By J. Jala | 11:26 PM October 29, 2020
A United States weather bureau’s new forecast on Thursday night upgraded tropical cyclone Rolly (international name Goni) into a typhoon that is likely to intensify into a super typhoon before its landfall over Luzon.
The United States Navy – United States Air Force Joint Typhoon Warning Center (JTWC) said Thursday that Rolly will reach peak strength at 130 knots (240.76 kilometers per hour) maximum sustained winds and gusts reaching 160 knots (more than 296 kilometers per hour) on October 31.
Rolly is the sixth tropical cyclone to enter the Philippine area of responsibility in the last month and a half.
The US JTWC classifies typhoons with wind speeds of at least 130 knots, which are equivalent to a Category 4 storm in the Saffir-Simpson scale—as super typhoons. Its readings are based on one-minute average measurements of sustained winds.
This different to the tropical cyclone intensity scale used by the Philippine state weather bureau PAGASA, which makes readings based on 10-minute average measurements of sustained winds.
As a result, the US JTWC’s wind readings are higher than PAGASA’s measurements.
Pagasa has so far categorized Rolly as a severe tropical storm as of early Thursday evening.
Rolly entered the Philippines’ jurisdiction at 5:30 p.m.
Pagasa’s latest advisory Thursday said Rolly has strengthened into a severe tropical storm, while moving westward and packing 95 kph maximum sustained winds and 115 kph gusts based on 10-minute average measurements.
It was last spotted 1,545 km east of Central Luzon and is expected to strengthen into a typhoon and move 1,140 km east of Casiguran, Aurora by Friday morning and 845 km east of Infanta, Quezon by Saturday.
It may bring heavy rains over those areas starting Friday or this weekend as it moves towards eastern sections of Central and Southern Luzon.