Rainy Undas weekend expected due to Amihan, shear line, and trough of LPA
MANILA – A wet Undas long weekend is expected due to several weather systems, according to PAGASA.
The northeast monsoon (Amihan) will prevail over Northern Luzon while the Shear Line will affect the eastern section of Luzon.
Shear line is the zone where the Amihan and Easterlies meet, with the differences in wind direction and temperature lead to cloud and thunderstorm formation.
Meanwhile, the trough of a low pressure area (LPA) over the Philippine Sea will bring rains over parts of Visayas and Mindanao.
As of 3 p.m. Friday, the LPA, embedded along the Intertropical Convergence Zone (ITCZ), was located 475 kilometers east of Borongan City, Eastern Samar.
It is unlikely to develop into a tropical cyclone as it may dissipate once it hits land.
On Saturday, October 31, and Sunday, November 1, cloudy skies with scattered rains will be experienced in Cagayan, Isabela, Aurora, Quezon, and Bicol Region due to the Shear Line and in Western Visayas, Negros Island Region, Central Visayas, Northern Mindanao, and Zamboanga Peninsula due to the trough of the LPA and ITCZ.
Meanwhile, Amihan will bring cool weather with isolated light rains over Batanes, Apayao, and Ilocos Norte.
By Monday, November 2, an Amihan surge will affect Northern and Central Luzon, and bring light rains over Cagayan, Isabela, and Aurora.
During the long weekend, Metro Manila and the rest of the country will be warm and humid, with occasions of cloudiness. Isolated rain showers or localized thunderstorms are likelier in the afternoon or evening.
Meanwhile, the tropical cyclone with international name In-fa will approach the northeastern corner of the Philippine area of responsibility during the weekend.
As of 3 p.m., it was located 2,560 kilometers east of Northern Luzon.
It has maximum sustained winds of 185 kilometers per hour with gustiness up to 230 kph.
In-fa may enter the PAR Tuesday or Wednesday next week and will be assigned the local name Samuel.
It will remain far from the Philippine landmass as it will recurve over the northern Philippine Sea during its brief stay inside the PAR.
The public is advised to continue monitoring weather updates as the forecast will still change.