By PDC’s Senior Weather
Specialist Glenn James
Current Tropical Cyclones:
Tropical Cyclone 05S (Darian)…is located approximately 1040 NM east-southeast of Diego Garcia
Northwest and Southwest Pacific Ocean, North and South Indian Oceans, and Arabian Sea:
South Indian Ocean
Tropical Cyclone 05S (Darian)
According to JTWC Warning number 9, sustained winds were 130 knots, with gusts to 160 knots.
Animated multi-spectral satellite imagery reveals that tropical cyclone Darian remains a highly symmetric quasi-annular system with a 20 NM eye and tight banding features. It is evident from the animated visible imagery loop that the system is experiencing slight northeasterly shear, as the low level circulation center (llcc) can be seen in northeastern corner of the larger upper level circulation center.
Without the luxury of current microwave imagery, it is impossible to discern the presence of a possible eye wall replacement cycle at this time. A slightly older microwave image revealed a robust inner eye wall with a possible secondary eye wall beginning to form.
TC 05S Darian has recently steadied up on a generally westward track under the steering influence of the ridge to the south. The system is still in a favorable environment, characterized by low vertical wind shear, warm sea surface temperatures, and moderate radial outflow.
As a result of recent slower track speeds, which allowed for upwelling of cooler waters and by the systems recent migration over relatively cooler sea surface temperatures, 05S will gradually weaken over the next 24 hours.
After 24 hours, as the system regains consistent forward progress and tracks further north of the 14th parallel. The system reenters relatively warmer waters, allowing for a generally consistent intensity through 72 hours. by this time, the ridge to the south is forecast to move off to the southwest, leaving the system under the influence of a near-equatorial ridge to the north, which will drive the system rather aggressively poleward.
This poleward shift will not only decrease track speeds which will allow for increased upwelling, but it will also place the system in increasingly cooler sea surface temperatures, all of which will decrease intensity. as a result, by 120 hours the system will be tracking generally southward and overall intensity will be reduced to around 70 knots.
>>> There’s an area of disturbed weather, being referred to as Invest 98B which is located approximately 357 NM southeast of Chennai, India
Animated IR and microwave images depict a broad low circulation center partially exposed to the southeast of flaring convection that is being sheared to the northwest.
Environmental analysis indicates 98B is in a marginally favorable environment for development with low to moderate (10-20 knot) vertical wind shear, offset by good divergence aloft and warm sea surface temperatures.
Global models are in good agreement that 98B will continue to track generally north over the next 24-48 hours and gradually intensify, however, the increasing vertical wind shear will likely hinder development into a significant tropical cyclone.
Maximum sustained surface winds are estimated at 20 to 25 knots.
The potential for the development of a significant tropical cyclone within the next 24 hours remains low.
>>> There’s an area of disturbed weather, being referred to as Invest 90S which is located approximately 98 NM northwest of Darwin, Australia
Animated IR imagery depicts an low level circulation obscured by disorganized flaring convection.
Environmental analysis indicates 90S is in a marginally favorable environment for development with moderate to high (20-30 knot) vertical wind shear, offset by good divergence aloft. Sea surface temperatures are very warm.
Global models are in good agreement that 90S will continue to track southward over the next 24-48 hours, and possibly intensify rapidly as it tracks into an area of decreasing vertical wind shear before it makes landfall over the Kimberley coast.
Maximum sustained surface winds are estimated at 25 to 30 knots.
The potential for the development of a significant tropical cyclone within the next 24 hours is upgraded to high.