Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

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.

 

Typhoon Phanfone Intensifying Rapidly

A very favorable environment of warm Sea Surface Temperatures and light upper level winds is allowing Typhoon Phanfone to intensify rapidly.  At 11:00 p.m. EDT on Wednesday the center of Phanfone was located at latitude 19.5°N and longitude 139.0°E which put it about 400 miles south-southwest of Iwo To.  Phanfone was moving toward the west-northwest at 17 m.p.h.  It had maximum sustained winds of 120 m.p.h. and gusts to 150 m.p.h.

Phanfone is moving around the western end of the subtropical high pressure system and its track should take a more northward turn.  When Phanfone gets to a higher latitude, it will encounter the upper level westerly flow which will turn it northeastward.  Guidance from numerical models suggest that Phanfone could be south of Japan in about 72 hours.

Phanfone will be in a favorable environment during the next 36 hours and further intensification is possible.  When Phanfone encounters the upper level westerly flow, wind shear will increase and it will start to weaken.  Phanfone will eventually make a transition to an extratropical cyclone as it moves northeastward over the North Pacific.

 

Tropical Storm Phanfone Forms East of Guam

A large area of low pressure east of Guam developed a core of thunderstorms and sufficient organization to prompt its classification as Tropical Storm Phanfone.  At 8:00 p.m. EDT on Monday the center of Phanfone was located at latitude 15.4°N and longitude 148.3°W which put it about 160 miles east of Saipan.  Phanfone was moving toward the 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.

Phanfone is expected to continue to move in a northwesterly direction for the next two or three days as it moves around the western end of a subtropical high pressure system.  Later in the week it is expected to take a more northerly turn and it could be south of Japan by the weekend.

Both the oceanic and atmospheric environment around Phanfone’s projected track appear favorable for intensification.  Phanfone is expected to become a typhoon later this week and a period of more rapid intensification is possible.  Eventually, as Phanfone moves farther north, westerly winds in the upper levels will increase wind shear and begin a weakening trend.

 

Tropical Storm Kammuri Develops North of Guam

A tropical depression north of Guam intensified into Tropical Storm Kammuri on Thursday.  At 8:00 p.m. EDT on Thursday the center of Kammuri was located at latitude 21.7°N and longitude 146.3°E which put it about 375 miles east-southeast of Iwo To.  Kammuri was moving toward the north-northwest at 8 m.p.h.  The maximum sustained wind speed was 50 m.p.h. and there were wind gusts to 65 m.p.h.
Kammuri is moving around the western edge of a subtropical ridge.  The ridge should continue to steer Kammuri toward the north until it begins to feel the effects of the upper level westerly winds.  The upper level westerlies should eventually turn Kammuri toward the northeast and the probability is high that it will pass southeast of Japan.
Kammuri is in a region of moderate wind shear and further intensification is possible.  It is also possible that Kammuri could reach typhoon intensity before the upper level westerly winds start to increase the wind shear.

Tropical Storm Fung-Wong Near Taiwan

At 5:00 p.m. EDT on Saturday the center of Tropical Storm Fung-Wong was located at latitude 21.5°N and longitude 120.0°W which put it about 250 miles south-southwest of Taipei Taiwan.  Fung-Wong was moving just slightly east of due north at 8 m.p.h.  The maximum sustained wind speed was 60 m.p.h. and there were gusts to 75 m.p.h.

Fung-Wong will likely move near or across Taiwan during the next few hours.  Locally heavy rainfall will be possible, especially in locations where the circulation around Fung-Wong pushes air up the slopes of mountains.  Flooding may be an issue in areas that experience heavy rainfall.  The heaviest rainfall will likely occur on the eastern slopes of mountains as Fung-Wong moves across southern Taiwan and brings easterly winds to those areas.  However, the potential for flooding along the western slopes of mountains, especially in northern Taiwan, may exist as the tropical storm moves north of the island and the wind shifts to a more westerly direction.

Fung-Wong will likely weaken as the circulation in the lower levels is disrupted by the mountains.  It could maintain tropical storm intensity and move toward eastern China once the center emerges back over the water.