Tag Archives: Tropical Storm Etau

Tropical Storm Etau Nears Vietnam, Vamco Threatens Philippines

Tropical Storm Etau neared Vietnam on Monday and newly formed Tropical Storm Vamco threatened the Philippines. At 4:00 a.m. EST on Monday the center of Tropical Storm Etau was located at latitude 12.8°N and longitude 111.6°E which put it about 170 miles (280 km) east of Tuy Hoa, Vietnam. Etau was moving toward the west at 15 m.p.h. (24 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 995 mb.

The distribution of thunderstorms around Tropical Storm Etau was asymmetrical. Etau was moving under the southern part of an upper level ridge over eastern Asia. The ridge was producing easterly winds which were blowing toward the top of Etau. Those winds were causing moderate vertical wind shear. The shear was causing the stronger thunderstorms to occur in bands on the western side of Tropical Storm Etau. The bands in the eastern side of Etau consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 150 miles (240 km) in the northern half of Tropical Storm Etau. Winds to tropical storm force only extended out 50 miles in the southern half of Etau.

Tropical Storm Etau will move south of a high pressure system over eastern Asia. The high will steer Etau toward the west during the next two days. On its anticipated track the center of Etau will make landfall in Vietnam near Tuy Hoa in about 12 hours.

Tropical Storm Etau will move through an environment that should allow it to maintain its intensity until it makes landfall in Vietnam. Etau will move over water where the Sea Surface Temperature is near 28°C. The upper level ridge over eastern Asia will continue to cause moderate vertical wind shear which will limit intensification.

Since the stronger thunderstorms are in the western half of Tropical Storm Etau, heavy rain will fall over central Vietnam before the center of Etau makes landfall. Etau will drop locally heavy rain over central Vietnam, northern Cambodia, southern Laos and northeastern Thailand. The ground is already saturated in that region and flash floods are likely.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Vamco developed east of the Philippines. At 4:00 a.m. EST on Monday the center of Tropical Storm Vamco was located at latitude 12.8°N and longitude 130.6°E which put it about 370 miles (605 km) east of Laoang, Philippines. Vamco 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 1002 mb. Tropical Storm Vamco is forecast to move toward Luzon and to strengthen into a typhoon.

Tropical Storm Etau Develops and Heads Toward Japan

A center of circulation developed within a large area of thunderstorms a few hundred miles south of Japan and the system has been designated Tropical Storm Etau.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Etau was located at latitude 25.3°N and longitude 138.5°E which put it about 720 miles (1160 km) south-southeast of Osaka, Japan.  Etau was moving toward the north at 11 m.p.h. (18 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 Tropical Storm Etau does have a low level center of circulation, most of the stronger thunderstorms are located north-northwest of the center.  Etau is moving over water where the Sea Surface Temperatures are warm enough to support intensification.  However, a large upper level trough west of Japan is producing southwesterly winds over the top of the tropical storm.  The circulation appears to be tilting toward the north with height because  of vertical wind shear.  Tilted tropical cyclones are unable to efficiently convert energy to wind speed and intensify.  Etau could intensify a little during the next 24 hours, but then it will run into much stronger upper level winds associated with the upper level trough.  Stronger vertical wind shear will cause Etau to begin to weaken before it reaches Japan.

A subtropical ridge east of Etau is steering it toward the north-northwest and that general motion is expected to continue for the next several days.  On its anticipated track Etau will approach the coast of Japan near Honshu and Shikoku.  Landfall somewhere between Nagoya and Kochi could occur in about 36 hours.  Etau’s biggest impact will be to increase rainfall as it moves inland.