Australia’s East Coast Endures Record-Breaking Spring Heat Amid Severe Storms

Key Takeaways

• Australia’s eastern seaboard is experiencing an ongoing heatwave, with Sydney and Brisbane on track for their hottest-ever springs.
• The heatwave is expected to fuel extreme weather, including severe thunderstorms and fire weather warnings.
• The south will experience cold weather, with snow expected in the ranges on the first day of summer.
• The contrast between the hot east coast and cold south is due to a change in wind patterns, with westerly winds bringing warm air to the east coast and cool air to the southern coastline.
• The heatwave is part of a larger trend of above-average temperatures since September, with Sydney and Brisbane experiencing record-breaking spring temperatures.

Introduction to the Heatwave
The eastern seaboard of Australia is currently experiencing an intense heatwave, with temperatures soaring to record-breaking heights. Both Sydney and Brisbane are on track to have their hottest-ever springs, with temperatures comfortably above all previous years dating back to the 1800s. The heatwave is expected to continue throughout the weekend, with temperatures in Sydney forecast to reach 32C to 34C on Saturday, and Brisbane’s maximums not expected to fall below 30C until Wednesday. This prolonged period of hot weather has triggered fire weather warnings from Sydney and the Hunter to the Central West, and has also led to a series of severe thunderstorms across Queensland and north-east New South Wales.

Record-Breaking Temperatures
The recent heat along Australia’s east coast is part of a larger trend of above-average temperatures since September. Sydney’s mean temperature this spring has exceeded 20C for the first time since the Observatory Hill station opened in 1858, a substantial 3C above the long-term average. Brisbane has averaged 23C, also a record, and around 2C above the long-term average. Daytime highs have been particularly high, especially in Sydney, where the season mean of 25.5C is only 0.2C below the summer average, while Brisbane’s maximums at 28.4C are less than 1C off the summer average. The number of hot days this spring has also been well above normal in both cities, with Brisbane on track for 25 days above 30C, more than double the average, and Sydney on track for 12 days above 30C, around triple the average.

Severe Thunderstorms
The heatwave has also led to a series of severe thunderstorms, with south-east Queensland being hammered by giant hail on Monday, and much of NSW being lashed by gales on Tuesday and Wednesday. The atmosphere on Saturday is again primed for thunderstorms along the eastern seaboard, due to humid, warm air at the surface and a deep trough extending from the tropics to the Tasman Sea. This pattern supports the formation of a long band of severe thunderstorms stretching about 2,000km from the Gulf of Carpentaria to the NSW north coast. A risk of severe thunderstorms on Saturday stretches from north Queensland to NSW, with warnings possible for wind, hail, and heavy rain.

Contrasting Weather Patterns
The contrast between the hot east coast and cold south is due to a change in wind patterns. A westerly airstream is bringing warm air to the east coast, while the southern coastline is experiencing cool air from the Southern Ocean. This contrast will be on full display during the coming days, with Adelaide’s temperatures expected to be about 10C below Sydney’s. The westerly winds are also bringing a series of cold fronts, trailed by waves of polar air, which will lead to snow on the highest peaks of Tasmania and the mainland on Sunday, ahead of the coldest air’s arrival on Monday, the first day of summer.

Snow in the South
The first day of summer will bring snow to the ranges, with modelling indicating that snow levels should be lower to around 1,300 metres on the mainland alps and 1,000m in Tasmania. This unusual weather pattern is a result of the rapid warming over the South Pole in September, which weakened the polar vortex and allowed the belt of westerlies to expand north. The resulting westerly winds are bringing cool air to the southern coastline, leading to cold temperatures and snow in the ranges. The contrast between the hot east coast and cold south is a remarkable example of the complexity and variability of Australia’s climate.