Tag Archives: the Philippines

Tropical Storm Ampil Moves Over Okinawa

Tropical Storm Ampil moved over Okinawa on Friday night.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Ampil was located at latitude 27.3°N and longitude 127.4°E which put it about 25 miles (40 km) north-northwest of Okinawa.  Ampil was moving toward the northwest at 21 m.p.h. (34 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 990 mb.

Drier air continued to circulated around Tropical Storm Ampil on Friday and the drier air prevented Ampil from intensifying.  Several bands of stronger thunderstorms were occurring northeast of the center of circulation and the strongest winds were occurring in those bands.  The bands in other parts of Tropical Storm Ampil consisted primarily of the showers and low clouds.  There was a distinct low level center of circulation, but there were few thunderstorms near the center.  Winds to tropical storm force extended out about 160 miles (260 km) from the center.

Tropical Storm Ampil is unlikely to intensify significantly before it makes landfall in China.  Ampil will move over water where the Sea Surface Temperature is near 28°C.  So, there will be enough energy in the ocean to support intensification.  There is a chance for some intensification on Saturday, if more thunderstorms develop near the center of circulation.  However, the drier air will inhibit the formation of taller thunderstorms and that will limit possible intensification..

Tropical Storm Ampil will move south of a subtropical ridge over the Western North Pacific Ocean.  The ridge will steer Ampil quickly toward the northwest.  On its anticipated track Tropical Storm Ampil will move quickly away from Okinawa and the Ryukyu Islands.  Ampil could approach the coast of China near Shanghai in about 24 hours.  Tropical Storm Ampil will bring gusty winds and locally heavy rain to the region of China around Shanghai.

Elsewhere over the Western North Pacific Ocean Tropical Depression 13W formed west of northern Luzon.  At 11:00 p.m. EDT on Friday the center of Tropical Depression 13W was located at latitude 18.0°N and longitude 118.9°E which put it about 140 miles (225 km) west of Laoag, Philippines.  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 998 mb.  The depression could bring locally heavy rain and cause flash floods over Luzon during the weekend.

Tropical Storm Son-tinh Moves Across Hainan Island

Tropical Storm Son-tinh moved across Hainan Island on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Son-tinh was located at latitude 18.9°N and longitude 108.5°E which put it about 15 miles (25 km) southwest of Dongfang, China.  Son-tinh was moving toward the west at 21 m.p.h. (34 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.

The center of Tropical Storm Son-tinh moved east to west across the southern half of Hainan Island on Tuesday.  In spite of moving over the island, the circulation of Tropical Storm Son-tinh retained its organization.  There was still a distinct low level center of circulation.  A primary rainband wrapped around the southern and eastern portions of the center.  Additional bands of showers and thunderstorms were revolving around the core of Son-tinh.  The strongest rainbands were in the western half of the tropical storm.  The circulation of Tropical Storm Son-tinh remains small.  Winds to tropical storm force only extend out about 70 miles (110 km) from the center of circulation.

Tropical Storm Son-tinh will move through an environment somewhat favorable for intensification during the next 12 hours.  Son-tinh will move over water where the Sea Surface Temperature is near 30°C.  It will move south of an upper level ridge.  The ridge will produce northeasterly winds which will blow toward the top of the circulation.  Those winds will create moderate vertical wind shear, but the shear will not be strong enough to prevent intensification.  Tropical Storm Son-tinh could strengthen after it moves west of Hainan Island and the center of circulation moves back over water.  Son-tinh is likely to reach the coast of Vietnam in 12 to 18 hours and it will weaken after landfall.

The ridge north of Son-tinh steered the tropical storm quickly toward the west on Tuesday.  It will continue to steer Tropical Storm Son-tinh in a general westerly direction on Wednesday.  On its anticipated track Tropical Storm Son-tinh will move steadily west of Hainan Island.  Locally heavy rain and gusty winds should gradually diminish there on Wednesday.  Son-tinh is likely to make landfall on the coast of Vietnam near Vinh in 12 to 18 hours and then move across Vietnam toward Laos.  Tropical Storm Son-tinh will bring gusty winds and locally heavy rain, but its impact will be lessened because of the small size of the circulation.  The heavy rain could cause flooding in isolated locations.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 12W formed east of Luzon.  At 11:00 p.m. EDT on Tuesday the center of Tropical Depression 12W was located at latitude 18.9°N and longitude 126.1°E which put it about 545 miles (875 km) south of Okinawa.  It was moving toward the west at 12 m.p.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 999 mb.

Tropical Storm Son-tinh Develops East of Hainan Island

Tropical Storm Son-tinh developed east of Hainan Island on Monday night.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Son-tinh was located at latitude 19.4°N and longitude 116.9°E which put it about 430 miles east of Hainan Island.  Son-tinh was moving toward the west at 24 m.p.h. (35 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.

A small circulation began west of Guam last week and then it moved north of the Philippines on Monday.  Thunderstorms would form near the circulation and then wind shear would blow the tops of the storms away.  A small area of thunderstorms eventually persisted near the center of circulation on Monday and the Japan Meteorological Agency designated the system as Tropical Storm Son-tinh.  There was a small tight center of circulation in Son-tinh, but strong upper level winds were causing the distribution of thunderstorms to be asymmetrical.  More of the thunderstorms were occurring west of the center.  The circulation of Son-tinh was relatively small.  Winds to tropical storm force only extended out 80 miles (130 km) from the center of circulation.

Tropical Storm Son-tinh will move through an environment marginally favorable for intensification.  Son-tinh will move over water where the Sea Surface Temperature is near 30°C.  Tropical Storm Son-tinh is moving south of an upper level ridge.  The ridge is producing strong easterly winds which are blowing toward the top of the circulation.  Those winds will cause strong vertical wind shear and the shear will limit intensification.  Tropical Storm Son-tinh could intensify a little before it reaches Hainan Island, but it will weaken when it moves over the island.

The ridge north of Son-tinh is steering the tropical storm rapidly toward the west and that general motion is forecast to continue on Tuesday.  On its anticipated track Tropical Storm Son-tinh will reach Hainan Island in about 18 hours.  Son-tinh will bring gusty winds and locally heavy rain.  Isolated flash floods could occur,but the overall impacts are likely to be minor.

Dangerous Typhoon Maria Churns Toward the Ryukyu Islands

Dangerous Typhoon Maria churned closer to the Ryukyu Islands on Sunday.  At 11:00 p.m. EDT on Sunday the center of Typhoon Maria was located at latitude 22.1°N and longitude 132.7°E which put it about 485 miles (780 km) southeast of Okinawa.  Maria was moving toward the west-northwest at 19 m.p.h. (31 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 922 mb.

Typhoon Maria has a large symmetrical circulation.  There is a circular eye with a diameter of 32 miles (52 km) at the center of Maria.  The eye is surrounded by a ring of strong thunderstorms and the strongest winds are occurring in that ring of storms.  Multiple bands of showers and thunderstorms are revolving around the core of Typhoon Maria.  Storms around the core are generating well developed upper level divergence which is pumping away large amounts of mass from the typhoon.

Winds to typhoon force extend out about 70 miles (110 km) from the center of circulation.  Winds to tropical storm force extend out about 230 miles (370 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Maria is 33.3.  The Hurricane Size Index (HSI) is 23.7 and the Hurricane Wind Intensity Size Index (HWISI) is 57.0.

Typhoon Maria will remain in an environment favorable for strong typhoons for another 24 to 36 hours.  Maria will move over water where the Sea Surface Temperature is near 29°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Maria will remain a large and dangerous typhoon for another day or two.

Typhoon Maria was moving south of a subtropical ridge over the Western North Pacific Ocean.  The ridge was steering Maria toward the west-northwest and a general motion toward the west-northwest is likely to continue for another day or two.  On its anticipated track Typhoon Maria will approach the southern Ryukyu Islands in about 24 hours.  Maria could be near northern Taiwan in about 36 hours and it could approach the coast of China in about 48 hours.

Typhoon Maria will bring strong winds, locally heavy rain and a significant storm surge.  Maria will be capable of causing major damage over a widespread area.

Powerful Typhoon Maria Spins East of Taiwan

Powerful Typhoon Maria spun east of Taiwan on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Maria was located at latitude 19.4°N and longitude 138.3°E which put it about 950 miles (1530 km) east-southeast of Okinawa.  Maria was moving toward the northwest at 13 m.p.h. (10 km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h).  The minimum surface pressure was 925 mb.

Typhoon Maria appeared to complete an eyewall replacement cycle on Saturday.  The completion of the cycle resulted in a  larger circulation.   There was an eye which had a diameter of 24 miles (38 km).  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of the circulation.  The rainbands northwest in the northwestern quadrant of Typhoon Maria were a little weaker than the bands in the other parts of the circulation.  Storms in the core of Maria were generating upper level divergence which was pumping mass away to the northeast of the typhoon.

Winds to typhoon force extended out about 70 miles (110 km/h) 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 Maria was 37.9.  The Hurricane Size Index (HSI) was 24.5 and the Hurricane Wind Intensity Size Index (HWISI) was 62.4.

Typhoon Maria will move through an environment mostly favorable for powerful typhoons on Sunday.   Maria will move over water where the Sea Surface Temperature is near 30°C.  It will move through an environment where the upper level winds are weak and there will be little vertical wind shear.  There appears to be some sinking motion and drier air northwest of Maria and that may be the reason why the rainbands were weaker in that part of the typhoon.  The drier air could inhibit further strengthening.  Typhoon Maria is likely to remain strong for another 24 to 48 hours.

Typhoon Maria was moving around the southern portion of a subtropical ridge over the Western North Pacific.  The ridge was steering Maria toward the northwest.  The ridge is forecast to strengthen and it will steer Typhoon Maria more toward the west-northwest.  On its anticipated track Typhoon Maria could approach the southern Ryukyu Islands in about 48 hours.  Maria could be near the northern end of Taiwan in about 60 hours.

Tropical Storm Prapiroon Moves Toward Okinawa

Tropical Storm Prapiroon moved closer to Okinawa on Saturday.  At 11:00 a.m. EDT on Saturday the center of Tropical Storm Prapiroon was located at latitude 22.4°N and longitude 128.3°E which put it about 315 miles (510 km) south of Okinawa.  Prapiroon was moving toward the northwest at 8 m.p.h. (13 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 992 mb.

There was a distinct center of circulation in the middle of Tropical Storm Prapiroon, but the distribution of thunderstorms was asymmetrical.  The stronger thunderstorms were occurring in bands south and east of the center of circulation.  The bands north and west of the center consisted primarily of showers and low clouds.  A large upper level ridge over Asia was producing northerly winds which were blowing toward the top of Tropical Storm Prapiroon.  Those winds were causing moderate vertical wind shear and they were probably the reason for the asymmetric distribution of thunderstorms.  Those winds were also blocking upper level divergence to the north and west of Prapiroon.

Tropical Storm Prapiroon will move through an area marginally favorable for intensification during the next 24 to 36 hours.  Prapiroon will move over water where the Sea Surface Temperature is near 29°C.  So, there will be enough energy in the upper ocean to support intensification.  The upper level ridge will continue to cause some vertical wind shear, but Tropical Storm Prapiroon could move into an area where the upper level winds are a little weaker on Sunday.  If the wind shear decreases, then Tropical Storm Prapiroon will intensify.  There is still a chance that Prapiroon could strengthen into a typhoon when it passes near Okinawa.

Tropical Storm Prapiroon is moving around the western end of a subtropical ridge over the Pacific Ocean which is steering the tropical storm toward the northwest.  Prapiroon is forecast to move more toward the north when it reaches the western end of the ridge in 12 to 24 hours.  On its anticipated track the center of Tropical Storm Prapiroon could approach Okinawa in 12 to 18 hours.  The center of Prapiroon will likely pass west of Okinawa which would bring the strongest winds and heaviest rain over Okinawa.

Tropical Storm Prapiroon Forms South-Southeast of Okinawa

A distinct center of circulation formed within an area of thunderstorms south-southeast of Okinawa on Thursday night and the Japan Meteorological Agency designated the system as Tropical Storm Prapiroon.  At 8:00 p.m. EDT on Thursday the center of Tropical Storm Prapiroon was located at latitude 20.0°N and longitude 130.2°E which put it about 500 miles (800 km) south-southeast of Okinawa.  Prapiroon was moving toward the west at 7 m.p.h. (11 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 998 mb.

The circulation of Tropical Storm Prapiroon was still organizing.  More thunderstorms were forming close to the center of circulation.  There were more thunderstorms west of the center than there were east of the center.  Several bands of showers and thunderstorms in the outer part of the circulation were revolving around the core of Tropical Storm Prapiroon.  The storms in the core were generating upper level divergence which was pumping mass away from the tropical storm.

Tropical Storm Prapiroon formed beneath an upper level ridge that developed between an upper level low northwest of the Philippines and a much larger upper low east of the Marianas.  The winds in the upper ridge will be weak and there will be little vertical wind shear.  Prapiroon will move over water where the Sea Surface Temperature is near 29°C.  Tropical Storm Prapiroon will move through an environment very favorable for intensification.  Prapiroon will strengthen and it could intensify rapidly once the inner core organizes.  Tropical Storm Prapiroon could strengthen into a typhoon in 24 to 48 hours.

Tropical Storm Prapiroon was moving around the southwestern part of a subtropical ridge which was steering the tropical storm toward the west.  Prapiroon will turn toward the north in 12 to 24 hours when it reaches the western end of the ridge.  On its anticipated track Tropical Storm Prapiroon could approach Okinawa in about 36 hours.  Prapiroon could be a typhoon when it nears Okinawa.

Tropical Storm Maliksi Forms East of Luzon, Ewiniar Brings Rain to South China.

Tropical Storm Maliksi formed east of Luzon on Thursday while Tropical Storm Ewiniar brought rain to parts of South China.  At 8:00 p.m. EDT on Thursday the center of Tropical Storm Maliksi was located at latitude 17.4°N and longitude 127.7°E which put it about 330 miles (535 km) east of Luzon.  Maliksi was moving toward the north at 4 m.p.h. (6 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.

The Japan Meteorological Agency designated an area of low pressure east of Luzon as Tropical Storm Maliksi late on Thursday.  There was a large counterclockwise circulation east of Luzon, but there were few thunderstorms near the center of the circulation.  Most of the thunderstorms were occurring in three bands in the outer portions of the circulation.  One band was located well to the west of the center of circulation, a second band was located well to the north of the center and the third band was located well to the east of the center.  The winds to tropical storm force were occurring in those bands.

Tropical Storm Maliksi will move through an environment favorable for intensification during the next 24 to 48 hours.  Maliksi will move over water where the Sea Surface Temperature is near 30°C.  Maliksi will move underneath an upper level ridge where the winds are weak and there will be little vertical wind shear.  The large circulation will be the primary factor inhibiting intensification in the short term.  Maliksi will intensify slowly until thunderstorms develop near the center of circulation and the strongest winds occur closer to the center.

Tropical Storm Maliksi will move around the western end of a subtropical ridge.  The ridge will steer Maliksi slowly toward the north.  When Tropical Storm Maliksi moves farther to the north westerly winds will begin to steer it toward the northeast.  On its anticipated track Tropical Storm Maliksi will remain east of Luzon.  The circulation of Maliksi is so large that rainbands on the western side of the circulation could affect the northern Philippines.

Elsewhere over the western North Pacific Ocean, Tropical Storm Ewiniar brought heavy rain to parts of South China.  Ewiniar made landfall on the coast of China near Yangjiang on Thursday.  At 8:00 p.m. EDT on Thursday the center of Tropical Storm Ewiniar was located at latitude 22.6°N and longitude 112.1°E which put it about 50 miles (80 km) northeast of Yangjiang, China.  Ewiniar was moving toward the north at 9 m.p.h. (15 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 998 mb.

The center of Tropical Storm Ewiniar was moving farther inland over South China.  The winds to tropical storm force were occurring in rainbands that were still over the South China Sea.  Ewiniar was dropping heavy rain over parts of western Guangdong province and over southern Zizhiqu province.  The heavy rain could cause flooding in those areas.

Tropical Storm Jelawat Strengthens West of Guam

Tropical Storm Jelawat strengthened west of Guam late on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Jelawat was located at latitude 12.3°N and longitude 135.5°E which put it about 230 miles (375 km) northwest of Yap and about 600 miles (970 km) west of Guam.  Jelawat was moving toward the north 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 994 mb.

After being affected by strong vertical wind shear for about 36 hours, Tropical Storm Jelawat began to strengthen late on Tuesday.  Many more thunderstorms formed near the center of circulation.  The circulation became much more symmetrical.  Bands of showers and thunderstorms formed in all parts of the circulation.  The storms near the center of circulation started to generate upper level divergence which pumped mass away from the tropical storm.

Tropical Storm Jelawat will be moving through an environment favorable for intensification during the next several days.  Jelawat will move over water where the Sea Surface Temperature is near 28°C.  Tropical Storm Jelawat is moving around the western end of an upper level ridge.  The ridge is producing southerly winds which are blowing toward the tropical storm.  The winds are producing some vertical wind shear, but the shear is not as strong as it has been.  Tropical Storm Jelawat will intensify during the next day or two and it could strengthen into a typhoon.

The ridge is steering Tropical Storm Jelawat toward the north and the northerly motion is expected to continue for another 12 to 24 hours.  Jelawat will move more toward the northeast in a day or so after it rounds the western end of the ridge.  On its anticipated track Tropical Storm Jelawat will move away from Yap and it will remain west of Guam.

Tropical Storm Jelawat Forms Near Yap

Tropical Storm Jelawat formed near Yap on Sunday.  At 2:00 p.m. EDT on Sunday the center of Tropical Storm Jelawat was located at latitude 7.6°N and longitude 138.4°E which put it about 120 miles (195 km) south of Yap.  Jelawat was moving toward the northwest at 14 m.p.h. (22 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 998 mb.

A low level center of circulation formed near the eastern edge of a cluster of thunderstorms near Yap on Sunday and the Japan Meteorological Agency designated the system as Tropical Storm Jelawat.  Tropical Storm Jelawat does not have a well organized circulation.  There is a distinct low level center of circulation, but most of the stronger thunderstorms are occurring west of the center of circulation.  The bands in the eastern half of the circulation consist mainly of showers and low clouds.  An upper level ridge over the Central North Pacific Ocean is producing strong easterly winds which are blowing across the top of the circulation.  Those winds are generating strong vertical wind shear and the shear is the main reason for the asymmetrical distribution of storms.

Tropical Storm Jelawat will be moving through an environment that is somewhat favorable for intensification.  Jelawat will move over water where the Sea Surface Temperature is near 28°C.  However, the upper level ridge will continue to cause vertical wind shear.  If the shear is not too strong and the circulation remains vertically coherent, then Tropical Storm Jelawat could strengthen during the next several days.   Some models predict this scenario and forecast that Jelawat will intensify into a typhoon.  Alternatively, if the wind shear increases further, strong upper level winds could blow the upper half of the circulation away from the lower level circulation.  If that occurs, Tropical Storm Jelawat will weaken.

The ridge over the Central North Pacific is steering Tropical Storm Jelawat toward the northwest.  Jelawat will reach the western end of the ridge in 12 to 24 hours.  The tropical storm will turn more toward the north when it reaches the end of the ridge.  On its anticipated track the center of Tropical Storm Jelawat is forecast to pass between Yap and Palau.