Tag Archives: Hainan Island

Tropical Storm Son-tinh Makes Landfall in Vietnam, Ampil Forms South of Okinawa

Tropical Storm Son-tinh made landfall in Vietnam on Wednesday while Tropical Storm Ampil formed south of Okinawa.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Son-tinh was located at latitude 19.1°N and longitude 105.5°E which put it about 30 miles (50 km) north-northwest of Vinh, Vietnam.  Son-tinh was moving toward the west at 14 m.p.h. (22 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 990 mb.

Tropical Storm Son-tinh strengthened on Wednesday after it moved away from Hainan Island.  A primary rainband wrapped around the western and southern side of the center of circulation and the inner end of the band began to evolve into a partial eyewall.  Thunderstorms in the core of Son-tinh generated upper level divergence which pumped away mass.  The removal of mass allowed the surface pressure to decrease.  A stronger pressure gradient force produced higher wind speeds.

Tropical Storm Son-tinh moved south of a ridge in the upper and middle troposphere.  The ridge steered Son-tinh steadily toward the west and the tropical storm made landfall just north of Vinh, Vietnam late on Wednesday.  Tropical Storm Son-tinh brought gusty winds and locally heavy rain to the coast of northern Vietnam around Vinh.  Son-tinh was also dropping locally heavy rain over portions of northern Vietnam and flash flooding could occur in some locations.

Tropical Storm Son-tinh will continue to move westward over northern Vietnam and northern Laos.  Son-tinh will weaken as the circulation moves inland.  It will continue to drop locally heavy rain and flash floods could occur in parts of northern Vietnam and northern Laos during the next several days.

The organization of former Tropical Depression 12W improved on Wednesday and the Japan Meteorological Agency designated the system as Tropical Storm Ampil.  At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Ampil was located at latitude 19.9°N and longitude 129.6°E which put it about 480 miles (775 km) south-southeast of Okinawa.  Ampil was moving toward the east-northeast 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 996 mb.

The circulation of Tropical Storm Ampil was not particularly well organized.  It exhibited characteristics of a hybrid low pressure system.  There was an upper low northwest of the low level circulation.  The upper low was causing strong southwesterly winds which were blowing across the top of the lower level circulation.  Those winds were causing significant vertical wind shear and they were tilting the circulation strongly toward the northeast.  The strongest bands of showers and thunderstorms were occurring south and west of the low level circulation.  Bands north and west of the center consisted primarily of showers and lower clouds.

The upper low will gradually move toward the west.  As the low moves westward, the vertical wind shear over Tropical Storm Ampil will start to decrease.  Ampil will move over water where the Sea Surface Temperature is near 29°C.  So, when the vertical wind shear decreases, then Tropical Storm Ampil will likely intensify.  Ampil could eventually strengthen into a typhoon in two or three days.

The upper low will initially will steer Tropical Storm Ampil toward the northeast.  When the upper low moves farther to the west on Thursday, then Ampil will move toward the north.  On its anticipated track the center of Tropical Storm Ampil could be near Okinawa and the Ryukyu Islands in two or three days.

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.

Tropical Storm Ewiniar Forms Near Coast of South China

Tropical Storm Ewiniar formed near the coast of South China late on Tuesday.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Ewiniar was located at latitude 20.9°N and longitude 110.5°E which put it about 50 miles (80 km) southeast of Zhanjiang, China.  Ewiniar was moving toward the northwest 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.

A distinct low level center of circulation consolidated in a cluster of showers and thunderstorms moving over the South China Sea near Hainan Island on Monday and the Japan Meteorological Agency designated the system as Tropical Storm Ewiniar.  Several bands of showers and thunderstorms developed west of the center of circulation.  Bands east of the center consisted primarily of showers and low clouds.  Winds to tropical storm force were occurring within 60 miles (95 km) of the center o circulation.

Tropical Storm Ewiniar has 12 to 24 hours during which it could intensify if the center remains over water.  The Sea Surface Temperature of the water near the coast of South China is about 30°C.  Ewiniar is under the southwestern portion of a narrow upper level ridge.  The ridge is producing weak southerly winds which are blowing toward the top of the circulation.  Those winds will cause some vertical wind shear but the shear will not be strong enough to prevent intensification.  Even though the atmospheric and oceanic environments are favorable for intensification, a portion of the circulation of Tropical Storm Ewiniar is already over land.  The friction caused by the flow of air over the land will inhibit intensification.  Tropical Storm Ewiniar could intensify a little more if the center remains over water.

The upper level ridge was steering Tropical Storm Ewiniar toward the northwest.  A general motion toward the north is expected for the next 24 to 48 hours.  On its anticipated track the center of Tropical Storm Ewiniar will move near the east coast of the Leizhou Peninsula.  Ewiniar could move inland near Wuchuan and Dianbai.  Tropical Storm Ewiniar will bring some gust winds to South China, but the greater risks are the potential for heavy rain and floods.

Tropical Storm Haikui Weakens Southeast of Hainan Island

Tropical Storm Haikui weakened as it moved southeast of Hainan Island on Saturday.  At 10:00 p.m. EST on Saturday the center of Tropical Storm Haikui was located at latitude 17.6°N and longitude 112.6°E which put it about 290 miles (470 km) east of Da Nang, Vietnam.  Haikui was moving toward the west-southwest 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 999 mb.

A combination of drier air and strong vertical wind shear weakened Tropical Storm Haikui on Saturday.  Strong northeasterly winds transported colder drier air from eastern Asia into the circulation of Tropical Storm Haikui.  The drier air reached the core of the circulation and it prevented the formation of new thunderstorms around the center of circulation.  Strong westerly winds in the upper levels were blowing over the top of the circulation.  The combination of northeasterly winds in the lower levels and westerly winds in the upper levels produced strong vertical wind shear.  The wind shear blew the upper portion of the circulation to the east of the low level core of Tropical Storm Haikui.  The core of Tropical Storm Haikui consists of a circular rotation of showers and low clouds.  The only thunderstorms are occurring in a rainband on the northeastern periphery of the circulation.

The strong wind vertical wind shear and drier air should continue to weaken Tropical Storm Haikui.  Haikui is likely to weaken to a tropical depression on Sunday.  Since the circulation exists primarily in the lower levels, it will be steered by the winds closer to the surface of the Earth.  The northeasterly winds in the lower levels will steer Tropical Storm Haikui toward the west- southwest.  On its anticipated track Tropical Storm Haikui will pass south of Hainan Island.  Haikui or its remnants could reach the coast of Vietnam in 36 to 48 hours.

Tropical Storm Haikui Moves Across South China Sea

Tropical Storm Haikui moved across the South China Sea on Friday.  At 10:00 p.m. EST on Friday the center of Tropical Storm Haikui was located at latitude 17.8°N and longitude 115.4°E which put it about 485 miles (785 km) east of Da Nang, Vietnam.  Haikui was moving toward the west-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 994 mb.

Tropical Storm Haikui strengthened slightly on Friday, but the circulation remained asymmetrical.  Most of the stronger thunderstorms were occurring east of the center of circulation.  A short primary rainband wrapped around the eastern side of the center.  Several other broken bands of showers and thunderstorms formed to the east of the primary rainband.  Bands of showers and storms were also located south of the center of circulation.  Storms near the core of Tropical Storm Haikui were generating some upper level divergence which was pumping mass away to the east of the tropical storm.  The bands in the western half of the circulation consisted primarily of low clouds and showers.

Tropical Storm Haikui will move through an environment marginally favorable for intensification during the next 24 to 36 hours.  Haikui will move over water where the Sea Surface Temperature is near 29°C.  Colder, drier air over eastern Asia was flowing toward the western side of Tropical Storm Haikui.  The upper level westerly winds of the middle latitudes were blowing just to the northwest of Tropical Storm Haikui.  Those winds were causing moderate vertical shear over the northwestern periphery of Haikui.  The winds over the core of Tropical Storm Haikui were weaker.  If Tropical Storm Haikui remains south of the stronger westerly winds, it could intensify a little more during the next 24 hours.

A ridge to the north of Haikui is steering the tropical storm toward the west-northwest.  The ridge is forecast to strengthen and Tropical Storm Haikui is likely to move more toward the west during the next several days.  On its anticipated track Tropical Storm Haikui will pass south of Hainan Island in about 48 hours.  Tropical Storm Haikui could reach the coast of Vietnam in less than three days.

Tropical Storm Haikui Develops Over the Philippines

Tropical Storm Haikui developed over the Philippines on Thursday.  At 4:00 p.m. EST on Thursday the center of Tropical Storm Haikui was located at latitude 14.6°N and longitude 119.8°E which put it about 50 miles (80 km) west-southwest of Manila, Philippines.  Haikui was moving toward the west-northwest 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).  Thee minimum surface pressure was 998 mb.

A center of circulation developed within an area of showers and thunderstorms over the Philippines and the Japan Meteorological Agency designated the system as Tropical Storm Haikui.  The circulation of Tropical Storm Haikui is still organizing.  Several areas of showers and thunderstorms are east and south of the center of circulation.  Broken bands of showers and storms are beginning to form farther away from the center.  There are fewer showers and thunderstorms in the western half of the circulation.

Tropical Storm Haikui will be moving through an environment that is somewhat favorable for intensification.  Haikui will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge centered northeast of the Philippines is producing easterly winds which are blowing toward the top of the circulation.  Those winds are causing moderate vertical wind shear.  Tropical Storm Haikui will move toward the western end of the ridge and the winds will blow from the southwest at that point.  So, the direction of the wind shear will change.  If Haikui stays far enough south, it will pass south of the stronger upper level winds and the tropical storm could intensify.

The ridge northeast of the Philippines is steering Tropical Storm Haikui toward the west-northwest and that general motion is expected to continue for several more days.  On its anticipated track Tropical Storm Haikui will move away from the Philippines across the South China Sea.  Haikui could approach Hainan Island in a few days.

Typhoon Khanun Makes Landfall in Southern China

Typhoon Khanun made landfall near Zhanjiang in southern China on Sunday.  At 5:00 p.m. EDT on Sunday the center of Typhoon Khanun was located at latitude 20.9°N and longitude 109.3°E which put it about 50 miles (80 km/h) south-southeast of Beihai, China.  Khanun was moving toward the west at 17 m.p.h. (27 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. (150 km/h).  The minimum surface pressure was 969 mb.

Typhoon Khanun brought gusty winds and locally heavy rain over coastal sections of southern China on Sunday.  Khanun has weakened since it made landfall.  An upper level ridge centered over eastern China is producing easterly winds which are blowing over the top of the circulation.  Those winds are causing strong vertical wind shear, which is pushing the upper half of the circulation to the west of low level circulation.  The circulation is pulling drier air from Asia into the western part of Typhoon Khanun and the drier air is wrapping around the southern and eastern sides of the circulation.   Interaction with land and strong vertical wind shear will continue to weaken Khanun on Monday.  Khanun will bring rain to southern China and northern Vietnam as it weakens.

Elsewhere over the western North Pacific Ocean Tropical Depression Twentyfive-W formed west of Yap.  At 5:00 p.m. EDT on Sunday the center of Tropical Depression Twentyfive-W was located at latitude 10.3°N and longitude 136.1°E which put it about 125 miles (200 km) west-northwest of Yap.  It was moving toward the north-northwest at 11 m.p.h. (17 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 999 mb.

The circulation of Tropical Depression Twentyfive-W is still organizing.  Most of the showers and thunderstorms are in a primary rainband that wraps around the eastern side of the circulation.  The depression is moving through an area favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is not much vertical wind shear.  Tropical Depression Twentyfive-W is likely to be become a tropical storm during the next 24 hours and it could become a typhoon in a couple of days.  The depression is forecast to move toward the north-northwest as it moves around the western end of a subtropical ridge over the Pacific Ocean.

Khanun Intensifies Into a Typhoon Southeast of Hong Kong

Tropical Storm Khanun intensified into a typhoon southeast of Hong Kong on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Khanun was located at latitude 20.1°N and longitude 114.2°W which put it about 170 miles (275 km) south-southeast of Hong Kong.  Khanun was moving toward the west-northwest at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 965 mb.

The circulation of Typhoon Khanun became much more well organized on Saturday.  A small circular eye formed at the center of circulation.  A tight ring of strong thunderstorms formed around the eye.  The strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Khanun.  There were many more showers and thunderstorms in the western half of the circulation.  The storms in the core of Khanun were generating upper level divergence which was pumping mass away to the west of the typhoon.  Winds to typhoon force extended out about 70 miles (110 km) from the center of circulation.  Winds to tropical storm force extended out about 250 miles (400 km) from the center.

Typhoon Khanun will move through an environment favorable for intensification for about another 12 to 18 hours.  Khanun will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge north of Typhoon Khanun is producing easterly winds which are blowing toward the top of the circulation.  The easterly winds are causing some vertical wind shear, but the shear is not strong enough to prevent intensification.  The circulation of Typhoon Khanun will interact with land in 12 to 18 hours and that interaction should halt further intensification.

The ridge north of Khanun has been steering the typhoon toward the west-northwest.  The ridge is forecast to strengthen on Sunday and it will steer Typhoon Khanun more toward the west.  On its anticipated track the center of Typhoon Khanun will pass south of Hong Kong and Macao on Sunday.  Khanun will approach the south coast of China near Zhanjiang in 12 to 18 hours.  Typhoon Khanun will bring strong gusty winds and locally heavy rain to southern China west of Hong Kong and Macao.  The heavy rain could cause flooding in some locations.  Typhoon Khanun will be weaker when it moves over the Gulf of Tongking in about 24 hours.

Tropical Storm Khanun Forms Near Luzon

Tropical Storm Khanun formed near northern Luzon on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Khanun was located near latitude 18.0°N and longitude 121.6°W which put it about 240 miles (390 km) north of Manila, Philippines.  Khanun 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 994 mb.

A center of circulation developed near the surface in an area of thunderstorms on Thursday and the Japan Meteorological Agency designated the system as Tropical Storm Khanun.  The circulation of Tropical Storm Khanun was still organizing.  The center of Khanun moved across northern Luzon and the passage over land interrupted the development of the circulation.  Despite the passage over land, a primary rainband wrapped around the western side of the circulation.  Additional bands of showers and thunderstorms developed in the western half of the circulation.  The rainbands were weaker in the eastern half of Khanun, especially in the part of the circulation still over northern Luzon.

Tropical Storm Khanun will move through an environment favorable for intensification when it moves over the South China Sea.  Khanun will move over water where the Sea Surface Temperature is near 30°C.  The tropical storm is moving under the western half of an upper level ridge.  The ridge is producing easterly winds which are blowing toward the top of the circulation.  Those winds are causing moderate vertical wind shear.  The shear will slow the rate of intensification, but it should not be strong enough to prevent Tropical Storm Khanun from intensifying.  Khanun should start to strengthen once the center move farther west of Luzon.  Tropical Storm Khanun is forecast to become a typhoon during the weekend.

Tropical Storm Khanun is moving south of a ridge which is steering the tropical storm toward the west.  A generally westward motion is expected to continue during the next several days.  On its anticipated track Tropical Storm Khanun could approach Hainan Island in about 48 hours.  Khanun is likely to be a typhoon at that time.