Tropical Cyclone 16S in Indian Ocean13.9S 97.7E
Tropical Cyclone 16S, located approximately 255 nm southwest of Cocos Island, Australia, has tracked west-southwestward at 07 knots over the past six hours.
Animated infrared satellite imagery depicts a large convective central dense overcast (CDO) with outflow primarily along the poleward semi-circle. The deepest convection is to the southwest of the low level circulation center (LLCC) due to the effects of easterly vertical wind shear (VWS). Upper-level analysis indicates that the LLCC is located just equatorward of the subtropical ridge axis with 10-15 knots of VWS.
Despite its proximity to the ridge axis, the outflow is currently being constrained by a complex upper level synoptic pattern, resulting in an intensification rate that is expected to be slightly less than climatological values. The current intensity is assessed at 40 knots. Maximum significant wave height is 16 feet.
TC 16S is tracking along the northwestern periphery of the subtropical ridge (STR) and is forecast to track west-southwestward to southwestward through TAU 72. After TAU 72, TC 16S will re-curve southward as a deep trough over the central Indian Ocean moves through. TC 16S should reach its peak intensity of 70 knots at this time as it rounds the ridge axis with minimal VWS. After TAU 72, the system will weaken as it encounters increasing VWS. Model guidance is in tight agreement through TAU 72 but diverges near the re-curve point. This forecast is in line with the previous forecast and is just slightly inside consensus after TAU 72. There is no evidence of extra-tropical transition until the system tracks south of 30s latitude (after TAU 120) and begins to interact with the midlatitude westerlies.