Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

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.

 

Typhoon Vongfong Turns Northward

Typhoon Vongfong has made the anticipated turn and it is now moving toward the north.  At 5:00 p.m. EDT the center of Typhoon Vongfong was located at latitude 20.3°N and longitude 129.5°E which put it about 440 miles south-southeast of Okinawa.  Vongfong was moving toward the north-northwest at 8 m.p.h.  The maximum sustained wind speed was 150 m.p.h. and there were gusts to 185 m.p.h.

Vongfong is moving around the western end of a subtropical high pressure system, which should continue to steer it in a generally northerly direction for the next 36-48 hours.  When Vongfong nears southwestern Japan, it will begin to encounter upper level westerly winds, which will push it toward the northeast.  The model guidance suggest that Vongfong could be very near the coast of Japan in about 72 hours.

Microwave satellite imagery suggests that a larger outer eye is wrapping around a small inner eye that represents the current center of Vongfong.  The start of an eyewall replacement cycle usually produces weakening of a tropical cyclone, although there can be some fluctuations in intensity.  When Vongfong gets closer to Japan, upper level westerly winds will increase the vertical wind shear.  More wind shear will speed up the weakening trend.  Current guidance suggests that Vongfong could still be a typhoon when it approaches Japan in about three days.  However, it is likely to weaken to a strong tropical storm as it moves across parts of Japan.  Even if it does weaken, Vongfong could still bring gusty winds and locally heavy rainfall.

 

Vongfong Intensifies Rapidly, Now a Super Typhoon

Typhoon Vongfong has been in an environment of warm Sea Surface Temperatures (SSTs) and light upper level winds, which is almost ideal for intensification of a tropical cyclone.  As  result it has intensified very rapidly and it has reached the intensity necessary to be classified as a Super Typhoon.  At 5:00 p.m. EDT the center of Typhoon Vongfong was located at latitude 17.6°N and longitude 133.2°E which put it about 700 miles southeast of Okinawa.  Vongfong was moving toward the west-northwest at 11 m.p.h.  The maximum sustained wind speed was 175 m.p.h., which made it the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale, and there were gusts to 215 m.p.h.  Vongfong is both stronger and larger than Typhoon Phanfone was.

Vongfong is being steered west-northwest by a subtropical high pressure system.  An upper level trough in the westerly flow at higher latitudes will approach Vongfong from the west.  Southerly winds on the east side of the trough will cause Vongfong to make a sharp turn toward the north during the next 24-36 hours.  It appears that Vongfong will continue to move northward during the rest of the week and it could approach southwestern Japan in five or six days.

Vongfong will remain in a very favorable environment for the next 24-48 hours and some further intensification is possible.  Eventually, the winds in the upper level trough will increase the wind shear over Vongfong.  At the same time Vongfong will be moving over cooler SSTs as it gets farther north.  So, a weakening trend could begin in about 48 hours.  However, Vongfong could still be a large typhoon as it approaches Japan.

 

Typhoon Vongfong Intensifying

Warm Sea Surface Temperatures and limited wind shear allowed Vongfong to intensify on Saturday and it is now a typhoon.  At 8:00 p.m. EDT on Saturday the center of Typhoon Vongfong was located near latitude 12.6°N and longitude 149.9°E which put it about 330 miles east-southeast of Guam.  Vongfong was moving toward the west-northwest at 21 m.p.h.  The maximum sustained wind speed was 80 m.p.h. and there were gusts to 100 m.p.h.

Clockwise flow around a subtropical high pressure system will keep Vongfong moving in a general west-northwesterly direction for several more days.  It could pass very near Guam during the next 24 hours.  Vongfong should remain in a favorable environment and further intensification is possible.

 

Typhoon Phanfone Approaching Japan

Typhoon Phanfone is approaching the southwestern part of Japan.  At 11:00 p.m. EDT the center of Phanfone was located at latitude 28.9°N and longitude 131.4°E which put it about 200 miles south of Miyazaki, Japan and about 670 miles southwest of Tokyo.  Phanfone was moving toward the north at 9 m.p.h.  The maximum sustained wind speed was 115 m.p.h. and there were gusts to 140 m.p.h.

Phanfone is already bringing rain and wind to parts of southwestern Japan.  It could bring gusty winds and locally heavy rainfall as it moves northeastward.  Phanfone is nearing the latitude of stronger upper level westerly winds.  Those winds will soon make Phanfone start to move toward the northeast.  Phanfone will move more quickly toward the northeast on Sunday afternoon and evening and it could be near Tokyo in about 24 hours.  The westerly winds will also increase the wind shear over Phanfone and create a weakening trend.  As more cooler air gets pulled into the circulation, Phanfone will begin a transition to an extratropical cyclone.

 

Tropical Storm Vongfong Forms East of Guam

A new tropical storm has formed east of Guam.  At 2:00 p.m. EDT on Friday the center of Tropical Storm Vongfong was located at latitude 9.1°N and longitude 156.3°E which put it about 820 miles east-southeast of Saipan.  Vongfong was moving toward the west-northwest at 15 m.p.h.  The maximum sustained wind speed was 50 m.p.h. and there were gusts to 65 m.p.h.

Vongfong is being steered by the same subtropical high that is also steering Typhoon Phanfone.  Clockwise flow around the southern portion of the high should keep Vongfong moving toward the west-northwest for the next several days.

Vongfong is over warm Sea Surface Temperatures and it has well developed upper level outflow.  The favorable environment should allow Vongfong to intensify and it is likely to become a typhoon during the weekend.  The projected path of Vongfong would take it near or just to the north of Guam in about 48 to 72 hours.

 

Typhoon Phanfone Turns Northwards

Strong Typhoon Phanfone has reached the western edge of a subtropical high pressure system and it is making the expected turn toward the north.  At 11:00 a.m. EDT on Friday the center of Phanfone was located at latitude 24.0°N and longitude 134.0°E which put it about 870 miles south-southwest of Tokyo, Japan.  Phanfone was moving toward the northwest at 12 m.p.h.  The maximum sustained wind speed was 120 m.p.h. and there were gusts to 150 m.p.h.

Phanfone went through an eyewall replacement cycle on Thursday in which the small inner eye dissipated and a much larger eye became apparent on satellite imagery.  The eyewall replacement cycle kept the intensity of Phanfone relatively constant.  Now that the inner eye is gone, the outer eye is likely to contract.  Phanfone remains over warm Sea Surface Temperatures and it is a favorable atmospheric environment.  So, some further intensification is possible during the next 24 hours.  In 24 to 36 hours Phanfone will be far enough north to begin to be influenced by upper level westerly winds.  The stronger upper level winds will increase wind shear over Phanfone and start a weakening process.  A combination of stronger wind shear and colder air to the north of Phanfone will initiate a process whereby it is transformed from a tropical cyclone to an extratropical cyclone.  It is difficult to determine the exact timing of the extratropical transition and Phanfone will be a powerful extratropical cyclone as it moves across the North Pacific.

Phanfone should gradually turn more toward the north during the next 24 hours as it moves around the western edge of the subtropical high pressure system.  It is likely to take a sharper turn to the northeast later in the weekend when it encounters the upper level westerlies.  Phanfone is likely to approach southern Japan in 36 to 48 hours.  Some models are indicating that it could cross parts of Central Japan, while other models keep the center south of Japan.  In either case Phanfone has the potential to brig locally heavy rain and gusty winds to portions of Japan.