Tag Archives: Tropical Depression

Tropical Depression Forms Southeast of Yap

A tropical depression formed southeast of Yap on Monday night. At 8:00 p.m. EDT on Monday the center of the tropical depression was located at latitude 7.1°N and longitude 139.9°E which put it about 200 miles (320 km) southeast of Yap. The tropical depression was nearly stationary. 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 low pressure exhibited more organization on Monday night and the Japan Meteorological Agency designated the system as a tropical depression. The circulation around the tropical depression was in the early stages of organization. There was a broad center of low pressure, but there were not a lot of thunderstorms near the center of circulation. Many of the stronger thunderstorms were occurring in two bands on the periphery of the tropical depression. The strongest rainband was north of the broad center of the depression. Another strong rainband was on the southern periphery of the circulation.

The tropical depression will be in an environment favorable for intensification during the next several days. The depression will be over water where the Sea Surface Temperatures will be near 30°C. It will be under the center of an upper level ridge over the Western North Pacific Ocean. The upper level winds are weak in the center of the ridge and there will be little vertical wind shear. The circulation around the tropical depression is forecast to gradually get better organized and it could strengthen to a tropical storm during the next 24 hours. The depression is forecast to intensify into a typhoon later this week.

The tropical depression will be in an area where the steering winds are weak during the next several days. It will remain nearly stationary during that time period. A subtropical high pressure system over the Western North Pacific Ocean will begin to steer the tropical depression toward the northwest later this week. On its anticipated track the tropical depression will pass near Yap. It will bring gusty winds and locally heavy rain. Persistent heavy rain could cause flash floods.

Tropical Depression Forms East of Sri Lanka

A Tropical Depression (also designated as Invest 98B) formed over the southern Bay of Bengal east of Sri Lanka on Monday. At 10:00 p.m. EST on Monday the center of a tropical depression was located at latitude 6.7°N and longitude 86.3°E which put it about 295 miles (475 km) east of Pottuvil, Sri Lanka. It was moving toward the west at 7 m.p.h. (11 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 1004 mb.

A low level center of circulation developed in an area of thunderstorms over the southern Bay of Bengal east of Sri Lanka on Monday. The circulation around the tropical depression was still organizing on Monday night. More thunderstorms were developing near the low level center. Bands of showers and thunderstorms were forming outside the center of circulation. Storms near the center started to generate upper level divergence which pumped mass away to the north and west of the tropical depression.

The tropical depression will move through a region somewhat favorable for intensification during the next 24 hours. The depression will move over water where the Sea Surface Temperature is near 29°C. It will move under the western end of an upper level ridge centered over Southeast Asia. The ridge will produce easterly winds which will blow toward the top of the depression. Those winds will cause moderate vertical wind shear. The shear will inhibit intensification, but it probably will not be strong enough to prevent the tropical depression from intensifying.

The tropical depression will move south of a high pressure system over India and the Bay of Bengal. The high will steer the depression toward the west during the next several days. On its anticipated track the tropical depression will approach Sri Lanka in about 36 hours. It will drop heavy rain over parts of Sri Lanka and flash floods could occur.