PAGASA: 'Fujiwhara effect' possible, but chances are slim

By Dharel Placido,

Posted at Aug 21 2012 10:28 AM | Updated as of Aug 21 2012 11:20 PM

MANILA, Philippines – A state weather forecaster on Tuesday said chances of a "Fujiwhara effect," or the interaction between two weather disturbances, occurring inside the Philippine Area of Responsibility (PAR) are slim.

PAGASA forecaster Rene Paciente said latest weather models show that the two cyclones – typhoon Igme (international codename: Tembin) and tropical storm Bolaven – are too far from each other to interact.

The Fujiwhara effect is characterized by two cyclones orbiting each other.

"Posible pero maliit ang chance, kasi pagpasok niya (Bolaven) sa 135 (degrees), nandito na si Igme sa Taiwan. Ang importante ay distance at halos parehas sila dapat malakas " Paciente told

Paciente said for two cyclones to interact, they must be at least 10 (latitude or longitude) degrees near each other.

Data from the US Joint Typhoon Warning Center showed that Bolaven, as of 2 a.m., was located 18 degrees north and 141 degrees east.

Bolaven was packing maximum winds of 45 knots (83.34 kph) and gustiness of 55 kph (101.86 kph).

Igme, on the other hand, was located 19.7 degrees north and 125.4 degrees east, or 380 kilometers east of Aparri, Cagayan as of 4 a.m.

It was packing maximum winds of 160 kph near the center and gustiness of up to 195 kph.

Paciente said Igme will be on its way outside PAR by the time Bolaven enters on Wednesday night or Thursday morning.

He said the southwest monsoon (habagat) will get weak as Bolaven, which will be locally named Julian once it enters PAR, approaches the country.

"Mayroon pa rin [epekto ang habagat] pero 'di gaanong kalakas. Magkakaroon ng divergence ng hangin, magkahiwalay - mayroong papunta kay Igme, may papunta kay Julian. Pero paglabas ni Igme at paglapit ni Julian, lalakas na ulit ang habagat," he said.

Meanwhile, PAGASA said storm warning signal number 1 remains up over Cagayan, and has been hoisted over Calayan, Babuyan and Batanes groups of islands.

It was moving northward at 11 kph. With this speed, Igme is expected to be 360 kms east northeast of Basco, Batanes on Thursday morning.

The typhoon will bring an estimated rainfall amount of between 10–25 mm per hour (moderate to heavy) within its 600-km diameter.