SYDNEY, Oct. 12 (Xinhua) -- Australia's Bureau of Meteorology released on Monday a severe weather outlook for October 2020 to April 2021 showing an increased risk of flooding for eastern Australia and tropical cyclones in the north, with roughly average potential for heatwaves and severe thunderstorms.
In late September, the bureau upgraded the La Nina alert to an active event, saying La Nina had developed in the Pacific Ocean, and warned changes in ocean temperatures and weather patterns over the Pacific are likely to remain until the end of this year.
The bureau said in the outlook that the current La Nina was likely to bring more rain to eastern and northern Australia, with some drought-affected areas already seeing rainfall deficiencies ease and water storage levels increase.
La Nina is a climate pattern associated with cooler than average sea surface temperatures in the central and eastern tropical Pacific Ocean. It typically results in above-average spring rainfall for Australia, and also means cooler days, more tropical cyclones and an earlier onset of the first rains of the wet season across the northern part of the country.
While recent decades have seen a decline in the number of tropical cyclones in Australia, climatologist Greg Browning said this summer is likely to buck that trend.
"On average Australia sees 9 to 11 tropical cyclones each year, with 4 crossing the coast. With La Nina this year we are expecting to see slightly more tropical cyclones than average, and the first one may arrive earlier than normal," Browning said.
He said communities right across northern Australia need to stay prepared now, and stay informed from the very start of the tropical cyclone season in October, right through until April.
Meanwhile, though earlier and more rainfall will bring a better weather condition for the prevention of bush fire, the bureau warned that people should not be complacent.
"This fire season we're expecting wetter than average conditions in eastern and northern Australia, so long-running large bushfires are less likely, however, a wetter spring can lead to abundant grass growth, which could increase fire danger as it naturally dries during summer," Browning said.
"Meanwhile, if dry conditions continue in southwest Western Australia as forecast, the potential for more fire weather days there could increase."
The Bureau's General Manager of Decision Support Services Sandy Whight also said the lower fire risk across much of Australia is no reason for complacency.
"Southern Australia is one of the most bushfire prone places in the world in any summer and it's important to remember that, right across Australia, even short periods of hot and windy weather will raise the fire risk, so communities need to have their bushfire plans ready."
The bureau also warned about the health risks that might be brought by longer heatwaves and more increased humidity.
"While heatwaves may not be as severe, the bureau's advice is that in southern areas they may last longer and be more humid - both of which can increase the risk to human health. Be sure to monitor the bureau's heatwave service, which provides information about the location and severity of heatwaves," the outlook said. Enditem
