Tag Archives: Tropical Storm Chanthu

Tropical Storm Chanthu Brings Gusty Winds and Rain to Japan

Tropical Storm Chanthu brought gusty winds and rain to parts of Japan on Friday. At 6:00 a.m. EDT on Friday the center of Tropical Storm Chanthu was located at latitude 33.7°N and longitude 130.6°E which put it about 10 miles (15 km) east of Fukuoka, Japan. Chanthu was moving toward the east-northeast 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 990 mb.

Tropical Storm Chanthu brought gusty winds to northern Kyushu and western Honshu on Friday. Winds to tropical storm force extended out 115 miles (185 km) from the center of Chanthu. The strongest winds were occurring in the parts of Chanthu’s circulation that were over water and in the mountains of western Japan. The heaviest rain was falling on the eastern side of Tropical Storm Chanthu.

Tropical Storm Chanthu will be steered quickly toward the east-northeast by the westerly winds in the middle latitudes. Tropical Storm Chanthu will move across Honshu during the next two days. The center of Tropical Storm Chanthu could be near Kyoto in 24 hours and near Tokyo in 36 hours. The upper level westerly winds will cause moderate vertical wind shear. The wind shear and movement across land will cause Chanthu to weaken gradually during the next 48 hours.

Tropical Storm Chanthu Spins between Japan and China

Tropical Storm Chanthu spun between Japan and China on Wednesday. At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Chanthu was located at latitude 30.5°N and longitude 125.2°E which put it about 360 miles (585 km) west-southwest of Kagoshima, Japan. Chanthu was moving toward the northwest at 4 m.p.h. (6 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 991 mb.

Tropical Storm Chanthu remained nearly stationary on Wednesday as it spun over the East China Sea between Japan and China. The atmospheric environment around Chanthu became more favorable for intensification when an upper level ridge moved over the tropical storm. Chanthu strengthened when the upper level ridge enhanced the upper level divergence that pumped more mass away from the tropical storm. The enhanced upper level divergence also contributed to the formation of more thunderstorms in the bands revolving around the center of Tropical Storm Chanthu. A rainband wrapped most of the way around the center of Chanthu and a new eye appeared to be forming at the center of the tropical storm. Winds to tropical storm force extended out 190 miles (305 km) on the northern side of Chanthu. Winds to tropical storm force extended out 90 miles (145 km) in the southern half of the circulation.

Tropical Storm Chanthu will move through an environment somewhat favorable for intensification during the next 24 hours. Chanthu will move over water where the Sea Surface Temperature is near 27˚C. Chanthu could mix cooler water to the surface while it remains nearly stationary, which could inhibit intensification. The upper level ridge will continue to enhance divergence, which will be favorable for intensification. Tropical Storm Chanthu is likely to intensify during the next 24 hours and it could strengthen back to a typhoon.

The steering winds are weak in the middle of the upper level ridge and Tropical Storm Chanthu may not move much during the next 12 to 18 hours. An upper level trough over eastern Asia will move eastward on Thursday. The upper level trough will start to steer Chanthu toward the west in 12 to 18 hours. On its anticipated track Tropical Storm Chanthu could approach Kyushu in 30 hours. Chanthu could be a typhoon when it reaches Kyushu. It will bring strong, gusty winds and locally heavy rain. Heavy rain could cause flash floods in some locations.

Chanthu Weakens to a Tropical Storm East of Shanghai

Former Typhoon Chanthu weakened to a tropical storm east of Shanghai on Monday night. At 11:00 p.m. EDT on Monday the center of Tropical Storm Chanthu was located at latitude 31.3°N and longitude 123.9°E which put it about 150 miles (240 km) east of Shanghai, China. Chanthu was moving toward the northeast at 4 m.p.h. (6 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 988 mb.

Former Typhoon Chanthu weakened to a tropical storm east of Shanghai. An upper level trough over eastern China was producing southwesterly winds that were blowing toward the top of Tropical Storm Chanthu. Those winds were causing moderate vertical wind shear. In addition, the circulation around Chanthu was pulling drier air from Asia into the tropical storm. The drier air was mixing with the rainbands. The eye and eyewall at the center of former Typhoon Chanthu weakened. Thunderstorms were occurring in bands in the northeastern periphery of Tropical Storm Chanthu. Bands in other parts of Chanthu consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 200 miles (300 km) from the center of Chanthu.

Tropical Storm Chanthu will be in an area where the steering winds are weak during the next 24 hours. Chanthu will not move very much during that time period. Since Tropical Storm Chanthu will not move very far, its circulation will mix cooler water to the surface. A combination of moderate vertical wind shear, drier air and cooler water will cause Tropical Storm Chanthu to weaken gradually. Southwesterly winds in the middle latitudes will start to steer Chanthu toward the northeast in a day or so.

Tropical Storm Chanthu Passes East of Tokyo

Tropical Storm Chanthu brought wind and rain to the east coast of Honshu as the center passed east of Tokyo on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Chanthu was located at latitude 37.4°N and longitude 141.6°E which put it about 105 miles (170 km) northeast of Tokyo, Japan.  Chanthu was moving toward the north-northeast 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 995 mb.

Tropical Storm Chanthu is starting the transition from a tropical cyclone to an extratropical cyclone.  It is still moving over water where the Sea Surface Temperature (SST) is near 26°C, but Chanthu will move over colder water during the next 24 hours.  An upper level trough west of Japan will sweep northwesterly winds over the top of Tropical Storm Chanthu.  The increased vertical wind shear will tilt the circulation of Chanthu toward the northeast.  The trough also contains cooler air.  A combination of cooler SSTs, more vertical wind shear and cooler air aloft will alter the structure of Chanthu and it will begin to look more like an extratropical cyclone on Wednesday.

The upper level trough will steer Chanthu in a generally north-northeasterly direction during the next 24 hours.  On its anticipated track Tropical Storm Chanthu will move roughly parallel to the coast of Honshu.  Chanthu is expected to move across Hokkaido later on Wednesday.

The rainbands in Tropical Storm Chanthu are capable of producing locally heavy rainfall.  Some flooding is possible in eastern Honshu and Hokkaido.  Wind damage should be minimal although fishing boats and other vessels along the northeast coast of Japan will have to deal with wind and waves.

Tropical Storm Chanthu Forms South of Japan

A center of circulation consolidated near a cluster of thunderstorms south of Japan on Saturday and the system was designated as Tropical Storm Chanthu.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Chanthu was located at latitude 21.2°N and longitude 143.1°E which put it about 295 miles (475 km) south-southeast of Iwo To.  Chanthu was moving toward the northeast at 14 m.p.h. (23 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.

Although a distinct center of circulation exists in the lower levels of Tropical Storm Chanthu, the storm is not well organized.  Southwesterly winds in the upper levels are causing vertical wind shear which is tilting the upper portion of the circulation toward the northeast.  Most of the thunderstorms associated with Tropical Storm Chanthu are occurring in the northeastern quadrant of the circulation.  Several broken rainbands extend into the southern portion of the circulation, but there are few thunderstorms in the western half of Chanthu.

Tropical Storm Chanthu is moving through an environment that is marginally favorable for intensification.  Chanthu is moving over water where the Sea Surface Temperature is near 30°C.  However, an upper level trough west of Chanthu is causing the southwesterly winds which are blowing across the top of the tropical storm.  Moderate vertical wind shear will inhibit intensification in the short term.  As Tropical Storm Chanthu moves farther north, it could move into a region where the upper level winds are not as strong.  If the vertical wind shear decreases, then Chanthu could intensify.

Winds from the upper level trough are steering Tropical Storm Chanthu toward the northeast.  As the tropical storm moves farther north, a subtropical ridge located east of Chanthu will steer it more toward the north.  On its anticipated track, the center of Tropical Storm Chanthu is expected to pass east of Iwo To in about 24 hours.  Tropical Storm Chanthu could be approaching the coast of Japan near Tokyo in about three or four days.