Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Typhoon Mawar Prompts Warning for Guam

Typhoon Mawar prompted the issuance of a Typhoon Warning for Guam on Monday. At 11:00 a.m. EDT on Monday the center of Typhoon Mawar was located at latitude 10.3°N and longitude 146.8°E which put it about 290 miles (465 km) south-southeast of Guam. Mawar was moving toward the north-northwest at 6 m.p.h. (10 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 Warning were in effect for Guam and Rota. Tropical Storm Warnings were in effect for Tinian and Saipan. Typhoon Watches were also in effect for Tinian and Saipan.

Typhoon Mawar continued to intensify on Monday morning. A small circular eye formed at the center of Mawar’s circulation. A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Mawar. Storms near the core of Mawar’s circulation generated strong upper level divergence that pumped mass away from the tropical storm in all directions. The removal of mass was causing the surface pressure to decrease.

The circulation around Typhoon Mawar was small. Winds to typhoon force extended out 40 miles (65 km) from the center of Mawar’s circulation. Winds to tropical storm force extended out 120 miles (190 km) from the center of Typhoon Mawar. The Hurricane Intensity Index (HII) for Typhoon Mawar was 17.8. The Hurricane Size Index (HSI) was 9.2 and the Hurricane Wind Intensity Size Index (HWISI) was 27.0. Mawar was similar in size and intensity to Hurricane Zeta when Zeta hit Louisiana in 2020.

Typhoon Mawar will move through an environment favorable for intensification during the next 36 hours. Mawar will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the western part of the axis of an upper level ridge over the Equatorial Pacific Ocean. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Typhoon Mawar will intensify during the next 36 hours. Mawar could intensify more rapidly at times. Typhoon Mawar is likely to strengthen to the equivalent of a major hurricane within 36 hours.

Typhoon Mawar will move around the western end of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Mawar toward the north-northwest during the next 36 hours. On its anticipated track, Typhoon Mawar will approach Guam in 36 hours. Mawar could be the equivalent of a major hurricane when it reaches the Marianas. Typhoon Mawar will bring strong winds and locally heavy rain to Guam, Rota, Tinian and Saipan. Mawar will move south of a subtropical high pressure system when it approaches the Marianas. The subtropical high will steer Mawar more toward the west-northwest later this week.

Mawar Strengthens to a Typhoon

Former Tropical Storm Mawar strengthened to a typhoon over the Western North Pacific Ocean south-southeast of Guam on Sunday morning. At 11:00 a.m. EDT on Sunday the center of Typhoon Mawar was located at latitude 8.3°N and longitude 148.1°E which put it about 455 miles (735 km) south-southeast of Guam. Mawar was moving toward the north-northwest at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h). The minimum surface pressure was 978 mb.

Typhoon Watches were in effect for Guam, Rota, Tinian and Saipan.

The circulation around Typhoon Mawar exhibited better organization on Sunday morning. The inner end of a rainband wrapped around the northern, western and southern sides of the center of Mawar’s circulation. Other bands of showers and thunderstorms were revolving around the center. Storms near the center of circulation generated strong upper level divergence that pumped mass away from the tropical storm in all directions. The removal of mass was causing the surface pressure to decrease. Winds to typhoon force extended out 40 miles (65 km) in the southern half of Mawar’s circulation. Winds to tropical storm force extended out 85 miles (135 km) from the center of Typhoon Mawar.

Typhoon Mawar will move through an environment favorable for intensification during the next 48 hours. Mawar will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the western end of the axis of an upper level ridge over the Equatorial Pacific Ocean. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Typhoon Mawar will intensify during the next 48 hours. Mawar could intensify rapidly after an inner core with an eye and an eyewall form. Typhoon Mawar could strengthen to the equivalent of a major hurricane within 48 hours.

Typhoon Mawar will move around the western end of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Mawar toward the north-northwest during the next 48 hours. On its anticipated track, Typhoon Mawar will approach the Marianas in 48 hours. Mawar could be the equivalent of a major hurricane when it reaches the Marianas. Typhoon Mawar will bring strong winds and locally heavy rain to Guam, Rota, Tinian and Saipan.

Tropical Storm Mawar Develops South-southeast of Guam

Tropical Storm Mawar developed over the Western North Pacific Ocean south-southeast of Guam on Saturday. At 5:00 p.m. EDT on Saturday the center of Tropical Storm Mawar was located at latitude 6.4°N and longitude 149.1°E which put it about 595 miles (960 km) south-southeast of Guam. Mawar 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 993 mb.

Typhoon Watches were in effect for Guam, Rota, Tinian and Saipan.

Former Tropical Depression 02W strengthened on Saturday and the Japan Meteorological Agency designated the system as Tropical Storm Mawar. The circulation around Tropical Storm Mawar was organizing quickly. The inner end of a rainband wrapped around the western and southern sides of the center of Mawar’s circulation. Other bands of showers and thunderstorms were revolving around the center. 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 65 miles (105 km) from the center of Tropical Storm Mawar.

Tropical Storm Mawar will move through an environment favorable for intensification during the next 48 hours. Mawar will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the western end of the axis of an upper level ridge over the Equatorial Pacific Ocean. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Tropical Storm Mawar will intensify during the next 48 hours. Mawar could intensify rapidly after an inner core with an eye and an eyewall form. Tropical Storm Mawar is likely to strengthen to a typhoon within 36 hours.

Tropical Storm Mawar will move around the western end of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Mawar toward the north-northwest during the next 48 hours. On its anticipated track, Tropical Storm Mawar will affect Pulawat during the next 24 hours. Mawar will bring gusty winds and locally heavy rain to Pulawat. Tropical Storm Mawar will approach the Marianas in 72 hours. Mawar will be a typhoon when it approaches the Marianas, which is why Typhoon Watches were issued for Guam, Rota, Tinian and Saipan.

Tropical Depression Forms South-southeast of Guam

A tropical depression formed over the Western North Pacific Ocean south-southeast of Guam on Friday. At 11:00 p.m. EDT on Friday the center of Tropical Depression 02W was located at latitude 5.6°N and longitude 149.0°E which put it about 115 miles (185 km) south of Pulawat and about 595 miles (960 km) south-southeast of Guam. Tropical Depression 02W was moving toward the north-northwest at 3 m.p.h. (5 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 1002 mb.

An area of low pressure over the Western North Pacific Ocean became better organized on Friday. The Japan Meteorological Agency classified the system as a tropical depression and the U.S. Joint Typhoon Warning Center designated the system as Tropical Depression 02W. The circulation around Tropical Depression 02W was organizing quickly on Friday night. Bands of showers and thunderstorms were revolving around the center of the tropical depression. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical depression. The removal of mass was causing the surface pressure to decrease.

Tropical Depression 02W will move through an environment favorable for intensification during the next 48 hours. The tropical depression will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the western end of the axis of an upper level ridge over the Equatorial Pacific Ocean. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Tropical Depression 02W will intensify during the next 48 hours. The tropical depression is likely to strengthen to a tropical storm during the next 12 hours. It is likely to intensify to a typhoon within 48 hours.

Tropical Depression 02W will move around the western end of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer the tropical depression toward the north-northwest during the next 48 hours. On its anticipated track, Tropical Depression 02W will affect Pulawat during the next 36 hours. Tropical Depression 02W will bring gusty winds and locally heavy rain to Pulawat. Tropical Depression 02W could reach the Marianas within four days. It is likely to be a typhoon when it reaches the Marianas.

Tropical Storm Sanvu Spins Northeast of Chuuk

Tropical Storm Sanvu was spinning over the Western North Pacific Ocean northeast of Chuuk on Friday morning. At 5:00 a.m. EDT on Friday the center of Tropical Storm Sanvu was located at latitude 10.2°N and longitude 156.0°E which put it about 345 miles (555 km) northeast of Chuuk. Sanvu was moving toward the northwest at 3 m.p.h. (5 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 994 mb.

Tropical Storm Sanvu strengthened during Thursday. More thunderstorms developed near the center of Sanvu’s circulation. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical storm. Even though Tropical Storm Sanvu strengthened, the distribution of thunderstorms became more asymmetrical. Most of the thunderstorms were occurring in bands in the eastern side of Sanvu’s circulation. Bands in the western half of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 70 miles (110 km) from the center of Tropical Storm Sanvu.

Tropical Storm Sanvu will move through an environment that will become unfavorable for intensification during the next 24 hours. Sanvu will move over water where the Sea Surface Temperatures are near 29˚C. However, it will move under the northern side of an upper level ridge over the equatorial Western North Pacific. The ridge will produce westerly winds that will blow toward the top of Sanvu’s circulation. Those winds will cause the vertical wind shear to increase. Stronger vertical wind shear is likely to cause Tropical Storm Sanvu to start to weaken during the next 24 hours.

Tropical Storm Sanvu will move around the southern side of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Sanvu toward the west-northwest during the next 24 hours. On its anticipated track, Tropical Storm Sanvu will pass north of Chuuk and Fananu during the weekend.

Tropical Storm Sanvu Develops Northwest of Pohnpei

Tropical Storm Sanvu developed over the Western North Pacific Ocean northwest of Pohnpei on Wednesday night. At 5:00 a.m. EDT on Thursday the center of Tropical Storm Sanvu was located at latitude 9.3°N and longitude 156.8°E which put it about 165 miles (265 km) north-northwest of Pohnpei. Sanvu 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 1000 mb.

Former Tropical Depression 01W strengthened on Wednesday night and the Japan Meteorological Agency designated the system as Tropical Storm Sanvu. The inner end of a rainband wrapped around the center of Sanvu’s circulation. 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 60 miles (95 km) from the center of circulation.

Tropical Storm Sanvu will move through an environment favorable for intensification during the next 24 hours. Sanvu will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the axis of an upper level ridge over the equatorial Western North Pacific Ocean. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Tropical Storm Sanvu could intensify during the next 24 hours. Sanvu will move under the northern side of the upper level ridge on Friday and the vertical wind shear will increase. Tropical Storm Sanvu is likely to weaken when the wind shear increases.

Tropical Storm Sanvu will move around the southern side of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Sanvu toward the northwest during the next 24 hours. On its anticipated track, Tropical Storm Sanvu will move farther away from Pohnpei. Sanvu will be northeast of Chuuk and Fananu on Thursday evening.

Tropical Depression 01W Forms South of Pohnpei

Tropical Depression 01W formed over the Western North Pacific Ocean south of Pohnpei on Wednesday morning. At 11:00 a.m. EDT on Wednesday the center of Tropical Depression 01W was located at latitude 5.2°N and longitude 158.2°E which put it about 145 miles (235 km) south of Pohnpei. Tropical Depression 01W was moving toward the west-northwest at 10 m.p.h. (16 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.

A low pressure system over the Western North Pacific Ocean south of Pohnpei strengthened on Wednesday morning and both the Japan Meteorological Agency and the U.S. Joint Typhoon Warning Center classified the system as a tropical depression. The circulation around Tropical Depression 01W exhibited more organization on Wednesday morning. Bands of showers and thunderstorms were revolving around the center of Tropical Depression 01W. Storms near the center generated upper level divergence that pumped mass away from the tropical depression.

Tropical Depression 01W will move through an environment favorable for intensification during the next 24 hours. The tropical depression will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the axis of an upper level ridge over the equatorial Western North Pacific Ocean. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Tropical Depression 01W is likely to intensify to a tropical storm during the next 24 hours.

Tropical Depression 01W will move around the southern side of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer the tropical depression toward the northwest during the next 24 hours. On its anticipated track, Tropical Depression 01W will pass west of Pohnpei. The tropical depression could be northeast of Chuuk and east of Fananu on Thursday.

Pakhar Weakens to a Tropical Depression

Former Tropical Storm Pakhar weakened to a tropical depression over the Western North Pacific Ocean northeast of the Philippines on Monday. At 4:00 p.m. EST on Monday the center of Tropical Depression Pakhar was located at latitude 19.3°N and longitude 131.1°E which put it about 745 miles (1205 km) east-northeast of Manila, Philippines. Pakhar was moving toward the southeast at 7 m.p.h. (21 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 1003 mb.

After strengthening on Sunday, former Tropical Storm Pakhar weakened to a tropical depression on Monday. An upper level trough west of Japan produced strong southwesterly winds that blew across the top of Pakhar’s circulation. Those winds caused strong vertical wind shear and they blew the top of former Tropical Storm Pakhar away to the northeast of the lower level circulation. The circulation around Tropical Depression Pakhar on Monday afternoon consisted of a swirl of showers and lower clouds. Any clouds that grew higher into the atmosphere were quickly sheared apart by the strong upper level winds.

The circulation around Tropical Depression Pakhar will spin down gradually during the next 24 hours. Pakhar will move over water where the Sea Surface Temperatures are near 28˚C. However, the upper level trough west of Japan will continue to cause strong vertical wind shear. The wind shear will prevent the development of new thunderstorms around Tropical Depression Pakhar.

Since the circulation around Tropical Depression Pakhar only exists in the lower levels of the atmosphere, it will be steered by the winds near the surface. Northeasterly winds will push Pakhar back toward the southwest. On its anticipated track, the circulation around Tropical Depression Pakhar should dissipate east of the Philippines during the next 48 hours.

Tropical Storm Pakhar Develops Northeast of the Philippines

Tropical Storm Pakhar developed over the Western North Pacific Ocean northeast of the Philippines on Sunday. At 10:00 a.m. EST on Sunday the center of Tropical Storm Pakhar was located at latitude 18.5°N and longitude 127.5°E which put it about 470 miles (755 km) east-northeast of Manila, Philippines. Pakhar was moving toward the northeast at 13 m.p.h. (20 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.

The circulation around a low pressure system northeast of the Philippines strengthened on Sunday and the Japan Meteorological Agency designated the system as Tropical Storm Pakhar. More thunderstorms developed near the center of Pakhar’s circulation. Bands of showers and thunderstorms were revolving around the center of Tropical Storm Pakhar. Storms near the center of Pakhar generated upper level divergence that pumped mass away to the northeast of the tropical storm. Winds to tropical storm force extended out 100 miles (160 km) from the center of circulation.

Tropical Storm Pakhar will move through an environment favorable for intensification during the next 18 hours. Pakhar will move over water where the Sea Surface Temperatures are near 28˚C. An upper level trough east of China will produce southwesterly winds that will blow toward the top of Pakhar’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification, but Tropical Storm Pakhar could strengthen during the next 18 hours. The upper level trough will move closer to Pakhar on Monday and the upper level winds will get stronger. More vertical wind shear will cause Tropical Storm Pakhar to weaken early next week.

The upper level trough over eastern China will steer Tropical Storm Pakhar toward the northeast during the next 24 hours. On its anticipated track, Pakhar will move farther away from the Philippines. When the vertical wind shear increases on Monday, strong upper level winds could blow the top off of Tropical Storm Pakhar. If that happens, then Pakhar will be steered by winds in the lower levels of the atmosphere. Those winds could steer Pakhar back toward the southwest early next week.

Tropical Storm Yamaneko Moves North of Wake Island

Tropical Storm Yamaneko moved north of Wake Island on Sunday. At 4:00 p.m. EST on Sunday the center of Tropical Storm Yamaneko was located at latitude 23.4°N and longitude 166.0°E which put it about 245 miles (395 km) north of Wake Island. Yamaneko was moving toward the north at 7 m.p.h. (11 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.

Tropical Storm Yamaneko moved farther north of Wake Island on Sunday. The distribution of thunderstorms in Yamaneko was asymmetrical. Thunderstorms were occurring in bands in the far eastern part of Tropical Storm Yamaneko. Bands in the rest of Yamaneko’s circulation consisted primarily of showers and lower clouds. An upper level trough southeast of Japan was producing strong southwesterly winds that were blowing across the top of Tropical Storm Yamaneko. Those winds were causing strong vertical wind shear. The strong vertical wind shear was causing the upper part of Yamaneko’s circulation to tilt toward the northeast. The strong upper level winds were also blowing off the tops of thunderstorms that started to form near the center of Yamaneko and in the western part of the circulation.

Tropical Storm Yamaneko will move through an environment that will cause it to make a transition to an extratropical cyclone during the next 36 hours. Yamaneko will move over water where the Sea Surface Temperatures are colder than 26˚C. The upper level trough southeast of Japan will continue to cause strong vertical wind shear. A combination of cooler water and strong vertical wind shear will cause Tropical Storm Yamaneko to make a transition to an extratropical cyclone.

The upper level trough will steer Tropical Storm Yamaneko toward the north-northeast during the next 36 hours. On its anticipated track, Tropical Storm Yamaneko will pass far to the west of Midway Island in 24 hours.