The season's first cyclone has weakened to a category 1 system as it moves toward the far north coast.
However, the tropical storm is expected to re-intensify, crossing the coast near Port Douglas, north of Cairns, by Wednesday afternoon as a category 2.
"If the system is slower and crosses overnight Wednesday or Thursday, a slim chance remains of a severe category 3 crossing," the Bureau of Meteorology said.
The first official tropical cyclone warning of the season was issued on Monday by the bureau for an area from Cooktown to just north of Townsville.
Gale-force winds are expected to hit communities in the warning zone from Tuesday which includes Cairns, Innisfail, Palm Island and Wujal Wujal.
Deputy Premier Steven Miles says Jasper will hit some of Queensland's most vulnerable communities. (Jono Searle/AAP PHOTOS)
Deputy Premier Steven Miles said there was a significant risk of flash flooding and a storm surge when the cyclone makes landfall.
"It will then progress across the Cape, affecting some of the most vulnerable Queensland communities," Mr Miles said.
A cyclone watch zone is also in place, extending inland and further north to Cape Melville.
People are bracing for power, internet and water cuts.
Flood watch and flash flooding warnings are current for the north tropical coast, parts of the Cape York Peninsula and the Gulf Country,
Evacuation centres have been set up in Cairns, Port Douglas and Cooktown.
Hundreds of support teams, including energy company workers, are heading north to assist as the cyclone approaches.
Late on Monday, Jasper was 425kms east of Cairns and about 365kms from Townsville with winds of 85 km/h and gusts of up to 120km/h.
Cairns Mayor Terry James urged locals to be prepared for up to five days without power, and up to 500mm of rain.
"The roads will be cut off, potentially the power will be cut off," he said.
"People should be preparing now to be isolated from lunch time tomorrow."
Cairns hospital is preparing for a possible storm surge.
"Emergency surgery will continue as normal, but people with non-urgent illnesses or injuries are urged not to use the hospital's emergency department, which may be busy treating cyclone casualties," a hospital spokesperson said.
⚠�🌀Tropical Cyclone Watch for — Bureau of Meteorology, Queensland (@BOM_Qld) #CycloneJasper has been issued for Cape Melville to Townsville, including #Cairns & #Cooktown. A Flood Watch and Severe Weather Warning are also current in the region. Monitor updates at https://t.co/FBmpsInT9o and on the BOM app. pic.twitter.com/SeltwMsq1MDecember 10, 2023
People have been asked to avoid travel in the area and not drive through flooded roads.
Wildlife rangers have closed mainland and island national parks - including camping areas - and protected areas between Mackay and Cape Melville.
About 450 Energy Queensland staff have been deployed to Rockhampton and Townsville in preparation for potential power outages.
A further 150 Energex crews are leaving southeast Queensland to assist.
Police will send around 40 officers to area.
Queensland's state disaster coordination centre has been activated in response to Jasper's threat, as have district and local disaster coordination centres.Â
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