Tropical Cyclone Asma

[Somerset Squall]

The southern hemisphere has woken from it's slumber, with the first tropical cyclone of the 2008/9 South Indian ocean season forming a few hundred miles northwest of Diego Garcia. The disturbance has been slowly organising and is now classified as a 35kt tropical storm, with deep convection persisting over an increasingly well defined centre. 01S is forecast to head southwestwards along the southern periphery of a steering ridge to the north. Sea temps are forecast to remain fairly warm and shear is expected to remain low to moderate, so intensification is predicted, and 01S is expected to be at 50kts by JTWC. Meteofrance also forecasts intensification aswell, and the storm is likely to get a name tomorrow as it continues to get better organised. It's far too early to say whether 01S will effect land in the future.

Satellite imagery of South Indian Ocean, you can clearly see the well defined 01S centre-left:

[Cookie]

nice to see the first system in the south Indian ocean

[Somerset Squall]

Indeed, will it be another very active season?

Moderate to high shear is displacing convection to the southwest of the partially exposed LLC of 01S this morning. This shear is expected to persist for another 24hrs or so before easing. Before it eases, little intensification is forecast, and 01S is likely to remain at 35kt intensity. Slow intensification will resume after 24hrs as 01S drifts southwestwards, remaining over sufficiently warm waters for this strengthening. Meteofrance and JTWC are largely in agreement with this idea.

[Somerset Squall]

01S continues to drift southwestwards. Shear continues to hamper development, and most of the convection is displaced southwest of the LLC. 01S is forecast to turn westwards as the subtropical steering ridge to the southeast builds south of the storm, blocking southward motion. 01S will be moving into a region of lower shear beyond 24hrs, which should allow some modest strengthening to begin.

[Somerset Squall]

01S has become the first named storm of the South Indian Ocean season, and has been called Asma. Asma has been struggling to intensify over the last 24hrs due to the continued northeasterly shear. However, this is now decreasing and has allowed some explosive convection over the centre, so Asma may now begin to get stronger. Intensification won't be rapid as the waters Asma is heading into will become slightly cooler but the lower shear should allow some modest strengthening. Asma is now moving westwards along the northern periphery of a subtropical steering ridge to the south. This motion is forecast to continue, and Meteofrance are keen to bring Asma onshore across eastern Madagascar in 3-4 days time. Asma obviously needs closely watching as Madagascar now seems under increased threat from the storm.

[Cookie]

Madagascar thats a name I haven't for a while!

thanks for the updates mate

[Somerset Squall]

Lower shear has allowed Asma to intensify, and JTWC have upped the intensity to 55kts earlier this morning. Since then, convection has decreased a little but there are some good banding features evident and even hints of an eye earlier in the day. Asma has wobbled northwards and thus the track forecast has also shifted northwards. It seems that the northern half of Madagascar are now most a risk from receiving a landfall from Asma later this week.

[Cookie]

its sounds daft to say but of the 3 current systems this looks the best

[Somerset Squall]

its sounds daft to say but of the 3 current systems this looks the best

Not a silly comment at all, it is the strongest of the three (Asma, 03A and Bavi) after all.

Asma has weakened today though. Shear has increased again and although Asma looked like it was nearing cat 1 status earlier it now has weakened to 45kts. Convection has shrunk but the LLC remains well defined. Asma is still on course for Northern Madagascar, but the question is- will Asma re-intensify? Shear is forecast to remain moderate to high and sea temps marginal, so Asma maintaining current intensity up until landfall is the most sensible option, as forecast by JTWC.

[Somerset Squall]

Strong shear continues to batter Asma, and the JTWC have issued their final warning on the system, as the LLC is now entirely exposed and the convection is waning. Intensity has been reduced to 35kts. The remnant low of Asma will continue westwards in a highly sheared environment and increasingly cool sea temps so regeneration is not expected.

[Cookie]

thanks for the great updates mate