Tropical Storm Dumile (07S) Tracking Southwestward Towards Madagascar11.1S 53.6E
On December 28 a low pressure area continued to organize, with a significant increase in convection, located just to the west of an anticyclone. Tropical Cyclone Dumile (07S), located approximately 525 nm north of La Reunion, has tracked southwestward at 03 knots over the past six hours. Maximum significant wave height is 21 feet.
Animated multispectral satellite imagery shows a well defined low level circulation center (LLCC) with a primary band of deep convection wrapping from the southern periphery into the northern half of the LLCC. The convection remains strongest near the center and in the northern half of the system.
The organization remains well defined but has struggled over the last 24 hours to intensify. Upper level analysis indicates the mesoscale anticyclone continues to provide good equatorward outflow, but has been weak on the poleward side of the system. This lack of strong dual outflow channels appears to be the main factor limiting stronger development.
The current intensity is estimated at 45 knots. Animated water vapor imagery shows the poleward outflow channel has started to improve in the past six hours and should help to intensify the system as it tracks south- southwestward along the northwestern extension of a deep layered subtropical ridge (STR) located to the southeast.
A mid-latitude trough, to the south of Madagascar, will track eastward weakening the western extent of the STR over the next 24 hours. As the trough tracks to the south of the STR, the STR itself will shift, bringing the track for TC 07S more southward.
In the extended forecast, a second mid-latitude trough will cross over southern Africa into the Indian Ocean and again weaken the STR, allowing the track for TC 07S to shift to the southeast. By TAU 96 the system is expected to begin weakening due to increasing vertical wind shear, decreasing sea surface temperatures and interaction with the second mid-latitude trough. Extra-tropical transition is expected to begin by TAU 120. Model guidance is in good agreement through TAU 48 but begins to differ in the timing of the recurvature to the southeast.