Tropical Cyclone Felleng Expected to Intensify – January 29th, 201311.4S 57.6E
Tropical Cyclone Felleng (13S), located approximately 460 nm north of La Reunion, has tracked westward at 10 knots over the past six hours.
Animated infrared satellite imagery shows significant improvement in the structure of banding convection wrapping around a developing eye feature over the past 12 hours. A recent SSMI 37h microwave pass shows a definitive eye with a fully developed eyewall.
Surface conditions remain favorable with sea surface temperatures (SST) near 29 degrees Celsius. Upper level analysis indicates the subtropical ridge (STR) to the south of TC 13S continues to provide a strong equatorward outflow channel, and the venting mechanism leading to the recent intensity increase observed.
Additionally, the developing point-source anticyclone, over the low level circulation center, has been making progress towards establishing an improved poleward outflow channel, but continues to be hindered by the southerly flow around the STR. A mid-latitude long-wave trough has started to weaken the western lobe of the STR, which will alter the system two-fold.
The first alteration will be an expansion of the poleward outflow channel outflow, and the second will be a shift to a more southern track around the eastern lobe of the str as the western lobe breaks down. The improving poleward outflow will allow the system to intensify through TAU 72. Decreasing SST values and increasing vertical wind shear beyond TAU 72 will lead to a slight weakening trend through the remainder of the forecast. Model guidance has come into tight agreement leading to high confidence in the forecast track.