Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Sinlaku Causes Typhoon Watch for Guam

The threat posed by Typhoon Sinlaku caused a Typhoon Watch to be issued for Guam, Rota, Tinian, and Saipan on Saturday.  At 11:00 a.m. EDT on Saturday the center of Typhoon Sinlaku was located at latitude 9.2°N and longitude 150.9°E which put the center about 535 miles (865 km) southeast of Guam.  Sinlaku was moving toward the northwest 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 965 mb.

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

Typhoon Sinlaku continued to strengthen on Saturday as it moved toward the southern Marianas.  A small circular eye was as the center of Sinlaku’s circulation.  The eye was surrounded by a 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 Typhoon Sinlaku.  Storms near the center of Sinlaku 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 Sinlaku continued to increase on Saturday.  Winds to typhoon force extended out 50 miles (80 km) from the center of Sinlaku’s circulation.  Winds to tropical storm force extended out 250 miles (400 km) in the northeastern quadrant of Typhoon Sinlaku.  Winds to tropical storm force extended out 165 miles (265 km) in the other quadrants of Sinlaku’s circulation.

Typhoon Sinlaku will move through an environment favorable for intensification during the next 24 hours.  Sinlaku will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the middle of an upper level ridge that is over the Western North Pacific Ocean.  The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear.  Typhoon Sinlaku will intensify during the next 24 hours.  Sinlaku could intensify rapidly at times. Typhoon Sinlaku is likely to strengthen to the equivalent of a major hurricane during the weekend.

Typhoon Sinlaku will move around the southwestern part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer Sinlaku toward the northwest during the next 24 hours.  On its anticipated track, Typhoon Sinlaku will move toward the southern Marianas.  Sinlaku will approach Guam in 48 hours.

Typhoon Sinlaku will be the equivalent of a major hurricane when it approaches the southern Marianas.  Sinlaku could bring very strong winds and locally heavy rain to Guam, Rota, Tinian, and Saipan.  Heavy rain is likely to cause flash floods in some locations.  Typhoon Sinlaku could cause a storm surge of up to 13 feet (4 meters) along parts of the coasts of the southern Marianas.

Sinlaku Rapidly Intensifies to a Typhoon

Former Tropical Storm Sinlaku rapidly intensified to a typhoon southeast of Guam on Friday.  At 11:00 p.m. EDT on Friday the center of Typhoon Sinlaku was located at latitude 8.7°N and longitude 151.5°E which put the center about 575 miles (930 km) southeast of Guam.  Sinlaku was moving toward the north at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (165 km/h).  The minimum surface pressure was 972 mb.

Former Tropical Storm Sinlaku rapidly intensified to a typhoon on Friday.  The inner end of a rainband wrapped around the center of Sinlaku’s circulation.  A small eye appeared to be forming at the center of Typhoon Sinlaku.  Bands of showers and thunderstorms were revolving around the center of Sinlaku’s circulation.  Storms near the center of Sinlaku 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 Sinlaku increased on Friday as Sinlaku rapidly intensified.  Winds to typhoon force extended out 50 miles (80 km) from the center of Sinlaku’s circulation.  Winds to tropical storm force extended out 185 miles (295 km) from the center of Typhoon Sinlaku.

Typhoon Sinlaku will move through an environment favorable for intensification during the next 24 hours.  Sinlaku will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the middle of an upper level ridge that is over the Western North Pacific Ocean. The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear.  Typhoon Sinlaku will intensify during the next 24 hours.  Sinlaku could continue to intensify rapidly.  Typhoon Sinlaku is likely to strengthen to the equivalent of a major hurricane during the weekend.

Typhoon Sinlaku will move around the southwestern part of a high pressure system that is over the Western North Pacific Ocean. The high pressure system will steer Sinlaku toward the northwest during the next 24 hours.  On its anticipated track, Typhoon Sinlaku will move toward the southern Marianas.  Sinlaku will approach Guam in less than three days.

Typhoon Sinlaku will continue to produce gusty winds and locally heavy rain over Chuuk before it moves farther away on Saturday.  Heavy rain could cause flash floods in some locations.

Typhoon Sinlaku will be the equivalent of a major hurricane when it approaches Guam.  Sinlaku could bring very strong winds and locally heavy rain to Guam.  Heavy rain is likely to cause flash floods in some locations.

Tropical Storm Sinlaku Forms Southeast of the Marianas

Tropical Storm Sinlaku formed southeast of the Marianas on Thursday.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Sinlaku was located at latitude 8.4°N and longitude 151.5°E which put the center about 65 miles (105 km) north-northwest of Chuuk.  Sinlaku was moving toward the northwest at 4 m.p.h. (6 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 994 mb.

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

The circulation around Tropical Storm Sinlaku exhibited more organization on Thursday afternoon.  More thunderstorms formed near the center of Sinlaku’s circulation.  More thunderstorms also developed in bands revolving around the center of Tropical Storm Sinlaku.  Storms near the center of Sinlaku began to generate upper level divergence that pumped mass away from the tropical storm.  The removal of mass caused the surface pressure to decrease.

The distribution of wind speeds around Tropical Storm Sinlaku was fairly symmetrical.  Winds to tropical storm force extended out 105 miles (165 km) from the center of Sinlaku’s circulation.

Tropical Storm Sinlaku will move through an environment favorable for intensification during the next 24 hours.  Sinlaku will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the southern part of an upper level ridge that is over the Western North Pacific Ocean.  The ridge will produce easterly winds that will blow toward the top of Sinlaku’s circulation.  Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification.  Tropical Storm Sinlaku will intensify during the next 24 hours.  Sinlaku is likely to strengthen to a typhoon within 36 hours.

Tropical Storm Sinlaku will move around the southwestern part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer Sinlaku toward the northwest during the next 24 hours.  On its anticipated track, Tropical Storm Sinlaku will move away from Chuuk,  Sinlaku could approach Guam in three or four days.

Tropical Storm Sinlaku will produce gusty winds and locally heavy rain over Chuuk before it moves farther away on Friday.  Heavy rain could cause flash floods in some locations.

Tropical Storm Nuri Meanders North of Yap

Tropical Storm Nuri meandered north of Yap on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Nuri was located at latitude 11.0°N and longitude 138.8°E which put the center about 105 miles (165 km) north-northeast of Yap.  Nuri was moving toward the east-northeast 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 Nuri struggled in a hostile environment on Wednesday.  An upper level ridge that was southeast of the Marianas produced strong southwesterly winds that blew across the top of Nuri’s circulation.  Those winds caused strong vertical wind shear.  Those winds also blew the tops off of thunderstorms near the center of Nuri’s circulation.  A few thunderstorms were still occurring in bands in the eastern periphery of Tropical Storm Nuri.  Bands in the other parts of Nuri’s circulation consisted primarily of showers and lower clouds.

Tropical Storm Nuri will move through an environment that will be unfavorable for intensification during the next 24 hours.  Nuri will move over water where the Sea Surface Temperatures are near 29°C.   However, the upper level ridge that is southeast of the Marianas will continue to produce strong southwesterly winds that will blow across the top of Nuri’s circulation.  Those winds will cause strong vertical wind shear.  In addition, Tropical Storm Nuri will be just to the south of a large area of drier air that originated over eastern Asia. The combination of strong vertical wind shear and drier air will cause Tropical Storm Nuri to weaken during the next 24 hours.

Tropical Storm Nuri will move around the western part of a high pressure system that is south of the Marianas.  The high pressure system will steer Nuri toward the east-northeast during the next 24 hours.  On its anticipated track, Tropical Storm Nuri will move toward the Marianas as it weakens.

Tropical Storm Nuri Forms North of Yap

Tropical Storm Nuri formed over the Western North Pacific Ocean north of Yap on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Nuri was located at latitude 11.63°N and longitude 138.4°E which put the center about 160 miles (260 km) north of Yap.  Nuri was moving toward the east at 3 m.p.h. (5 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 strengthened on Tuesday and the Japan Meteorological Agency designated the system as Tropical Storm Nuri.

Thunderstorms formed near the center of Tropical Storm Nuri on Tuesday.  Even so, the distribution of thunderstorms in Tropical Storm Nuri was asymmetrical.  Most of the thunderstorms were occurring in bands in the northern half of Nuri’s circulation.  Bands in the southern half of Tropical Storm Nuri consisted primarily of showers and lower clouds.  Storms near the center of Nuri started to generate some upper level divergence that pumped mass away to the north and east of the tropical storm.

Tropical Storm Nuri will move through an environment that will be mostly unfavorable for intensification.  Nuri will move over water where the Sea Surface Temperatures are near 29°C.   It will move under the western part of an upper level ridge that is south of the Marianas.  The upper level ridge will produce southerly winds that will blow toward the top of Nuri’s circulation.  Those winds will cause moderate vertical wind shear.  In addition, Tropical Storm Nuri formed just to the south of a large area of drier air that originated over eastern Asia.  The combination of moderate vertical wind shear and drier air is likely to prevent Tropical Storm Nuri from intensifying during the next 24 hours.

Tropical Storm Nuri will move around the western part of a high pressure system that is south of the Marianas.  The high pressure system will steer Nuri toward the east-northeast during the next 24 hours.  On its anticipated track, Tropical Storm Nuri will move toward the Marianas.

Tropical Storm Nuri cold bring gusty winds and locally heavy rain to the Marianas later this week.

Tropical Storm Penha Brings Wind and Rain to Southern Philippines

Tropical Storm Penha brought wind and rain to the southern Philippines on Thursday.  At 10:00 a.m. EST on Thursday the center of Tropical Storm Penha was located at latitude 8.7°N and longitude 126.4°E which put the center about 20 miles (30 km) east of Lianga, Philippines.  Penha was moving toward the west-northwest at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1001 mb.

Tropical Storm Penha brought wind and rain to the southern Philippines on Thursday.  Bands in the western side of Penha’s circulation were dropping rain on northern Mindanao, Leyte, Samar, Bohol, Cebu, and Negros.  Heavy rain could cause flash floods in some locations.

The area of strongest winds in Tropical Storm Penha was relatively small.  Winds to tropical storm force extended out 65 miles (105 km) from the center of Penha’s circulation.

Tropical Storm Penha will move around the southern part of the high pressure system that is south of Japan.  The high pressure system will steer Penha toward the west-northwest during the next 24 hours.  On its anticipated track, Tropical Storm Penha will move across northern Mindanao during the next few hours.  Penha will reach the Bohol Sea in 12 hours.  Tropical Storm Penha will be over the northern Sulu Sea in 24 hours.

Tropical Storm Penha will move into an environment that will be unfavorable for intensification during the next 24 hours. Tropical Storm Penha will weaken while the center moves over northern Mindanao.   Penha will then 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 upper level ridge will produce strong southeasterly winds that will blow toward the top of Penha’s circulation.  The winds will cause strong vertical wind shear.  In addition, Penha will move into a region of drier air by the time it reaches the northern part of the Sulu Sea.  The strong vertical wind shear and the drier air will cause Tropical Storm Penha to continue to weaken even when the center gets back of water.

 

Depression Strengthens to Tropical Storm Penha

A tropical depression over the Western North Pacific Ocean east of Mindanao strengthened to Tropical Storm Penha on Wednesday morning.  At 10:00 a.m. EST on Wednesday the center of Tropical Storm Penha was located at latitude 8.6°N and longitude 131.0°E which put the center about 330 miles (530 km) west of Tandag, Philippines.  Penha was moving toward the west at 13 m.p.h. (21 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 tropical depression east of Mindanao strengthened on Wednesday morning and the Japan Meteorological Agency designated the system as Tropical Storm Penha.

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

The circulation around Tropical Storm Penha was interacting with a large high pressure system that was south of Japan.  The interaction with the high pressure system was causing the distribution of wind speeds in Penha to be asymmetrical.  Winds to tropical storm force extended out 100 miles (160 km) in the northern side of Tropical Storm Penha.  Winds to tropical storm force only extended out 25 miles (40 km) in the southern half of Penha’s circulation.

Tropical Storm Penha will move through an environment somewhat favorable for intensification during the next 24 hours.  Penha 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 upper level ridge will produce southeasterly winds that will blow toward the top of Penha’s circulation.  The winds will cause moderate vertical wind shear.  The moderate vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification.  Tropical Storm Penha could intensify slowly during the next 24 hours.

Tropical Storm Penha will move around the southern part of the high pressure system that is south of Japan.  The high pressure system will steer Penha toward the west during the next 24 hours.  On its anticipated track, Tropical Storm Penha will reach Mindanao in 24 hours.

Tropical Storm Penha will bring strong winds and locally heavy rain to Mindanao and the rest of the southern Philippines.  Heavy rain could cause flash floods in some locations.

Tropical Depression Forms East of the Philippines

A tropical depression formed over the Western North Pacific Ocean east of the Philippines on Tuesday morning.  At 10:00 a.m. EST on Tuesday the center of the tropical depression was located at latitude 9.1°N and longitude 135.0°E which put the center about 125 miles (200 km) north of Palau.  The tropical depression was moving toward the west 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.

A low pressure system over the Western North Pacific Ocean east of the Philippines strengthened on Tuesday morning and the Japan Meteorological Agency designated the system as a tropical depression.

The circulation around the tropical depression was gradually getting more organized.  More thunderstorms were developing in bands revolving around the center of the tropical depression.  Storms near the center of circulation 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 24 hours.  The tropical depression 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 upper level ridge will produce easterly winds that will blow toward the top of the depression’s circulation.  The winds will cause moderate vertical wind shear.  The moderate vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  The tropical depression is likely to intensify to a tropical storm during the next 24 hours.

Th tropical depression will move around the southern part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer the tropical depression toward the west during the next 24 hours.  On its anticipated track, the tropical depression will move toward the southern Philippines.

 

Nokaen Strengthens Back to a Tropical Storm

Former Tropical Depression Nokaen strengthened back to a tropical storm over the Western North Pacific Ocean on Monday night.  At 10:00 a.m. EST on Tuesday the center of the Tropical Storm Nokaen was located at latitude 17.4°N and longitude 132.3°E which put the center about 700 miles (1130 km) northwest of Yap.  Nokaen was moving toward the east 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 1000 mb.

After weakening to a tropical depression on Sunday, Nokaen strengthened back to a tropical storm on Monday night.  Thunderstorms developed in several bands in the eastern side of Tropical Storm Nokaen.  Bands in the western side of Nokaen’s circulation still consisted primarily of showers and lower clouds.  The thunderstorms in the eastern side of Nokaen started to generate some upper level divergence that pumped mass away to the east of the tropical storm.

The strongest winds were occurring in the western side of Tropical Storm Nokaen.  Winds to tropical storm force extended out 115 miles (185 km) in the western half of Nokaen’s circulation.  The winds in the the eastern side of Tropical Storm Nokaen were blowing at less than tropical storm force.

Tropical Storm Nokaen will move through an environment that will be unfavorable for intensification during the next 24 hours.  Nokaen will move over water where the Sea Surface Temperatures are near 28°C.  However, it will continue to be surrounded by drier air.  In addition, Tropical Storm Nokaen will move under the southern portion of the midlatitude upper level westerly winds.  Those winds will cause vertical wind shear.  The drier air and the vertical wind shear will prevent Tropical Storm Nokaen from intensifying.

Tropical Storm Nokaen will move around the northwestern part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer Nokaen toward the east during the next 24 hours.  On its anticipated track, Tropical Storm Nokaen will remain northwest of Yap.

Nokaen Weakens to a Tropical Depression

Former Tropical Storm Nokaen weakened to a tropical depression over the Western North Pacific Ocean east of Luzon on Monday morning.  At 10:00 a.m. EST on Monday the center of the Tropical Depression Nokaen was located at latitude 17.1°N and longitude 127.4°E which put the center about 365 miles (530 km) east-southeast of Aparri, Philippines.  Nokaen was moving toward the northeast 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 1000 mb.

Former Tropical Storm Nokaen continued to move through an environment containing drier air on Monday.  The drier air caused most of the thunderstorms in Tropical Depression Nokaen to dissipate.  A few thunderstorms were still occurring in a band in the far northern periphery of Nokaen’s circulation.  The bands in the other parts of Tropical Depression Nokaen consisted primarily of showers and lower clouds.

Tropical Depression Nokaen will move through an environment that will be unfavorable for intensification during the next 24 hours.  Nokaen will move over water where the Sea Surface Temperatures are near 28°C.  However, it will continue to be surrounded by drier air.  In addition, Tropical Depression Nokaen will move under the southern portion of the midlatitude upper level westerly winds.  Those winds will cause vertical wind shear.  The drier air and the vertical wind shear will cause the circulation around Tropical Depression Nokaen to continue to weaken.

Tropical Depression Nokaen will move around the western end of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer Nokaen toward the east-northeast during the next 24 hours.  On its anticipated track, Tropical Depression Nokaen will continue to move farther away from Luzon as it gradually spins down.