Tropical cyclone “Opong” (international name: Bualoi) intensified into a typhoon on Thursday evening, Sept. 25, prompting the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) to raise Signal No. 4 over five areas in Eastern Visayas and Bicol Region.

Opong had earlier packed maximum sustained winds of 110 kilometers per hour (kph) and gusts of up to 135 kph, when it was still a severe tropical storm.

By 11 p.m., it had strengthened to 120 kph maximum sustained winds near the center and up to 165 kph gusts, while moving west northwest at 25 kph.

PAGASA said its center was last located over the coastal waters of Dolores, Eastern Samar.

The typhoon is expected to make its first landfall over Northern Samar or the northern portion of Eastern Samar between midnight and early Friday, Sept. 26.

It may make a second landfall over Sorsogon or Masbate later Friday morning before crossing Bicol Region, southern Calabarzon, and northern Mimaropa.

Opong is expected to emerge over the West Philippine Sea by early Saturday, Sept. 27, where re-intensification is likely, and eventually exit the Philippine Area of Responsibility.

Signal No. 4, the second-highest cyclone warning, was hoisted over Northern Samar, northern and central portions of Eastern Samar and Samar, Sorsogon, and eastern part of Masbate, including Ticao Island.

Signal No. 3 was raised over the rest of Masbate, including Burias Island, Albay, western portion of Camarines Sur, southern Quezon, Marinduque, Romblon, central and southern portions of Oriental Mindoro, the rest of Eastern Samar, the rest of Samar, extreme northern portion of Leyte, and Biliran.

Signal No. 2 was in effect over Catanduanes, the rest of Camarines Sur, Camarines Norte, central and eastern portions of Quezon, Laguna, Rizal, Cavite, Batangas, the rest of Oriental Mindoro, Occidental Mindoro, including Lubang Islands, Calamian Islands, Metro Manila, southern portion of Bataan, eastern portion of Southern Leyte, northern and central portions of Leyte, northern portion of Cebu, including Camotes and Bantayan Islands, extreme northern portion of Negros Occidental, Capiz, Aklan, northwestern portion of Antique, including Caluya Islands, Dinagat Islands, Siargao Islands, and Bucas Grande Islands.

Signal No. 1 was up over the central and southern portions of Isabela, Quirino, Nueva Vizcaya, Ifugao, southwestern portion of Mountain Province, Benguet, southern portion of Ilocos Sur, La Union, Pangasinan, Aurora, Nueva Ecija, Tarlac, Zambales, the rest of Bataan, Pampanga, Bulacan, the rest of Quezon, Cuyo Islands, northern portion of mainland Palawan, the rest of Southern Leyte, eastern and central portions of Bohol, the central portion of Cebu, northern portion of Negros Oriental, northern and central portions of Negros Occidental, central portion of Iloilo, central portion of Antique, and the rest of Surigao del Norte.

PAGASA warned that Opong may bring moderate to torrential rains over parts of Luzon and Visayas over the next two days.

From Thursday evening to Friday evening, Sept. 26, intense to torrential rains (more than 200 millimeters) may prevail over Northern Samar, Eastern Samar, Samar, Biliran, Sorsogon, Masbate, Oriental Mindoro, and Romblon.

Heavy to intense rains (100-200 mm) may also affect Occidental Mindoro, Quezon, Batangas, Camarines Norte, Catanduanes, Camarines Sur, Albay, Marinduque, Aklan, Capiz, Cebu, Bohol, Leyte, Southern Leyte, and Dinagat Islands.

Moderate to heavy rains (50-100 mm) may be experienced in Aurora, Laguna, Cavite, Metro Manila, Bataan, Rizal, Camiguin, and Surigao del Norte.

From Friday evening to Saturday evening, Sept. 27, heavy to intense rains may persist in Occidental Mindoro, Oriental Mindoro, Batangas, and Cavite.

Laguna, Marinduque, and Romblon may also continue to experience moderate to heavy rains.

The southwest monsoon (habagat), enhanced by Opong may also bring heavy to intense rains from Thursday evening to Friday evening over Antique, Iloilo, Guimaras, and Negros Occidental.

Meanwhile, moderate to heavy monsoon rains may affect Palawan, Negros Oriental, and Siquijor.

From Friday evening to Saturday evening, heavy to intense rains due to habagat may persist in Antique, and moderate to heavy rains in Palawan and Iloilo.

A life-threatening storm surge exceeding three meters is expected within 36 hours in low-lying and exposed coastal areas of Zambales, Bataan, Metro Manila, Calabarzon, Oriental Mindoro, Occidental Mindoro, including Lubang Island, Marinduque, Romblon, Palawan, Bicol Region, Northern Samar, Eastern Samar, Samar, Biliran, Leyte, Cebu, Aklan, Antique, Capiz, Dinagat Islands, and Siargao Island.

Mariners operating motorbancas and other small vessels are advised to take precaution and, if possible, avoid sailing under these conditions.