Tag Archives: Philippines

Tropical Storm Koppu Forms North of Yap

In spite of significant vertical wind shear a surface circulation has been consolidating inside an area of thunderstorms north of Yap.  The system has been designated Tropical Storm Koppu.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Koppu was located at latitude 15.7°N and longitude 137.1°E which put it about 430 miles (690 km) north of Yap.  Koppu was moving toward the west at 14 m.p.h. (23 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 993 mb.

Significant vertical wind shear is inhibiting the organization of Tropical Storm Koppu.  An upper level ridge north of Koppu is generating strong northeasterly winds over the top of the tropical storm.  The vertical wind shear is causing most of the strong thunderstorms to be located southwest of the center of circulation.  The only other deep convection is occurring in a band that is west of the core of the circulation.

Koppu is over water where the Sea Surface Temperature is near 30°C and so there is plenty of energy in the upper ocean.  The wind shear will inhibit intensification for another 24 to 48 hours before it starts to subside.  Koppu could intensify much more quickly later this week when it moves into an area where the upper level winds are lighter.  Koppu could become a typhoon withing 36 to 48 hours and it could be a strong typhoon by the end of the week.

A subtropical ridge is steering Tropical Storm Koppu quickly to the west.  That general motion is expected to continue for the rest of the week.  On its anticipated track Koppu could be approaching northern Luzon in about three or four days.  It could be a significant typhoon by that time.

Tropical Storms Mujigae and Choi-Wan Form Over NW Pacific

Two new tropical storms with the names of Mujigae and Choi-Wan have formed over the western North Pacific Ocean.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Mujigae was located at latitude 17.4°N and longitude 117.3°E which put it about 275 miles (445 km) northwest of Manila, Philippines.  Mujigae was moving toward the west-northwest at 17 m.p.h.  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 990 mb.

At 11:00 a.m. EDT on Friday the center of Tropical Storm Choi-Wan was located at latitude 19.2°N and longitude 166.4°E which put it about 15 miles (20 km) south-southeast of Wake Island.  Choi-Wan was moving toward the west-northwest 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 996 mb.

Tropical Storm Mujigae organized quickly after the system move west of the Philippines.  A primary curved rainband wrapped around the western and southern sides of the center of circulation.  A possible eye is apparent intermittently on infrared satellite imagery.  Upper level divergence is beginning to occur both north and south of the center.  Mujigae is moving over water where the Sea Surface Temperature is near 28°C and there is not enough vertical wind shear to prevent intensification.  A period of rapid intensification is possible and Mujigae could become a typhoon in 12 to 24 hours.

A subtropical ridge is steering Mujigae toward the west-northwest and that general motion is expected to continue for the next several days.  On its anticipated track, Mujigae could be approaching the southern coast of China in 36 hours.  It could bring strong winds and heavy rain when it makes landfall.

Tropical Storm Choi-Wan is still in the organizational stage.  It has a large broad circulation without a well developed inner core.  Winds to tropical storm force are occurring in clusters of thunderstorms.  Choi-Wan is over Sea Surface Temperatures near 29°C, but there is moderate vertical wind shear over the northern part of the tropical storm.  The wind shear is expected to decrease in a day or two and Choi-Wan is forecast to become a typhoon.

Choi-Wan is between two subtropical ridges and the steering currents are relatively weak.  In a day or two the western ridge is expected to steer Choi-Wan toward the northwest.  Choi-Wan will cause squally weather on Wake Island for 24 to 48 hours.

Typhoon Goni Turning North, May Threaten Okinawa

Typhoon Goni is slowly turning toward the north and moving away from northern Luzon.  At 5:00 p.m. EDT on Friday the center of Typhoon Goni was located at latitude 19.8°N and longitude 122.5°E which put it about 330 miles (530 km) south-southeast of Taipei, Taiwan and about 615 miles (990 km) southwest of Okinawa.  Goni was moving toward the north at 2 m.p.h. (3 km/h).  The maximum sustained wind speed was 105 m.p.h. (120 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 956 mb.

Typhoon Goni will still be moving over warm Sea Surface Temperatures for the next several days and it has a chance to intensify.  The upper level winds are relatively light over the typhoon and there is not much vertical wind shear along its immediate path.  There appears to be an upper level outflow channel to the northeast.  Given the favorable environment Goni could intensify on Saturday.

Goni is moving around the western end of a subtropical high pressure system and it should begin to move toward the northeast a little more quickly.  On its anticipated track Goni could be near Ishigaki Jima in about 36 hours and near Okinawa in about 48 hours.  It could still be a strong typhoon at that time.  Goni could still by a typhoon when it approaches southwestern Kyushu in about three days.

Typhoon Goni Moving Closer to Northern Luzon and Taiwan

Typhoon Goni moved steadily westward on Wednesday and it got closer to northern Luzon and Taiwan.  At 11:00 p.m. EDT on Wednesday the center of Typhoon Goni was located at latitude 18.9°N and longitude 125.3°E which put it about 350 miles (565 km) southeast of Taipei, Taiwan.  Goni was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 130 m.p.h. (215 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 937 mb.

Typhoon Goni intensified on Wednesday and it is a very well organized tropical cyclone.  It has a large well formed eye.  The circulation is symmetrical although there are more thunderstorms in the south half of the typhoon.  Upper level divergence is well developed and it is pumping out mass in all directions.  Goni remains over warm Sea Surface Temperatures and the upper level winds are relatively light.  Some further intensification is possible during the next day or so.  Goni could run into stronger upper level winds in two or three days which would create more vertical wind shear and start to weaken the typhoon.

A subtropical ridge has been steering Goni toward the west and it is expected to do so again on Thursday.  However, Goni is nearing the western end of the ridge and it is forecast to turn to the north on Friday.  Goni appears to have moved more slowly during the past few hours, which may be an indication that it is reaching the western end of the ridge.  An upper level trough northwest of Goni is expected to turn Goni toward the northeast during the weekend and then accelerate it toward western Japan.

On its anticipated track, the center of Goni is expected to pass northeast of Luzon.  However, the circulation is large enough that some of northern Luzon could experience strong winds and heavy rain.  The center of Goni is forecast to pass east of Taiwan, but it could also bring strong winds heavy rain to some locations there as well.  The core of Goni could pass very near Ishigaki Jima and bring very strong winds and heavy rain to the islands in that area.

Typhoon Goni Heading West

Typhoon Goni moved steadily westward away from the Mariana Islands on Monday.  At 11:00 p.m. EDT on Monday the center of Typhoon Goni was located at latitude 18.3°N and longitude 135.3°E which put it about 780 miles (1260 km) southeast of Okinawa.  Goni was moving toward the west at 19 m.p.h. (31 km/).  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 944 mb.

Goni appeared to go through an eyewall replacement cycle on Monday which resulted in a reduction in the maximum wind speed.  As the tiny pinhole inner eye weakened, the stronger winds were located in the larger outer eyewall.  The reduction in wind speed could be temporary, if the outer eye begins to contract.  Goni remains in a favorable environment.  It is moving over warm Sea Surface Temperature and the vertical wind shear is very modest.  The circulation is producing upper level divergence in all directions.  Goni will remain in a favorable environment for another two or three days and it should remain strong during that time period.

A subtropical ridge is steering Goni toward the west-northwest and that steering pattern is expect to continue for another 48 to 72 hours.  Later this week an upper level trough could approach the typhoon from the northwest.  Southwesterly winds on the eastern side of the trough could turn Goni toward the north later this week. On its anticipated track Goni could be near Taiwan, the northern Philippines or Okinawa when it makes that turn.

Goni Intensifies Rapidly Into a Strong Typhoon

Goni intensified rapidly from a tropical storm into a strong typhoon on Sunday.  At 11:00 p.m. EDT on Sunday the center of Typhoon Goni was located at latitude 16.7°N and longitude 141.1°E which put it about 265 miles (425 km) west of Anatahan.  Goni was moving toward the west-northwest at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 130 m.p.h. (215 km/h) which made Goni the equivalent of a major hurricane.  There were wind gusts to 160 m.p.h. (260 km/h) and the minimum surface pressure was 937 mb.

The circulation of Goni organized quickly on Sunday and it was able to intensify rapidly.  The primary rainband wrapped tightly around the center of circulation and a tiny pinhole eye formed in the center.  The band continued to wrap about the core of the circulation and it could be about to form a second, larger concentric eyewall.  The structure of Goni looks a lot like the circulation of Typhoon Soudelor did when it intensified rapidly.  Light easterly winds in the upper levels enhanced divergence to the west of Goni and pumped out mass allowing the pressure to fall rapidly.

Goni is moving over water where the Sea Surface Temperatures are warm.  The vertical wind shear is minimal and further intensification is possible.  If concentric eyewalls form, eyewall replacement cycles could produce fluctuations in intensity.

A subtropical ridge is steering Goni toward the west-northwest and that general steering pattern is expected to continue for another three or four days.  At that time Goni could be near the western end of the subtropical ridge.  An upper level trough in the mid-latitude westerlies could approach the typhoon from the northwest and turn it toward the north.

Tropical Storm Linfa Heading for Taiwan

Tropical Storm Linfa crossed northern Luzon and turned for Taiwan on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Linfa was located at latitude 19.0°N and longitude 119.4°E which put it about 230 miles (370 km) south-southwest of Hengchun, Taiwan.  Linfa was moving toward the north-northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 45 m.p.h. (70 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 992 mb.

The circulation of Tropical Storm Linfa was relatively intact after it crossed northern Luzon and it moved back over water.  However, an upper level ridge over eastern Asia generated northeasterly winds that were strong enough to blow the top off of the circulation.  Strong upper level wind shear is making it difficult for new thunderstorms to form near the center of circulation.  Although Linfa will be moving over warm water, the wind shear will limit intensification.

Linfa has reached the western end of the subtropical ridge that has been steering the tropical storm.  It has turned toward the north and that general movement is expected to continue.  On its anticipated track Linfa could approach southern Taiwan in about two days.  It could bring locally heavy rain to parts of Taiwan.

Tropical Storm Linfa Makes Landfall in Northern Luzon

Tropical Storm Linfa made landfall in northern Luzon on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Linfa was located at latitude 17.8°N and longitude 121.7°E which put it near Tuguegarao, Philippines.  Linfa was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 m.p.h.) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 989 mb.   Linfa is bringing gusty winds and locally heavy rain to parts of northern Luzon.

Linfa should continue to weaken during the next 12 to 18 hours while the center is over land.  If the circulation is intact when it moves back over water, then the tropical storm may intensify once it gets north of the Philippines.  Linfa will soon reach the western end of a subtropical ridge which has been steering it toward the west.  When Linfa reaches the end of the ridge, it will likely turn toward the north.  The tropical storm could approach Taiwan in 48 to 72 hours.

Tropical Storm Linfa Nearing Northern Luzon

Tropical Storm Linfa is moving steadily toward the coast of northern Luzon.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Linfa was located at latitude 16.1°N and longitude 123.9°E which put it about 230 miles (370 km) east-northeast of Manila, Philippines.  Linfa was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 989 mb.

Tropical Storm Linfa has a small circulation, but it appears to be intensifying quickly.  A circular area of strong thunderstorms has developed around the center of circulation and it is producing strong upper level outflow.  Linfa is over water where the Sea Surface Temperature is near 30°C.  An upper level ridge northwest of the tropical storm is producing some vertical wind shear, but the shear does not seem to be enough to prevent intensification.  Linfa has about 18 hours to intensify before it reaches the coast of Luzon and it could attain typhoon intensity before it gets there.  Mountains in northern Luzon will disrupt the lowers levels of the circulation and Linfa will weaken after if makes landfall.

A subtropical ridge is steering Linfa toward the northwest and that steering pattern is expected to continue until the tropical storm makes landfall in northern Luzon.   Linfa will reach the western end of the subtropical ridge while it is over Luzon and if the circulation remains intact vertically, it will turn toward the north.  On its anticipated track Linfa will make landfall in northern Luzon in about 18 hours.  It is expected to eventually turn north toward Taiwan and the southern islands of Japan.  Linfa cold bring strong winds and locally heavy rainfall for parts of northern Luzon.  Heavy rainfall could contribute to flooding and mudslides in some locations.

Tropical Storm Linfa Forms East of the Philippines

A well defined low level circulation developed in an area of thunderstorms east of the Philippines on Thursday and the system was designated as Tropical Storm Linfa (10W).  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Linfa was located at latitude 16.3°N and longitude 127.6°E which put it about 470 miles (760 km) east-northeast of Manila, Philippines.  Linfa was moving toward the northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 45 m.p.h. (70 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 993 mb.

Linfa developed over water where the Sea Surface Temperature (SST) is near 30°C,  There is sufficient energy in the upper ocean to support intensification.  An upper level ridge centered northwest of Linfa is producing northeasterly winds over the top of the circulation and most of the thunderstorms are occurring west of the center.  The vertical wind shear is modest and some upper level divergence is present, especially over the western half of the circulation.  The vertical wind shear is expected to remain moderate and Linfa could intensify during the next several days.  If the upper level winds weaken, then a period of more rapid intensification is possible.

Linfa is being steered by a subtropical ridge located to the east of the tropical storm.  The ridge is expected to steer it toward the northwest in the short term.  As Linfa reaches the western end of the ridge it is expected to be steered more toward the north.  The timing of the turn toward the north will be important because it will determine if Linfa moves over the northern Philippines or moves northeast of that area.  The timing on the turn to the north will also determine the potential risk for Taiwan.  Another factor that could complicated the track forecast is a potential interaction with Typhoon Chan-hom which is abut 1500 miles (2400 km) east-southeast of Linfa.