Severe Tropical Cyclone Alenga

2-9 December 2011


Severe Tropical Cyclone (STC) Alenga formed during an active phase of the Madden-Julian Oscillation (MJO) to the west of Java. The tropical low pressure system initially moved southwest into the La Reunion Tropical Cyclone Warning Centre's (TCWC) area of responsibility (AOR). The southwest movement of the tropical low slowed and early on 6 December STC Alenga began to move to the southeast. Alenga crossed 90 degrees East (oE) Longitude into the Perth TCWC's AOR around 0000 UTC 7 December with an intensity of 45 knots (10 minute mean wind speed, 1 knot = 1.852 kilometres/hour). Conditions were favourable for development and STC Alenga continued to intensify. The cyclone reached a peak intensity of 75 knots at 0600 UTC 8 December. From this point Alenga weakened rapidly under the influence of increased wind shear and cooler sea surface temperatures. The cyclone weakened to below cyclone strength by 0600 UTC 9 December.

For more information see the TC Alenga Report (pdf).

Track and Intensity

Best Track of Tropical Cyclone Alenga

Please note, the intensity analysis of Tropical Cyclone Alenga is only included whilst within Australia's area of responsibility (east of °E).