Tropical Storm Jelawat Develops East of Mindanao

Tropical Storm Jelawat developed east of Mindanao on Saturday night. At 7:00 p.m. EST on Saturday the center of Tropical Storm Jelawat was located at latitude 7.5°N and longitude 129.2°E which put it about 180 miles (290 km) east of Baganga, Philippines. Jelawat was moving toward the west at 9 m.p.h. (15 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.

A tropical depression that formed on Saturday morning strengthened, and the Japan Meteorological Agency upgraded the system to Tropical Storm Jelawat. Thunderstorms were occurring in bands in the western and northern sides of Tropical Storm Jelawat. Bands in the eastern and southern parts of the Jelawat’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 storm.

The circulation around Tropical Storm Jelawat was interacting with a large high pressure system over the Western North Pacific Ocean and East Asia. The pressure gradient between the high pressure system and Jelawat’s circulation was producing a large area of tropical storm force winds in the western side of Jelawat. Winds to tropical storm force extended out 250 miles (400 km) in the western side of Jelawat. Winds to tropical storm force extended out 170 miles (280 km) in the eastern side of the circulation.

Tropical Storm Jelawat will move through an environment marginally favorable for intensification during the next 18 hours. Jelawat 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 Jelawat’s circulation. Those winds will cause moderate vertical wind shear. The vertical wind shear will inhibit intensification. Tropical Storm Jelawat could intensify a little more, if the upper level winds do not get any stronger. When the upper level winds get stronger, then Jelawat will weaken.

Tropical Storm Jelawat 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 Jelawat toward the west. On its anticipated track Tropical Storm Jelawat will reach Mindanao in 18 hours. Jelawat will bring gusty winds and locally heavy rain to Mindanao. Heavy rain could cause flash floods in some locations.