After Luzon and Visayas experienced rains in the past days, Mindanao should brace for downpour today.
According to PAGASA, although Tropical Storm “Maring” and Typhoon “Lannie” exited the Philippine Area of Responsibility (PAR) yesterday, the Intertropical Convergence Zone (ITCZ), an area of wind convergence and series of low pressures, prevails in the southern area.
Due to the ITCZ, cloudy skies with scattered rain showers and thunderstorms will be experienced in Palawan and Mindanao where possible lightning, occasionally heavy rains, strong winds and flash floods are expected. Meanwhile, the rest of Luzon and Visayas will experience an improved weather condition: partly cloudy to cloudy skies will prevail only with isolated rain showers.
Two Tropical Cyclones inside PAR
Many were surprised by the presence of two weather disturbances (Maring and Lannie) inside PAR this week. But according to PAGASA, it was not the first such event has happened.
On September 30, 2009, “Pepeng” entered PAR with “Quedan” following on October 5. The approaching Typhoon Quedan “pulled back” the exiting Typhoon Pepeng, causing a Fujiwhara effect, an interaction of two Tropical Cyclones.
In general, two Tropical Cyclones may start to affect each other when the distance between them is about 1,350 kilometers. When this occurs, the Tropical Cyclones will rotate around each other in a counter-clockwise direction in the Northern Hemisphere.
This year, Lannie developed into a Tropical Cyclone inside PAR on September 11 while Maring entered PAR a few hours later. The two weather disturbances also exited PAR on the same day, on September 13.