A low-pressure system off the Queensland coast has developed into a cyclone, the Bureau of Meteorology (BOM) says.
BOM said the system in the Coral Sea, to be known as Tropical Cyclone Gabrielle, "will remain well offshore", although it is expected to produce "dangerous coastal conditions" along the southern and central Queensland coast over coming days.
Senior meteorologist Harry Clark said the system had been moving in a south-westerly direction but was forecast to drift towards the south-east while intensifying.
"So potentially [it] could reach severe tropical cyclone status by Friday," he said.
There was "reasonable confidence" the system would recurve away from the Queensland coast, moving more towards Norfolk Island and eventually in the direction of New Zealand, Mr Clark said.
But he said Queensland was still likely to feel the impact of the system as it moved past.
"It is expected to remain off the Queensland coast," Mr Clark said.
"The main effects will be an increase in winds around coastal waters around Townsville and Sandy Cape, on top of on K'gari (Fraser Island)."
Cruise ship turned back
A cruise ship travelling along the Queensland coast towards the South Pacific has been forced to change paths to avoid the intensifying weather system.
A Carnival Cruise Line spokesperson confirmed the change of course, citing safety reasons.
"Due to unfavourable weather conditions, Carnival Luminosa is unable to visit its scheduled South Pacific ports following the ship's departure from Brisbane on Sunday," the spokesperson said.
"The ongoing safety of our guests and crew remains our priority and we thank guests for their understanding as we coordinate the remainder of our voyage."
Mr Clark from the BOM said large swells were likely along parts of the coast, but any significant rain from the system would most likely be confined to offshore areas.
"We will see a large and powerful easterly swell build across the south-east Queensland coastline towards the end of the week, so Thursday, Friday and into [the] early weekend," he said.
"Certainly, we could not rule out some coastal erosion as a result of that as well.
"We will see a bit of an increase in showers along the Queensland coastline, but no widespread heavy rain predicted out of that system."
Norfolk Island likely to be buffeted by Gabrielle
Mr Clark said out of all the areas of Australia, Norfolk Island was most likely to see some impacts from the cyclone.
He said even if the system did not directly impact or come within 50 kilometres of the island, there would still be an increase in wind and waves.
"Particularly Saturday and into Sunday is likely when we could see that tropical cyclone move towards that region,” he said.
"We could see some very large waves in excess of 5 metres across much of the island, but also see wind gusts approaching almost category two strength if it was to cross or come very close to the island.
"We could see some heavy rainfall as well."
Mr Clark said BOM would keep a "close eye" on the system over the coming days.
Turbulent times for turtle hatchlings
For more than 40 years, Bev McLachlan has been watching over nesting turtles at a special spot on the Queensland coast.
Bev and her husband Nev spend every summer camped at Wreck Rock, halfway between Bundaberg and Agnes Water, collecting data on the turtles that come ashore each night to lay eggs.
The couple said big seas can pose problems for hatchlings.
"Obviously our biggest concerns are the nests on the beach that haven't hatched, we were concerned a couple of weeks ago when we had the full moon and 3.6 metre high tides," Ms McLachlan said.
"That was inundating nests and if we have a cyclone pushing behind it that will be even worse."
"What the poor little guys do is they dig out of their nest for seven to 10 days, then they run out to the water and spend five days in a frenzy trying to get into the current to get down the east Australian coast, across to New Zealand and over to Peru where they stay for a few years.
"So, if the seas are rough, they will be in for a rough time."
Meanwhile, Hervey Bay-based dive boat operator Ed Gibson is also watching the system closely.
"Weather is a wonderful thing, and it can do what it wants so we are doing our normal preparations just in case," he said.
"It's quite stable for now but you can feel the future forecasts changing rapidly, and I think Thursday and Friday we should be in for a bit of a blow.
"Hopefully the little monster moves offshore and keeps away from land."
Another 'burst of heat' on the cards
Mr Clark from the BOM said Queensland could also experience another "burst of heat" over the weekend.
"We do see winds across much of Queensland turn southerly or even south-westerly, which is a little unusual for this time of year," he said.
"Almost paradoxically, we could see heat build across Queensland, including south-east in Queensland."
He said large parts of south-east Queensland could see temperatures in the mid-30s, and low 40s for the southern interior.
"At this stage, [it] does not look to be as humid as the last heatwave," Mr Clark said.