Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Typhoon Hagupit Still Moving Toward the Philippines

Although Typhoon Hagupit has weakened somewhat, it still has the potential to bring strong winds and heavy rain to portions of the central and northern Philippines.  At 10:00 p.m. EDT on Thursday the center of Typhoon Hagupit was located at latitude 12.0°N and longitude 129.3°E which put it about 400 miles east of Legaspi, Philippines and about 610 miles east-southeast of Manila.  Hagupit was moving toward the west-northwest at 8 m.p.h.  The maximum sustained wind speed was 140 m.p.h. and there were gusts to 170 m.p.h.

As the forward movement of Hagupit slowed, easterly winds in the upper troposphere generated more wind shear and the typhoon has slowly weakened.  This weakening trend is likely to continue even though Hagupit will be moving over warm Sea Surface Temperatures.  Hagupit is still expected to be a significant typhoon when it begins to near the Philippines in about 36 hours.

Hagupit is being steering to the west-northwest by a subtropical ridge to its north.  A trough in the upper level westerly flow near Japan is expected to temporarily weaken the ridge and the forward motion of Hagupit could slow further.  However, after the upper level trough moves northeast of the ridge, the ridge is expected to strengthen again and steer Hagupit into the Philippines.  Hagupit could be very near the island of Samar in about 36 hours.  It is expected to cross the most southeastern portion of Luzon in about 54 hours and the center could be near Manila in  about 96 hours.

Although Hagupit is likely to weaken further before it reaches the Philippines it could bring strong winds and heavy rain.  The center is expected to pass just south of the Mayon Volcano and the potential for flooding and mudslides exists.  Moving over the islands of the Philippines will also weaken Hagupit, but it could still be a typhoon when it approaches Manila.

 

Hagupit Intensifies Rapidly Into a Super Typhoon

Typhoon Hagupit continued to intensify rapidly on Wednesday and it is now the equivalent of a Category 5 hurricane.  At 7:00 p.m. EST on Wednesday the center of Super Typhoon Hagupit was located at latitude 9.8°N and longitude 133.9°E which put it about 175 miles north of Palau, about 600 miles east of Tacloban, Philippines and about 930 miles east-southeast of Manila.  Hagupit was moving toward the west-northwest at 17 m.p.h.  The maximum sustained wind speed was 175 m.p.h. and there were estimated gusts to 215 m.p.h.

Hagupit is in a very favorable environment.  It is over warm Sea Surface Temperatures and the upper level winds are light.  Upper level outflow is well developed and it is pumping out mass in all directions.  The environment is capable of supporting a little further intensification.  However, when tropical cyclones become as intense as Hagupit, they often undergo eyewall replacement cycles, which can produce fluctuations in intensity.  Hagupit is expected to remain an intense typhoon during the next two to three days.

A subtropical ridge north of Hagupit is steering the typhoon toward the west-northwest.  The ridge is expected to steer Hagupit in the same general direction during the next 48 hours.  After that time an upper level trough in the westerly flow near Japan is expected to weaken the subtropical ridge and the forward motion of Hagupit could slow down.  There is much more uncertainty about the track forecast beyond three days.  One set of forecast models is predicting that Hagupit will turn toward the north before it reaches the Philippines.  However, another set of forecast models keeps Hagupit moving westward and reaching the Philippines during the weekend.  Given the intensity of Hagupit, it could be a destructive typhoon if it does move through the Philippines.

 

Typhoon Hagupit Intensies Rapidly As It Nears Yap

Typhoon Hagupit intensified rapidly on Tuesday.  At 10:00 p.m. EST on Tuesday the center of Typhoon Hagupit was located at latitude 7.9°N and longitude 139.5°E which put it about 190 miles southeast of Yap and about 1330 miles east-southeast of Manila, Philippines.  Hagupit was moving toward the west-northwest at 21 m.p.h.  The maximum sustained wind speed had increased to 105 m.p.h. and there were gusts to 130 m.p.h.

Hagupit is in an environment favorable for further intensification.  It is moving over warm Sea Surface Temperatures (SSTs) and the upper level winds remain light.  The upper level outflow is well developed and it continues to pump out mass and allow the surface pressure to decrease.  Hagupit is likely to continue to intensify on Wednesday and it could reach Super Typhoon intensity in several days.

Hagupit is being steered toward the west-northwest by a subtropical ridge located to its north.  On this track the center of Hagupit will pass just south of Yap in a few hours.  An upper level trough in the westerly flow near Japan will weaken the subtropical ridge and Hagupit is likely to move more slowly in two or three days.  The winds at the steering level will be weak in three or four days and the longer term track of Hagupit is more uncertain.  There is a possibility that it could be steered westward toward the Philippines.

Tropical Storm Hagupit Organizing Rapidly South of Guam

Tropical Depression 22W organized rapidly on Monday and intensified into Tropical Storm Hagupit.  At 10:00 p.m. EST on Monday the center of Tropical Storm Hagupit was located at latitude 6.1°N and longitude 146.0°E which put it about 490 miles south-southeast of Guam and about 570 miles east-southeast of Yap.  Hagupit was moving toward the west at 24 m.p.h.  The maximum sustained wind speed was 65 m.p.h. and there were gusts to 80 m.p.h.

Hagupit has developed multiple spiral bands of thunderstorms and there are some indications that an eye may be forming at the center of the circulation.  There is a large and well developed circulation around the tropical storm.  The winds in the upper levels are relatively light and upper level divergence continues to pump out mass from the center of circulation.  Hagupit will continue to move over warm Sea Surface Temperatures and the environment is favorable for continued intensification.  Hagupit could become a typhoon on Tuesday and it could be a strong typhoon in several days.

A subtropical ridge north of Hagupit is steering the storm toward the west and it is likely to steer the tropical storm in a general west-northwesterly direction during the next 48-72 hours.  The projected path would bring Hagupit very close to Yap in about 36 hours.   There is more uncertainty about the possible track of Hagupit after it passes Yap because an upper level trough moving north of the storm could weaken the subtropical ridge.  If the ridge weakens, the winds at the steering level could become weaken and the motion of Hagupit could slow.

 

Tropical Depression 22W Forms South of Chuuk

A new tropical depression has formed over the Western North Pacific Ocean.  At 11:00 p.m. EST on Sunday the center of Tropical Depression 22W (TD 22W) was located at latitude 4.8°N and longitude 152.8°E which put it about 150 miles south-southeast of Chuuk and about 800 miles southeast of Guam.  TD 22W was moving toward the west-northwest at 8 m.p.h.  The maximum sustained wind speed was 35 m.p.h. and there were gusts to 45 m.p.h.

Thunderstorms were increasing near the center of TD 22W and it was showing increased signs of organization.  There was an area of thunderstorms at the core of the circulation and spiral bands of convection were developing outside the core.  TD 22W is over warm Sea Surface Temperatures (SSTs) and the upper level winds are not too strong.  The environment is favorable for intensification and upper level divergence is occurring over the eastern half of the circulation.  TD 22W is likely to intensify into a tropical storm on Monday.  Further intensification is likely over the next few days as the storm remains over warm SSTs and a period of more rapid intensification is possible.

TD 22W is being steered to the west-northwest by a subtropical ridge that is located to the north of it.  The subtropical ridge is likely to continue to steer TD 22W in that same general direction during the next two or three days.  The storm could be a typhoon by the time it nears Yap.

 

Tropical Storm Sinlaku Intensifying As It Approaches Vietnam

Tropical Storm Sinlaku is intensifying as it approaches the coast of Vietnam.  At 7:00 p.m. EST on Friday the center of Tropical Storm Sinlaku was located at latitude 12.8°N and longitude 111.7°E which put it about 200 miles east-southeast of Quy Nonh and about 310 miles southeast of Da Nang, Vietnam.  Sinlaku was moving toward the west at 12 m.p.h.  The maximum sustained wind speed was 65 m.p.h. and there were gusts to 80 m.p.h.

As the forward motion of Sinlaku slowed, the wind shear decreased.  Warm Sea Surface Temperatures (SSTs) and well developed upper level outflow created an environment favorable for intensification and the inner core of the tropical storm became better organized.  A ring of convection is forming around the center of the circulation and there are some satellite indications that an eye may be forming.  Sinlaku will remain over warm SSTs as it moves toward Vietnam and further intensification is likely.  It is possible that Sinlaku could reach typhoon intensity before it makes landfall.

Sinlaku is being steered toward the west-northwest by a subtropical ridge to its north.  That steering pattern should remain in place and Sinlaku could make landfall in 12-18 hours.  It will bring strong winds to the coast of central Vietnam and it could produce locally heavy rainfall over parts of Southeast Asia as it moves inland.

 

Tropical Storm Sinlaku Develops Over South China Sea

Spiral banding and other organizational features have increased around Tropical Depression 21W and it has intensified into Tropical Storm Sinlaku.  At 7:00 p.m. EST on Thursday the center of Tropical Storm Sinlaku was located at latitude 10.9°N and longitude 117.3°E which put it about 360 miles southwest of Manila, Philippines and about 650 miles east-southeast of Quy Nohn, Vietnam.  Sinlaku was moving toward the west-northwest at 23 m.p.h.  The maximum sustained wind speed was 40 m.p.h. and there were gusts to 50 m.p.h.

Sinlaku is being steered to the west-northwest by a subtropical ridge located to its north and that steering pattern is expected to continue for the next two or three days.  Sinlaku could be near the coast of Vietnam in about 42 hours.  The spirals bands of thunderstorms are increasing in organization and the upper level outflow is increasing.  Sinlaku will remain over warm Sea Surface Temperatures as it moves toward Vietnam.  The environmental factors suggest further intensification is likely, although the rapid forward motion of Sinlaku could limit the rate of intensification.  If Sinlaku were to move more slowly, then a faster rate of intensification night be possible.

Sinlaku is likely to bring some gusty winds to the coast of central Vietnam and it could produce locally heavy rainfall over parts of Southeast Asia as it moves inland in two or three days.

 

Tropical Depression 21W Bringing Rain to Central Philippines

Tropical Depression 21W (TD 21W) is bringing rain to parts of the Central Philippines as it moves toward the west-northwest.  At 7:00 p.m. EST on Wednesday the center of TD 21W was located at latitude 9.8°N and longitude 122.9°E which put it about 70 miles east of Cebu and about 350 miles south-southeast of Manila.  TD21W was moving toward the west-northwest at 20 m.p.h.  The maximum sustained wind speed was 35 m.p.h. and there were gusts to 45 m.p.h.

TD 21W appears to be developing some spiral bands of showers and thunderstorms and it could become more organized as it moves away from the Philippines.  It is over warm Sea Surface Temperatures and upper level outflow appears to be developing.  As a result of those factors TD 21W could intensify into a tropical storm during the next 24-36 hours.  Available guidance suggest that TD 21W will continue to move in a general west-northwesterly direction and it could approach the coast of Vietnam in about three days.

Nuri Intensifies Into a Super Typhoon

Typhoon Nuri intensified rapidly and it has now reached Super Typhoon status.  At 1:00 p.m. EST on Sunday the center of Nuri was located at latitude 17.9°N and longitude 132.3°E which put it about 650 miles south-southeast of Okinawa.  Nuri was moving toward the north-northwest at 8 m.p.h.  The maximum sustained wind speed was estimated to be 175 m.p.h. which made Nuri the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.

Nuri is moving around the western end of a subtropical ridge.   It is anticipated that the upper level westerly winds in the middle latitudes will begin to turn Nuri more toward the northeast over the next few days.  The guidance from numerical models suggest that Nuri will pass southeast of Japan during the middle of next week.

Nuri has been over warm Sea Surface Temperatures and in an area where the upper level winds are light.  It has well developed outflow and the energy from the ocean has allowed it to strengthen rapidly.  It is possible that Nuri become a little stronger during the next few hours.  Once Nuri moves farther north, the upper level westerly winds will increase the wind shear and inhibit outflow on the western side of the circulation.  Those factors will put Nuri on a weakening trend that will continue until it makes a transformation into an extratropical cyclone as it passes south of Japan.

Typhoon Vongfong Approaching Okinawa

Typhoon Vongfong is approaching Okinawa and the island is already feeling the effects of the large circulation around the typhoon.  Kadena Air Force base has been reporting sustained winds to tropical storm force for 12 hours.  At 4:00 p.m. EDT the current observation at Kadena was heavy rain with northeast winds sustained at 47 m.p.h. and gusts to 71 m.p.h.

At 2:00 p.m. EDT the center of Typhoon Vongfong was located at latitude 23.8°N and longitude 128.9°E which put it about 200 miles south-southeast of Okinawa.  Vongfong was moving toward the north-northwest at 10 m.p.h.  The maximum sustained wind speed was 125 m.p.h. and there were gusts to 155 m.p.h.

Vongfong is starting to experience a little more wind shear and it is moving into a less favorable environment.  However, it is a large typhoon and the weakening process is likely to occur slowly for the next day or so.  As a result Vongfong will bring high winds and heavy rain to Okinawa for another 12-24 hours.

When Vongfong gets north of Okinawa, it will encounter strong westerly winds.  Those stronger winds will turn it toward the northeast.  The westerly winds will also increase wind shear over Vongfong and cause it to weaken more rapidly in a couple of days.  Vongfong could still be a typhoon when in approaches southwestern Japan.