Summary
Tropical cyclone Irma developed from an area of deep convection in the northern Gulf of Carpentaria that had persisted for several days prior to 19 January. During this period the upper-level flow was quite zonal and hence unfavorable for cyclogenesis but the vigorous monsoon continued and by the morning of 19 January a Chinese research vessel anchored in the northern Gulf reported winds up to 74 km/h in the westerly flow to the north of the incipient depression. The low continued to intensify as it moved in a west-southwesterlv direction across the Gulf of Carpentaria and at 1200 UTC 19 January, when gales had developed through all sectors, the low was upgraded to a cyclone.
After crossing the coast at 1200 UTC 20 January, Irma moved in a south-southwesterly direction almost parallel to the coast for the next nine hours before resuming a southwesterly track and heading further inland. Irma became a very active rain depression and produced areas of flooding in the central Northern Territory. Rainfall figures from the area included a 24-hour total of 409 mm at Larrimah. A number of people had to be evacuated from Birrimba Station as floodwaters threatened their homestead. The lowest pressure recorded was 989.9 hPa at Roper Bar after lrma had made landfall. The strongest wind reported was 111 km/h from a ship west of Groore Eylandt just prior to landfall.
Wind damage caused by Irma was only slight.
Track and intensity
All times in UTC.
