Typhoon 'Chedeng' will gain more strength, US scientists warn

'Chedeng' stronger than Ondoy, DOST official says

MANILA, Philippines - Typhoon Chedeng (international name: Songda) will become stronger as it nears the Philippines, U.S. military weather forecasters warned on Wednesday.

The typhoon is already packing maximum sustained winds of 150 kilometers near the center and gustiness of up to 185 kph, according to weather bureau PAGASA, in its 11 p.m. tropical cyclone update.

Chedeng has intensified over the past 12 hours in the highly favorable environment of the Philippine Sea, according to the Hawaii-based Joint Typhoon Warning Center (JTWC). The center is a joint U.S. Navy-Air Force task force that is responsible for issuing tropical cyclone warnings for all branches of the U.S. Department of Defense and other U.S. government agencies.

"Favorable oceanographic conditions will allow for continued intensification," the JTWC said in a report.

It added that the typhoon will only weaken after skirting the country's eastern section and upon reaching the waters north of Okinawa, Japan.

While PAGASA predicts Chedeng to make landfall over the Aurora-Isabela area on Friday afternoon, the JTWC believes that the typhoon will miss Luzon and stay at sea.

PAGASA said that based on their data, Chedeng is estimated to have rainfall of between 32-64 millimeters per hour.

Science and Technology Undersecretary Graciano Yumul, in an interview on ANC's Top Story on Wednesday, said compared to tropical storm Ondoy (Ketsana) in 2009, Chedeng is "stronger" since the rainfall brought by Ondoy - averaging 56 mm/h - was due to the storm and an intertropical convergence zone, while Chedeng's rainfall is solely due to the typhoon.

PAGASA said Chedeng was spotted 310 kilometers east northeast of Catarman, Northern Samar, as of 10 p.m. Wednesday.

The storm is moving northwest at 15 kph and is expected to be 190 km east of Baler, Aurora province on Thursday night.

Public storm warning signal number 2 has been raised over Catanduanes, Sorsogon, Albay, Camarines Sur, Camarines Norte, and Samar Provinces.

Meanwhile, storm warning signal number 1 is in effect over Cagayan, Isabela, Quirino, Aurora, Quezon, Polillo Island, Marinduque, Burias, Ticao Island, Masbate, Northern Leyte, and Biliran Island.

"Residents in low lying and mountainous areas under signals #2 and #1 are alerted against possible flashfloods and landslides. Likewise, those living in coastal areas are alerted against big waves or storm surges generated by this tropical cyclone," PAGASA warned.

EXTREME WEATHER FORECAST FOR LAYMEN: Joint Typhoon Warning Center ...

In order for a cyclone to form, the ocean waters need to be warm, at least 26°C. Above the warm ocean, water evaporates and form clouds. If there is low air pressure where the clouds are formed, it pulls them in and they begin to rotate. It is the Earth’s rotation and spinning on its axis that causes the cyclone’s clouds to rotate. Clouds will continue to form and begin spinning more.

Global Perspectives on Tropical Cyclones, From Science to Mitigation

Hurricanes, a reference handbook

Evaluation of JTWC (Joint Typhoon Warning Center) Tropical Cyclone Objective Forecast Aids (1978-1985).

Early warning systems for natural disaster reduction

Hurricanes and Climate Change