of Japan during the next 24 hours. The rain over Honshu will diminish when Meari moves away from the coast.

Tropical Storm Meari will move through an environment unfavorable for a tropical cyclone during the next several days. Meari will move over water where the Sea Surface Temperatures are colder than 26˚C. The upper level trough will continue to produce southwesterly winds that will blow toward the top of Meari’s circulation. Those winds will cause moderate vertical wind shear. The combination of colder Sea Surface Temperatures and moderate vertical wind shear could cause Tropical Storm Meari to make a transition to an extratropical cyclone during the next 48 hours. Meari could strengthen a little during the transition to an extatropical cyclone.

Tropical Storm Meari Forms South of Japan

Tropical Storm Meari formed over the Western North Pacific Ocean south of Japan on Thursday afternoon. At 5:00 p.m. EDT on Thursday the center of Tropical Storm Meari was located at latitude 29.2°N and longitude 136.0°E which put it about 500 miles (805 km) south-southwest of Tokyo, Japan. Meari was moving toward the north 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 1003 mb.

The circulation around an area of low pressure over the Western North Pacific Ocean south of Japan strengthened on Thursday afternoon and the Japan Meteorological Agency designated the system as Tropical Storm Meari. The distribution of thunderstorms around Tropical Storm Meari was asymmetrical. Thunderstorms were occurring in bands in the southern half of Meari’s circulation. Bands in the northern half of the circulation consisted primarily of showers and lower clouds. Tropical Storm Meari was under the southern part of a narrow upper level ridge south of Japan that extended from east to west. The upper level ridge was producing northerly winds that were blowing toward the top of Meari. The winds were causing vertical wind shear and they were the reason for the asymmetrical distribution of thunderstorms. Winds to tropical storm force extended out 90 miles (145 km) in the southeastern quadrant of Tropical Storm Meari. The wind in the other parts of Meari’s circulation was blowing at less than tropical storm force.

Tropical Storm Meari will move through an environment somewhat favorable for intensification during the next 36 hours. Meari will move over water where the Sea Surface Temperatures are near 28˚C. The narrow upper level ridge south of Japan will continue to cause moderate vertical wind shear during the next 12 hours. The wind shear will inhibit intensification during the next few hours. Tropical Storm Meari will move under the axis of the upper level ridge on Friday. The upper level winds are weak near the axis of the ridge and the vertical wind shear will decrease on Friday. Tropical Storm Meari will be in an environment favorable for intensification while it is under the axis of the ridge.

Tropical Storm Meari will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean. The high pressure system will steer Meari toward the north during the next 18 hours. Meari will move toward the northeast later on Friday after it moves around the western end of the high pressure system. On its anticipated track Tropical Storm Meari will approach the coast of Honshu near Tokyo in 36 hours. Meari could be a strong tropical storm when it nears Tokyo. Tropical Storm Meari will bring gusty winds and locally heavy rain to the region around Tokyo on Saturday.

Tropical Storm Mulan Brings Rain to Southern China

Tropical Storm Mulan brought rain to southern China on Wednesday. At 11:00 a.m. EDT on Wednesday the center of Tropical Storm Mulan was located at latitude 20.9°N and longitude 108.9°E which put it about 40 miles (60 km) southwest of Beihai, China. Mulan was moving toward the west-northwest at 16 m.p.h. (26 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 998 mb.

Rainbands on the northern side of Tropical Storm Mulan brought rain to parts of southern China on Wednesday. Rain fell over coastal parts of southern China from Hong Kong to the border with Vietnam. Tropical Storm Mulan also dropped locally heavy rain on Hainan Island. Rainbands in the northwestern part of Mulan’s circulation brought rain to northeastern Vietnam.

Tropical Storm Mulan will move across the Gulf of Tonkin during the next 12 hours toward northern Vietnam. Mulan will move south of a high pressure system over the Western North Pacific Ocean and eastern China. The high pressure system will steer Mulan toward the west-northwest during the next day or so. On its anticipated track the center of Tropical Storm Mulan will make landfall on the coast of northeastern Vietnam in about 12 hours.

Tropical Storm Mulan will move through an environment marginally favorable for intensification during the next few hours. Mulan will move over water where the Sea Surface Temperatures are near 30˚C. It will move under the southern part of an upper level ridge centered over eastern Asia. The upper level ridge will produce easterly winds that will blow toward the top of Mulan’s circulation. Those winds will cause some vertical wind shear and the shear will inhibit intensification. Tropical Storm Mulan is likely to maintain its current intensity during the next 12 hours, but it could strengthen a little prior to landfall in northeastern Vietnam.