Tropical Storm Prapiroon has entered the Philippine Area of Responsibility and has been given the local name 'Bagyong Nina' by PAGASA. The system continues to move across the Philippine Sea; it was last located approximately 1,150km southeast of Okinawa or about 1,300km east of the island of Luzon. Maximum sustained winds are now up to 95kph with gusts of up to 120kph. Prapiroon is moving westward at 10kph.
IR Image from NRLMRY
Latest satellite image shows an improving cyclone with good overall convective activity. Strong convection is still scattered and the central dense overcast is still in its infancy. Prapiroon is being helped by an anti-cyclone situated directly overhead the system providing good radial outflow and weak wind shear. Furthermore, sea surface temperatures are warm across the Philippine Sea which should help the storm intensify further.
Forecast Track (NOT OFFICIAL!)
A series of troughs moving across China will lead to a highly complex atmosphere and steering factor in the region. The dynamic changes in the atmosphere being forecast in the next few days are producing a high disagreement among computer models and even forecasting agencies in the region. With that said, we have low confidence with our preliminary forecast and for now, we have decided to side with JTWC, GFS, and the European model for our track.
We are forecasting Prapiroon to continue moving very slowly to the west in the next 2 days. It should turn to the north by Thursday as trough dives in from the west. However, we expect the subtropical ridge to rebuild and could steer Prapiroon to the west again by Friday. What we are somewhat certain of is that the Prapiroon will remain the Philippine Sea region in the next 3 to 5 days and should be far out to directly affect any land.
We'll have another update for Prapiroon tomorrow morning.
Issued (0930 UTC) 530pm PhT 100812