Philippines: Tropical Storm Conson tracking west-northwestward over southern Bicol Region Sept. 7 /update 2

Event

Tropical Storm Conson (known in the Philippines as Jolina) is tracking west-northwestward over Masbate Province, Bicol Region, Philippines Sept. 7. As of 17:00 PHT, the storm's center of circulation was approximately 341 km (212 miles) southeast of Manila, Philippines. Forecast models indicate the system will weaken slightly over the coming days as it tracks northwestward over the Philippines' inner seas; interaction with land will prevent significant development. Conson will likely track across Bicol Region Sept. 7 before making landfall as a tropical storm over Marinduque Province, Mimaropa Region, early Sept. 8. The storm is subsequently forecast to maintain tropical storm-force winds as it tracks northwestward and makes another landfall over Quezon Province, Calabarzon Region on the afternoon of Sept. 8. Conson then likely to transit the southern parts of the National Capital Region, making a close approach to Manila, the evening of Sept. 8. and make another landfall near Bataan Province, Central Luzon Region, late Sept. 8 before exiting into the South China Sea early Sept. 9. The system is forecast to intensify into a severe tropical storm while in the South China Sea and make a close approach to Hainan Province, China, early Sept. 12 before strengthening into a typhoon later that day. The storm's track and intensity forecast remain somewhat uncertain, and the system may change accordingly over the coming days.

Reports indicate that at least 286,000 people are without power across Eastern Visayas Region.

Government Advisories
As of Sept. 7, officials in the Philippines forecast that heavy rains associated with Tropical Storm Conson will affect Leyte, Biliran, Samar, Northern Samar provinces in Eastern Visayas Region and Marinduque and Romblon in the Mimaropa Region as well as the Bicol Region and southern Quezon Province, Calabarzon Region through Sept. 8. Moderate-to-heavy rainfall is likely over the same period in the rest of Calabarzon and Visayas regions as well as Mindoro Province. Authorities have issued tropical cyclone wind signals for multiple areas, notably including a Tropical Cyclone Wind Signal 2 (i.e., indicating damaging gale-force winds) for most of Bicol Region, as well as for the western portion of Northern Samar, northern Biliran, and extreme northwestern Samar provinces in Eastern Visayas Region, southern Quezon, Laguna, and southeastern Batangas provinces in Calabarzon Region and Marinduque and Romblon provinces in Mimaropa Region.

Authorities will likely issue new warnings or update existing advisories throughout the system's progression in the coming days. Weather warnings could remain active even after the system's immediate threat has diminished, as some areas may still be highly susceptible to rain-induced hazards. The possibility of localized evacuations cannot be discounted if weather conditions prove particularly hazardous.

Hazardous Conditions
The storm may bring heavy rainfall, strong winds, and rough seas to coastal areas of the central and northern Philippines over the coming days. Sustained heavy rainfall could trigger flooding in low-lying communities near streams, creeks, rivers, and urban areas with easily overwhelmed or a lack of stormwater drainage systems. Sites located downstream of large reservoirs could experience flash flooding after relatively short periods of intense rainfall. Rain-induced landslides are possible in steeply sloped terrains. Flooding could isolate some communities for several days. Prolonged swells and storm surge generated by the system will likely result in coastal flooding. Persistent onshore flow could make it difficult for the surge to recede and for water levels to decrease in coastal river catchments. Storm surge of up to 0.5-1 meter (2-3 feet) is possible for coastal areas of Biliran, Sorsogon, Samar, and Masbate provinces through Sept. 8. Large waves of 2.5-5 m (8-16 feet) are possible for areas under Tropical Cyclone Wind Signal 2 warnings.

Transport
In addition to the immediate threat to personal safety, inclement weather associated with the storm could trigger localized business, transport, and utility disruptions. Floodwaters and debris flows could render some bridges or roadways impassable, impacting overland travel in and around affected areas. Areal flooding in urban locations could also result in severe traffic congestion, while strong winds will pose a hazard to high-profile vehicles. Heavy rain and low visibility may trigger flight disruptions at regional airports. As of Sept. 7, Ninoy Aquino International Airport (MNL) has canceled at least two flights due to adverse weather at their destinations. Authorities have also canceled at least four flights at Legazpi Domestic Airport (LGP). Flights would likely resume over the coming days after the weather improves. In Leyte Province, Eastern Visayas Region, the Jaro-Dagami-Burauen-Lapaz Road, Barangay Canlingga, Dagami Town and the Santa Rosario-Villaba Road, Villaba Municipiliaty are impassable due to flooding. The Philippine Coast Guard reports that multiple ports across Eastern Visayas and Bicol regions are closed due to the storm, stranding at least 1,946 people.

Disruptions triggered by inclement weather and resultant hazards, such as flooding, could persist well after weather conditions have improved. If there is severe damage to infrastructure, repair or reconstruction efforts may exacerbate residual disruptions.

Health
Stagnant pools of water during and after flooding increase the incidence of insect- and waterborne diseases, such as dengue fever, cholera, and malaria. The threat of these disease outbreaks is usually elevated in the low-income or underdeveloped areas of major urban centers due to the presence of incomplete or open sewer lines. The latent threat of waterborne contaminants from inundated industrial sites cannot be discounted; exposure to raw sewage and other hazardous materials mixed with floodwaters poses a serious health threat.

Advice

Activate contingency plans in areas where officials forecast tropical storm or typhoon conditions. Heed any evacuation orders that may be issued. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the potential for severe flooding and storm surge. Stockpile water, batteries, and other essentials in advance. Charge battery-powered devices when electricity is available; restrict the use of cellular phones to emergencies only. Power down mobile devices when not in use. Keep important documents and necessary medications in waterproof containers. Observe strict food and water precautions, as municipalities could issue boil-water advisories following flooding events. Take precautions against insect- and waterborne diseases in the coming weeks.

Plan accordingly for protracted commercial, transport, and logistics disruptions in areas in the path of the storm, especially if vital infrastructure is damaged. Seek updated information on road conditions before driving or routing shipments through areas where flooding has occurred. Confirm flights before checking out of hotels or driving to the airport; clearing passenger backlogs may take several days in some locations.

Resources

Joint Typhoon Warning Center
Philippine Atmospheric, Geophysical and Astronomical Services Administration