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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 Storm Nepartak Strengthens East of Tokyo

Tropical Storm Nepartak strengthened east of Tokyo on Monday night. At 11:00 p.m. EDT on Monday the center of Tropical Storm Nepartak was located at latitude 35.4°N and longitude 142.3°E which put it about 160 miles (260 km) east of Tokyo, Japan. Nepartak was moving toward the north-northwest at 5 m.p.h. (8 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 992 mb.

Tropical Storm Nepartak exhibited a structure a little more like a tropical cyclone on Monday night. Nepartak was embedded in the center of an upper level low. The center of Tropical Storm Nepartak was under the center of the upper level low and the circulation assumed a more circular shape. Bands of showers and thunderstorms were revolving around the center of Nepartak. Winds to tropical storm force extended out 160 miles (260 km) in the eastern side of the circulation. Winds to tropical storm force extended out 100 miles (160 km) in the western side of Nepartak.

Tropical Storm Nepartak will move through an environment capable of supporting a tropical storm during the next 18 hours. Nepartak will move over water where the Sea Surface Temperatures are near 26°C. Since Tropical Storm Nepartak is embedded at the center of an upper level low, the winds are blowing from the same direction at all levels in the troposphere. So, there will be little vertical wind shear. Tropical Storm Nepartak will likely maintain its intensity during the next 18 hours and it could strengthen a little more.

The upper level low and Tropical Storm Nepartak are forecast to drift toward the northwest during the next 24 hours. On its anticipated track the center of Nepartak could make landfall on the northern coast of Honshu near Sendai in about 18 hours. Tropical Storm Nepartak will bring gusty winds and locally heavy rain to parts of northern Honshu. Nepartak already generated waves along the coast of Honshu and some Olympic events at coastal sites were postponed.

Elsewhere, Tropical Storm In-Fa continued to drop heavy rain over parts of eastern China. At 11:00 p.m. EDT on Monday the center of Tropical Storm In-Fa was located at latitude 31.2°N and longitude 119.5°E which put it about 100 miles (160 km) west of Shanghai, China. In-Fa was moving toward the west-northwest at 4 m.p.h. (6 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 982 mb.

Tropical Storm In-Fa Makes Landfall near Shanghai

Tropical Storm In-Fa made landfall on the east coast of China near Shanghai on Sunday. At 5:00 p.m. EDT on Sunday the center of Tropical Storm In-Fa was located at latitude 30.6°N and longitude 121.4°E which put it about 50 miles (80 km) south of Shanghai, China. In-Fa was moving toward the northwest at 6 m.p.h. (10 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 987 mb.

Tropical Storm In-Fa weakened slowly as it approached the east coast of China. The circulation around In-Fa pulled drier air from Asia into the western side of the former typhoon. The drier air caused thunderstorms in the western half of Tropical Storm In-Fa to weaken. The strongest thunderstorms were occurring in bands on the eastern side of In-Fa. Bands in the western half of the tropical storm consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 165 miles (270 km) on the eastern side of In-Fa. The strongest winds were occurring over the waters of the East China Sea. Winds to tropical storm force extended out 80 miles on the western side of the circulation.

Tropical Storm In-Fa will move slowly toward the northwest, which will take it farther inland over eastern China. The circulation around In-Fa will weaken gradually as the tropical storm moves farther inland. Tropical Storm In-Fa will bring gusty winds and locally heavy rain to the region around Shanghai and Ningbo. Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Nepartak swirled southwest of Japan. At 5:00 p.m. EDT on Sunday the center of Tropical Storm Nepartak was located at latitude 33.4°N and longitude 149.7°E which put it about 630 miles (1015 km) east-southeast of Tokyo, Japan. Nepartak was moving toward the north 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 998 mb.

Typhoon Haishen Drops Heavy Rain over South Korea

Typhoon Haishen dropped heavy rain over South Korea on Sunday night. Haishen weakened to a tropical storm after it made landfall on South Korea.   At 11:00 p.m. EDT on Sunday the center of Tropical Storm Haishen was located at latitude 36.6°N and longitude 128.8°E which put it about 30 miles north-northwest of Busan, South Korea.  Haishen was moving toward the north at 27 m.p.h. (43 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 969 mb.

The center of Typhoon Haishen passed just to the west of Kyushu earlier on Sunday.  A weather station at Makurazaki, Japan reported a wind speed of 65 m.p.h. (105 km/h) and a pressure of 966.6 mb.

Typhoon Haishen began dropping heavy rain over parts of South Korea hours before the center made landfall west of Busan.  Heavy rain was falling on some of the same places that also received heavy rain from Typhoon Maysak a few days ago.  The additional rain will cause flash floods in some locations.  Tropical Storm Haishen will continue to weak as it moves rapidly toward the north.

Typhoon Haishen Brings Wind and Rain to Northern Ryukyu Islands

Typhoon Haishen brought wind and rain to the northern Ryukyu Islands on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Haishen was located at latitude 28.3°N and longitude 130.4°E which put it about 170 miles (280 km) east-northeast of Okinawa.  Haishen was moving toward the north-northwest at 15 m.p.h. (24 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 945 mb.

The center of Typhoon Haishen passed west of Minami-Daito Jima on Saturday.  A weather station there measured a wind speed of 72 m.p.h. (116 km/h) and a pressure of 943.6 mb.

The circulation around around Typhoon Haishen developed concentric eyewalls on Saturday.  The smaller original eyewall started to weaken as low level convergence became more concentrated into the much larger outer eyewall.  The strongest winds were originally found in the inner eyewall, but those wind speeds decreased.  The stronger winds were blowing in the larger outer eyewall on Saturday night.

The concentric eyewall structure produced an increase in the size of the circulation around Typhoon Haishen.  Winds to typhoon force extended out 100 miles (160 km) from the center of circulation.  Winds to tropical storm force extended out 325 miles (530 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Haishen was 19.2.  The Hurricane Size Index (HSI) was 37.2 and the Hurricane Wind Intensity Size Index (HWISI) was 56.4.  Typhoon Haishen was capable of causing widespread serious damage.

Typhoon Haishen will move into a less favorable environment during the next 24 hours.  Haishen will move over water where the Sea Surface Temperature is near 28°C.  Drier air over Asia will get pulled into the circulation.  Wind shear will increase when Typhoon Haishen moves farther north because it will get closer to the upper level westerly winds in the middle latitudes.  The effects of the concentric eyewalls, drier air and more wind shear will cause Typhoon Haishen to gradually weaken.

Typhoon Haishen will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Haishen toward the north.  On its anticipated track the center of Typhoon Haishen will pass near the western part of Kyushu in about 12 hours.  Haishen will reach South Korea in about 24 hours.  Typhoon Haishen will bring strong winds and heavy rain to parts of Kyushu and South Korea.  Heavy rain could cause flash floods, especially in places that received heavy rain from Typhoon Maysak a few days ago.

Typhoon Haishen Intensifies to Equivalent of Major Hurricane

Typhoon Haishen intensified to the equivalent of a major hurricane over the Western North Pacific Ocean on Thursday.  At 5:00 p.m. EDT on Thursday the center of Typhoon Haishen was located at latitude 21.4°N and longitude 135.4°E which put it about 405 miles (650 km) southeast of Minamidaitojima, Japan.  Haishen was moving toward the west-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 938 mb.

Typhoon Haishen intensified rapidly on Thursday.  A circular eye became more visible on conventional 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 Haishen.  Storms near the core generated strong upper level divergence which pumped mass away from the typhoon.

The circulation around Typhoon Haishen increased in size on Thursday.  Winds to typhoon force extended out 65 miles (105 km) from the center of circulation.  Winds to tropical storm force extended out 215 miles (315 km) from the center.  The Hurricane Intensity Index (HII) was 29.9.  The Hurricane Size Index (HSI) was 23.5 and the Hurricane Wind Intensity Size Index (HWISI) was 53.4.  Typhoon Haishen was capable of causing widespread significant damage.

Typhoon Haishen will move through an environment favorable for intensification during the next 24 hours.  Haishen will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Haishen could strengthen to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.

Typhoon Haishen will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Typhoon Haishen toward the northwest during the next 36 hours.  Haishen will move more toward the north when it reaches the western end of the high pressure system.  On its anticipated track Typhoon Haishen could reach Minamidaitojima in about 36 hours.  Haishen could approach the northern Ryukyu Islands in about 48 hours.  Typhoon Haishen could hit South Korea in a little over three days.

Typhoon Maysak Brings Wind and Rain to South Korea

Typhoon Maysak brought wind and rain to South Korea on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Typhoon Maysak was located at latitude 36.9°N and longitude 128.9°E which put it about 30 miles (50 km) north-northwest of Busan, South Korea.  Maysak was moving toward the north-northeast at 30 m.p.h. (50 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 950 mb.

The center of Typhoon Maysak made landfall on the south coast of South Korea west of Busan on Wednesday.  The large circulation around Maysak brought gusty winds and heavy rain to much of the Korean Peninsula.  Winds to typhoon force extended out 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out 200 miles (320 km) from the center.  The heavy rain was falling on ground that was saturated by previous tropical cyclones and other weather systems.  The rain will likely cause widespread flash flooding.

Typhoon Maysak was being steered quickly toward the north by an upper level trough over eastern Asia.  On its anticipated track the center of Maysak will move along the east coast of the Korean Peninsula.  Typhoon Maysak will weaken and it will made a transition to an extratropical cyclone during the next 24 hours.

Elsewhere over the Western North Pacific Ocean, Typhoon Haishen strengthened south of Iwo To.  At 5:00 p.m. EDT on Wednesday the center of Typhoon Haishen was located at latitude 20.3°N and longitude 138.8°E which put it about 350 miles (560 km) south-southwest of Iwo To.  Haishen was moving toward the west-northwest at 13 m.p.h. (20 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 979 mb.

Typhoon Haishen will move through an environment favorable for intensification during the next 36 to 48 hours.  Haishen will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Haishen will continue to intensify and it is likely to strengthen into the equivalent of a major hurricane.

Typhoon Haishen will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Haishen toward the northwest during the next several days.  On its anticipated track Typhoon Haishen could approach the northern Ryukyu Islands in about 72 hours.  Haishen could eventually bring wind and rain to the same areas in Kyushu and South Korea affected by Typhoon Maysak.

Large Typhoon Maysak Churns Toward South Korea

Large, powerful Typhoon Maysak churned toward South Korea on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Typhoon Maysak was located at latitude 30.1°N and longitude 126.9°E which put it about 405 miles (655 km) south-southwest of Busan, South Korea.  Maysak was moving toward the north-northeast at 13 m.p.h. (20 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 932 mb.

Typhoon Maysak neared the completion of an eyewall replacement cycle on Tuesday which resulted in an increase in the size of the circulation.  The original inner eyewall had not quite dissipated, but low level convergence was focused on the much larger outer eyewall.  Winds to typhoon force extended out 90 miles (145 km) from the center of circulation.  Winds to tropical storm force extended out 240 miles (390 km) from the center of Maysak.

Typhoon Maysak was a large, dangerous tropical cyclone.  The Hurricane Intensity Index (HII) was 25.1.  The Hurricane Size Index (HSI) was 27.5 and the Hurricane Wind Intensity Size Index (HWISI) was 52.6.  Typhoon Maysak was capable of causing widespread major damage.

Since Typhoon Maysak was near the end of an eyewall replacement cycle, it will likely weaken slowly during the next 18 hours.  Maysak will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough over eastern Asia will approach Typhoon Maysak on Wednesday.  The trough will produce southwesterly winds which will blow toward the top of the circulation.  Those winds will cause more vertical wind shear and the shear will cause Typhoon Maysak to weaken more quickly.

Typhoon Maysak will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Maysak toward the north during the next 24 hours.  On its anticipated track the core of Typhoon Maysak is likely to pass west of Kyushu.  Maysak could reach South Korea in about 18 hours.  Typhoon Maysak could be the equivalent of a large, major hurricane when it gets to South Korea.  Maysak will produce very strong winds over South Korea.  It will also drop heavy rain and flash floods could occur.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Haishen strengthened south of Iwo To.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Haishen was located at latitude 20.1°N and longitude 142.8°E which put it about 340 miles (545 km) south-southeast of Iwo To.  Haishen was moving toward the west-southwest at 8 m.p.h. (13 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 1000 mb.  Tropical Storm Haishen is forecast to strengthen into a typhoon and it could move toward western Japan later this week.