MANILA - Leon is continuing to intensify as it moves over the West Philippine Sea and is expected to develop into a severe tropical storm by Thursday, PAGASA said Wednesday.

In its 11 p.m. weather bulletin, PAGASA said Leon was last spotted 550 km west-northwest of Coron, Palawan packing maximum sustained winds of 85 kph near the center and 105 kph gusts.

The weather disturbance is projected to leave the Philippine area of responsibility (PAR) on Thursday morning and make landfall over northern or central Vietnam on Friday afternoon or evening.

No tropical cyclone wind signal is currently in effect, said PAGASA.

Intermittent gusts due to the southwest monsoon may however be experienced over Batanes, Babuyan Islands, Mimaropa and Western Visayas.

On Wednesday night through Thursday, the southwest monsoon enhanced by Leon will bring light to moderate with at times heavy rains over Mimaropa, Western Visayas and Zamboanga Peninsula, said PAGASA.

The weather agency warned flooding and landslides may occur during heavy or prolonged rainfall in areas highly susceptible to these hazards.

PAGASA also said a gale warning is in effect over the western seaboards of Palawan (including Kalayaan Islands), Occidental Mindoro, Zambales, and Bataan due to rough to very rough seas, with waves of 2.8 m-4.5 m. Sea travel is risky over these areas.

Moderate to rough seas, with waves of 1.2m to 3.1m, will prevail over the seaboards of the rest of the country. Fishers and residents with small seacrafts are advised to take precautions out at sea.

Visit the ABS-CBN Weather Center for more updates.