October 14, 2024
Satellite, radar and lightning image across Australia this afternoon. Source: Weatherwatch MetCentre.
This afternoon, a scattering of storms was present across all mainland states—something more typically seen in the middle of summer rather than in October. While storms in October are very common, they tend to be confined to smaller regions of the country due to lower moisture levels at this time of year, resulting in more isolated activity.
Warmer Oceans Contributing to Widespread Storm Activity
As discussed in our seasonal outlook, the warm ocean temperatures are contributing to an influx of moisture across the country. This is being aided by a very broad region of cold air in the upper atmosphere across the southern half of the continent. The combination of these factors has resulted in today’s widespread shower and storm activity, which will continue into the coming days ahead of a much stronger cold front expected later this week, bringing drier air.
ACCESS G 500mb temperatures 4am EST Tuesday October 15, 2024. This shows a broad region of cold air across the southern half of the country which is combining with elevated levels of moisture to produce shower and storm activity. Source: Weatherwatch MetCentre.
Severe Storms Hit Sydney, Adelaide Possibly Next in Line
While severe storms hit Sydney today, bringing heavy rainfall and small hail, the next major area of concern is Adelaide. Thunderstorm setups in South Australia are inherently complex because they develop differently than in the eastern states. In South Australia, storms are often "elevated," meaning they don’t develop from surface moisture, but rather from moisture several kilometres above the surface. This often results in high thunderstorm bases, producing spectacular lightning shows but with limited rainfall.
ACCESS G sounding for Adelaide for Tuesday morning showing moderate levels of instability in a cold atmosphere. Elevated, or mid-level storm activity is likely to be the main driving force behind this storm activity Source: Weatherwatch MetCentre.
However, this time the cold air in the upper atmosphere could increase the potential for hail overnight and into tomorrow morning in the Adelaide region. Further storms are likely to continue tomorrow which could carry further hail and severe thunderstorm threats.
More Storms in NSW Tomorrow
Tomorrow, remnant activity from South Australia will track into inland NSW and is likely to generate further shower and storm activity which could carry further damaging wind gust and large hail threats (albeit isolated).
ACCESS G Lifted Index charts showing instability will heavily favour areas of southeastern Australia during the next four days - a change from recent weeks. Source: Weatherwatch MetCentre.
More Storms Possible Mid-Week
Further storm activity may develop in South Australia, western NSW, and western Victoria on Wednesday and Thursday as moisture pools into a surface trough ahead of a much stronger cold front. This front could bring wild and windy conditions to South Australia on Thursday, before impacting southeastern Australia on Friday.
Next five days rainfall from ACCESS G. Source: Weatherwatch MetCentre.
Windy End to the Week
The cold front expected later in the week is likely to bring the potential for extensive gales across NSW, Victoria and South Australia. So far, the severe weather season has mostly impacted northern NSW and southern Queensland - but with severe weather spreading to other areas of the country, remember to stay informed with the weather and monitor any warnings.
850mb winds from the ACCESS G model for Thursday and Friday showing a large low bringing strong winds later in the week. Source: Weatherwatch MetCentre.
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