The storm system is the first tropical cyclone to form in Queensland waters in December in an El Nino year.
Jasper was about 1250km east northeast of Cairns at 4am (AEST) on Friday and moving south across the Coral Sea at 10km/h, the Bureau of Meteorology said.
Over the weekend Jasper is likely to weaken while also turning west towards the Queensland coast.
"While the timing of a coastal impact remains highly uncertain, the highest risk of a cyclone impact lies between Cooktown and Mackay, including Cairns and Townsville," the bureau said in a cyclone update.
"As Jasper approaches the coast there is a risk of re-intensification and the potential for severe impacts."Â
Senior meteorologist Laura Boekel has warned the coastal region directly impacted by the cyclone may not be the only area affected.
"It may impact further away from where it is crossing," she said on Thursday.
"We can see large impacts from tropical cyclones, especially when it comes to rainfall and flooding."
She said potential cyclone affects included storm surges causing coastal flooding, damaging or destructive winds and heavy, widespread rainfall.
The bureau is issuing regular updates to keep communities informed.
Australia's cyclone season is usually from November to April, typically peaking in Queensland in February and March.
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