Tag Archives: 04W

Tropical Storm Hagupit Almost a Typhoon

Tropical Storm Hagupit intensified to almost typhoon strength east of Taiwan on Sunday.  At 11:00 p.m. EDT on Sunday the center of Typhoon Hagupit was located at latitude 25.4°N and longitude 123.2°E which put it about 130 miles (215 km) east of Taipei, Taiwan.  Hagupit was moving toward the north-northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 985 mb.

The circulation around Tropical Storm Hagupit exhibited much greater organization on Sunday night.  The inner end of a rainband wrapped around the center of circulation and an eye emerged on visible satellite imagery.  The eye was surrounded by a 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 Hagupit.  The strongest rainbands were in the eastern half of the circulation.  Bands in the western half of the tropical storm consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out 115 miles (185 km) from the center of circulation.

Tropical Storm Hagupit will move through an environment favorable for intensification during the next 24 hours.  Hagupit 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.  Tropical Storm Hagupit will intensify into a typhoon during the next 6 to 12 hours.

Tropical Storm Hagupit will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Hagupit toward the north-northwest during the next 24 to 36 hours.  On its anticipated track Hagupit will approach the coast of China south of Shanghai near Wenzhou in about 24 hours.  It will bring gusty winds and locally heavy rain to the east coast of China.  Heavy rain could cause flash floods in some locations.

Elsewhere, former Tropical Storm Sinlaku dropped locally heavy rain on northern Vietnam and Laos.  At 2:00 p.m. EDT on Sunday the center of Tropical Depression Sinlaku was located at latitude 19.7°N and longitude 103.6°E which put it about 150 miles (240 km) north of Vientiane, Laos.  Sinlaku 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 996 mb.

Tropical Storms Sinlaku & Hagupit Form over West Pacific

Tropical Storms Sinlaku and Hagupit formed over the Western North Pacific Ocean on Saturday.  At 11:00 a.m. EDT on Saturday the center of Tropical Storm Sinlaku was located at latitude 19.4°N and longitude 107.1°E which put it about 90 miles (145 km) southeast of Nam Dinh, Vietnam.  Sinlaku was moving toward the northwest at 12 m.p.h. (19 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.

The circulation around a low pressure system near Vietnam exhibited greater organization on Saturday and the Japan Meteorological Agency designated the system as Tropical Storm Sinlaku.  Bands of showers and thunderstorms were revolving around the center of Sinlaku.  There were more thunderstorms in the bands on the western side of the circulation.  Winds to tropical storm force extended out 110 miles (185 km) from the center of circulation.

Tropical Storm Sinlaku has about 12 hours to strengthen before it makes landfall in northern Vietnam.  Sinlaku will move over water where the Sea Surface Temperature is near 30°.  It will move under the southeast part of an upper level ridge over Asia.  The ridge will produce easterly winds which will blow toward the top of Sinlaku.  Those winds will cause moderate vertical wind shear and the shear will limit intensification.  Tropical Storm Sinlaku will bring gusty winds and rain to northern Vietnam on Sunday.

The circulation around a second low pressure system east of Taiwan also exhibited more organization on Saturday and the Japan Meteorological Agency designated that system as Tropical Storm Hagupit.  At 11:00 a.m. EDT on Saturday the center of Tropical Storm Hagupit was located at latitude 21.8°N and longitude 126.5°W which put it about 220 miles (350 km) southeast of Ishigaki, Japan.  Hagupit was moving toward the northwest at 13 m.p.h. (20 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 1003 mb.

The circulation around Tropical Storm Hagupit was still organizing on Saturday.  Thunderstorms were developing in bands in the eastern half of Hagupit.  Bands in the western side of the circulation consisted primarily of showers and lower clouds.  Storms near the center of Hagupit were generating upper level divergence which was pumping mass away to the east of the tropical storm.

Tropical Storm Hagupit will move through an environment favorable for intensification.  Hagupit will move over water where the Sea Surface Temperature is near 30°C.  Hagupit will move into a region where the upper level winds are weaker and there will not be a lot of vertical wind shear.  Tropical Storm Hagupit is likely to intensify during the next 24 to 36 hours.

Tropical Storm Hagupit will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high will steer Hagupit toward the northwest during the next several days.  On its anticipated track the center of Tropical Storm Hagupit will pass near Ishigaki, Japan in about 24 hours.  Hagupit will approach the coast of China south of Shanghai in about 48 hours.

Tropical Depression 04W Forms East of the Northern Marianas

Tropical Depression 04W formed east of the Northern Marianas very late on Friday.  At 11:00 p.m. EDT on Friday the center of Tropical Depression 04W was located at latitude 18.8°N and longitude 148.5°E which put it about 185 miles (300 km) east of Agrihan.  It was moving toward the 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 1003 mb.

An area of showers and thunderstorms persisted for much of the past week east of the Northern Marianas.  Several smaller centers of circulation formed within the area of showers and storms, but those centers ran into strong upper level winds and weakened because strong vertical wind shear and they dissipated.  Another center formed on Friday, but the upper level winds were a little weaker and the center persisted.  An upper level trough south of Japan was still producing southwesterly winds which were blowing toward the top of the circulation.  Those winds were producing moderate vertical wind shear, but the center of circulation persisted.  Most of the thunderstorms were occurring in bands east of the center of circulation.  The bands west of the center consisted primarily of low clouds and showers.

Tropical Depression will move through an area marginally favorable for intensification during the next 24 hours.  it will move over water where the Sea Surface Temperatures are near 28°C.  So, there will be enough energy in the upper ocean to support some intensification.  The upper level trough south of Japan will continue to cause moderate vertical wind shear, but the upper level winds could be weak enough to allow for further intensification.  Tropical Depression 04W could strengthen into a tropical storm on Saturday.

Tropical Depression 04W is moving near the southwestern part of a ridge over the North Pacific Ocean.  The ridge is steering the depression toward the northwest and that general motion is expected to continue for another day or two.  On its anticipated track Tropical Depression 04W is expected to pass near the northernmost Mariana Islands.  It could pass near Asuncion Island, the Maug Islands, Supply Reef and Farallon de Pajaros.  Tropical Depression 04W could bring gust winds, locally heavy rain and higher waves to those places.

Tropical Storm Merbok Makes Landfall Near Hong Kong

Tropical Storm Merbok made landfall near Hong Kong on Monday.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Merbok was located at latitude 23.5°N and longitude 114.9°E which put it about 55 miles (85 km) north-northeast of Hong Kong.  Merbok was moving toward the north at 11 m.p.h. (17 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 1005 mb.

Tropical Storm Merbok intensified before it made landfall and the maximum sustained wind speed was around 55 m.p.h. (85 km/h) at the time of landfall.  Merbok began to weaken after landfall and the strongest winds are now occurring in bands over the the open water.  Merbok is producing locally heavy rain in bands east of the center if circulation.  The heavy rains represent the greatest risk and flooding is possible over parts of eastern China.  Merbok is a fairly small tropical storm and the heavier rain will fall primarily to the east of the track of Merbok.  Merbok should gradually spin down as it moves farther inland.

Tropical Storm Merbok Moves Closer to China

Tropical Depression 04W intensified into Tropical Storm Merbok on Sunday as it moved closer to the coast of China.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Merbok was located at latitude 19.9°N and longitude 115.7°E which put it about 220 miles (360 km) south-southeast of Hong Kong.  Merbok was moving toward the north-northwest at 16 m.p.h. (26 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.

The structure of Tropical Storm Merbok is asymmetrical.  Most of the thunderstorms are occurring east and south of the center of circulation.  A primary rainband curves about halfway around the southeastern side of the center.  Additional bands of showers and thunderstorms exist outside the core in southeastern half of Merbok.  There are bands in the northwestern half of the circulation but they consists primarily of low clouds and showers.  The thunderstorms in the primary rainband are producing upper level divergence which is pumping out mass to the south of Tropical Storm Merbok.

Tropical Storm Merbok is moving through an environment that is marginally favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 29°C.  Merbok is moving under the eastern end of an upper level ridge which is producing northerly winds which are blowing toward the top of the tropical storm.  Those northerly winds are creating moderate vertical wind shear, but they are also enhancing the upper level divergence to the south of Merbok.  Tropical Storm Merbok appears to be pulling some drier air from China into the northwestern part of the circulation.  The combination of moderate vertical wind shear and drier air could be the reason for the asymmetrical distribution of thunderstorms.

Tropical Storm Merbok has a chance to intensify a little more before it makes landfall.  The effects of the moderate vertical wind shear and drier air should limit any intensification and Merbok is likely to remain a tropical storm until it makes landfall.

Merbok is moving around the western end of a subtropical ridge which is steering the tropical storm toward the north-northwest.  That general motion is expected to continue for another day or so.  On its anticipated track the center of Tropical Storm Merbok will reach the coast of China between Hong Kong and Shantou in 12 to 18 hours.  Tropical Storm Merbok will bring gust winds and locally heavy rain.  When Merbok moves inland over eastern China, it will reach the westerly winds in the middle latitudes and those winds will turn the tropical storm toward the east.

Tropical Depression 04W Forms West of Luzon

Tropical Depression 04W formed west of Luzon on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Depression 04W was located at latitude 16.6°N and longitude 116.8°E which put it about 430 miles (690 km) south-southeast of Hong Kong.  The depression was moving toward the northwest 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 1006 mb.

An area of thunderstorms moved west-northwestward across the Philippines and a circulation slowly consolidated around a distinct center.  The center of circulation became well enough defined on Saturday to cause the system to be classified as Tropical Depression 04W.  The inner core of the depression is still organizing.  A band of thunderstorms wrapped around the western and southern sides of the center of circulation.  Additional bands of showers and thunderstorms developed in other parts of the depression.  The area of showers and thunderstorms southwest of the center began to generate upper level divergence which pumped mass away from the depression.

Tropical Depression 04W will be moving through an environment that is favorable for intensification.  The depression will move over water where the Sea Surface Temperature is near 30°C.  The depression is moving under the eastern end of an upper level ridge.  The ridge is producing northerly winds which are blowing toward the top of the circulation.  The vertical wind shear may be part of the reason why there are more thunderstorms south of the center of circulation, but the shear is not strong enough to prevent intensification.  Tropical Depression 04W is expected to intensify into a tropical storm during the next 24 hours.

Tropical Depression 04W is moving around the western end of a subtropical ridge which is steering it toward the northwest.  A general northwesterly motion is expected for another 36 to 48 hours.  A turn toward the east will occur after that time.  On its anticipated track Tropical Depression 04W could be near Hong Kong in about 36 hours.  Tropical Depression 04W will have strengthened into a tropical storm by that time and there is a chance it could intensify into a typhoon by the time it nears the coast of China.