A tropical depression east of the Philippines strengthened on Wednesday and the Japan Meteorological Agency designated the system as Tropical Storm Kai-tak.  At 10:00 p.m. EST on Wednesday the center of Tropical Storm Kai-tak was located at latitude 11.2°N and longitude 127.2°E which put it about 150 miles (240 km) east of Tacloban, Philippines.  Kai-tak was moving toward the west-northwest at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1000 mb.

The circulation of Tropical Storm Kai-tak strengthened on Wednesday, but the distribution of thunderstorms was still asymmetrical.  Most of the stronger storms were occurring in bands in the western half of the circulation.  There were few thunderstorms in the eastern half of Kai-tak.  The center of circulation was located near the eastern edge of the strong thunderstorms.  The storms in the western half of the circulation were generating upper level divergence which was pumping mass away to the west of the tropical storm.

Tropical Storm Kai-tak will move through an environment that is marginally favorable for intensification.  Kai-tak will move over water where the Sea Surface Temperature is near 29°C.  So, there is enough energy in the upper ocean to support intensification.  However an upper level ridge east of the Philippines is producing easterly winds which are blowing toward the top of the circulation.  Those winds are causing moderate vertical wind shear and the shear is probably the reason for the asymmetrical distribution of thunderstorms.  The moderate shear will limit the intensification of Tropical Storma Kai-tak.  Kai-tak could intensify slowly during the next day or two.  The center of Kai-tak will pass over some of the Philippines and the interaction with those islands will weaken the tropical storm.

The winds at the steering levels are weaker than the upper level easterlies.  Tropical Storm Kai-tak is forecast to move slowly toward the west-northwest during the next several days, but it could be nearly stationary at times.  On its anticipated track the center of Tropical Storm Kai-tak could move very near Samar during the next 24 to 48 hours.

Tropical Storm Kai-tak is already dropping heavy rain over parts of Samar and Leyte.  The slow movement of Kai-tak could result in prolonged periods of heavy rain in that region.  The heavy rain has the potential to cause serious floods and mudslides.