Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Tropical Storm Nuri Meanders North of Yap

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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

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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.

Tropical Storm Nokaen Weakens East of the Philippines

Tropical Storm Nokaen weakened east of the Philippines on Sunday morning.  At 10:00 a.m. EST on Sunday the center of the Tropical Storm Nokaen was located at latitude 15.5°N and longitude 125.9°E which put the center about 310 miles (500 km) east-southeast of Casiguran, Philippines.  Nokaen was moving toward the north-northeast at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 998 mb.

A combination of drier air and vertical wind shear caused Tropical Storm Nokaen to weaken east of the Philippines on Sunday morning.  A large high pressure system over eastern Asia was transporting drier air into the environment around Tropical Storm Nokaen.  The drier air caused many of the thunderstorms in Nokaen’s circulation to dissipate.  An upper level ridge over the Western North Pacific Ocean was producing southerly winds that blew the tops off of many of the thunderstorms remaining in Tropical Storm Nokaen.

Most of the bands in Tropical Storm Nokaen consisted primarily of showers and lower clouds on Sunday morning.  A few new thunderstorms formed northeast of the center of Nokaen’s circulation.  The dissipation of many of the thunderstorms in Nokaen reduced the upper level divergence.   Without thunderstorms to pump mass away from Nokaen, convergence in the lower levels of the atmosphere caused the surface pressure to increase.

The distribution of wind speeds in Tropical Storm Nokaen remained asymmetrical.  Winds to tropical storm force extended out 115 miles (185 km) in the northern half of Nokaen’s circulation.  Winds to tropical storm force extended out only 25 miles (40 km) in the southern half of Tropical Storm Nokaen.

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, the western end of the upper level ridge over the Western North Pacific Ocean will continue to produce southerly winds that will blow toward the top of Nokaen’s circulation.  Those winds will cause strong vertical wind shear.  In addition drier air will continue to surround Tropical Storm Nokaen.  Tropical Storm Nokaen is likely to continue to weaken slowly during the next 24 hours.

Tropical Storm 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 northeast during the next 24 hours.  On its anticipated track, the center of Tropical Storm Nokaen will move farther away from Luzon.

Tropical Storm Nokaen Passes East of Luzon

Tropical Storm Nokaen was passing just to the east of Luzon on Saturday morning.  At 10:00 a.m. EST on Saturday the center of the Tropical Storm Nokaen was located at latitude 15.2°N and longitude 124.1°E which put the center about 185 miles (300 km) east-southeast of Casiguran, Philippines.  Nokaen was moving toward the northwest at 13 m.p.h. (21 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 993 mb.

Tropical Storm Nokaen strengthened a little more as it moved east of Luzon on Saturday morning.  Even though Nokaen was stronger, the distribution of thunderstorms remained asymmetrical.  Thunderstorms were occurring in bands in the western and northern parts of Tropical Storm Nokaen.  Bands in the eastern and southern parts of Nokaen’s circulation consisted primarily of showers and lower clouds.  Storms near the center of Nokaen 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 Nokaen was interacting with a high pressure system over eastern Asia.  The interaction was causing a large area of strong winds in the northwestern quadrant of Nokaen’s circulation.  Winds to tropical storm force extended out 150 miles (240 km) in the northwestern quadrant of Tropical Storm Nokaen.  Winds to tropical storm force only extended out 60 miles (95 km) in the other quadrants of Nokaen’s circulation.

Tropical Storm Nokaen will move through an environment that will become unfavorable for intensification during the next 24 hours.  Nokaen will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the western end of an upper level ridge that is over the Western North Pacific Ocean.  The upper level ridge will produce southeasterly winds that will blow toward the top of Nokaen’s circulation.  Those winds will cause the vertical wind shear to increase.  Tropical Storm Nokaen will start to weaken when the vertical wind shear increases.

Tropical Storm 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 north during the next 24 hours.  On its anticipated track, the center of Tropical Storm Nokaen will remain east of Luzon.

Bands in the western side of Tropical Storm Nokaen will bring gusty winds and locally heavy rain to parts of Luzon.  Heavy rain could cause flash floods in some locations.

Tropical Cyclone Nokaen Nears the Philippines

Tropical Storm Nokaen moved nearer to the Philippines on Friday morning.  At 10:00 a.m. EST on Friday the center of the Tropical Storm Nokaen was located at latitude 12.4°N and longitude 126.7°E which put the center about 115 miles (185 km) east of Laoang, Philippines.  Nokaen 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 997 mb.

Tropical Storm Nokaen strengthened on Friday morning as it moved closer to the Philippines.  More thunderstorms formed near the center of Nokaen’s circulation.  More thunderstorms also developed in bands in the western side of Tropical Storm Nokaen.  Bands in the eastern side of Nokaen’s circulation still consisted primarily of showers and lower clouds.  Storms near the center of Nokaen generated more upper level divergence that pumped mass away from the tropical storm.  The removal of more mass caused the surface pressure to decrease.

The strongest winds were occurring in the northwestern part of Tropical Storm Nokaen.  Winds to tropical storm force extended out 150 miles (240 km) in the northwestern quadrant of Nokaen’s circulation.  The winds in the other parts of Tropical Storm Nokaen were blowing at less than tropical storm force.

Tropical Storm Nokaen will move through an environment somewhat favorable for intensification during the next 24 hours.  Nokaen will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the western end of an upper level ridge that is over the Western North Pacific Ocean.  The upper level ridge will produce southeasterly winds that will blow toward the top of Nokaen’s circulation.  Those 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 Nokaen could continue to intensify during the next 24 hours.

Tropical Storm 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 northwest during the next 24 hours.  On its anticipated track, the center of Tropical Storm Nokaen will be near Samar on in 24 hours.

Bands in the western side of Nokaen’s circulation are already bringing gusty winds and locally heavy rain to Samar, Catanduanes Island, and southeastern Luzon.  Heavy rain is likely to cause flash floods in some locations.