Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Typhoon Danas Hits Taiwan

Typhoon Danas hit Taiwan on Sunday.  At 11:00 a.m. EDT on Sunday the center of Typhoon Danas was located at latitude 23.5°N and longitude 120.0°E which put the center about 75 miles (120 km) southwest of Taichung, Taiwan.  Danas was moving toward the northeast at 13 m.p.h. (21 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 958 mb.

Typhoon Danas rapidly intensified to the equivalent of a Category 2 hurricane on the Saffir-Simpson Scale as it approached Taiwan on Sunday.  The inner end of a rainband wrapped around the center of Danas’ circulation.  A circular eye with a diameter of 16 miles (26 km) formed at the center of Typhoon Danas.  Other bands of showers and thunderstorms were revolving around the core of Danas’ circulation.

The size of the circulation around Typhoon Danas increased when Danas rapidly intensified.  Winds to typhoon force extended out 35 miles (55 km) from the center of Danas’ circulation.  Winds to tropical storm force extended out 160 miles (260 km) in the eastern side of Typhoon Danas.  Winds to tropical storm force extended out 85 miles (135 km) in the western side of Danas.

The Hurricane Intensity Index (HII) for Typhoon Danas is 17.8.  The Hurricane Size Index (HSI) is 14.4 and the Hurricane Wind Intensity Size Index (HWISI) is 32.2.  Typhoon Danas is similar in size and intensity to Hurricane Sally when Sally hit Alabama in 2020.

Typhoon Danas will bring strong, gusty winds and heavy rain to Taiwan.  Heavy rain is likely to cause flash floods and mudslides.  Widespread outages of electricity are possible.  Typhoon Danas could also cause a storm surge of up to 10 feet (3 meters) along parts of the coast of Taiwan.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Mun continued to churn east of Japan.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Mun was located at latitude 33.9°N and longitude 149.4°E which put the center about 545 miles (875 km) east of Tokyo, Japan.  Mun was moving toward the north at 9 m.p.h. (15 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 982 mb.

Danas Intensifies to a Typhoon Southwest of Taiwan

Former Tropical Storm Danas intensified to a typhoon over the South China Sea southwest of Taiwan on Saturday.  At 5:00 p.m. EDT on Saturday the center of Typhoon Danas was located at latitude 21.4°N and longitude 118.3°E which put the center about 170 miles (275 km) southwest of Kaohsiung, Taiwan.  Danas was moving toward the north-northeast at 4 m.p.h. (6 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 977 mb.

Former Tropical Storm Dana intensified to a typhoon over the South China Sea southwest of Taiwan on Saturday.  The distribution of thunderstorms in Typhoon Danas became more symmetrical as Danas intensified.  More thunderstorms developed near the center of Danas’ circulation.  More thunderstorms also formed in bands revolving around the center of Typhoon Danas.  Storms near the center of Danas generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The size of the circulation around Typhoon Danas increased as Danas intensified.  Winds to typhoon force extended out 35 miles (55 km) from the center of Danas’ circulation.  Winds to tropical storm force extended out 140 miles (220 km) from the center of Typhoon Danas.

Typhoon Danas will move through an environment mostly favorable for intensification during the next 18 hours.  Danas will move over water where where the Sea Surface Temperatures are near 29°C.  It will move under the western part of an upper level ridge over that is centered east of Taiwan.  The upper level ridge will produce southwesterly winds that will blow toward the top of Danas’ circulation.  Those winds will cause some vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be enough to prevent intensification. Typhoon Danas will intensify during the next 18 hours.  Danas could intensify rapidly at times.

Typhoon Danas will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Danas toward the north-northeast during the next 24 hours.  On its anticipated track, Typhoon Danas will approach the west coast of Taiwan in 18 hours.

Typhoon Danas will bring strong winds and locally heavy rain to Taiwan. Heavy rain is likely to cause flash floods. Typhoon Danas could also cause a storm surge of up to 10 feet (3 meters) along parts of the coast of Taiwan.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Mun continued to churn east-southeast of Japan.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Mun was located at latitude 32.0°N and longitude 148.9°E which put the center about 575 miles (925 km) east-southeast of Tokyo, Japan.  Mun was moving toward the northeast at 8 m.p.h. (13 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 983 mb.

Tropical Storm Danas Forms Southwest of Taiwan

Tropical Storm Danas formed over the South China Sea southwest of Taiwan on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Danas was located at latitude 20.2°N and longitude 117.3°E which put the center about 265 miles (430 km) southwest of Kaohsiung, Taiwan.  Danas was moving toward the west at 5 m.p.h. (8 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 994 mb.

A low pressure system over the South China Sea southwest of Taiwan strengthened on Friday and the Japan Meteorological Agency designated the system as Tropical Storm Danas.

The distribution of thunderstorms in Tropical Storm Danas was asymmetrical.  Thunderstorms were occurring in bands in the southern half of Danas’ circulation.  Bands in the northern half of Tropical Storm Danas consisted primarily of showers and lower clouds.  Storms near the center of Danas generated upper level divergence that pumped mass away to the south of the tropical storm.  The removal of mass caused the surface pressure to decrease.

The circulation around Tropical Storm Danas was small.  Winds to tropical storm force extended out 70 miles (110 km) from the center of Danas’ circulation.

Tropical Storm Danas will move through an environment mostly favorable for intensification during the next 24 hours.  Danas will move over water where where the Sea Surface Temperatures are near 29°C.  It will move under the southern part of an upper level ridge over eastern China.  The upper level ridge will produce northeasterly winds that will blow toward the top of Danas’ circulation.  Those winds will cause moderate vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Storm Danas will intensify during the next 24 hours.  Danas could strengthen to a typhoon during the weekend,

Tropical Storm Danas will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Danas toward the north during the next 24 hours.  On its anticipated track,  Tropical Storm Danas will move toward the Taiwan Strait.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Mun continued to meander southeast of Japan.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Mun was located at latitude 30.8°N and longitude 146.3°E which put the center about 485 miles (780 km) southeast of Tokyo, Japan.  Mun was moving toward the northeast at 9 m.p.h. (15 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 985 mb.

Tropical Storm Mun Spins Southeast of Japan

Tropical Storm Mun was spinning over the Western North Pacific Ocean southeast of Japan on Thursday evening.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Mun was located at latitude 29.9°N and longitude 144.9°E which put the center about 495 miles (795 km) southeast of Tokyo, Japan.  Mun was moving toward the north at 7 m.p.h. (11 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 Mun strengthened on Thursday as it spun over the Western North Pacific Ocean southeast of Japan.  The circulation around Tropical Storm Mun became more symmetrical.  More thunderstorms developed near the center of Mun’s circulation.  Thunderstorms were also occurring in bands revolving around the center of Tropical Storm Mun.  Storms near the center of Mun generated upper level divergence that pumped mass away from the tropical storm.  The removal of mass caused the surface pressure to decrease.

The circulation around Tropical Storm Mun was small.  Winds to tropical storm force extended out 60 miles (95 km) from the center of Mun’s circulation.

Tropical Storm Mun will move through an environment that will be favorable for intensification during the next 24 hours.  Mun will move over water where where the Sea Surface Temperatures are near 27°C.  An upper level low south of Japan will produce southwesterly winds that will blow toward the top of Mun’s circulation.  Those winds will cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification, but the shear will probably not be enough to prevent intensification.  Tropical Storm Mun is likely to intensify during the next 24 hours.  Mun could strengthen to a typhoon.

Tropical Storm Mun will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Mun toward the northeast during the next 24 hours.  On its anticipated track, Tropical Storm Mun will move farther away from Honshu.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 05W formed south of Taiwan.  At 11:00 p.m. EDT on Thursday the center of Tropical Depression 05W was located at latitude 19.7°N and longitude 118.6°E which put the center about 305 miles (495 km) south-southwest of Kaohsiung, Taiwan.  The tropical depression was moving toward the west-southwest at 7 m.p.h. (11 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 1001 mb.

Tropical Storm Mun Forms Southeast of Japan

Tropical Storm Mun formed over the Western North Pacific Ocean southeast of Japan on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Mun was located at latitude 27.1°N and longitude 145.5°E which put the center about 680 miles (1100 km) south-southeast of Tokyo, Japan.  Mun was moving toward the northwest 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 1000 mb.

A low pressure system over the Western North Pacific Ocean southeast of Japan strengthened on Wednesday and the Japan Meteorological Agency designated the system as Tropical Storm Mun.

Tropical Storm Mun was under the eastern side of an upper level low southeast of Japan.  The upper level low was producing southwesterly winds that were blowing across the eastern part of Mun’s circulation.  Those winds were causing moderate vertical wind shear.  The vertical wind shear was causing the distribution of thunderstorms in Tropical Storm Mun to be asymmetrical.  Thunderstorms were occurring in bands in the western side of Mun’s circulation.  Bands in the eastern side of Tropical Storm Mun consisted primarily of showers and lower clouds.  Storms near the center of Mun generated upper level divergence that pumped mass away to the northeast of the tropical storm.

The vertical wind shear was also affecting the distribution of wind speeds in Tropical Storm Mun.  Winds to tropical storm force extended out 85 miles (135 km) in the northern side of Mun’s circulation.  Winds to tropical storm force extended out 40 miles (65 km) in the southern part of Tropical Storm Mun.

Tropical Storm Mun will move through an environment that will be somewhat favorable for intensification during the next 24 hours.  Mun will move over water where where the Sea Surface Temperatures are near 28°C.  However, the upper level low southeast of Japan will continue to cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification.  Tropical Storm Mun could intensify during the next 24 hours if the vertical wind shear does not increase.

The upper level low southeast of Japan will steer Tropical Storm Mun toward the north-northwest during the next 24 hours.  On its anticipated track, Tropical Storm Mun will move toward eastern Japan.  Mun could meander east of Japan during the next few days.

Sepat Weakens to a Tropical Depression

Former Tropical Storm Sepat weakened to a tropical depression over the Western North Pacific Ocean south of Japan on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Depression Sepat was located at latitude 32.4°N and longitude 139.5°E which put the center about 230 miles (370 km) south of Tokyo, Japan.  Sepat was moving toward the north-northwest at 8 m.p.h. (13 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.

Former Tropical Storm Sepat weakened to a tropical depression on Tuesday as it moved over the Western North Pacific Ocean south of Japan.  Many of the thunderstorms in Sepat’s circulation dissipated.  A few thunderstorms were still occurring in the southeastern quadrant of Tropical Depression Sepat.  Most of the bands revolving around the center of Sepat’s circulation consisted primarily of showers and lower clouds.

Tropical Depression Sepat will move through an environment that will be unfavorable for intensification during the next 24 hours.  Sepat will move over water where where the Sea Surface Temperatures are near 25°C.  It will move under the northern part of an upper level ridge south of Japan.  The upper level ridge will produce west-southwesterly winds that will blow toward the top of Sepat’s circulation.  Those winds will cause strong vertical wind shear.  The strong vertical wind shear and marginal Sea Surface Temperatures will cause Tropical Depression Sepat to continue to weaken during the next 24 hours.

Tropical Depression Sepat will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Sepat toward the north during the next 24 hours.  On its anticipated track, Tropical Depression Sepat will approach eastern Honshu in 12 hours.  The center of Sepat’s circulation is likely to pass just to the southeast of Tokyo.

Tropical Depression Sepat is likely to bring gusty winds and rain to the part of Honshu southeast of Tokyo.

Tropical Storm Sepat Moves Toward Honshu

Tropical Storm Sepat moved toward Honshu on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Sepat was located at latitude 29.7°N and longitude 140.7°E which put the center about 420 miles (680 km) south of Tokyo, Japan.  Sepat was moving toward the northwest at 14 m.p.h. (22 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.

Tropical Storm Sepat strengthened a little on Monday morning, but Sepat was showing signs of weakening on Monday evening.  Thunderstorms were still occurring near the center of Tropical Storm Sepat.  Thunderstorms were also occurring bands revolving around the center of Sepat’s circulation.  Storms near the center of Sepat generated upper level divergence that pumped mass away from the tropical storm.  The removal of mass in the upper levels was balanced by the inflow of mass in the lower levels of Tropical Storm Sepat.  The balance of upper level divergence and inflow in the lower levels caused the surface pressure to remain steady.

The distribution of wind speeds in Tropical Storm Sepat was asymmetrical.  Winds to tropical storm force extended out 110 miles (175 km) in the eastern side of Sepat’s circulation.  The winds in the western side of Tropical Storm Sepat were blowing at less than tropical storm force.

Tropical Storm Sepat will move through an environment that will become unfavorable for intensification during the next 24 hours.  Sepat will move over water where where the Sea Surface Temperatures are near 26°C.  It will move under the northern part of an upper level low south of Japan.  The upper level low will produce northeasterly winds that will blow toward the top of Sepat’s circulation.  Those winds will cause moderate vertical wind shear.  The vertical wind shear  and marginal Sea Surface Temperatures will cause Tropical Storm Sepat to weaken during the next 24 hours.  Sepat is likely to weaken to a tropical depression on Tuesday.

Tropical Storm Sepat will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Sepat toward the north-northwest during the next 24 hours.  On its anticipated track, Tropical Storm Sepat will continue to move toward Honshu.

Tropical Storm Sepat Forms Southeast of Japan

Tropical Storm Sepat formed over the Western North Pacific Ocean southeast of Japan on Sunday night.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Sepat was located at latitude 25.1°N and longitude 144.3°E which put the center about 215 miles (345 km) east of Iwo To.  Sepat was moving toward the northwest at 12 m.p.h. (19 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 1004 mb.

A low pressure system over the Western North Pacific Ocean southeast of Japan strengthened on Sunday night and the Japan Meteorological Agency designated the system as Tropical Storm Sepat.  The distribution of thunderstorms in Tropical Storm Sepat was asymmetrical.  Thunderstorms were occurring in bands in the northern side of Sepat’s circulation.  The bands in the southern side of Tropical Storm Sepat consisted primarily of showers and lower clouds.

Tropical Storm Sepat was under the eastern side of an upper level low that was south of Japan.  The upper level low was producing southerly winds that were blowing toward the top of Sepat’s circulation.  Those winds were causing moderate vertical wind shear.  The wind shear was causing the asymmetrical distribution of thunderstorms.

The distribution of wind speeds in Tropical Storm Sepat was also asymmetrical.  Winds to tropical storm force extended out 110 miles (175 km) in the eastern side of Sepat’s circulation.  The winds in the western side of Tropical Storm Sepat were blowing at less than tropical storm force.

Tropical Storm Sepat will move through an environment somewhat favorable for intensification during the next 24 hours.  Sepat will move over water where where the Sea Surface Temperatures are near 28°C.  The upper level low south of Japan will continue to cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Tropical Storm Sepat is likely to intensify during the next 24 hours.

Tropical Storm Sepat will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system and the upper low south of Japan will steer Sepat toward the north-northwest during the next 24 hours.  On its anticipated track, Tropical Storm Sepat will move toward Honshu.

Tropical Storm Wutip Makes Landfall in Southern China

Tropical Storm Wutip made landfall on the coast of southern China near Lianjiang on Friday night.  At 5:00 a.m. EDT on Saturday the center of Tropical Storm Wutip was located at latitude 21.7°N and longitude 110.3°E which put the center about 15 miles (25 km) southwest of Lianjiang, China.  Wutip was moving toward the northeast at 13 m.p.h. (21 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 Wutip strengthened to a typhoon just before it made landfall in southern China on Friday night.  Wutip weakened back to a tropical storm after it made landfall.  The circulation around Tropical Storm Wutip was small.  Winds to tropical storm force extended out 100 miles (160 km) from the center of Wutip’s circulation.

Tropical Storm Wutip will move around the northwestern part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Wutip toward the northeast during the next 24 hours.  On its anticipated track, Tropical Storm Wutip will move across Guangdong.  Wutip will pass north of Hong Kong.

Tropical Storm Wutip will bring strong winds and heavy rain to southern China.  The strongest winds and heaviest rain will occur in Guangdong . Heavy rain could cause flash floods in some locations.

Tropical Storm Wutip will weaken gradually as it moves across southern China.

Wutip Strengthens to a Typhoon Near Southern China

Former Tropical Storm Wutip strengthened to a typhoon near southern China on Friday evening.  At 11:00 p.m. EDT on Friday the center of Typhoon Wutip was located at latitude 20.8°N and longitude 109.4°E which put the center about 80 miles (130 km) southwest of Lianjiang, China.  Wutip was moving toward the north-northeast at 7 m.p.h. (11 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.

Former Tropical Storm Wutip strengthened to a typhoon as it neared the coast of southern China on Friday evening.  The inner end of a rainband wrapped around the center of Wutip’s circulation.  A small circular eye with a diameter of 15 miles (24 km) formed at the center of Typhoon Wutip.  The eye was surrounded by a thin ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Wutip’s circulation.  Storms near the center of Wutip generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The size of the circulation around Typhoon Wutip decreased a little on Friday.  Winds to typhoon force extended out 25 miles (40 km) from the center of Wutip’s circulation.  Winds to tropical storm force extended out 100 miles (160 km) from the center of Typhoon Wutip.

Typhoon Wutip will move through an environment favorable for intensification during the next few hours before it makes landfall in China.  Wutip will move over water where where the Sea Surface Temperatures are near 30°C.  It will move under the axis of an upper level ridge over eastern China.  The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear.  However, much of the southeastern part of Wutip’s circulation will pass over Hainan.  The increased friction over land will slow the winds in that part of Tropical Storm Wutip.  Typhoon Wutip could intensify a little more during the next few hours.

Tropical Storm Wutip will move around the western part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Wutip toward the northeast during the next 24 hours.  On its anticipated track, the center Typhoon Wutip will make landfall on the coast of southern China southwest of Lianjiang.

Typhoon Wutip will bring strong winds and heavy rain to southern China on Saturday.  The strongest winds and heaviest rain will occur in Guangdong and eastern Guangxi.  Heavy rain could cause flash floods in some locations.