Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Tropical Storm Chaba Forms over South China Sea

Tropical Storm Chaba formed over the South China Sea south of Hong Kong on Wednesday night. At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Chaba was located at latitude 15.7°N and longitude 115.1°E which put it about 440 miles (710 km) south of Hong Kong, China. Chaba was moving toward the northeast at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1000 mb.

The circulation around a low pressure system over the South China Sea south of Hong Kong strengthened on Wednesday night and the Japan Meteorological Agency designated the system as Tropical Storm Chaba. The distribution of thunderstorms around Tropical Storm Chaba was asymmetrical. The strongest thunderstorms were occurring in bands in the western half of Chaba’s circulation. Bands in the eastern half of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 115 miles (185 km) from the center of circulation.

An upper level ridge over southern China was producing northeasterly winds that were blowing toward the top of Tropical Storm Chaba. Those winds were causing moderate vertical wind shear. The wind shear was contributing to the asymmetrical distribution of thunderstorms.

Tropical Storm Chaba will move through an environment somewhat favorable for intensification during the 36 hours. Chaba will move over water where the Sea Surface Temperatures are near 29˚C. However, the upper level ridge over southern China will continue to cause vertical wind shear. The wind shear will inhibit intensification, but the shear will not be strong enough to prevent some intensification of Chaba. Tropical Storm Chaba is likely to intensify gradually during the next 36 hours.

Tropical Storm Chaba will move around the western end of a high pressure system over the Western North Pacific Ocean during the next 36 hours. The high will steer Chaba toward the north-northwest. On its anticipated track Tropical Storm Chaba could approach Hainan Island and the coast of southern China in 36 hours.

Typhoon Malakas Brings Winds and Rain to Iwo To

Typhoon Malakas brought strong winds and heavy rain to Iwo To on Thursday. At 5:00 p.m. EDT on Thursday the center of Typhoon Malakas was located at latitude 25.6°N and longitude 140.4°E which put it about 100 miles (160 km) west of Two To. Malakas was moving toward the north-northeast at 24 m.p.h (39 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 964 mb.

Typhoon Malakas weakened as it approached Iwo To, but Malakas still brought strong winds and heavy rain to the island. An upper level trough near Japan was producing strong southwesterly winds that were blowing toward the top of Malakas’ circulation. Those winds were causing strong vertical wind shear and the shear was affecting the distribution of thunderstorms. The strongest thunderstorms were occurring in bands in the eastern half of Typhoon Malakas. Bands in the western half of the circulation consisted primarily of showers and lower clouds.

There continued to be a large circulation around Typhoon Malakas. Winds to typhoon force extended out 60 miles (95 km) from the center of Malakas. Winds to tropical storm force extended out 200 miles (320 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Malakas was 17.8. The Hurricane Size Index (HSI) was 21.1 and the Hurricane Wind Intensity Size Index (HWISI) was 38.9.

Typhoon Malakas will move through an environment unfavorable for intensification during the next 36 hours. Malakas will move over water where the Sea Surface Temperatures are near 23˚C. The upper level trough near Japan will continue to produce strong southwesterly winds that will blow toward the top of the typhoon’s circulation. Those winds will cause strong vertical wind shear. Typhoon Malakas will continue to weaken during the next 36 hours. The combination of colder water and strong vertical wind shear will cause Malakas to make a transition to a strong extratropical cyclone.

The upper level trough near Japan will steer Typhoon Malakas quickly toward the northeast during the next 36 hours. On its anticipated track Typhoon Malakas will cross the Ogasawara Islands during the next 24 hours. Malakas will bring strong winds and heavy rain the Ogasawara Islands. Heavy rain could cause flash floods in some locations. Weather conditions should improve on Iwo To on Friday when Malakas moves away from the island.

Typhoon Malakas Intensifies to Equivalent of Cat. 4 Hurricane

Typhoon Malakas intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Wednesday morning. At 11:00 a.m. EDT on Wednesday the center of Typhoon Malakas was located at latitude 19.3°N and longitude 137.5°E which put it about 475 miles (770 km) south-southwest of Two To. Malakas 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 939 mb.

Typhoon Malakas strengthened to the equivalent of a Cat. 4 hurricane on the Saffir-Simpson Scale over the Western North Pacific Ocean south-southwest of Iwo To on Wednesday morning. A circular eye with a diameter of 30 miles (50 km) was at the center of Malakas’ 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 to Typhoon Malakas. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The circulation around Typhoon Malakas was large. Winds to typhoon force extended out 65 miles (105 km) from the center of Malakas. Winds to tropical storm force extended out 260 miles (415 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Malakas was 25.1. The Hurricane Size Index (HSI) was 24.0 and the Hurricane Wind Intensity Size Index (HWISI) was 49.1.

Typhoon Malakas will move into an environment unfavorable for intensification during the next 12 hours. Malakas will move over water where the Sea Surface Temperatures are near 26˚C. An upper level trough west of Japan will move toward Malakas. When the upper level trough gets closer to Typhoon Malakas, it will produce southwesterly winds that will blow toward the top of the typhoon’s circulation. Those winds will cause the vertical wind shear to increase. When the shear increases, Typhoon Malakas will start to weaken.

The upper level trough west of Japan will steer Typhoon Malakas toward the north-northeast during the next 24 hours. On its anticipated track Malakas could approach Iwo To in 30 hours. Typhoon Malakas will bring strong winds and heavy rain to Iwo To and the Ogasawara Islands. Heavy rain could cause flash floods in some locations.

Typhoon Malakas Strengthens to Equivalent of a Major Hurricane

Typhoon Malakas strengthened to the equivalent of a major hurricane southwest of Iwo To on Tuesday night. At 11:00 p.m. EDT on Tuesday the center of Typhoon Malakas was located at latitude 17.7°N and longitude 136.6°E which put it about 605 miles (980 km) southwest of Two To. Malakas was moving toward the northeast at 9 m.p.h (15 km/h). The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h). The minimum surface pressure was 953 mb.

Typhoon Malakas strengthened quickly to the equivalent of a major hurricane over the Western North Pacific Ocean southwest of Iwo To on Tuesday night. A circular eye with a diameter of 25 miles (40 km) was at the center of Malakas’ 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 to Typhoon Malakas. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The size of the circulation around Typhoon Malakas increased on Tuesday. Winds to typhoon force extended out 75 miles (120 km) from the center of Malakas. Winds to tropical storm force extended out 240 miles (390 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Malakas was 22.1. The Hurricane Size Index (HSI) was 25.6 and the Hurricane Wind Intensity Size Index (HWISI) was 47.7.

Typhoon Malakas will move through an environment favorable for intensification during the next 12 hours. Malakas will move over water where the Sea Surface Temperatures are near 27˚C. It will move under the western part of an upper level ridge over the Western North Pacific Ocean. The ridge will produce southerly winds that will blow toward the top of Malakas’ circulation. The winds at lower levels in the atmosphere will also blow from the south and there will not be much vertical wind shear. Typhoon Malakas could continue to intensify during the next 12 hours. An upper level trough west of Japan will move toward Malakas on Wednesday. When the upper level trough gets closer to Malakas, it will produce southwesterly winds that will blow toward the top of the typhoon’s circulation. Those winds will cause the vertical wind shear to increase. When the shear increases later on Wednesday Typhoon Malakas could start to weaken.

The upper level trough west of Japan will start to steer Typhoon Malakas toward the northeast at a faster speed later on Wednesday. On its anticipated track Malakas could approach Iwo To in 36 hours. Typhoon Malakas will bring strong winds and locally heavy rain to Iwo To and the Ogasawara Islands.

Typhoon Malakas Intensifies Southwest of Iwo To

Typhoon Malakas intensified southwest of Iwo To on Tuesday morning. At 5:00 a.m. EDT on Tuesday the center of Typhoon Malakas was located at latitude 16.1°N and longitude 135.2°E which put it about 740 miles (1195 km) southwest of Two To. Malakas was moving toward the north at 5 m.p.h (8 km/h). The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h). The minimum surface pressure was 967 mb.

Typhoon Malakas intensified more quickly over the Western North Pacific Ocean southwest of Iwo To on Tuesday morning. A circular eye developed at the center of Malakas’ 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 Malakas. Storms near the core generated upper level divergence that pumped mass away from the typhoon. Winds to typhoon force extended out 45 miles (75 km) from the center of Malakas. Winds to tropical storm force extended out 190 miles (305 km) from the center of circulation.

Typhoon Malakas will move through an environment favorable for intensification during the next 24 hours. Malakas will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the western part of an upper level ridge over the Western North Pacific Ocean. The ridge will produce southerly winds that will blow toward the top of Malakas’ circulation. The winds at lower levels in the atmosphere will also blow from the south and there will not be much vertical wind shear. Typhoon Malakas will intensify during the next 24 hours. Malakas could undergo a period of rapid intensification since an inner core with an eye and an eyewall has developed. Typhoon Malakas could strengthen to a the equivalent of a major hurricane during the next 24 hours.

Typhoon Malakas will move around the western part of a high pressure system over the Western North Pacific Ocean during the next 24 hours. The high pressure system will steer Malakas toward the north during that time period. Typhoon Malakas will move toward the northeast after it moves around the western end of the high pressure system. On its anticipated track Malakas could approach Iwo To in 48 hours.

Elsewhere over the Western North Pacific Ocean, Tropical Depression Megi weakened just east of the Philippines. There were reports of mudslides and casualties caused by heavy rain dropped by Megi. At 5:00 a.m. EDT on Tuesday the center of Tropical Depression Megi was located at latitude 11.0°N and longitude 126.0°E which put it about 30 miles (50 km) east of Guiuan, Philippines. Megi was moving toward the east 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 1004 mb.

Malakas Intensifies to a Typhoon North of Yap

Former Tropical Storm Malakas intensified to a typhoon north of Yap on Monday. At 11:00 a.m. EDT on Monday the center of Typhoon Malakas was located at latitude 14.5°N and longitude 135.6°E which put it about 365 miles (585 km) north-northwest of Yap. Malakas was moving toward the north-northwest at 9 m.p.h (15 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 976 mb.

Former Tropical Storm Malakas intensified to a typhoon on Monday over the Western North Pacific Ocean. The inner end of a rainband wrapped around the western, southern and eastern sides of the center of Malakas. An eyewall appeared to be forming, but the rainband had not yet wrapped completely around the northern side of the center of circulation. Other bands of showers and thunderstorms were revolving around the core of Typhoon Malakas. Storms near the core generated upper level divergence that pumped mass away from the typhoon. Winds to typhoon force extended out 25 miles (40 km) from the center of Malakas. Winds to tropical storm force extended out 250 miles (400 km) from the center of circulation.

Typhoon Malakas will move through an environment favorable for intensification during the next 36 hours. Malakas will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the western part of an upper level ridge over the Western North Pacific Ocean. The ridge will produce southerly winds that will blow toward the top of Malakas’ circulation. Those winds will cause some vertical wind shear. The wind shear will inhibit intensification, but the shear will not be large enough to prevent strengthening. Typhoon Malakas will intensify during the next 36 hours. Malakas could intensify more rapidly after an inner core with an eye and an eyewall develops. Typhoon Malakas could strengthen to a the equivalent of a major hurricane.

Typhoon Malakas will move around the western part of a high pressure system over the Western North Pacific Ocean during the next several days. The high pressure system will steer Malakas toward the north during the next 36 hours. On its anticipated track Typhoon Malakas will remain west of the Marianas during the next several days. Malakas will move toward the northeast after it moves around the western end of the high pressure system. Typhoon Malakas could approach Iwo To in three days.

Elsewhere over the Western North Pacific Ocean, Tropical Depression Megi dropped heavy rain over the central Philippines. There were reports of mudslides and casualties caused by the heavy rain. At 11:00 a.m. EDT on Monday the center of Tropical Depression Megi was located at latitude 11.3°N and longitude 124.0°E which put it about 40 miles (65 km) south-southeast of Placer, Philippines. Megi was moving toward the northwest at 5 m.p.h (8 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 1004 mb.

Tropical Storm Malakas Passes Between Guam and Yap

Tropical Storm Malakas passed between Guam and Yap on Saturday night. At 11:00 p.m. EDT on Saturday the center of Tropical Storm Malakas was located at latitude 12.0°N and longitude 139.7°E which put it about 345 miles (555 km) west of Guam. Malakas was moving toward the northwest at 29 m.p.h (46 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 982 mb.

Tropical Storm Malakas brought gusty winds and heavy rain to Fais on Saturday night as it passed between Guam and Yap. The circulation around Malakas strengthened on Saturday. The heaviest rain was occurring in a band that was wrapping around the southern side of the center of Tropical Storm Malakas. Other bands of showers and thunderstorms were revolving around the center of Malakas. 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 130 miles (210 km) from the center of Malakas.

Tropical Storm Malakas will move through an environment mostly favorable for intensification during the next 36 hours. Malakas will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the southwestern part of an upper level ridge over the Western North Pacific Ocean. The ridge will produce southeasterly winds that will blow toward the top of Malakas’ circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification, but the shear will not be large enough to prevent strengthening. Tropical Storm Malakas will intensify during the next 36 hours. Malakas could strengthen to a typhoon during the next 24 hours.

Tropical Storm Malakas will move around the western part of a high pressure system over the Western North Pacific Ocean during the next several days. The high pressure system will steer Malakas toward the northwest during the next 24 hours. On its anticipated track Tropical Storm Malakas will remain west of the Marianas during the next several days. Malakas will move more toward the north when it reaches the western end of the high pressure system. Malakas could approach Iwo To in four days.

Elsewhere over the Western North Pacific Ocean, former Tropical Depression 03W strengthened to Tropical Storm Megi near the Philippines. At 11:00 p.m. EDT on Saturday the center of Tropical Storm Megi was located at latitude 11.3°N and longitude 125.9°E which put it about 25 miles (40 km) east of Guiuan, Philippines. Megi was moving toward the northwest 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 998 mb. Tropical Storm Megi could drop heavy rain over Samar and Leyte. Locally heavy rain could cause flash floods in some locations.

Tropical Storm Malakas Spins South-southwest of Guam

Tropical Storm Malakas spun south-southwest of Guam on Friday night. At 11:00 p.m. EDT on Friday the center of Tropical Storm Malakas was located at latitude 7.4°N and longitude 144.1°E which put it about 460 miles (740 km) south-southwest of Guam. Malakas was moving toward the north at 6 m.p.h (10 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.

An upper level ridge over the Western North Pacific strengthened on Friday and that increased the vertical wind shear affecting Tropical Storm Malakas. The increased wind shear prevented Malakas from strengthening on Friday. When the upper level ridge strengthened, the easterly winds blowing toward the top of Malakas’ circulation strengthened. Those stronger upper level winds increased the vertical wind shear and they caused the distribution of thunderstorms around Tropical Storm Malakas to become asymmetrical. The strongest thunderstorms were occurring in bands in the western half of Malakas’ circulation. Bands in the eastern half of the tropical storm consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 90 miles (145 km) from the center of circulation.

Tropical Storm Malakas will move through an environment more favorable for intensification during the next 36 hours. Malakas will move over water where the Sea Surface Temperatures are 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 that will blow toward the top of Malakas’ circulation. Those winds will cause some vertical wind shear, but the shear is forecast to decrease during the weekend. Tropical Storm Malakas will intensify during the next 36 hours. Malakas could strengthen to a typhoon during the weekend.

Tropical Storm Malakas will move around the southwestern part of a high pressure system over the Western North Pacific Ocean during the next several days. The high pressure system will steer Malakas toward the northwest. On its anticipated track Tropical Storm Malakas could pass between Guam and Yap during the weekend.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 03W developed east of the Philippines. At 11:00 p.m. EDT on Friday the center of Tropical Depression 03W was located at latitude 10.8°N and longitude 126.8°E which put it about 265 miles (425 km) southeast of Legazpi, Philippines. The tropical depression was moving toward the south-southwest at 4 m.p.h (6 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 1006 mb.

Tropical Depression 02W Strengthens to Tropical Storm Malakas

Former Tropical Depression 02W strengthened to Tropical Storm Malakas south of Guam on Thursday. At 11:00 p.m. EDT on Thursday the center of Tropical Storm Malakas was located at latitude 5.3°N and longitude 146.2°E which put it about 605 miles (970 km) south of Guam. Malakas was moving toward the northwest at 8 m.p.h (13 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.

Tropical Storm Malakas was strengthening on Thursday night. Malakas exhibited more organization on satellite images. More thunderstorms were developing in all parts of the circulation around Tropical Storm Malakas. Bands of showers and thunderstorms were revolving around the center of Malakas. 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) in the northern half of Malakas’ circulation. Winds to tropical storm force extended out 90 miles (145 km) in the southern half of the circulation.

Tropical Storm Malakas will move through an environment favorable for intensification during the next 36 hours. Malakas will move over water where the Sea Surface Temperatures are 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 that will blow toward the top of Malakas’ circulation. The winds will also be blowing from the east at most other levels in the troposphere. Since the winds will be blowing from the same direction at different levels, there will be little vertical wind shear. Tropical Storm Malakas will intensify during the next 36 hours. Malakas could strengthen to a typhoon within the next 48 hours.

Tropical Storm Malakas will move around the southwestern part of a high pressure system over the Western North Pacific Ocean during the next several days. The high pressure system will steer Malakas toward the northwest. On its anticipated track Tropical Storm Malakas could pass between Guam and Yap in 48 hours.

Tropical Depression Forms South-Southeast of Guam

A tropical depression formed south-southeast of Guam on Wednesday. At 11:00 a.m. EDT on Wednesday the center of the tropical depression was located at latitude 3.6°N and longitude 148.0°E which put it about 675 miles (1090 km) south-southeast of Guam. The tropical depression was moving toward the west at 6 m.p.h (10 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.

A low pressure system over the Western North Pacific Ocean south-southeast of Guam strengthened on Wednesday and the Japan Meteorological Agency designated the system as a tropical depression. The circulation around the tropical depression exhibited more organization on Wednesday morning. More thunderstorms developed near the center of circulation. Bands of showers and thunderstorms started to revolve around the center of the tropical depression. Storms near the center began to generate upper level divergence that pumped mass away from the tropical depression.

The tropical depression will move through an environment favorable for intensification during the next 36 hours. It will move over water where the Sea Surface Temperatures are near 29˚C. The tropical depression will move through an area where the winds will be blowing from the east at most levels in the troposphere. Since the winds will be blowing from the same direction at different levels, there will be little vertical wind shear. The tropical depression will intensify during the next 36 hours to a tropical storm. It could eventually strengthen to a typhoon in a few days.

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-northwest during the next 36 hours. On its anticipated track the tropical depression will pass south of Guam.