The center of Tropical Depression Tembin passed near the southern tip of Vietnam on Monday night. At 10:00 p.m. EST on Monday the center of Tropical Depression Tembin was located at latitude 8.5°N and longitude 104.6°E which put it about 200 miles (320 km) southwest of Ho Chi Minh City, Vietnam. Tembin was moving toward the west at 14 m.p.h. (22 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 1005 mb.
An upper level ridge north of Tropical Depression Tembin continued to produce strong easterly winds which were blowing across the top of the circulation. Those winds were causing strong vertical wind shear. The shear was strong enough to prevent thunderstorm from developing in most parts of the circulation of Tropical Depression Tembin. A few thunderstorms formed in the extreme northwestern portion of the circulation, but most of the circulation consisted of bands of low clouds and showers. The strong shear and lack of tall thunderstorms caused the wind speeds at the surface to decrease and Tembin weakened to a tropical depression.
Tropical Depression Tembin will remain in an environment that is unfavorable for intensification. Tembin will move over water where the Sea Surface Temperature is near 29°C. So, there is enough energy in the upper ocean to support intensification. However, the upper ridge will continue to produce strong easterly winds. The vertical wind shear is likely to cause the circulation of Tropical Depression Tembin to spin down.
The ridge north of Tembin has been steering the tropical depression toward the west and a general westerly motion is expected to continue for another day or two. On its anticipated track Tropical Depression Tembin will move across the Gulf of Thailand. The center of Tropical Depression Tembin could reach the coast of Thailand near Sichon in about 36 hours.
Typhoon Tembin moved nearer to southern Vietnam on Sunday. At 10:00 p.m. EST on Sunday the center of Typhoon Tembin was located at latitude 8.0°N and longitude 109.3°E which put it about 290 miles (470 km) southeast of Ho Chi Minh City, Vietnam. Tembin was moving toward the west at 13 m.p.h. (21 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. (145 km/h). The minimum surface pressure was 979 mb.
Typhoon Tembin weakened during the past 12 hours as it moved over the South China Sea. An upper level ridge north of Tembin generated stronger easterly winds on Sunday which increased the vertical wind shear. The strong upper level winds weakened the rainbands in the eastern half of the circulation of Typhoon Tembin. Those winds also tilted the upper portion of the circulation toward the west. The low level circulation of Typhoon Tembin remained well organized, but the storms around the center weakened. The strongest thunderstorms were occurring in bands west of the core of Tembin. Winds to typhoon force extended out about 40 miles (65 km) from the center in the northern half of the circulation and about 25 miles (40 km) in the southern half. Winds to tropical storm force extended out about 155 miles (250 km) from the center.
Typhoon Tembin is likely to continue to weaken on Monday. Typhoon Tembin will move over water where the Sea Surface Temperature is near 29°C. However, the upper level ridge is likely to continue to generate strong easterly winds and the significant vertical wind shear will make it difficult for tall thunderstorms to develop around much of the circulation. The wind shear will probably weaken Tembin to a tropical storm on Monday.
The ridge north of Tembin is steering the typhoon toward the west and a general westerly motion is expected to continue for several more days. On its anticipated track the center of Typhoon Tembin will pass near the southern tip of Vietnam in about 24 hours. Tembin will likely move into the Gulf of Thailand as a tropical storm or tropical depression.
The heavy rain with Typhoon Tembin is occurring in bands west of the core of the typhoon. So, the heavy rain will begin to fall before the center of circulation reaches places. The heaviest rain will fall over the Mouths of the Mekong River and the part of Vietnam south of that area. The rain could be heavy enough to cause floods in some locations. Gusty winds could produce isolated damage as well in the southern part of Vietnam.