Tag Archives: Tropical Storm Dianmu

Tropical Storm Mindulle Brings Wind and Rain to Marianas, Dianmu Hits Vietnam

Tropical Storm Mindulle brought wind and rain to the Marianas on Thursday and Tropical Storm Dianmu hit Vietnam. At 11:00 a.m. EDT on Thursday the center of Tropical Storm Mindulle was located at latitude 14.1°N and longitude 142.3°E which put it about 175 miles (280 km) west-northwest of Guam. Mindulle moving toward the west-northwest at 23 m.p.h. (37 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.

Tropical Storm Mindulle brought wind and rain to the Marianas including Guam on Thursday. Tropical Storm Warnings were in effect for Guam, Rota, Tinian and Saipan. Mindulle was intensifying as it moved across the Marianas. More thunderstorms developed about the center of circulation. Bands of showers and thunderstorms were revolving the center of Tropical Storm Mindulle. Storms near the center generated upper level divergence that pumped mass away from the tropical storm. The strongest winds were occurring in the northeastern part of Mindulle. Winds to tropical storm force extended out 150 miles (240 km) in the northeastern quadrant to Mindulle.

Tropical Storm Mindulle will move through an environment favorable for intensification during the next few days. Mindulle will move over water where the Sea Surface Temperatures are near 30˚C. It will move into a region where the upper level winds are weak and there will be little vertical wind shear. Tropical Storm Mindulle will continue to intensify during the next 36 hours. Mindulle could strengthen to a typhoon in 24 hours. Mindulle could intensify more rapidly after an inner core becomes more well developed. It could intensify to the equivalent of a major hurricane during the weekend.

Tropical Storm Mindulle will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean during the next several days. The high will steer Mindulle toward the northwest during the next 48 hours. On its anticipated track Tropical Storm Mindulle will move quickly away from the Marianas. Mindulle could approach the Ryukyu Islands in a few days.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Dianmu bought wind and rain to central Vietnam. At 11:00 a.m. EDT on Thursday the center of Tropical Storm Dianmu was located at latitude 15.4°N and longitude 108.3°E which put it about 15 miles (25 km) southeast of Tam Ky, Vietnam. Dianmu was moving toward the northwest at 17 m.p.h. (28 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. Tropical Storm Dianmu will weaken as it moves inlands over Southeast Asia. Dianmu will bring gusty winds and locally heavy rain to central Vietnam, southern Laos and northern Cambodia. Heavy rain could cause flash floods in some locations.

Tropical Storm Dianmu Forms Near Hainan Island

A center of circulation developed within a larger cyclonic rotation associated with the monsoon near Hainan Island and the Japan Meteorological Agency classified the system as Tropical Storm Dianmu.  At 5:00 a.m. EDT on Thursday the center of Tropical Storm Dianmu was located at latitude 20.5°N and longitude 109.7°E which put it about 265 miles (430 km) east of Hanoi, Vietnam.  Dianmu was moving toward the west 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 985 mb.

The circulation of Tropical Storm Dianmu consists of a smaller counterclockwise rotation inside a much larger cyclonic flow associated with the monsoonal circulation.  Thunderstorms clustered around the western and southern portion of the smaller counterclockwise rotation and a distinct inner core developed that is separate from the broader center of the monsoonal gyre.  Additional spiral bands formed outside the core.  The thunderstorms are generating upper level divergence, primarily to the south and west of Tropical Storm Diamnu.

Tropical Storm Dianmu is moving through an environment that is favorable for additional strengthening.  It is moving over water where the Sea Surface Temperature is near 31°C.  An upper level ridge centered over China is producing easterly winds which are blowing across the top of Tropical Storm Dianmu.  Those winds are causing moderate vertical wind shear, which is slowing the rate of intensification of the tropical storm.  The proximity of Dianmu to the coast is also slowing the rate of intensification.  Tropical Storm Dianmu has 12 to 18 hours to intensify before it moves over land.

The upper level ridge over China is steering Tropical Storm Dianmu toward the west and that general motion is expected to continue.  On its anticipated track the center of Tropical Storm Dianmu could reach the coast of Vietnam in 12 to 18 hours.  Dianmu could cause some minimal wind damage and storm surge, but heavy rain will be the greatest threat.  Tropical Storm Dianmu could cause flash flooding when it moves inland over Southeast Asia.