MANILA, Philippines -- Tropical storm "Cosme" (international codename: Halong) strengthened as it moved closer to northern and central Luzon late Saturday morning, the Philippine Atmospheric Geophysical Astronomical Services Administration (PAGASA) said.

At 10 a.m., the eye of the storm, which packs maximum sustained winds of 105 kilometers per hour and gusts of up to 135 kilometers near the center, was located 130 kilometers west of Iba town in Zambales province, the state weather bureau said.

The storm will make landfall over Ilocos Sur province Saturday evening and will be over Aparri town in Cagayan province by Sunday morning, after crossing northern Luzon overnight, PAGASA said in a bulletin.

By Monday morning, the storm was forecast to be at 460 kilometers northeast of Basco town in Batanes province, on its way to Okinawa, Japan, it said.

Public storm signal number 3 (100 to 185 kilometer per hour winds) was raised over the provinces of Zambales, Pangasinan, La Union, Ilocos Norte, and Ilocos Sur.

Signal number 2 (60 to 100 kilometer per hour winds) was hoisted in the provinces of Bataan, Tarlac, Pampanga, Nueva Ecija, Nueva Vizcaya, Benguet, Ifugao, Mt. Province, Kalinga and Abra.

Signal number 1 (30 to 60 kilometer per hour winds) was raised over Metro Manila, the provinces of Batangas, Cavite, Laguna, Rizal, Bulacan, northern Quezon, Aurora, Quirino, Isabela, Cagayan, Apayao, Batanes, and Lubang Island.

The storm will enhance the southwest monsoon, bringing rains to southern Luzon and western Visayas, PAGASA said.