Philippines: Adverse weather forecast to continue across much of the country through at least Dec. 14 /update 1

Severe weather is forecast to continue across much of the Philippines through at least Dec. 14. A combination of a stationary front known as a Shear Line, the northeast monsoon, and easterly trade winds are expected to bring heavy rainfall and thunderstorms to most regions. As of Dec. 11, the Philippine Atmospheric, Geophysical, and Astronomical Administration (PAGASA) has issued a weather advisory for heavy rainfall over parts of the country. Heavy-to-intense rainfall of 10-20 cm (4-8 inches) is forecast over Quezon province Dec. 11-12 and moderate-to-heavy rainfall of 5-10 cm (2-4 inches) is forecast across Isabela, Aurora, Camarines Norte, and Camarines Sur provinces Dec. 11-12, Quezon, Camarines Norte, and Camarines Sur provinces Dec. 12-13, and Quezon, Camarines Norte, Camarines Sur, and Catanduanes Dec. 13-14.

Pagasa has issued the following flood advisories across the country as of Dec. 11:

• Extreme general flood advisories (second-highest level on a four-tier scale): Albay, Camarines Norte, Camarines Sur, Catanduanes, and Sorsogon provinces in Bicol region and Laguna, Quezon, and Rizal provinces in Calabarzon Region.

• Severe general flood advisories: Agusan Del Norte, Dinagat Islands, Surigao Del Norte, and Surigao Del Sur provinces in Caraga Region; Bohol, Cebu, Negros Oriental, and Siquijor provinces in Central Visayas Region; Occidental Mindoro, Oriental Mindoro, Palawan, and Romblon provinces in Mimaropa Region; Aklan, Antique, Capiz, Guimaras, Iloilo, and Negros Occidental provinces in Western Visayas Region; and Zamboanga Del Norte, Zamboanga Del Sur, and Zamboanga Sibugay provinces in Zamboanga Peninsula Region.

• Moderate general flood advisories: Eastern Samar, Leyte, Northern Samar, Samar, and Southern Leyte provinces in Eastern Visayas Region.

Officials could update and extend the coverage of weather alerts over the coming days.

Much of the Philippines is still recovering from severe flooding and landslides brought about by the succession of tropical systems moving across the region over recent weeks. Northern and central regions were the worst affected; however, records indicate the storms impacted 17 of the country's 18 regions. Six storm systems made landfall or passed close to the country since Oct. 24: Tropical Storm Trami (named Kristine in the Philippines) made landfall in Divilacan Town, Isabela Province, at around 00:30 Oct. 24; Tropical Storm Kong-rey (named Leon in the Philippines) made a close approach to northeastern Luzon Oct. 30-31; Tropical Storm Yinxing (named Marce in the Philippines) passed over the north coast of Luzon Nov. 7; Typhoon Toraji (named Nika in the Philippines) made landfall near Dilasag in Aurora Province early Nov. 11; Typhoon Usagi (named Ofel in the Philippines) passed over far northeastern Luzon and past the most of the island regions of the Philippines Nov. 14; and finally Super Typhoon Man-yi (name Pepito in the Philippines) made landfall over Catanduanes Island late Nov. 16 and Dipaculao in Aurora Province the afternoon of Nov. 17. Further rainfall could lead to additional flooding and landslides as well as exacerbate the situation and hamper recovery efforts.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rain has saturated the soil.

Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Disruptions to electricity and telecommunications services are possible where significant flooding or landslides impact utility networks.

Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters. Severe weather could also trigger flight delays and cancellations at regional airports. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas with heavy rainfall and potential track inundation.

Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.