Low Pressure System Forms South of Java

A small, but well organized area of low pressure developed just to the south of Java on Sunday.  The low pressure system is currently designated as Invest 95S, but it could become a tropical cyclone during the next several days.  At 10:00 p.m. EST on Sunday the center of Invest 95S was located at latitude 8.9°S and longitude 109.8°E which put it about 100 miles (160 km) southwest of Yogyakarta, Indonesia.  It was moving toward the northeast at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 998 mb.

The circulation of Invest 95S is small but well formed.  There is a distinct low level center of circulation.  Two well formed narrow rainbands wrapped around the southern and northeastern sides of the center.  Other rainbands developed just outside the core of the circulation.  Storms near the center of circulation were generating some upper level divergence which was pumping out mass and allowing the surface pressure to decrease.

Invest 95S will move through an environment that is mostly favorable for intensification.  It will move over water where the Sea Surface Temperature is near 29°C.  Invest 95S is near the center of an upper level ridge.  The upper level winds blowing over the top of the low pressure system are weak and there is not a lot of vertical wind shear.  The proximity of the circulation to Java is the only factor likely to inhibit intensification.  If the center of circulation remains south of Java, then there is a good chance it could intensify into a tropical cyclone.

The ridge north of Invest 95S is steering the system slowly toward the northeast and a general easterly motion is expected to continue during the next 24 hours.  Guidance from numerical models diverges in a day or so.  Some models to suggest the northeasterly motion will continue and the low pressure system will move across Java.  Other models predict a turn toward the south in a day or so.  There is a high degree of uncertainty about the future track of Invest 95S.