By PDC’s Senior Weather
Specialist Glenn James
Tropical Cyclone 25S (Karim), is located approximately 390 NM west-northwest of the Christmas Islands
According to the JTWC Warning number 2, sustained winds were 45 knots with gusts to near 55 knots.
An exposed, well-defined low-level circulation center (llcc) with flaring convection over the center and persistent, curved deep convective banding over the western periphery. A microwave image shows the bulk of the deep convective banding over the western semicircle with shallow banding wrapping into the llcc.
Environmental conditions are marginally favorable with low to moderate easterly vertical wind shear hindering convective development over the eastern semicircle.
TC 25S will track slowly poleward along the western periphery of the ridge through 48 hours, with gradual intensification to a peak of 60 knots by 48 hours.
After 48 hours, the system will accelerate poleward as it tracks within the enhanced flow between a broad mid-latitude trough and a subtropical ridge to the east.
Rapid weakening will occur as the system encounters increasing vertical wind shear and dry air entrainment. After 96 hours, the system will weaken and stall as it encounters a strong high building to the south, effectively blocking further poleward motion.
TC 25S should dissipate by 120 hours with the remnants tracking back toward the equator under the low-level southeasterly flow associated with the aforementioned high.