October 31, 2024
Giant Hail at Delaney's Creek on October 31, 2024. Credit: Jay Wright / Severe Weather Australia
Storms containing giant hail swept through areas of Southeast Queensland and Northeast NSW today. One particularly destructive storm complex formed over the Brisbane Valley before tracking northeast, bringing large to giant hail to the Moreton and Sunshine Coast Hinterland areas. Meanwhile, isolated supercells also generated large hail across areas of northeastern NSW.
Loop of today's severe storms with hail sizes and thunderstorm intensity markers included. Note how the storm in the Brisbane Valley left moves (tracks more north) as it becomes more intense. Source: MetCentre HailTracker
Why These Storms Are Producing Giant Hail
The primary factors behind today’s large hail included strong instability and extremely cold air in the upper atmosphere, with temperatures at 500mb (about 5.5km altitude) sitting around -15°C—ideal conditions for large hail development. Additionally, a seabreeze front enhanced storms by providing strong, humid inflow, boosting storm intensity.
ACCESS 500mb temperatures today. The upper trough (shown across eastern Australia) was a significant driving force behind today's hail activity. Source: MetCentre
Second Wave of Severe Storms Expected Tomorrow (Friday)
Unfortunately, a second round of severe storms is expected tomorrow in Southeast Queensland, with the potential for locally dangerous storms driven by a southeast change moving through the region. Southeast changes are known to produce high-end and sometimes supercellular thunderstorms, raising the risk of severe weather once again.
Southeast change setups are often volatile because of the additional wind shear that develops just behind the change. The southeasterly direction creates significant atmospheric turning (helicity), which can support supercell development. Strengthening low-level winds behind the change also help counteract the cool outflow winds that can weaken storms, much like today’s seabreeze aided storm strength.
ACCESS CAPE & Sounding. Moderate to strong levels of instability are forecast for Southeast Queensland tomorrow (Friday). Sounding also shows good directional wind shear in the lower atmosphere due to the low level winds opposing the mid-level winds (along with strong levels of instability). Source: MetCentre
Stay Alert and Prepared
Given the potential for severe storms tomorrow, it’s important to stay safe and prepared:
Keep cars under cover to avoid hail damage, but avoid parking under trees.
Monitor warnings closely and keep an eye on the MetCentre radar, which dynamically updates storm intensity every five minutes, allowing you to track each storm’s strength.
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