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Somerset Squall

Tropical Cyclone Anggrek

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92S has become the second tropical cyclone of the South Indian Ocean cyclone season 2010/11, located a couple hundred miles north of the Cocos Islands. Intensity is 35kts, according to the JTWC. 02S is in TCWC Jakarta's area of responsibility (which is the eastern South Indian Ocean, north of 10S, between 90E and 125E. The last storm to form in this area was Durga in 2007.), and if it gets upgraded by them, 02S will receive the name Anggrek. If 02S moves south of 10S before being upgraded, it will receive the next name in Australia's list, which is Tasha (following the last Australian cyclone, Sean, back in April).

02S is in an environment of warm water but moderate shear. The shear is still giving 02S a lopsided look, with the bulk of the convective activity located west of the LLC. However, as 02S moves south, shear is set to decrease, which will allow 02S to strengthen decently.

02S is set to scrape near or directly hit the Cocos Islands in a few days. Dependent on the forecast of shear easing, 02S could be a fairly potent cyclone by this point. Therefore, residents need to keep a close eye on, and prepare for 02S. Flooding rains, storm surge and destructive winds are possible.

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02S has strengthened to 40kts and has been upgraded to Tropical Cyclone Anggrek. Moderate shear is still impinging on Anggrek, which has actually partially exposed the LLC on the eastern side of the convective mass. Banding on the south and west sides of the cyclone remain impressive however, and when shear eases this evening, the banding should wrap around the eastern quadrant and allow some steady intensification over warm water. After 48hrs, Anggrek should weaken as waters cool sharply and shear elevates again.

Anggrek should move southwards towards the Cocos Islands as the cyclone travels along the western periphery of a steering ridge to the east. The Cocos Islands still need to be on alert for a visit from Anggrek in a couple days.

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Shear has eased over Anggrek, and the cyclone has intensified to 50kts. The convection is fully covering the LLC now, and the convective canopy is also expanding, a sign of a healthy system. With low shear and warm sea temps over the next couple of days, Anggrek should strengthen further before conditions deteriorate as the cyclone swings southwestwards. Cocos Islands are still in Anggrek's firing line, so the residents need to brace themselves for damaging winds, and flooding caused by rain and storm surge.

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Anggrek peaked at 55kts but has since weakened to 50kts. Luckily, the cyclone to a more easterly track than expected meaning the Cocos Islands missed the worst of the storm. Aside from this, Anggrek has stuck largely to the track forecast and is now moving southwestwards over cooler waters. This is what is causing the weakening, which will be rather slow at first. Once the shear increases again, an accelerated rate of weakening is expected followed by dissipation in around 3-4 days time.

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Anggrek has weakened at a faster than anticipated rate, and intensity is down to 30kts. JTWC have issued their final warning on the system, indicating that re-generation is not likely as shear rises further and waters continue to cool.

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