Will Kristine make a U-turn once it exits PAR? PAGASA answers

Severe Tropical Storm Kristine (international name: Trami) is headed to the West Philippine Sea after lashing parts of the country, particularly Luzon, with strong winds and torrential rains, killing at least 20 people.

In its tropical cyclone bulletin at 5 p.m. Thursday, the state weather bureau PAGASA said Kristine would likely exit the Philippine Area of Responsibility on Friday afternoon.

However, PAGASA said ''there is a developing forecast situation wherein Kristine will be looping over the West Philippine Sea on Sunday (October 27) and Monday (October 28) and move eastward or east northwestward towards the general direction of the PAR region.''

This scenario, according to PAGASA, ''heavily depends'' on the behavior of the low pressure area east of northeastern Mindanao, which is expected to develop into a tropical depression within the next 24 hours.

Fujiwhara effect?

Meteorologists refer to the interaction of two tropical cyclones as the Fujiwhara effect.

According to the U.S. National Weather Service, when two tropical cyclones ''spinning in the same direction pass close enough to each other, they begin an intense dance around their common center.''

The Hong Kong Observatory said that the two storms should be roughly 1,350 kilometers apart for this to occur.

At 2 p.m. Thursday, the LPA was located 2,465 km away from the coast of northeastern Mindanao.

''The stronger cyclone tends to have a dominant effect on the track of the weaker one. The interaction will end when: there is a stronger influence of a large scale weather system from outside, one of the tropical cyclones weakens or the two cyclones merge,'' the Hong Kong Observatory said.

PAGASA said its forecast model for October 31 to November 6 showed that the potential tropical cyclone would ''continue to move northwestward toward the eastern part of Northern Luzon before recurving toward Taiwan.'' — VBL, GMA Integrated News