Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Tropical Cyclone Pola Strengthens to Equivalent of Hurricane/Typhoon

Tropical Cyclone Pola strengthened to the equivalent of a hurricane/typhoon on Wednesday.  At 4:00 a.m. EST on Wednesday the center of Tropical Cyclone Pola was located at latitude 20.2°S and longitude 177.6°W which put it about 170 miles (275 km) west-northwest of Nuku’alofa, Tonga.  Pola was moving toward the south-southwest at 8 m.p.h. (13 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 969 mb.

There was a small, circular eye at the center of Tropical Cyclone Pola.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Storms near the core of Pola were generating upper level divergence which was pumping mass away from the tropical cyclone.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Pola.  The strongest rainbands were occurring in the northwestern half of the circulation.  Bands in the southeastern half of Pola consisted primarily of showers and lower clouds.  Winds to hurricane/typhoon force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out about 160 miles (260 km) from the center.

Tropical Cyclone Pola will move through an environment favorable for support a strong tropical cyclone for another day or so.  Pola will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weak and there will not be much vertical wind shear.  Tropical Cyclone Pola could strengthen during the next 24 hours.  Pola will stat to move over cooler water on Thursday.  An upper level trough will approach Tropical Cyclone Pola from the west.  The trough will produce northwesterly winds which will increase the vertical wind shear.  A combination of cooler water and more vertical wind shear will cause Pola to weaken.  Tropical Cyclone Pola could make a transition to an extratropical cyclone later this week.

Tropical Cyclone Pola will move around the western end of a subtropical ridge over the South Pacific Ocean.  The ridge will steer Pola toward the south-southwest during the next day or two.  Eventually, the upper level trough will turn Tropical Cyclone Pola toward the southeast.  On its anticipated track the core of Pola and the strongest winds will pass west of Tonga.  Rainbands on the eastern side of the circulation could bring gusty winds and heavy rain at times to parts of Tonga.

Elsewhere, Typhoo Wutip continued to weaken west-northwest of the Marianas.  At 4:00 a.m. EST on Wednesday the center of Typhoon Wutip was located at latitude 16.3°N and longitude 139.4°E which put it about 370 miles (595 km) west-northwest of Guam.  Wutip was moving toward the north-northwest at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 981 mb.

Tropical Cyclone Pola Organizes Quickly Between Fiji and Tonga

Tropical Cyclone Pola organized quickly between Fiji and Tonga on Tuesday.  At 4:00 p.m. EST on Tuesday the center of Tropical Cyclone Pola was located at latitude 18.8°S and longitude 176.7°W which put it about 185 miles (295 km) north-northwest of Nuku’alofa, Tonga.  Pola was moving toward the south at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 55 m.p.h. (90 km/h) and there were wind gusts to 70 m.p.h. (110 km/h).  The minimum surface pressure was 988 mb.

A well organized low level center of circulation consolidated within a much larger area of showers and thunderstorms north of Tonga on Tuesday and the Fiji Meteorological Service classified the system as Tropical Cyclone Pola.  A small circular eye was beginning to appear at the center of circulation on some satellite images.  The eye was surrounded by a narrow ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Storms near the center of Pola were generating upper level divergence which was pumping mass away from the tropical cyclone.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Pola.  Winds to tropical storm force extended out about 175 miles (280 km) from the center of circulation.

Tropical Cyclone Pola will move through an environment favorable for intensification during the next 24 to 36 hours.  Pola will move over water where the Sea Surface Temperature is near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Pola will intensify during the next day or so and it could strengthen into the equivalent of a hurricane/typhoon.  Pola will move over colder water and into a region where the upper level winds are stronger later this week and it will start to weaken at that time.

Tropical Cyclone Pola will move around the northwestern portion of a subtropical ridge over the South Pacific Ocean.  The ridge will steer Pola in a southward direction.  On its anticipated track the core and strongest part of Tropical Cyclone Pola will pass west of Tonga.  The outer rainbands on the western side of the circulation could bring gusty winds and locally heavy rain to parts of southeastern Fiji.  Rainbands on the eastern side of the circulation could also bring gusty winds and locally heavy rain to parts of Tonga.

Elsewhere, Typhoon Wutip was weakening west of the Marianas.  At 4:00 p.m. EST on Tuesday the center of Typhoon Wutip was located at latitude 15.7°N and longitude 139.9°E which put it about 345 miles (560 km) west-northwest of Guam.  Wutip was moving toward the north at 3 m.p.h. (5 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (215 km/h).  The minimum surface pressure was 972 mb.

Typhoon Wutip Strengthens to Equivalent of a Category 5 Hurricane

Typhoon Wutip strengthened into the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Monday.  At 5:00 a.m. EST on Monday the center of Typhoon Wutip was located at latitude 14.0°N and longitude 140.1°E which put it about 300 miles (480 km) west-northwest of Guam.  Wutip was moving toward the north-northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km.h) and there were wind gusts to 195 m.p.h. (315 km/h).  The minimum surface pressure was 929 mb.

Typhoon Wutip completed an eyewall replacement cycle on Sunday and then it rapidly intensified into the equivalent of a Category 5 hurricane.  The inner eyewall dissipated completely and the outer eyewall contracted around a circular, symmetrical eye.  A ring of strong thunderstorms surrounded the new eye and the strongest winds were occurring in that ring of storms.  Storms near the core of Typhoon Wutip were generating strong upper level divergence which was pumping mass away from the typhoon.  Bands of showers and thunderstorms were revolving around the core of Wutip.

Winds to typhoon force extended out about 45 miles (75 km) from the center of Typhoon Wutip.  Winds to tropical storm force extended out about 160 miles (260 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Wutip was 35.0.  The Hurricane Size Index (HSI) was 16.6 and the Hurricane Wind Intensity Size Index (HWISI) was 51.6.

Typhoon Wutip will remain in an environment capable of supporting a strong typhoon for another 12 to 24 hours.  Wutip will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  A band of stronger westerly winds north of the Philippines will approach Typhoon Wutip in another day or so.  Those winds will cause the vertical wind shear to increase and the increased shear will cause Wutip to weaken.

Typhoon Wutip will move southwest of a subtropical ridge over the Western North Pacific Ocean.  The ridge is forecast to steer Wutip in a west-northwesterly direction.  On its forecast track Typhoon Wutip will gradually move farther away from the Northern Marianas.

Powerful Typhoon Wutip Moving West of Guam

Powerful Typhoon Wutip moved west of Guam on Saturday.  At 10:00 p.m. EST on Saturday the center of Typhoon Wutip was located at latitude 12.9°N and longitude 141.9°E which put it about 170 miles (280 km) west-southwest of Guam.  Wutip was moving toward the northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 924 mb.  Typhoon Wutip was the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.

Visible and microwave satellite imagery  indicated that Typhoon Wutip may have started an eyewall replacement cycle.  An inner rainband wrapped around the original eye and eyewall.  An outer eyewall formed around the original inner eyewall.  The strongest winds were occurring in the inner eyewall.  The eyewall replacement cycle and the formation of an outer eyewall contributed to an increase in the size of Typhoon Wutip.  Winds to typhoon force extended out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out about 200 miles (320 km) from the center.

The Hurricane Intensity Index (HII) for Typhoon Wutip was 33.3.  The Hurricane Size Index (HSI) was 21.5 and the Hurricane Wind Intensity Size Index (HWISI) was 54.8.

Typhoon Wutip will move into an environment that will gradually become less favorable for strong typhoons.  Wutip will move over water where the Sea Surface Temperature is near 27°C.  The eyewall replacement cycle will cause Typhoon Wutip to weaken when the inner eyewall starts to dissipate.  Wutip also appears to be moving toward a region of drier air.  Rainbands in the western side of Typhoon Wutip seemed to be weakening as they moved into the region of drier air.  Typhoon Wutip will weaken during the next few days.

Typhoon Wutip will move southwest of a subtropical ridge over the Western North Pacific Ocean.  The ridge will steer Wutip toward the northwest during the next several days.  On its anticipated track Typhoon Wutip will move away from the Marianas.

Typhoon Wutip Strengthens to Equivalent of a Major Hurricane South of Guam

Typhoon Wutip strengthened into the equivalent of a major hurricane south of Guam on Friday.  At 10:00 a.m. EST on Friday the center of Typhoon Wutip was located at latitude 10.1°N and longitude 144.7°E which put it about 240 miles (385 km) south of Guam.  Wutip was moving toward the northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 949 mb.

Tropical Storm Warnings were in effect for Guam, Rota and Faraulep.  Tropical Storm Watches have been issued for Tinian, Saipan, Agrihan and Pagan.

Typhoon Wutip was a very well organized tropical cyclone.  A small eye was at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Wutip.  Storms near the core were generating upper level divergence which was pumping mass away from the typhoon.

Typhoon Wutip had a large circulation.  Winds to typhoon force extended out about 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out about 185 miles (295 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Wutip was 22.1.  The Hurricane Size Index (HSI) was 17.3 and The Hurricane Wind Intensity Size Index (HWISI) was 39.4.  Typhoon Wutip was capable of causing major damage.

Typhoon Wutip may be near its peak intensity.  Wutip will move over water where the Sea Surface Temperature is near 29°C.  So, there is enough energy in the upper ocean to support a strong typhoon.  Typhoon Wutip has been in an area where the upper level winds were weak and there was little vertical wind shear.  The shear will remain small for another 12 to 24 hours.  Then an upper level trough will approach Typhoon Wutip from the west in a day or so.  The trough will bring southwesterly winds and the vertical wind shear will increase.  Wutip will start to weaken when the shear increases.

Typhoon Wutip will move around the western end of a subtropical ridge over the Western North Pacific Ocean.  Wutip will gradually turn more toward the north while it moves around the end of the ridge.  On its anticipated track the core of Typhoon Wutip will pass west of Guam and the Northern Marianas.  Wutip could bring winds to tropical storm force to Guam and some of the other islands, which is why the warnings and watches were issued.

Wutip Intensifies Into a Typhoon Southeast of Guam

Former Tropical Storm Wutip intensified into a typhoon southeast of Guam on Wednesday.  At 10:00 p.m. EST on Wednesday the center of Typhoon Wutip was located at latitude 6.5°N and longitude 150.0°E which put it about 640 miles (1035 km) southeast of Guam.  Wutip was moving toward the west-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 979 mb.

Tropical Storm Watches have been issued for Guam, Rota, Tinian and Saipan.  A Typhoon Warning is in effect for Satawal and Puluwat.  A Tropical Storm Warning and a Typhoon Watch are in effect for Ulul and Faraulep.

Typhoon Wutip continued to exhibit better organization on Wednesday.  A cluster of thunderstorms remained near the center of circulation.  A band of storms wrapped around the southern side of the center, which could indicate the start of the formation of an eyewall.  Other bands of showers and thunderstorms were revolving around the core of Typhoon Wutip.  Storms near the core were generating upper level divergence which was pumping mass away from the typhoon.  Winds to typhoon force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out about 160 miles (260 km) from the center.

Typhoon Wutip will move through an environment favorable for intensification for several more days.  Wutip will move over water where the Sea Surface Temperature is near 30°C.  Typhoon Wutip will move around the western end of an upper level ridge.  The ridge will produce easterly winds which will blow toward the top of the circulation.  Those winds will create some vertical wind shear, but the wind shear will not be great enough to prevent intensification.  Typhoon Wutip will continue to intensify and it could strengthen into the equivalent of a major hurricane within 36 hours.

The ridge will steer Typhoon Wutip in a northwesterly direction during the next 48 hours.  Wutip is likely to turn more toward the north-northwest when it approaches the western end of the ridge.  On its anticipated track Typhoon Wutip could be south of Guam in 36 to 48 hours.  Wutip could be the equivalent of a major hurricane at that time.

Elsewhere, Tropical Cyclone Oma continued to spin over the Coral Sea between New Caledonia and Australia.  At 10:00 p.m. EST on Wednesday the center of Tropical Cyclone Oma was located at latitude 22.7°S and longitude159.8°E which put it about 560 miles (905 km) northeast of Brisbane, Australia.  Oma was moving toward the southwest at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 981 mb.

Tropical Storm Wutip Forms Southeast of Chuuk

Tropical Storm Wutip formed southeast of Chuuk on Tuesday.  At 4:00 p.m. EST on Tuesday the center of Tropical Storm Wutip was located at latitude 4.6°N and longitude 155.2°E which put it about 295 miles (475 km) southeast of Chuuk.  Wutip was moving toward the west at 15 m.p.h. (24 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 Typhoon Watch was issued for Puluwat and Satawal.  A Tropical Storm Warning was in effect for Nukuoro, Losep, and Chuuk.  A Tropical Storm Watch was issued for Fananu and Ulul.

Thunderstorms developed near the center of a low pressure system southeast of Chuuk on Tuesday and the Japan Meteorological Agency designated the system as Tropical Storm Wutip.  Thunderstorms continued to form near the center of Wutip and those storms were starting to generate upper level divergence.  Bands of showers and thunderstorms formed in the northern and western portions of the circulation.  Bands south and east of the center consisted primarily of showers and lower clouds although there were a few thunderstorms in some of those bands.  Winds to tropical storm force extended out about 150 miles (245 km) from the center of circulation in the northern half of Wutip and out about 100 miles (160 km) in the southern half of the tropical storm.

Tropical Storm Wutip will move through an environment favorable for intensification.  Wutip will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge east of Tropical Storm Wutip will produce easterly winds which will cause some vertical wind shear.  However, the wind shear will not be strong enough to prevent intensification.  Tropical Storm Wutip will intensify during the next several days.  Wutip could strengthen into a typhoon with 24 to 36 hours.  A period of rapid intensification could occur once an inner core becomes more well organized.  Tropical Storm Wutip could strengthen to the equivalent of a major hurricane in three or four days.

Tropical Storm Wutip will move around the western end of a subtropical ridge.  The ridge will steer Wutip toward the northwest during the next few days.  On its anticipated track Tropical Storm Wutip could approach Guam in three days.  Wutip is likely to be a typhoon at that time.

Tropical Storm Pabuk Brings Wind and Rain to Southern Thailand

Tropical Storm Pabuk brought wind and rain to southern Thailand on Friday.  At 5:00 p.m. EST on Friday the center of Tropical Storm Pabuk was located at latitude 8.7°N and longitude 98.5°E which put it about 60 miles (95 km) northeast of Phuket, Thailand.  Pabuk was moving toward the west-northwest at 10 m.p.h. (16 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 Pabuk made landfall near Sichon in southern Thailand.  Pabuk brought gusty winds to much of the Isthmus of Kra.  It also dropped heavy rain over parts of southern Thailand.  Tropical Storm Pabuk weakened when it crossed the Isthmus of Kra, but the core of the circulation appears to have remained intact.  Pabuk is moving over the Andaman Sea and it still has a well defined low level center of circulation.  Several bands of showers and thunderstorms are revolving around the core of the tropical storm.  Additional bands of showers and thunderstorms are located in the northeastern part of the circulation which is over the Gulf of Thailand.

Tropical Storm Pabuk will move into an environment favorable for intensification during the next 24 to 36 hours.  Pabuk will move over water where the Sea Surface Temperature is near 28°C.  An upper level ridge over the Western North Pacific Ocean will produce southeasterly winds which will blow toward the top of the circulation.  Those winds will cause moderate vertical wind shear, which will inhibit intensification.  However, the wind shear may not be strong enough to prevent Tropical Storm Pabuk from strengthening.

Tropical Storm Pabuk will continue to move around the western end of the ridge over the Western North Pacific Ocean.  The ridge will steer Pabuk toward the west-northwest for another 24 to 36 hours.  Pabuk will turn more toward the north when it reaches the western end of the ridge.  On its anticipated track Tropical Storm Pabuk will reach the Andaman Islands in about 36 hours.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 01W formed southeast of the Marshall Islands.  At 4:00 p.m. EST on Friday the center of Tropical Depression 01W was located at latitude 4.9°N and longitude 174.0°E which put it about 250 miles (400 km) southeast of Majuro, Marshall Islands.  It was moving toward the northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1004 mb.  Tropical Depression 01W is forecast to move toward the west-northwest and strengthen.  On its anticipated track it could move toward Majuro, Kwajalein, Ujelang, and the Marianas.

Tropical Storm Pabuk Nears Southern Thailand

Tropical Storm Pabuk neared southern Thailand late on Thursday.  At 10:00 p.m. EST on Thursday the center of Tropical Storm Pabuk was located at latitude 8.0°N and longitude 101.0°E which put it about 110 miles (170 km) southeast of Sichon, Thailand.  Pabuk was moving toward the west-northwest at 16 m.p.h. (26 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 988 mb.

Tropical Storm Pabuk exhibited more organization on Thursday.  A broken ring of showers and thunderstorms surrounded the center of circulation.  Stronger thunderstorms were occurring in the western part of the ring, while weaker storms and showers comprised the rest of the ring.  Several bands of thunderstorms were on the western side of Tropical Storm Pabuk.  Bands of showers and thunderstorms were also on the eastern side of the circulation.  Storms near the center of circulation were generating upper level divergence which was pumping mass away to the northwest of the tropical storm.  Winds to tropical storm force extended out about 100 miles (160 km) from the center.

Tropical Storm Pabuk will move through an environment favorable for intensification for the next six to twelve hours.  Pabuk will move over water where the Sea Surface Temperature is near 28°C.  It will move around the western end of a subtropical ridge over the Western North Pacific Ocean.  The ridge will produce southeasterly winds which will blow toward the top of the circulation.  Those winds will cause moderate vertical wind shear which will inhibit intensification.  Pabuk could intensify during the short term.  It will reach the coast of southern Thailand in less than 12 hours.  Tropical Storm Pabuk will weaken when it moves across the Isthmus of Kra.  Pabuk could strengthen again when it moves over the Andaman Sea in a day or so.

Tropical Storm Pabuk will move around the western end of the subtropical ridge, which will steer the tropical storm in a northwesterly direction.  On its anticipated track Tropical Storm Pabuk will make landfall on the coast of southern Thailand near Sichon in a few hours.  Pabuk will move across the Isthmus of Kra and into the Andaman Sea in a day or so.  Tropical Storm Pabuk could reach the Andaman Islands within 60 hours.

Tropical Storm Pabuk will bring gusty winds and heavy rain to southern Thailand.  Heavy rain could cause flash floods, especially in areas of steeper terrain.

Tropical Storm Pabuk Forms Over South China Sea

Tropical Storm Pabuk formed over the South China Sea near Pulau Laut on Tuesday.  At 10:00 p.m. EST on Tuesday the center of Tropical Storm Pabuk was located at latitude 5.9°N and longitude 108.2°E which put it about 675 miles (1090 km) east-southeast of Chumphon, Thailand.  Pabuk was moving toward the west at 6 m.p.h. (10 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.

More thunderstorms developed near the western side of the center of Tropical Depression 36W and the Japan Meteorological Agency designated the system as Tropical Storm Pabuk.  The distribution of thunderstorms around Tropical Storm Pabuk was asymmetrical.  Many of the stronger thunderstorms were occurring west of the center of circulation.  Pabuk was near the western end of a subtropical ridge over the Western North Pacific Ocean.  The ridge was producing southeasterly winds which were blowing toward the top of the circulation.  Those winds were causing moderate vertical wind shear and they were inhibiting upper level divergence to the west of Tropical Storm Pabuk.  The wind shear was also probably causing the asymmetrical distribution of thunderstorms.  Several bands of showers and thunderstorms were located on the northern periphery of Pabuk.

Tropical Storm Pabuk will move through an environment somewhat favorable for intensification.  Pabuk will move over water where the Sea Surface Temperature is near 28°C.  The upper level ridge over the Western North Pacific will continue to cause vertical wind shear, but the strength of the upper level winds could weaken slightly.  Wind shear will inhibit intensification, but Tropical Storm Pabuk is likely to strengthen during the next 24 to 48 hours.

The ridge over the Western North Pacific will steer Tropical Storm Pabuk toward the west-northwest during the next several days.  On its anticipated track Pabuk could approach southern Thailand in 48 to 60 hours.