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Invest 99W has a medium chance of developing into a tropical cyclone in the next 24 hours.

An area of convection (Invest 99W) has persisted near 17.5N 123.3E, approximately 107 nautical miles east-southeast of Aparri, Philippines.

Animated multispectral satellite imagery and a 16/04:48 UTC atms 165 GHz image depict strong mid-level turning with formative banding wrapping into a ragged low level circulation center.

Environmental analysis reveals warm sea surface temperatures (29-30°C), low (<15 knots) vertical wind shear, good equatorward outflow, and strong poleward outflow enhanced by a tutt cell positioned to the northeast.

Global models, mainly GFS and ecmwf, are in general agreement that Invest 99W will continue to track west-northwestward over luzon with limited intensification until the system emerges over the South China Sea.

Maximum sustained surface winds are estimated at 10 to 15 knots. Minimum sea level pressure is estimated to be near 1006 mb.

The potential for the development of a significant tropical cyclone within the next 24 hours is medium.

Information provided by JTWC.