Australian Weather

06 Dec 2025, 6:16AM UTC

Hot, dry and windy weather caused Extreme fire danger across parts of NSW on Saturday, with parts of the state registering their highest temperatures in 5 to 6 years, while other areas endured damaging winds and severe thunderstorms. Saturday’s volatile weather was caused by a hot air mass flowing over NSW on the northern side of a low pressure trough. This weather pattern also caused damaging winds and severe thunderstorms, both of which prompted warnings from the Bureau of Meteorology. Hottest weather in years as fires take hold Temperatures soared in the state’s west as Tibooburra reached 44.2°C, while Bourke, Brewon and White Cliffs all got above 43°C on Saturday. In the state’s east, Gosford hit 42.0°C and Badgerys Creek in Sydney climbed to 41.9°C. Several locations in NSW had their hottest day in about 5 to 6 years on Saturday. Gosford’s 42°C was its highest temperature since January 2020, while Dubbo’s 42.1°C was its hottest day since December 2020. Image: Modelled maximum temperature on Saturday, December 6, according to the ECMWF-HRES model. Source: Weatherzone. The sweltering heat combined with dry winds to create Extreme fire danger ratings in some parts of the state. This hot, dry and windy weather caused numerous fires to burn out of control, including a blaze in Koolewong near Gosford that destroyed a number of homes. Thunderstorms erupt in the west The low pressure trough passing over NSW on Saturday triggered thunderstorms over a broad area of the state’s Central West and North West. These thunderstorms prompted a warning for damaging wind gusts. Weatherzone’s Total Lightning Network detected 50,000 lightning pulses within 400 km of Nyngan, NSW during three hours on Saturday afternoon. Image: Lightning pulses detected within a 400 km radius of Nyngan, NSW during the three hours ending at 4:30pm AEDT on Saturday, December 6, 2025. Source: Weatherzone. Early-summer heatwave Saturday’s hot weather is part of a heatwave that has been gripping parts of NSW over the last few days, with Severe heatwave conditions experienced in some areas. Severe heatwaves are the second highest level in the three-tiered heatwave intensity scale used in Australia. These heatwaves are likely to be challenging for vulnerable people, including older people, particularly those with medical conditions. Based on average maximum temperatures between Thursday and Saturday, some areas in eastern NSW just had their warmest three-day December period in about 20 years. Image: Heatwave severity over the three days from Thursday to Saturday this week. Source: Weatherzone. Cool change on the way, before more warmth returns A cool southerly change will move over much of NSW on Saturday night into Sunday morning, reaching Sydney around 6 am on Sunday, before weakening over the state’s north on Sunday. This southerly will flush the heat out of much of the state and bring some respite into the beginning of next week. This relief will be short-lived through, with another warm air mass building over NSW in the middle of next week. Fortunately, this next round of heat won’t be as intense as this week’s heatwave and fire danger ratings shouldn’t be as high as Saturday.

05 Dec 2025, 5:33AM UTC

Australia’s East Coast could be impacted by periods of strong waves over the next couple of weeks as tropical cyclone activity increases in the Coral Sea and southwest Pacific Ocean. A number of these computer models are forecasting the development of tropical lows or cyclones over the Coral Sea and southwest Pacific over the next two weeks. Image: Four computer models predicting tropical lows or cyclones being active east of Australia late next week. Source: Weatherzone. This increased potential for tropical systems in the region is partly driven by an active phase of the Madden-Julian Oscillation (MJO) moving into the western Pacific region. The MJO causes an increase in cloud and thunderstorm activity when active over a region. This enhanced storminess can help create low pressure systems that can deepen into tropical cyclones. Image: Conceptual visualization of the MJO moving over the north of Australia, increasing thunderstorm, rain and tropical low activity. Source: Weatherzone. Along with this active phase of the MJO, oceans are very warm across the Coral Sea and southwest Pacific. This is partly due to the weak La Niña conditions currently in place across the Pacific. These warm sea surface temperatures greatly increase the potential for tropical cyclone development, which requires waters warmer than 26.5°C. Currently oceans across the region are 2-3°C warmer than normal, with waters even warm enough to support a tropical cyclone off southeast Queensland. Image: Sea surface temperatures around Australia on Thursday, December 4, 2025. Source: DTN. How will Australia be impacted? Fortunately for those in eastern Australian, there is only a low chance of a tropical cyclone being within the Australian region in the next 7 days. If a tropical cyclone does form, it will most likely be located a long way off Australia’s east coast and pose very little direct threat to the Australian mainland. However, tropical cyclones generate very large seas that radiate across the oceans, and these long-range swells can impact Australia’s coastline from thousands of kilometres away. Over the weekend, an area of low pressure will deepen near or just south of Fiji, potentially briefly reaching tropical cyclone intensity early next week before undergoing extra-tropical transition. While this system will remain around 2,000-2,500 kilometres east of Australia, enhanced easterly trade winds around the low, with more powerful 35-45 knots winds near the core, will generate a large area of swell generation, directed towards Australia. Image: DTN’s OneFX Significant Wave Heights reaching 5 to 6 m generated on Tuesday, December 9, 2025. Source: Weatherzone. Large seas generated by the low should reach 5 to 6 m over parts of the southwest Pacific between Fiji and New Zealand early next week. This area of large waves being over 2,000 kilometres away from Australia’s East Coast will take about 3 to 4 days to propagate and reach the Australian mainland. Across this journey, the swell height will significantly decrease, but the wave period will increase. Image: DTN’s OneFX Peak Wave Period showing easterly swell propagating across the Tasman and lower Coral seas next week. Source: Weatherzone In deep open ocean waters, longer period swell travels faster than short period swell, so coastal parts of eastern Australia could see swell “front runners” as early as Thursday afternoon (December 11). These swell propagation leaders should come in with periods of 14 to 15 seconds, and small amplitudes of less than a metre. The bulk of the swell energy is then expected to fill into Friday, December 12, with coasts from the NSW South Coast to Queensland’s K’gari experiencing 1 to 1.5 m swell at 12 second periods, and up to 2 m around the NSW Northern Rivers and southeast Queensland. Looking further ahead, another tropical low could develop just south of the Solomon Islands from mid-next week. While most models feature a low developing in the far northeast of the Coral Sea next week, different model and model runs vary on the intensity and location of the system. Image: GFS weather forecast of Mean Sea Level Pressure (MSLP) and 10 m wind speeds between Sunday, December 7, 2025, and Thursday, December 18, 2025. Source: TropicalTidbits.com This possible tropical cyclone could come within 1,000-1,500 kilometres of northeast NSW and southeast Queensland from around Saturday, December 13. The potential for significant easterly swell generation will greatly depend on the proximity, intensity and movement of the system. Why long period easterly swell can be dangerous and disruptive Easterly swells are especially hazardous for Austarlia’s east coast because they can bypass the headlands and breakwalls that protect beaches, ports and harbours from the more typical south swells that impact NSW and southeast Queensland. These easterly swells can enhance coastal erosion across beaches usually protected from south swells. Long period “groundswell” energy often goes unnoticed underneath ships at sea, but can be highly disruptive as the energy surges into ports and harbours. The “waves” of deep water energy surging into ports can cause ships to drag on their moorings and anchors. Seiching can also amplify this water movement as the energy sloshes within the port boundaries, increasing horizontal and vertical ship movements. Be sure to check the latest coastal warnings in eastern Australia over the next two weeks before heading down to the beach.