Post by Admin on Nov 9, 2015 7:40:35 GMT 8
Low Latitude Track of Tropical Cyclones During November-December
During the “Ber” months, landfalling Tropical Cyclones across the Philippines dramatically increase despite the decrease on their last-quarter formation.
This is because tropical cyclones during the latter part of the year follow a low-latitude westerly track.
These are the factors behind this weather phenomenon:
The start of the winter season is signified by the migration of the ITCZ (Inter-Tropical Convergence Zone) to lower latitudes. When the trade winds of the ITCZ converge near the equator, Low Pressure Areas (LPAs) tend to develop near the equator as well, thus affecting the Central and Southern parts of the Philippines.
The “Ber” months also signify a change in the seasonal winds, from Southwest Monsoon (Habagat) to Northeast Monsoon (Amihan). The Northeast monsoon is related to strong High Pressure Areas (HPAs) over China, Taiwan, and the southern part of Japan, which will decrease the tropical cyclones’ tendency to move northward.
Instead, HPAs will push tropical cyclones to traverse in a general westerly direction towards the Bicol-Mindoro Area, Visayas-Palawan Area, or Mindanao. (see Figure 01).
Figure 1 – Average tracks of Tropical Cyclones during November-December crossing either Bicol Region, Visayas, Mindanao, and Palawan.
During the “Ber” months, landfalling Tropical Cyclones across the Philippines dramatically increase despite the decrease on their last-quarter formation.
This is because tropical cyclones during the latter part of the year follow a low-latitude westerly track.
These are the factors behind this weather phenomenon:
The start of the winter season is signified by the migration of the ITCZ (Inter-Tropical Convergence Zone) to lower latitudes. When the trade winds of the ITCZ converge near the equator, Low Pressure Areas (LPAs) tend to develop near the equator as well, thus affecting the Central and Southern parts of the Philippines.
The “Ber” months also signify a change in the seasonal winds, from Southwest Monsoon (Habagat) to Northeast Monsoon (Amihan). The Northeast monsoon is related to strong High Pressure Areas (HPAs) over China, Taiwan, and the southern part of Japan, which will decrease the tropical cyclones’ tendency to move northward.
Instead, HPAs will push tropical cyclones to traverse in a general westerly direction towards the Bicol-Mindoro Area, Visayas-Palawan Area, or Mindanao. (see Figure 01).
Figure 1 – Average tracks of Tropical Cyclones during November-December crossing either Bicol Region, Visayas, Mindanao, and Palawan.