Some rains due to the trough or extension of tropical storm "Siony" (international name "Atsani") may affect parts of Cagayan Valley ahead of a possible landfall later this week.
The Philippine Atmospheric, Geophysical, and Astronomical Services Administration estimated the location of Siony at 620 kilometers of Aparri, Cagayan (18.1°N, 127.5°E) before noon Monday, packing maximum sustained winds of 65 kilometers per hour near the center and gustiness of up to 80 kph and moving relatively fast at 40 kph west-northwest.
PAGASA said Siony will likely to continue to move west-northwest or northwest Monday before slowing down and becoming almost stationary by Tuesday morning through Wednesday morning.
Afterwards, Siony may move west-southwest or west towards extreme Northern Luzon for a possible landfall towards the weekend.
However, PAGASA said there is still a "high degree of uncertainty" in the forecast track due to Siony's projected "erratic movement" in the next 48 hours,
Siony will likely remain a tropical storm within the next 36 to 48 hours.
PAGASA said although the storm is still far from landmass, its trough may begin to bring light to moderate with at times heavy rains over Batanes, Cagayan, and Isabela.
It warned that flooding and rain-induced landslides may occur during heavy or prolonged rainfall especially in areas that are highly susceptible to these hazards.
If its projected track does not change, Siony will be about 605 kms east of Calayan, Cagayan (19.9°N, 127.2°E) by Tuesday morning; 635 kms east of Calayan (19.2°N, 127.5°E) by Wednesday morning; 345 kms east of Aparri (18.2°N, 124.9°E) by Thursday morning; 230 kms west of Calayan (18.9°N, 119.3°E) by Friday morning; and 710 kms west of Calayan (19.5°N, 114.7°E) or outside the Philippine Area of Responsibility by Saturday morning.