A northeast sea breeze blowing over a warm offshore current has brought a scattered armada of bluebottles to shore over the past few days, heralding an early start to the warmer months.
The local water temperature has reached about 18 degrees, Beachwatch correspondent Dave Anderson says, rising between one and two degrees in the last fortnight.
That's brought in the bubbly blue jellyfish, which typically float in vast patches as big as football fields offshore, into the shallow water on the high tide.
Any beachgoing regular would know the misfortune of catching a bluebottle sting, which comes up in whip-like lines and sores in parts of the skin that come in contact with the tentacles.
Mr Anderson remembers the "Three Stooges" show of his own run-in some time back, showing up to emergency among a band of local surfers who had come afoul of a recent wave. Still, he says the local bluebottle - sometimes called a Pacific Man-o-War after its sail-like fin - is more nuisance (if a painful one) than deadly.
The bluebottle is, interestingly, not one organism but a colony of four separate organisms called zooids that depend on one another for survival.
Their arrival, Mr Anderson said, usually heralded the warmer months are on the way coupled with warmer waters.
"The water needs to get to about 20 degrees for the sail to open up and inflate into a bubble," he explained.
The city woke to a cloudless and warm morning on Friday, with patchy conditions expected for the weekend ahead. There was a chance of showers and a possible thunderstorm in the forecast for Saturday morning before a break of sunny weather on Sunday and Monday and a return to possible showers on Tuesday.
Forecasters for the Bureau of Meteorology were tracking a cold front crossing the western districts on Friday that was expected to reach the northeast by Saturday. A more significant cold front looks set to cross the eastern districts on Tuesday, with a cool, fresh, and gusty southerly wind change in its wake.
Mr Anderson said a possible north-westerly over the weekend would likely push the bluebottles back out to sea.
