Tag Archives: WP16

Tropical Storm Nangka Forms over South China Sea

Tropical Storm Nangka formed over the South China Sea on Monday.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Nangka was located at latitude 18.3°N and longitude 113.8°E which put it about 200 miles (325 km) east of Hainan Island.  Nangka was moving toward the west at 17 m.p.h. (28 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 996 mb.

More thunderstorms developed near the center of a low pressure system over the South China Sea on Monday and the Japan Meteorological Agency designated the system as Tropical Storm Nangka.  The circulation around Tropical Storm Nangka exhibited more organization on Monday.  More thunderstorms formed near the center of Nangka.  Bands of showers and thunderstorms were revolving around the center of circulation.  Storms near the center generated upper level divergence which pumped mass away to the west of the tropical storm.  Winds to tropical storm force extended out 75 miles (120 km) from the center.

Tropical Storm Nangka will move through an environment favorable for intensification during the next 12 to 18 hours.  Nangka will move over water where the Sea Surface Temperature is near 30°C.  It will move south of an upper level ridge over eastern Asia.  The ridge will produce easterly winds which will blow toward the top of Tropical Storm Nangka.  Those winds will cause moderate vertical which shear.  The shear will slow the rate of intensification, but it will not be strong enough to keep Nangka from intensifying.  Tropical Storm Nangka will weaken in a day or so while the tropical storm moves over Hainan Island.  Nangka could restrengthen when it moves west of Hainan.

Tropical Storm Nangka will move south of a high pressure system over eastern Asia.  The high will steer Nangka toward the west-northwest.  On its anticipated track Tropical Storm Nangka will reach Hainan Island in less than 18 hours.  Nangka will bring gusty winds and locally heavy rain to Hainan.  Flash floods could occur in some locations.  Tropical Storm Nangka will reach northern Vietnam in two days.

Elsewhere over the Western North Pacific Ocean, Tropical Depression Chan-hom was weakening southeast of Japan.  At 5:00 a.m. EDT on Monday the center of Tropical Depression Chan-hom was located at latitude 29.2°N and longitude 142.5°E which put it about 400 miles (645 km) south-southeast of Tokyp, Japan.  Chan-hom was moving toward the south at 9 m.p.h (15 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind guts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1000 mb.

Tropical Storm Linfa Makes Landfall in Vietnam

Tropical Storm Linfa made landfall on the coast of Vietnam on Sunday.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Linfa was located at latitude 15.4°N and longitude 107.4°E which put it about 50 miles (80 km) east of Lamam, Laos.  Linfa was moving toward the west at 6 m.p.h. (10 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 1000 mb.

The center of Tropical Storm Linfa made landfall on the central coast of Vietnam south of Da Nang on Sunday.  Linfa brought tropical storm force winds to the portion of the coast south of Da Nang.  Tropical Storm Linfa dropped heavy rain over central Vietnam, southern Laos and northeastern Cambodia.  Linfa is forecast to continue to move toward the west and it will be over northeastern Thailand on Monday.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Chan-hom weakened southeast of Japan and a new tropical depression formed west of the Philippines.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Chan-hom was located at latitude 31.1°N and longitude 142.2°E which put it about 300 miles (485 km) south-southeast of Tokyo, Japan.  Chan-hom was moving toward the southeast at 8 m.p.h. (13 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 1000 mb.

At 11:00 a.m. EDT on Sunday the center of Tropical Depression 18W was located at latitude 17.1°N and longitude 118.3°E which put it about 700 miles (1130 km) east of Da Nang, Vietnam.  The depression was moving toward the west at 10 m.p.h. (16 km/h).  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 1002 mb.

Tropical Storm Linfa Forms East of Vietnam

Tropical Storm Linfa formed east of Vietnam on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Linfa was located at latitude 15.0°N and longitude 109.9°E which put it about 155 miles (250 km) east-southeast of Da Nang, Vietnam.  Linfa was moving toward the west at 21 m.p.h. (34 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 997 mb.

More thunderstorms developed near the center of a low pressure system over the South China Sea east of Vietnam and the Japan Meteorological Agency designated the system as Tropical Storm Linfa on Saturday.  The circulation around Tropical Storm Linfa exhbited better organization.  More thunderstorms formed near the center of circulation.  Bands of showers and thunderstorms were revolving around the center of Linfa.  Storms near the center generated upper level divergence which pumped mass away to the west of the tropical storm.  Winds to tropical storm force extended out 100 miles (160 km) from the center of Linfa.

A high pressure system over eastern Asia will steer Tropical Storm Linfa quickly toward the west during the next two days.  On its anticipated track Linfa will make landfall on the coast of Vietnam south of Da Nang in about 8 hours.  Tropical Storm Linfa will move through an environment favorable for intensification until it makes landfall.  Linfa will move over water where the Sea Surface Temperature is near 29°C.  It will move under the southern part of an upper level ridge.  The ridge will produce easterly winds which will blow toward the top of Tropical Storm Linfa.  Those winds will cause moderate vertical wind shear.  The shear will limit the rate of intensification but Linfa will strengthen before it makes landfall.

Tropical Storm Linfa will make landfall on the coast of Vietnam south of Da Nang in a few hours.  Linfa will bring gusty winds and locally heavy rain to parts of central Vietnam, southern Laos, northern Cambodia and northeastern Thailand.  Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Chan-hom was passing south of Japan.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Chan-hom was located at latitude 32.0°N and longitude 139.8°E which put it about 215 miles (345 km) south of Tokyo, Japan.  Chan-hom was moving toward the east at 15 m.p.h. (24 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 985 mb.

Typhoon Chan-hom Turns Toward Japan

Typhoon Chan-hom turned toward Japan on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Typhoon Chan-hom was located at latitude 27.5°N and longitude 132.9°W which put it about 515 miles (825 km) south-southwest of Osaka, Japan.  Chan-hom was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 973 mb.

Typhoon Chan-hom strengthened slowly on Wednesday.  An eye with a diameter of 35 miles (55 km) formed at the center of Chan-hom.  The eye was surrounded by a broken ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Chan-hom.  Storms near the core generated upper level divergence which pumped mass away to the northeast of the typhoon.

The circulation around Typhoon Chan-hom was large.  Winds to typhoon force extended out 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out 200 miles (320 km) from the center of Chan-hom.

Typhoon Chan-hom will move through an environment somewhat favorable for intensification during the next 24 hours.  Chan-hom will move over water where the Sea Surface Temperature is near 28°C.  It will move under the western end of an upper level ridge.  The ridge will produce southerly winds which will blow toward the top of Typhoon Chan-hom.  Those winds will cause moderate vertical wind shear, which will inhibit intensification.  The wind shear will limit intensification, but Chan-hom could get stronger during the next 24 hours.  An upper level trough over eastern Asia will cause stronger southwesterly winds to blow toward Typhoon Chan-hom in a day or so.  Those winds will cause stronger vertical wind shear and they will cause Chan-hom to start to weaken.

Typhoon Chan-hom will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean during the next 48 hours.  The high will steer Chan-hom toward the north during that time period.  The upper trough over eastern Asia will turn Typhoon Chan-hom toward the northeast during the weekend.  On its anticipated track Typhoon Chan-hom will be southeast of Kyushu and south of Shikoku in about 48 hours.

Tropical Storm Chan-hom Forms Southwest of Iwo To

Tropical Storm Chan-hom formed southwest of Iwo To on Sunday night.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Chan-hom was located at latitude 22.8°N and longitude 139.0°E which put it about 215 miles (345 km) southwest of Iwo To.  Chan-hom 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 998 mb.

More thunderstorms developed near the center of a low pressure system southwest of Iwo To on Sunday night and the Japan Meteorological Agency designated the system as Tropical Storm Chan-hom.  The circulation around Tropical Storm Chan-hom was still organizing.  Thunderstorms were forming near the center of circulation, but the distribution of storms was asymmetrical.  The strongest thunderstorms were developing in bands in the southern half of the tropical storm.  Bands in the northern half of Chan-hom consisted mainly of showers and lower clouds.  Storms near the center of circulation generated upper level divergence which pumped mass away to the west of the tropical storm.  Winds to tropical storm force extended out 100 miles (165 km) in the southeastern quadrant of Tropical Storm Chan-hom.  Winds in the other parts of Chan-hom were blowing at less than tropical storm force.

Tropical Storm Chan-hom will move through an environment favorable for intensification during the next several days.  Chan-hom will move over water where the Sea Surface Temperature is near 28°C.  It will move around the southern side of an upper level ridge.  The ridge will produce easterly winds which will blow toward the top of Tropical Storm Chan-hom.  Those winds will cause some vertical wind shear.  The shear will inhibit intensification but it will not be strong enough to prevent Chan-hom from intensifying.   Tropical Storm Chan-hom could strengthen into a typhoon within 72 hours.

Tropical Storm Chan-hom will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Chan-hom toward the northwest during the next two to three days.  On its anticipated track Tropical Storm Chan-hom could approach the northern Ryukyu Islands and southwestern Japan by the end of the week.

Lingling Strengthens to Typhoon South of Ryukyu Islands

Former Tropical Storm Lingling strengthened to a typhoon south of the Ryukyu Islands on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Typhoon Lingling was located at latitude 21.7°N and longitude 124.3°E which put it about 180 miles (295 km) south of Ishigaki, Japan.  Lingling was moving toward the north at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 979 mb.

Typhoon Lingling exhibited much greater organization on Tuesday.  A circular eye with a diameter of 30 miles (50 km) developed at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Lingling.  The strongest rainbands were occurring in the southeastern half of the circulation.  Storms near the core of Lingling were generating upper level divergence which was pumping mass away from the typhoon.  Winds to typhoon force extended out about 30 miles from the center of circulation.  Winds to tropical storm force extended out about 140 miles (220 km) from the center.

Typhoon Lingling will move through an environment favorable for intensification during the next 24 to 48 hours.  Lingling will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Lingling is likely to continue to intensify and it could strengthen into the equivalent of a major hurricane in a couple of days.

Typhoon Lingling is moving around the western end of a large subtropical ridge over the Western North Pacific Ocean.  The ridge will steer Lingling toward the north during the next several days.  On its anticipated track Typhoon Lingling could reach the southern Ryukyu Islands within 24 hours.  Lingling will bring strong, gusty winds and heavy rain to those islands.  Typhoon Lingling could approach Kyushu and South Korea in about three days.

Elsewhere over the Western North Pacific Ocean, Tropical Depression Kajiki was dropping heavy rain over parts of Vietnam and Laos.  At 11:00 a.m. EDT on Tuesday the center of Tropical Depression Kajiki was located at latitude 16.4°N and longitude 107.3°E which put it about 65 miles (105 km) west-northwest of Da Nang, Vietnam.  Kajiki was moving toward the west at 8 m.p.h. (13 km/h).  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.

Tropical Storm Kajiki Forms Near Vietnam

Tropical Storm Kajiki formed near the coast of Vietnam on Monday.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Kajiki was located at latitude 16.6°N and longitude 107.6°E which put it about 50 miles (80 km) northeast of Vinh Linh, Vietnam.  Kajiki was moving toward the southwest at 10 m.p.h. (16 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 wind speed around a low pressure system just east of the coast of Vietnam increased to 40 m.p.h. (65 km/h) on Monday and the Japan Meteorological Agency designated the system as Tropical Storm Kajiki.  The distribution of thunderstorms around Kajiki was asymmetrical.  Many of the stronger thunderstorms were occurring in bands in the western half of the circulation.  Bands in the eastern half of Tropical Storm Kajiki contained fewer thunderstorms.  Kajiki was moving south of an upper level ridge over eastern Asia.  The ridge was producing northeasterly winds which were blowing toward the top of the tropical storm.  Those winds were causing moderate vertical wind shear and they were the reason for the asymmetrical distribution of thunderstorms.

The upper level ridge will steer Tropical Storm Kajiki toward the southwest during the next 12 to 24 hours.  On it anticipated track Kajiki will reach the coast of Vietnam within 12 hours.  Even though Tropical Storm Kajiki will move over water where the Sea Surface Temperature is near 30°C, it will have only a few hours to strengthen before the center reaches the coast.  Kajiki will bring some gusty winds to the coast, but the greater risk is for heavy rain.  Tropical Storm Kajiki will drop locally heavy rain over parts of central Vietnam and northern Laos.  Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Lingling was strengthening as it north toward the southern Ryukyu Islands.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Lingling was located at latitude 19.5°N and longitude 124.1°E which put it about 565 miles (915 km) south-southwest of Okinawa.  Lingling was moving toward the north-northwest at 13 m.p.h. (20 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 994 mb.  Tropical Storm Lingling is forecast to strengthen into a typhoon before it reaches the southern Ryukyu Islands.

Tropical Storm Pakhar Makes Landfall Near Macau

Tropical Storm Pakhar sped across the South China Sea and made landfall on the coast of China near Macau.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Pakhar was located at latitude 22.3°N and longitude 112.7°E which put it about 60 miles (95 km) southwest of Hong Kong.  Pakhar was moving toward the northwest at 27 m.p.h. (43 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 987 mb.

Tropical Storm Pakhar will bring gusty winds and locally heavy rain as it quickly moves inland over southern China.  The wind and rain will hinder the efforts in the area to recover from Typhoon Hato.  Fortunately, Tropical Storm Pakhar is a fairly small storm.  Winds to tropical storm force only extend out about 80 miles (130 km) from the center of circulation.  The small size of Pakhar and its rapid rate of movement will limit the impact of the tropical storm.  Tropical Storm Pakhar should spin down fairly quickly as it rapidly moves inland.

Tropical Storm Pakhar Forms East of Luzon

Tropical Storm Pakhar formed east of Luzon on Thursday.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Pakhar was located at latitude 15.2°N and longitude 124.7°E which put it about 280 miles (455 km) east of Manila, Philippines.  Pakhar was moving toward the west at 13 m.p.h. (21 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 1000 mb.

A center of circulation developed on the eastern edge of a cluster of thunderstorms east of Luzon on Thursday and the Japan Meteorological Agency designated the system as Tropical Storm Pakhar.  The circulation of Pakhar is still in the early organizational stages.  Most of the showers and thunderstorms are occurring west of the center of circulation.  An upper level ridge north of Pakhar is producing easterly winds which are blowing across the circulation.  Those easterly winds are probably responsible for the asymmetrical distribution of thunderstorms on the western side of the tropical storm.

Tropical Storm Pakhar will move through an environment that will be somewhat favorable for intensification during the next 12 to 18 hours.  Pakhar will move over water where the Sea Surface Temperature (SST) is near 30°C.  The easterly winds in the upper levels are causing moderate vertical wind shear and the shear will inhibit intensification.  Tropical Storm Pakhar will weaken when it moves across Luzon.  After Pakhar moves out over the South China Sea, it will move back over water where the SST is near 30°C.  The forecast suggests that there could be less vertical wind shear at that time and Pakhar has a chance to intensify into a typhoon when it moves away from the Philippines.

Pakhar is being steered westward by a subtropical ridge north of the tropical storm.  Pakhar is forecast to turn more toward the northwest when it crosses Luzon.  On its anticipated track Tropical Storm Pakhar will reach the coast of Luzon near Baler in 12 to 18 hours.  Pakhar is forecast to continue moving toward the northwest and it could make another landfall in China west of Hong Kong in about three days.  However, there is more uncertainty about the future track of Pakhar after the tropical storm exits Luzon.

Tropical Storm Pakhar could bring heavy rain to Luzon and cause flooding in some locations.  If Tropical Storm Pakhar intensifies over the South China Sea and makes landfall west of Hong Kong as a typhoon, it could seriously affect the efforts to recover from damage caused by Typhoon Hato which hit that same area a few days ago.

Extremely Powerful Typhoon Meranti Nearing Southern Taiwan

The center of extremely powerful Typhoon Meranti moved closer to the southern end of Taiwan during the past few hours.  At 5:00 p.m. EDT on Tuesday the center of Typhoon Meranti was located at latitude 21.1°N and longitude 121.3°E which put it about 65 miles (105 km) south-southeast of Hengchun, Taiwan.  Meranti was moving toward the west-northwest at 11 m.p.h. (18 km/h).  The maximum sustained wind speed was 190 m.p.h. (305 km/h) and there were wind gusts to 230 m.p.h. (370 km/h).  The minimum surface pressure was 887 mb.

Typhoon Meranti is large and powerful.  The Hurricane Intensity Index (HII) is 46.1.  The Hurricane Size Index (HSI) is 27.9 and the Hurricane Wind Intensity Size Index (HWISI) is 74.0.  As a source of comparison, when Hurriane Katrina was at its peak intensity as a Category 5 hurricane over the Gulf of Mexico in 2005, its HII was 38.6, its HSI was 33.7, and its HWISI was 72.3.  Typhoon Meranti is stronger than Hurricane Katrina was, but Meranti is a little smaller than Katrina was in 2005.  The indices suggest that Typhoon Meranti is capable of causing widespread catastrophic damage.

The circulation of Typhoon Meranti is symmetrical and very well organized.  It possess a tight core consisting of a small inner eye surrounded by a ring of very tall thunderstorms.  A second, larger outer eyewall completely surrounds the inner eye.  The strongest winds are occurring in the inner eyewall near the center of circulation.  Winds to typhoon force are also occurring in the outer eyewall and extend out at least 80 miles (130 km) from the center of circulation.  Additional bands of strong thunderstorms are rotating around the outer eyewall.  Typhoon Meranti is generating strong upper level divergence which is pumping out large quantities of mass and is allowing the surface pressure to be so low.

Typhoon Meranti is probably at its peak intensity.  It is still moving over water where the Sea Surface Temperature is near 31°C.  However, the northwestern edge of the outer eyewall appears to be moving over the southern end of Taiwan.  As more of the circulation moves over Taiwan, there will be some disruption of the airflow.  The center of Typhoon Meranti could move very close to the southern tip of Taiwan.  If the center of Meranti moves over southern Taiwan, then the typhoon will weaken more quickly.  It currently appears that the center of Typhoon Meranti could move just south of the southern tip of Taiwan, and on that track the typhoon would not weaken as quickly.  When Typhoon Meranti moves west of Taiwan, it will move over slightly cooler SSTs before it reaches China.  Meranti will weaken more before it reaches China, but it will still be a significant typhoon when it makes landfall there.

The center of Typhoon Meranti is wobbling a little as the inner eye rotates around inside the outer eyewall.  If one averages the wobbles, then then core of Meranti is moving on a general west-northwesterly track.  On its anticipated track, the center of Typhoon Meranti will pass very near the southern end of Taiwan during the next few hours.  It could turn slightly toward the northwest as it moves west of Taiwan.  Typhoon Meranti could make a landfall on the coast of China between Xiamen and Shantou in about 24 hours.

Typhoon Meranti is an extremely dangerous storm.  It is capable of causing widespread catastrophic wind damage.  In addition, its intensity and size will produce very heavy rainfall, especially on the eastern slopes of the mountains on Taiwan.  Flash flooding is likely.  Typhoon Meranti will also produce heavy rain over eastern China and additional flooding is likely in that region.  Typhoon Meranti will also cause a significant storm surge in low lying coastal areas.