Tag Archives: Invest 91W

Tropical Depression Forms East of the Philippines

A tropical depression formed over the Western North Pacific Ocean east of the Philippines on Saturday morning. At 7:00 a.m. EST on Saturday the center of a tropical depression was located at latitude 7.4°N and longitude 131.5°E which put it about 335 miles (540 km) east of Baganga, Philippines. The tropical depression was moving toward the west at 18 m.p.h. (30 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 1006 mb.

More thunderstorms formed near the center of a low pressure system over the Western North Pacific Ocean east of Mindanao on Saturday morning and the Japan Meteorological Agency designated the system as a tropical depression. Thunderstorms were occurring in bands in the western and northern sides of the tropical depression. Bands in the eastern and southern parts of the depression’s circulation consisted primarily of showers and lower clouds. Storms near the center of circulation generated upper level divergence that pumped mass away to the west of the tropical depression.

The tropical depression will move through an environment somewhat favorable for intensification during the next 24 hours. The tropical depression will move over water where the Sea Surface Temperatures are near 29°C. It will move under the southern part of an upper level ridge over the Western North Pacific Ocean east of the Philippines. The upper level ridge will produce easterly winds that will blow toward the top of the depression’s circulation. Those winds will cause moderate vertical wind shear. The vertical wind shear will inhibit intensification, but the shear may not be enough to stop intensification. The tropical depression could strengthen to a tropical storm, if the upper level winds do not get any stronger.

The tropical depression will move around the southern side of a high pressure system over the Western North Pacific Ocean and East Asia. The high pressure system will steer the tropical depression toward the west. On its anticipated track the tropical depression will reach Mindanao in less than 24 hours. The tropical depression will bring gusty winds and locally heavy rain to Mindanao. Heavy rain could cause flash floods in some locations.