Summary
Severe Tropical Cyclone Jasper peaked as a category 5 cyclone in the Coral Sea, south of the Solomon Islands before weakening to a category 1 system, south of Willis Island. Jasper then moved westwards and redeveloped into a category 2 cyclone before crossing the far north Queensland coast, in the vicinity of Wujal Wujal at 1000 UTC 13 December 2023 (8 pm AEST, UTC+10h).
A tropical low (02U) formed east of the Solomon Islands during 2 December and moved to the west then south, into the Solomon Sea over the next couple of days. It reached tropical cyclone intensity at 1200 UTC 5 December, about 160 nm (295 km) west of Honiara.
Jasper continued to move south into the northern Coral Sea, south of Solomon Islands while developing. Jasper reached severe category 3 strength at 0600 UTC 6 December, 24 hours after being named. Jasper continued to strengthen on 7-8 December as it moved to the south, reaching a peak 10-minute mean wind intensity of 115 kn (213 km/h) at 0000 UTC 8 December. From later that evening, Jasper encountered an unfavourable environment and began to weaken.
From 9 December, a ridge to the south began to influence Jasper's movement and Jasper started to turn to the west, while continuing to weaken. During 11 December, Jasper passed about 75 nm (140 km) to the south of Willis Island and by this stage it had weakened to a category 1 cyclone.
Jasper continued to move in a general westward direction and reintensified to a category 2 cyclone before it crossed the north Queensland coast near the community of Wujal Wujal, about 65 nm (120 km) north northwest of Cairns, at 1000 UTC 13 December. The region to the south of the centre extending to Port Douglas experienced the strongest winds with gusts estimated to 70 kn (130 km/h).
Once Jasper crossed the coast, it weakened quickly, and decreased to below tropical cyclone intensity at 1400 UTC 13 December. Ex-tropical cyclone Jasper then stalled as a tropical low-pressure system over the Cape York Peninsula for the next several days, before dissipating over land on 17 December.
A surface trough developed over the weekend of 16-17 December, extending from ex-tropical cyclone Jasper eastward across the north tropical Queensland coast into the Coral Sea. Moist northeasterly winds from the Coral Sea converged along this near-stationary trough with easterly winds strengthened by a building ridge in the Tasman Sea. Persistent heavy to intense rain fell over the north tropical Queensland coast area. This rain fell in river catchments that were already wet due to earlier rainfall from Jasper's landfall, resulting in widespread flooding in the region.
For more information see the TC Jasper Report (docx).
Track and Intensity
