Forecast models are signaling the potential development of a low pressure area (LPA) in the Philippine Sea as early as this weekend, though meteorologists caution that no organized system exists at this time and environmental conditions remain mixed.
The latest runs from the ECMWF, GFS, ICON, and Google DeepMind show a consistent signal for a broad area of low pressure forming east of the Visayas between Nov. 23 and 24. While GFS suggests the possibility of a stronger system, most models depict a weak circulation that may enhance rainfall but struggle to intensify significantly.
Satellite imagery early Thursday shows no defined center of rotation, with only a large burst of convection south of Guam and east of Palau. Any potential development would require the disturbance to move farther north, away from the equator, to take advantage of stronger Coriolis force.
The larger-scale environment is being strongly influenced by the subtropical ridge over the North Pacific and the northeast monsoon, which has established a pronounced shear line over northern Luzon. This same monsoon flow has produced heavy rainfall and flooding in parts of Vietnam.
Forecasters say that while a tropical depression cannot be ruled out, the interaction between the developing disturbance and the northeast monsoon may limit significant strengthening. The more likely scenario, they note, is enhanced rainfall along the Bicol Region, Eastern Visayas, and northeastern Mindanao early next week.
“Given the lack of organization on satellite and the strong monsoonal shear, a high-end storm is unlikely at this time,” Speta said. “But a low pressure area forming and interacting with the monsoon could still bring meaningful rainfall.”
PAGASA has not yet declared an LPA, though the agency is monitoring the region and has assigned a medium chance of development.
The ongoing shear line remains the more immediate weather concern for much of the northern Philippines, bringing cloudiness, cooler temperatures, and intermittent showers.
Residents are encouraged to monitor updates from PAGASA, JMA, and JTWC as the system evolves.