Tropical Cyclone Hilwa

[Somerset Squall]

A tropical cyclone has formed several hundred miles northwest of the NW Australian mainland and is heading westwards, further out into the south indian ocean. Convection is wrapping nicely around 13S' LLC, which is small but very well defined. Small cyclones such as this can intensify or weaken rapidly. 13S is likely to intensify given that shear is low and waters are warm.

[Konstantinos]

It has direction toward Madagascar... This region is active.

[Somerset Squall]

13S has struggled over the last 36hrs and has very slowly intensified to 50kts. However, the cyclone is in real trouble this evening. Convection has drastically reduced leaving the well defined LLC almost entirely exposed. This is somewhat surprising as the shear affecting 13S has now eased and waters are still warm under the cyclone on the west-southwestward track. Unless this convection makes a comeback, the LLC will unravel. Conditions appear favourable enough so 13S should survive but based on recent convective trends any further intensification will be slow.

[aggy]

is there a chance the two cyclones could meet as gio is tracking eastwards

[Somerset Squall]

This looked possible for a while, MeteoFrance were actually forecasting this earlier with Giovanna moving south of Madagascar then northeastwards towards TC 13S, however, Giovanna is now expected to sharply turn and dissipate over Madagascar without moving back out into the Indian Ocean.

[aggy]

would of been interesting

[Somerset Squall]

Well, there seems like there might be a bit of interaction between the two storms after all now Aggy. Giovanna is now moving eastwards south of Madagascar and 13S is expected to get pretty close to TC Giovanna over the coming days. The systems aren't forecasted to merge however, with 13S taking a southward dive and Giovanna swinging to the north.

13S weakened to an intensity of 35kts pretty much after I posted, and has remained at that intensity ever since. Convection has flared but never fully persisted over the last 36hrs. 13S has been battling some outflow restrictions and moderate shear which has prevented intensification. The cyclone is still expected to restrengthen and peak at 50kts again as shear should ease and the trough responsible for hindering the outflow moves away. However, I am somewhat skeptical based on the history of this storm. One thing looks likely however, 13S should not threaten land.

[Somerset Squall]

13S has remained in a steady state until this afternoon, where some much deeper convection has formed. 13S has finally been given a name, and is now classified as Tropical Cyclone Hilwa. Hilwa's recent surge of convective activity may be a sign of some intensification at last, but I don't expect Hilwa to suprass it's first peak of 50kts prior to bowing out of the tropics. Intensity is still 35kts at present.

Edited February 20, 2012 by Somerset Squall

[Somerset Squall]

Intensity rose to 40kts, but in a similar fashion to Giovanna, Hilwa has been destroyed by shear as the cyclone moves southwards around the western periphery of the steering ridge to the east. Re-generation is not expected.

[Somerset Squall]

Convection is clinging on to the south side of Hilwa this evening, and MeteoFrance still has Hilwa as a tropical storm, which I think is a little generous. Fighting on the way out, but I expext MeteoFrance to follow JTWC very soon in dissipating Hilwa.