The potential for the development of a significant tropical cyclone within the next 24 hours is upgraded to medium.
-- Joint Typhoon Warning Center
Invest 91W to have a "Likely " chance of developing into a Tropical Depression within the next 24 hours at 60%
-- Manila TC Admin
Invest 91W, now located at 12.5N 153.5E -- 950 km East-Southeast of Guam, has shown further organization overnight. Winds within the LPA are now at 20 Knots (35 KPH). The system is moving West at 18-20 KPH
The Joint Typhoon Warning Center has rated Invest 91W as Medium.
An upper level low is providing an outflow channel to the system, thus aiding its development, Rainclouds from the system are now causing showers in the Southern Marianas Islands.
Forecast Model support is good, with the system tracking over Guam/Marianas Islands in the coming days before making a track through the Philippine Sea.
Whether Invest 91W will affect the Philippines remains to be seen as some model runs indicate a recurve towards Japan in the far future, thus long-range track forecasts confidence are very low.