Philippine Sea: Tropical Depression 16W tracking west-northwestward in the Philippine Sea as of Aug. 20 /update 6

Event

Tropical Depression 16W is tracking west-northwestward in the Philippine Sea as of Aug. 20. As of 12:00 JST Aug. 20, the storm's center of circulation was approximately 892 km (555 miles) south-southeast of Kadena Air Base, Okinawa Prefecture, Japan. Forecast models indicate that 16W will strengthen into a tropical storm while turning to track northwest Aug. 20. The storm is likely to continue tracking northwest, enter the East China Sea, and make a close approach to Okinawa Island, Okinawa Prefecture, Japan early Aug. 22. The system is forecast to weaken into a tropical depression as it turns to track northwards across the East China Sea through early Aug 23 before turning to track northeast towards Kyushu, and making landfall as a tropical depression over Tsushima Island, Nagasaki Prefecture, early Aug. 24. Some uncertainty remains in the track and intensity forecast in the coming days.

Government Advisories
No warnings and watches are in effect. Officials could issue new warnings and/or watches in response to the developing system in the coming days.

Hazardous Conditions
The storm may bring heavy rainfall and rough seas to coastal areas of Japan and South Korea 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. Torrential precipitation could trigger flash floods and mudslides.

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.

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. Heavy rain and low visibility may trigger flight disruptions at regional airports.

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 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

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 high potential for severe flooding and storm surge. Stockpile water, batteries, and other essentials in advance. Seek updated information on road conditions before driving or routing shipments through areas where flooding has occurred.

Resources

Joint Typhoon Warning Center (JTWC)
Japan Meteorological Agency
Korea Meteorological Administration