The storm quickly intensified and became a Category 5 tropical cyclone on 7 December; the Joint Typhoon Warning Center (JTWC) estimated sustained winds of 220 km/h (140 mph).

Its low-level circulation centre became totally exposed and it maintained a poorly defined convective structure as it approached northern Queensland.

[3][4] At this stage, the system was located within a favourable environment for further development with radial outflow in the upper troposphere, low vertical wind shear, and warm (30–31 °C) sea surface temperatures.

[5] During 4 December, the system subsequently crossed 160°E, where it exited the South Pacific basin and entered the Australian region—which prompted the FMS to pass the primary warning responsibility to the BoM.

[6][7] The low was in a favourable environment, evident by excellent radial outflow, deep convective banding and very low shear, resulting the United States Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert (TCFA) later that day, projecting a high likelihood of a significant tropical cyclone developing.

[9] The BoM followed suit at 06:00 UTC on 5 December—officially upgrading the system to a Category 1 tropical cyclone on the Australian scale and assigning the name Jasper.

[12] Jasper rapidly intensified into a Category 3 severe tropical cyclone, fuelled by warm sea surface temperatures and low wind shear.

[14] Late on the next day, the BoM reported that Jasper had peaked in intensity around 06:00 UTC as a high-end Category 5 severe tropical cyclone,[15] with estimated maximum 10-minute sustained winds of 215 km/h (130 mph), and a central barometric pressure of 926 hPa (27.34 inHg).

[20] Jasper managed to maintain its intensity while battling unfavorable conditions, but soon significantly weakened due to strong (20–25 km/h (12–16 mph) vertical wind shear.

[47] They warned that the system was expected to produce gale-force winds, rough seas, moderate to heavy swells of 2.5–4.5 metres (8.2–14.8 ft) and coastal flooding over the islands.

[49] In anticipation of the possibility of Jasper making landfall on the Queensland coast at tropical cyclone intensity, the Australian Bureau of Meteorology (BoM) issued a number of official warnings to the public in advance of the system's arrival.

Upon weakening to Category 1 strength at 12:00 UTC on 11 December, several storm warnings and a cyclone watch were issued for coastal and inland areas between Cooktown and Townsville.

[54] Meteorology staff on Willis Island, about 450 kilometres (280 mi) from the coast were evacuated by the Royal Australian Navy (RAN) before the cyclone passed through the area on 11 December.

[55] Tourists towns prepared for flooding as they were in the firing line of the cyclone, while homeless people were offered shelter through local charities before Jasper arrived.

[74][75] Queensland Fire and Emergency Services swift water rescue crews and QSES were also tasked with numerous requests for evacuations, within the coastal suburbs.