Tag Archives: WP18

Tropical Storm Nangka Makes Landfall in Vietnam

Tropical Storm Nangka made landfall on the coast of northern Vietnam on Wednesday morning.  Nangka weakened to a tropical depression after the center moved over land.  At 8:00 a.m. EDT on Wednesday the center of Tropical Depression Nangka was located at latitude 20.0°N and longitude 105.0°E which put it about 80 miles (130 km) southwest of Hanoi, Vietnam.  Nangka was moving toward the west at 12 m.p.h. (19 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.

The center of Tropical Storm Nangka made landfall on the coast of Vietnam about 70 miles (110 km) southeast of Hanoi on Wednesday morning.  Nangka brought gusty winds and heavy rain to the northern coast of Vietnam.  Nangka quickly weakened to a tropical depression when it moved westward over northern VIetnam.  Bands of showers and thunderstorms dropped locally heavy rain over parts of northern Vietnam.

Tropical Depression Nangka will continue to move toward the west until the circulation spins down over northern Laos on Thursday.  Nangka will continue to drop locally heavy rain over parts of northern Vietnam and northern Laos during the next 24 hours.  Heavy rain could cause flash floods in some locations.

Tropical Storm Nangka Brings Wind and Rain to Hainan

Tropical Storm Nangka brought wind and rain to Hainan Island on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Nangka was located at latitude 19.1°N and longitude 110.0°E which put it about 70 miles south-southwest of Haikou, China.  Nangka was moving toward the west-northwest at 9 m.p.h. (15 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 987 mb.

The center of Tropical Storm Nangka moved directly across Hainan Island on Tuesday.  Nangka strengthened before it made landfall on the east coast of Hainan.  Winds to tropical storm force extended out 200 miles (320 km) from the center of Tropical Storm Nangka.  So, Nangka may have produced tropical storm force winds over much of Hainan.  Thunderstorms near the center of circulation and in bands revolving around the center were dropping heavy rain over parts of Hainan.  The heavy rain was likely to cause flash floods in some locations.

Tropical Storm Nangka will weaken while it moves across Hainan.  Nangka will move into an environment favorable for intensification for about 12 hours when it moves west of Hainan Island.  Nangka 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 over eastern Asia.  The ridge will produce easterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent Tropical Storm Nangka from strengthening again.

Tropical Storm Nangka will move south of a high pressure system over eastern Asia.  The high will steer Nangka toward the west during the next 48 hours.  Tropical Storm Nangka will move west of Hainan Island in about 6 hours.  On its anticipated track Nangka will make landfall on the northern coast of Vietnam southeast of Hanoi in about 18 hours.  Tropical Storm Nangka will bring gusty winds and locally heavy rain to northern Vietnam.  Heavy rain will cause flash floods in some locations.

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.

Tapah Strengthens to a Typhoon Southwest of Japan

Former Tropical Storm Tapah strengthened into a typhoon southwest of Japan on Saturday.  At 11:00 a.m. EDT on Saturday the center of Typhoon Tapah was located at latitude 29.2°N and longitude 125.9°E which put it about 380 miles (610 km) southwest of Nagasaki, Japan.  Tapah was moving toward the north at 12 m.p.h. (19 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 972 mb.

The circulation around Typhoon Tapah was very large.  Winds to tropical storm force extended out 250 miles (400 km) from the center of circulation.  There was a large eye with a diameter of 60 miles (95 km) at the center of Typhoon Tapah.  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 large eye of Tapah.  It appeared on satellite imagery as if some drier air might be wrapping around the southeastern side of the circulation.

Typhoon Tapah will move through an environment that could allow it to maintain its current intensity for another 12 to 24 hours.  Tapah will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough over eastern Asia will produce southwesterly winds which will cause some vertical wind shear, but the shear may not be strong enough to weaken Tapah today.  Typhoon Tapah will move under stronger upper level westerly winds in the middle latitudes on Sunday and the increase in wind shear will weaken the typhoon.  Stronger wind shear and cooler Sea Surface Temperatures will cause Typhoon Tapah to begin a transition into an extratropical cyclone on Sunday.

Typhoon Tapah will move around the western end of a subtropical ridge over the Western North Pacific Ocean during the next 12 to 18 hours.  The ridge will steer Tapah toward the north during that time period.  The stronger westerly winds in the middle latitudes will turn Tapah toward the northeast on Sunday.  On its anticipated track the center of Typhoon Tapah will be west of Kyushu in about 12 to 18 hours.  The center of Tapah could pass between South Korea and Japan on Sunday and then it will move over the Sea of Japan.  Because it has such a large circulation Typhoon Tapah could bring gusty winds and locally heavy rain to parts of Kyushu, Honshu and South Korea.

Tropical Storm Tapah Develops East of Taiwan

Tropical Storm Tapah developed east of Taiwan on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Tapah was located at latitude 23.3°N and longitude 126.5°E which put it about 150 miles (245 km) east-southeast of Ishigaki, Japan.  Tapah was moving toward the west at 7 m.p.h. (11 km/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 965 mb.

A distinct low level center of circulation formed on the northern side of an area of thunderstorms east of Taiwan on Thursday and the Japan Meteorological Agency designated the system as Tropical Storm Tapah.  The distribution of thunderstorms around Tapah was asymmetrical.  Most of the thunderstorms  were occurring in bands in the southern half of the circulation.  Bands in the northern half of the tropical storm consisted primarily of showers and lower clouds.  Storm on the southern side of the center began to generate upper level divergence which pumped mass away from the tropical storm.  The circulation around Tropical Storm Tapah was very large.  Winds to tropical storm force extended out about 250 miles (400 km) from the center of circulation.

Tropical Storm Tapah will move through an environment favorable for intensification during the next several days.  Tapah will move over water where the Sea Surface Temperature is near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Some drier air north of Tropical Storm Tapah could inhibit the development of bands of thunderstorms on the northern side of the circulation.  Tropical Storm Tapah is likely to intensify and it could strengthen into a typhoon during the weekend.

Tropical Storm Tapah will move around the western end of a subtropical ridge over the Western North Pacific Ocean.  The ridge will steer Tapah more toward the northwest on Friday.  Tapah will move more toward the north when it rounds the western end of the ridge.  On its anticipated track Tropical Storm Tapah could move over the southern Ryukyu Islands in about 12 hours.  The center of Tapah could pass west of Okinawa in about 24 hours.

Tropical Storm Yagi Makes Landfall on East Coast of China

Tropical Storm Yagi made landfall on the east coast of China between Wenzhou and Taizhou on Sunday.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Yagi was located at latitude 28.4°N and longitude 121.7°E which put it about 35 miles (55 km) south of Taizhou, China.  Yagi was moving toward the northwest at 16 m.p.h. (26 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 987 mb.

Tropical Storm Yagi was moving steadily inland over Zhejiang province between Wenzhou and Taizhou.  The strongest winds were occurring in bands of thunderstorms east of the center of circulation that were over the coastal waters of the East China Sea.  The wind in those areas will diminish when Yagi moves farther inland.  The greatest risk will be locally heavy rain falling over parts of Zhejiang province.  Rainfall could be enhanced where the wind blows up the slopes of mountains and steep terrain increases the potential for flash floods.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Leepi moved closer to Iwo To and Tropical Depression 20W formed southwest of Hong Kong.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Leepi was located at latitude 24.1°N and longitude 141.2°E which put it about 85 miles (135 km) south-southeast of Iwo To.  Leepi was moving toward the north-northwest at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 55 m.p.h. (90 km/h) and there were wind gusts to 70 m.p.h. (110 km/h).  The minimum surface pressure was 992 mb.

At 11:00 a.m. EDT on Sunday the center of Tropical Depression 20W was located at latitude 20.7°N and longitude 112.4°E which put it about 85 miles (135 km) southwest of Macao.  It was moving toward the east-southeast at 3 m.p.h. (5 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 996 mb.

Tropical Storm Leepi Forms Southeast of Iwo To

Tropical Storm Leepi formed southeast of Iwo To on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Leepi was located at latitude 21.5°N and longitude 142.7°W which put it about 285 miles (465 km) south-southeast of Iwo To.  Leepi was moving toward the north-northwest at 12 m.p.h. (19 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 995 mb.

A distinct center of circulation developed within an area of thunderstorms between the Northern Marianas and Iwo To and the Japan Meteorological Agency designated the system as Tropical Storm Leepi.  The distribution of thunderstorms around Tropical Storm Leepi was very asymmetrical.  The stronger thunderstorms were all occurring in bands in the eastern half of the circulation.  The bands in the western half of the circulation consisted of showers and low clouds.  Storms near the center of Leepi were generating upper level divergence which was pumping mass away to the northeast of the tropical storm.

Tropical Storm Leepi will move through an environment somewhat favorable for intensification during the next 12 to 24 hours.  Leepi will move over water where the Sea Surface Temperature is near 29°C.  An upper level trough northeast of the tropical storm was producing southwesterly winds which were causing moderate vertical wind shear.  The wind shear was inhibiting the divergence to the west of Tropical Storm Leepi.  The tropical storm also appeared to be drawing drier air into the western side of the circulation.  Leepi could intensify on Sunday, but it will move into an area of stronger upper level winds in a day or so.  Increased vertical wind shear will likely start to weaken Tropical Storm Leepi after that occurrs.

Tropical Storm Leepi will move near the western end of a ridge in the middle troposphere.  The ridge will Leepi in a general motion toward the northwest.  On its anticipated track Tropical Storm Leepi will move near Iwo To in about 24 hours.  Leepi could approach the northern Ryukyu Islands and Kyushu in about three days.

Elsewhere over the Western North Pacific, Tropical Storm Yagi passed over the southern Ryukyu Islands on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Yagi was located at latitude 25.6°N and longitude 124.8°E which put it about 250 miles (400 km) east of Taipei, Taiwan.  Yagi was moving toward the west 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 993 mb.

Typhoon Shanshan Brushes East Coast of Honshu

Typhoon Shanshan brushed the east coast of Honshu late on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Typhoon Shanshan was located at latitude 36.8°N and longitude 141.5°E which put it about 40 miles (65 km) east of Iwaki, Japan.  Shanshan was moving toward the north at 12 m.p.h. (19 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 975 mb.

The center of Typhoon Shanshan moved very close to the east coast of Honshu near Choshi on Wednesday and then it moved nearly parallel to the coast.  The stronger winds and heavier rain were occurring on the eastern side of Shanshan, and they passed east of Honshu.  The winds were weaker and the rain was lighter in the western side of Typhoon Shanshan.  Winds to tropical storm force were occurring near the east coast of Honshu.  The typhoon had little effect on the weather near Tokyo.  Some locations near the coast did have a period of heavier rain after the center of Typhoon Shanshan passed and the winds blew from the southwest toward the coast.

Typhoon Shanshan will affect the coast of Honshu for another six to twelve hours, while the center moves nearly parallel to the coast.  Shanshan will reach an area where stronger westerly winds are blowing in the middle and upper troposphere.  Those winds will turn Typhoon Shanshan toward the east and they will push it away from Japan.  The stronger winds will also cause significant vertical wind shear.  Shanshan will move over cooler water when it turns eastward.  The combination of vertical wind shear and cooler water will cause Typhoon Shanshan to weaken and it could make a transition to an extratropical cyclone in a day or two.

Elsewhere over the Western North Pacific, Tropical Storm Yagi formed southeast of Okinawa on Wednesday.  At 11:00 p.m. EDT the center of Tropical Storm Yagi was located at latitude 21.3°N and longitude 133.6°E which put it about 530 miles (855 km) southeast of Okinawa.  Yagi was moving toward the northwest 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 993 mb.

Tropical Storm Mawar Nears Landfall in China

Tropical Storm Mawar moved closer to a landfall in China on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Mawar was located at latitude 22.2°N and longitude 116.4°E which put it about 150 miles (240 km) east of Hong Kong.  Mawar was moving toward the west-northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 55 m.p.h. (90 km/h) and there were wind gusts to 70 m.p.h. (110 km/h).  The minimum surface pressure was 989 mb.

The circulation of Tropical Storm Mawar is very asymmetrical.  Most of the thunderstorms are located south of the center of circulation.  A primary rainband is just south of the center of circulation and there are several other bands farther south of the center.  Recent visible satellite images suggest that the eastern end of the primary rainband could be trying to wrap around the center.  Thunderstorms in the primary rainband were generating some upper level divergence which was pumping mass away to the southwest of the tropical storm.

Tropical Storm Mawar will move through an environment that is somewhat favorable for intensification during the next 12 to 18 hours.  Mawar will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge centered over China is producing northeasterly winds which are blowing toward the top of the circulation.  Those winds are generating moderate vertical wind shear.  Those winds may also be the reason for the asymmetrical distribution of thunderstorms.  Mawar could intensify before it makes landfall in China.

Tropical Storm Mawar is being steered slowly toward the west-northwest by a ridge near Japan.  That general motion is expected to continue for the next several days.  On its anticipated track Tropical Storm Mawar will make landfall in China east of Hong Kong in 12 to 18 hours.  Mawar will bring gusty winds and locally heavy rain to parts of Guangdong province.  The rain could contribute to flooding in some locations.  Mawar is likely to weaken steadily after it makes landfall.

Typhoon Malakas Bringing Gusty Winds and Rain to Shikoku and Honshu

Typhoon Malakas is bringing wind and rain to coastal areas of Shikoku and Honshu.  At 11:00 p.m. EDT on Monday the center of Typhoon Malakas was located near latitude 33.4°N and longitude 134.7°W which put it about 90 miles (145 km) southwest of Osaka, Japan.  Malakas was moving toward the northeast at 25 m.p.h. (40 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.

The structure of Typhoon Malakas is starting the transition from a tropical cyclone to an extratropical cyclone.  It retains an eye, but the thunderstorms in the southern part of the eyewall are thinning.  Most of the other thunderstorms are in rainbands north of the center of circulation.  Cooler, drier air is wrapping around the southern side of the circulation.  The strongest winds are occurring over the water near the center of circulation.  Heavy rain is falling over eastern Shikoku and southwestern Honshu near Osaka and Nagoya.

Although Typhoon Malakas is moving over water where the Sea Surface Temperature is near 28°C, it will continue to weaken as it makes the transition to an extratropical cyclone.  An upper level trough west of Japan is producing southwesterly winds which are blowing across the top of the circulation.  Also, almost half of the circulation is moving over land and the center will move over coastal sections of Honshu.  Increasing vertical wind shear and the added friction caused by the land will weaken Malakas to a tropical storm on Tuesday.

The upper level trough is steering Typhoon Malakas quickly toward the northeast and that general motion is expected to continue.  On its anticipated track Typhoon Malakas will pass south of Osaka and Nagoya.  The center of then Tropical Storm Malakas will move near Tokyo in about 18 hours.  Malakas will continue to bring gusty winds to coastal parts of Honshu.