In meteorology, 'Fujiwhara effect' applies to the interaction of two tropical cyclones. In general, two tropical cyclones may start to affect each other when the distance between them is around 12 latitude degrees (about 1350 kilometers). When this occurs, The tropical cyclones will rotate around one another in a counter-clockwise direction (in Northern Hemisphere) about their geometric centre. The centre needs not be the middle of the axis. 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. Source
This kind of weather condition implies dark clouds, chilly wind and rain showers. Some affected people and places from the last flooding incident about two weeks ago may not be aware of this but it is actually what they are experiencing right now. The interaction of two tropical cyclones refers to the devastating Ondoy and the tropical depression Pepeng which remained stationary as of today.