Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Typhoon Champi Brings Wind and Rain to Iwo To

Typhoon Champi brought wind and rain to Iwo To on Friday night. At 11:00 p.m. EDT on Friday the center of Typhoon Champi was located at latitude 25.4°N and longitude 139.9°E which put it about 105 miles (165 km) west of Iwo To. Champi was moving toward the north at 13 m.p.h. (20 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 982 mb.

Bands of showers and thunderstorms on the eastern side of Typhoon Champi brought wind and rain to Iwo To on Friday night. Although the center of Champi was passing west of Iwo To, the circulation around the typhoon was producing gusty winds and rain over the island. The core of Typhoon Champi was passing west of Iwo To. Winds to typhoon force extended out 25 miles (40 km) from the center of Champi. However, winds to tropical storm force extended out 100 miles (160 km) from the center of circulation.

Typhoon Champi will move through an environment unfavorable for intensification during the next several days. Champi will move over water where the Sea Surface Temperatures are near 27°C. It will move under the southeastern part of an upper level trough over Japan. The trough will produce southwesterly winds which will blow toward the top of the typhoon. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification, but Typhoon Champi could maintain its intensity during the next 12 hours. The vertical wind shear will increase on Saturday, when Champi moves closer to the upper level trough. Typhoon Champi will weaken when the shear increases. Champi will also move over cooler water by Sunday.

The upper level trough over Japan will steer Typhoon Champi toward the northeast during the weekend. On its anticipated track Champi will move away from Iwo To on Saturday. Typhoon Champi could be southeast of Tokyo in 30 hours.

Champi Strengthens to a Typhoon Southwest of Iwo To

Former Tropical Storm Chanpi strengthened to a typhoon southwest of Iwo To on Friday morning. At 5:00 a.m. EDT on Friday the center of Typhoon Champi was located at latitude 22.5°N and longitude 139.2°E which put it about 230 miles (370 km) southwest of Iwo To. Champi was moving toward the north at 11 m.p.h. (17 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 982 mb.

The circulation around Typhoon Champi exhibited better organization on Friday morning. There was a small, circular eye at the center of Champi. 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 Champi. The strongest rainband wrapped around the northern, western and southern sides of Champi. Bands in the eastern side of the typhoon consisted mainly of showers and lower clouds. The circulation around Typhoon Champi was relatively small. Winds to typhoon force extended out 30 miles (50 km) from the center of Champi. Winds to tropical storm force extended out 100 miles (160 km) from the center of circulation.

Typhoon Champi will move through an environment somewhat favorable for intensification during the next 24 hours. Champi will move over water where the Sea Surface Temperatures are near 29°C. It will move under the southeastern part of an upper level trough over Japan. The trough will produce southwesterly winds which will blow toward the top of the typhoon. Those winds will cause some vertical wind shear. The wind shear will inhibit intensification, but Typhoon Champi could strengthen during the next 24 hours. The vertical wind shear will increase during the weekend, when Champi moves closer to the upper level trough.

Typhoon Champi will move around the western end of a surface high pressure system during the next 24 hours. The high will steer Champi toward the north during that time period. On its anticipated track the center of Typhoon Champi will pass west of Iwo To on Friday night. Bands on the eastern side of Champi could bring gusty winds and locally heavy rain to Iwo To. The upper level trough over Japan will steer Typhoon Champi toward the northeast during the weekend. Champi could be southeast of Tokyo in 48 hours.

Tropical Storm Champi Strengthens South of Iwo To

Tropical Storm Champi strengthened south of Iwo To on Wednesday. At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Champi was located at latitude 18.9°N and longitude 140.1°E which put it about 435 miles (680 km) south of Iwo To. Champi was moving toward the north at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h). The minimum surface pressure was 992 mb.

Tropical Storm Champi continued to strengthen on Wednesday. The inner end of a rainband wrapped most of the way around the center of Champi. Stronger thunderstorms were occurring in bands east and south of the center of circulation. Bands in the northwestern side of the tropical storm consisted primarily of showers and lower clouds. 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 70 miles (110 km) from the center of Champi.

Tropical Storm Champi will move through an environment favorable for intensification during the next 36 hours. Champi will move over an area where the Sea Surface Temperatures are near 29°C. It will move under the southeastern portion of an upper level ridge centered east of the Philippines. The ridge will produce northeasterly winds that will blow toward the top of the tropical storm. Those winds will cause some vertical wind shear. The vertical wind shear will slow the rate of intensification, but it will not be large enough prevent Tropical Storm Champi from strengthening. Champi will intensify during the next 36 hours and it is forecast to strengthen to a typhoon.

Tropical Storm Champi will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean during the next 48 hours. The high will steer Champi toward the north during the next two days. On its anticipated track Tropical Storm Champi could be southwest of Iwo To in 36 hours.

Tropical Storm Champi Develops West of the Marianas

Tropical Storm Champi developed west of the Marianas on Tuesday night. At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Champi was located at latitude 15.3°N and longitude 139.9°E which put it about 320 miles (515 km) west-northwest of Guam. Champi was moving toward the west-northwest at 9 m.p.h. (15 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 former Tropical Depression 06W strengthened on Tuesday night and the Japan Meteorological Agency designated the system as Tropical Storm Champi. More thunderstorms formed near the center of Tropical Storm Champi. The inner end of a rainband wrapped around the eastern and northern sides of the center of Champi. Other bands of showers and thunderstorms were revolving around the center of circulation. Storms near the center generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 50 miles (80 km) from the center of circulation.

Tropical Storm Champi will move through an environment favorable for intensification during the next 48 hours. Champi will move over an area where the Sea Surface Temperatures are near 29°C. It will move between an upper level low northeast of the Marianas and and upper level ridge over eastern Asia. The upper level winds are weak between the upper low and the ridge and there will be little vertical wind shear. Tropical Storm Champi will intensify during the next 48 hours and it could strengthen to a typhoon.

Tropical Storm Champi will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean during the next 48 hours. The high will steer Champi toward the north during the next several days. On its anticipated track Tropical Storm Champi could be southwest of Iwo To in 48 hours.

Tropical Depression Forms Southeast of Guam, Warning Issued

Tropical Depression 06W formed southeast of Guam on Sunday night and a Tropical Storm Warning was issued for Guam. At 5:00 a.m. EDT on Monday the center of Tropical Depression 06W was located at latitude 12.1°N and longitude 146.0°E which put it about 160 miles (260 km) southeast of Guam. Tropical Depression 06W was moving toward the west-northwest at 13 m.p.h. (20 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 Tropical Storm Warning was issued for Guam. A Tropical Storm Watch was issued for Rota.

A circulation center developed in a cluster of thunderstorms southeast of Guam on Sunday night and the Joint Typhoon Warning Center designated the system as Tropical Depression 06W. The distribution of thunderstorms around Tropical Depression 06W was asymmetrical. The strongest thunderstorms were occurring in bands on the eastern side of the tropical depression. Bands in the western half of the circulation consisted primarily of showers and lower clouds. Storms near the center of Tropical Depression 06W began to generate upper level divergence that pumped mass away from the tropical depression.

Tropical Depression 06W will move through an environment that is somewhat favorable for intensification during the next several days. The depression will move over an area where the Sea Surface Temperatures are near 29°C. It will move south of an upper level ridge over the Western North Pacific Ocean. The ridge will produce easterly winds that will blow toward the top of Tropical Depression 06W. Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification. The tropical depression will move into an area where drier air is sinking toward the surface. The drier air will limit the formation of thunderstorms on the western side of the circulation and it will inhibit intensification. Tropical Depression 06W is forecast to intensify to a tropical storm during the next 24 hours.

Tropical Depression 06W will move around the western side of a subtropical high pressure system over the Western North Pacific Ocean. The high will steer the depression toward the northwest during the next 24 hours. On its anticipated track Tropical Depression 06W will pass near Guam in 12 hours. The tropical depression will bring gusty winds and heavy rain to parts of Guam. It will move more toward the north when it reaches the western end of the high pressure system.

Tropical Storm Koguma Nears Vietnam

The center of Tropical Storm Koguma moved closer to northern Vietnam on Saturday. At 11:00 a.m. EDT on Saturday the center of Tropical Storm Koguma was located at latitude 20.2°N and longitude 106.9°E which put it about 115 miles (185 km) southeast of Hanoi, Vietnam. Koguma was moving toward the northwest at 20 m.p.h. (32 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 997 mb.

The circulation around former Tropical Depression 05W strengthened slightly on Saturday and the system was upgraded to Tropical Storm Koguma. Even though the circulation around the former tropical depression was a little stronger, the distribution of thunderstorms around Tropical Storm Koguma was still asymmetrical. The strongest thunderstorms were occurring in bands southwest of the center of Koguma. Bands in the other parts of the tropical storm consisted primarily of showers and lower clouds. An upper level ridge centered over southern China was producing moderate northeasterly winds that were blowing toward the top of the depression. Those winds were causing moderate vertical wind shear and they were also causing the asymmetrical distribution of thunderstorms.

Tropical Storm Koguma will move into an environment only marginally favorable for intensification during the next few hours. Koguma will move over an area where the Sea Surface Temperatures are near 30°C. However, the upper level ridge over southern China will continue to produce moderate vertical wind shear. The moderate wind shear will keep Tropical Storm Koguma from strengthening significantly before it reaches Vietnam. The circulation around Koguma will weaken after the center moves over Vietnam.

Tropical Storm Koguma will move around the southern part of a subtropical high pressure system over the Western North Pacific Ocean during the next 24 hours. The high pressure system will steer Koguma toward the northwest. On its anticipated track the center of Tropical Storm Koguma will make landfall on the coast of northern Vietnam south of Haiphong in a few hours. Koguma will bring gusty winds to parts of northern Vietnam. Since the heaviest rain is falling southwest of the center of Tropical Storm Koguma, heavy rain is already falling over parts of northern Vietnam, northern Laos and extreme northeastern Thailand. The heavy rain could cause flash floods in some locations.

Tropical Depression Forms South of Hainan Island

A tropical depression formed just to the south of Hainan Island on Friday night. At 11:00 p.m. EDT on Friday the center of Tropical Depression 05W was located at latitude 18.3°N and longitude 109.5°E which put it about 35 miles (55 km) south of Sanya, China. The depression was moving toward the west at 16 m.p.h. (26 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.

Thunderstorms developed closer to the center of a low pressure system south of Hainan Island on Friday night and both the Japan Meteorological Agency and the Joint Typhoon Warning Center designated the system as a tropical depression. The distribution of thunderstorms around Tropical Depression 05W was asymmetrical. The strongest thunderstorms were occurring in bands southwest of the center of the tropical depression. Bands in the other parts of the circulation consisted primarily of showers and lower clouds. An upper level ridge centered over southern China was producing moderate northeasterly winds that were blowing toward the top of the depression. Those winds were causing moderate vertical wind shear and they were also causing the asymmetrical distribution of thunderstorms.

The center of Tropical Depression 05W will move near Hainan Island during the next few hours. The northern half of the circulation around the tropical depression will be over Hainan Island, which will inhibit intensification. Tropical Depression 05W will move into an environment favorable for intensification when it moves west of Hainan Island. The tropical depression will move over an area where the Sea Surface Temperatures are near 30°C. The upper level ridge over southern China will continue to produce moderate vertical wind shear. Even with the moderate wind shear, Tropical Depression 05W is likely to intensify to a tropical storm during the next 24 hours.

Tropical Depression 05W will move around the southern part of a subtropical high pressure system over the Western North Pacific Ocean during the next 36 hours. The high pressure system will steer the tropical depression toward the west-northwest. On its anticipated track the center of Tropical Depression 05W will pass near the southern part of Hainan Island. Since the strongest thunderstorms are in the southwestern part of the circulation, the tropical depression will cause mainly gustier winds over Hainan Island. Tropical Depression 05W could approach northern Vietnam in 24 hours. It could bring gusty winds and locally heavy rain to parts of northern Vietnam. Heavy rain could cause flash floods in some locations.

Tropical Storm Choi-wan Moves Toward Taiwan

Tropical Storm Choi-wan moved toward Taiwan on Thursday. At 5:00 p.m. EDT on Thursday the center of Tropical Storm Choi-wan was located at latitude 20.0°N and longitude 118.9°E which put it about 185 miles (300 km) south-southwest of Taiwan. Choi-wan was moving toward the north-northeast at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1002 mb.

Tropical Storm Choi-wan turned toward the north-northeast on Thursday which put it on a track towards southern Taiwan. The distribution of thunderstorms around Choi-wan was asymmetrical. The strongest thunderstorms were occurring in bands in the southwestern quadrant of Tropical Storm Choi-wan. Bands in the other quadrants of Choi-wan consisted primarily of showers and lower clouds. The distribution of wind speeds around Tropical Storm Choi-wan was also asymmetrical. Winds to tropical storm force extended out 125 miles (200 km) on the western side of Choi-wan. Winds to tropical storm force only extended out 65 miles (105 km) on the eastern side of the circulation.

Tropical Storm Choi-wan will move through an area that is mostly unfavorable for intensification during the next 36 hours. The center of Choi-wan will move over an area where the Sea Surface Temperatures are near 30°C. However, an upper level ridge centered over southern China will produce moderate northeasterly winds that will blow toward the top of the tropical storm. Those winds will cause moderate vertical wind shear and they are already responsible for the asymmetrical distribution of thunderstorms. The moderate vertical wind shear will likely prevent intensification of Tropical Storm Choi-wan.

Tropical Storm Choi-wan will move around the northwestern part of a subtropical high pressure system over the Western North Pacific Ocean. The high pressure system will steer Choi-wan toward the north-northeast during the next 24 hours. On its anticipated track the center of Tropical Storm Choi-wan will reach southern Taiwan in 12 hours. Choi-wan could drop locally heavy rain over parts of southern Taiwan. Flash floods could occur in some locations. Tropical Storm Choi-wan could approach the southern Ryuku Islands in 24 hours. Choi-wan could bring a period of gusty winds to southern Taiwan and the southern Ryukyu Islands.

Tropical Storm Choi-wan Drops Rain on Luzon

Tropical Storm Choi-wan dropped rain on parts of Luzon around Manila on Wednesday. At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Choi-wan was located at latitude 15.5°N and longitude 119.6°E which put it about 85 miles (135 km) west-northwest of Manila, Philippines. Choi-wan was moving toward the 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 1002 mb.

The center of Tropical Storm Choi-wan passed just south of Manila before the tropical storm moved west of Luzon. Bands near the center of Choi-wan dropped rain on parts of Luzon near Manila. Other bands in the southern half of Tropical Storm Choi-wan dropped rain on Mindoro. Choi-wan was still producing a few winds that were blowing at tropical storm force, but Manila did not report any winds that were that strong.

Tropical Storm Choi-wan exhibited an organized circulation on Wednesday afternoon. The inner end of a rainband wrapped around the western, southern and eastern sides of the center of Choi-wan. Other bands of thunderstorms were in the southern half of the tropical storm. Bands in the northern half of Tropical Storm Choi-wan consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 35 miles (55 km) from the center of Choi-wan.

Tropical Storm Choi-wan will move through an area that is marginally favorable for intensification during the next 24 hours. The center of Choi-wan will move over the South China Sea where the Sea Surface Temperatures are near 30°C. However, an upper level ridge centered over southern China will cause moderate vertical wind shear. The wind shear will limit the potential for intensification, but Tropical Storm Choi-wan could get a little stronger during the next 24 hours.

Tropical Storm Choi-wan will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean. The high pressure system will steer Choi-wan toward the north during the next 24 hours. On its anticipated track the center of Tropical Storm Choi-wan will move northwest of Luzon during the next 24 hours. Choi-wan will turn toward the northeast on Friday after it moves around the western end of the high pressure system. Tropical Storm Choi-wan could approach the southern end of Taiwan in 36 hours.

Tropical Storm Choi-wan Brings Rain to Philippines

Tropical Storm Choi-wan brought rain to the central Philippines on Tuesday. At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Choi-wan was located at latitude 13.1°N and longitude 121.9°E which put it about 155 miles (250 km) southeast of Manila, Philippines. Choi-wan was moving toward the west-northwest at 17 m.p.h. (28 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.

The center of Tropical Storm Choi-wan made an initial landfall on the east coast of Samar and then it moved west-northwest across the central Philippines. Choi-wan moved across the Sibuyan Sea and it was centered southeast of Manila on Tuesday night. The circulation around Tropical Storm Choi-wan weakened when the center passed over Samar, but it was still producing a small area of tropical storm force winds. Winds to tropical storm force extended out 35 miles (55 km) from the center of Choi-wan.

Tropical Storm Choi-wan dropped locally heavy rain over parts of Samar, Masbate, Panay and Mindoro on Tuesday. An upper level ridge centered over southern China was producing northeasterly winds which were blowing toward the top of Choi-wan. Those winds were producing moderate vertical wind shear and they causing the heavier rain to fall in bands in the southern half of Tropical Storm Choi-wan. Bands in the northern half of the tropical storm consisted primarily of showers and lower clouds.

Tropical Storm Choi-wan will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean. The high pressure system will steer Choi-wan toward the north-northwest during the next several days. On its anticipated track the center of Tropical Storm Choi-wan could pass just south of Manila in 12 hours. Choi-wan could drop locally heavy rain on Mindoro and western Luzon. Heavy rain could cause flash floods in some locations.

Tropical Storm Choi-wan will move through an environment that is mostly unfavorable for intensification. Choi-wan will move over water where the Sea Surface Temperatures are near 30°C. However, the upper level ridge center over southern China will continue to cause moderate vertical wind shear. The wind shear will limit the potential for intensification. The eastern side of the circulation around Tropical Storm Choi-wan will be over Luzon during the next 24 hours, which will also be unfavorable for intensification.