Philippines: Tropical Storm Ma-on tracking northwestward across South China Sea early Aug. 24 /update 4

Event

Tropical Storm Ma-on (known in the Philippines as Florita) is tracking northwestward across the South China Sea as of early Aug. 24 after making landfall over Maconacon Town in Isabela Province, Philippines, early Aug. 23 and transiting northern Luzon. As of 02:00 PHT, the system's center of circulation was approximately 335 km (208 miles) west of Calayan, Cagayan, Philippines.

Forecast models indicate that the storm will continue its track northwest across the South China Sea, strengthening further into a typhoon by the morning of Aug. 25 and making landfall over western Guangdong Province, China, just west of Macau later the same day. After landfall, the storm is likely to weaken rapidly as it tracks across southern Guangxi province in China, far northeastern Vietnam, then southern Yunnan Province in China before dissipating over southwestern Yunnan Province the afternoon of Aug. 27. Some uncertainty remains in the track and intensity forecast. Significant changes could occur in the coming days.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) has warned of light to moderate rain, with periods of heavy downpours, over the Cordillera Administrative Region and Ilocos Region as well as Isabela, Cagayan, Zambales, and Bataan provinces through at least the afternoon Aug. 24. Moderate to heavy rainfall is likely over the rest of central and southern Luzon over the same period. Gale warnings remain in effect over the seaboards of northern and central Luzon.

The China Meteorological Administration has issued a blue (lowest level on a four-tier scale) typhoon warning while Taiwan's Central Weather Bureau has issued yellow (lowest level on a four-tier scale) heavy rain advisories for Kaohsiung City and Pingtung County. Officials could update and extend the coverage of the relevant weather alerts over the coming days.

Authorities in the Philippines have preemptively evacuated more than 500 people from flood and landslide-prone areas in Cagayan Valley Region and Cordillera Administrative Region. Falling trees in Cagayan Province have injured at least two people. Public schools and government offices across the National Capital Region and Cavite, Laguna, Rizal, Bulacan, Zambales, and Bataan provinces are suspended through at least Aug. 24.

The Philippine National Railways (PNR) has canceled some metro north and metro south train services in the National Capital Region due to flooding.

Heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. Localized evacuations, flash flooding, and landslides are possible if weather conditions prove hazardous.

The inclement weather could trigger localized business, transport, and utility disruptions, rendering some bridges or roadways impassable. Flight disruptions at airports in the affected region and temporary port closures are also possible. Raw sewage and other hazardous materials mixed with floodwaters pose a severe health threat.

Advice

Activate contingency plans in areas where officials forecast tropical storm 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
China Meteorological Administration
Taiwan Central Weather Bureau
Vietnam National Centre for Hydro-Meteorological Forecasting (NCHMF)