An epic thunderstorm lit up the South Coast last night, with huge strikes of lightning illuminating the sky for much of the night.
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The storm began to roll through about 7.30pm Thursday night, bringing with it some powerful cracks of thunders and an incredible electrical light show.
Bureau of Metorology duty forecaster Rebecca Farr said the storms were caused by a trough stretching from inland NSW across to the coast.
“The storms were happening along that trough and stayed fairly stationary over the coast,” she said.
“The storms formed on this line and moved in the same area, which caused the continuous storm activity.”
While there was some rainfall associated with the storm, the Nowra region received very little, measuring below 5mm in most parts. Just over 7mm fell over Ulladulla while 11mm fell at Lake Tabourie.
Ms Farr said the storm hadn’t moved too much, which could lead to further storms on Friday afternoon.
“These storms could be severe as we are expecting to see some damaging wind gusts,” she said.
According to the Bureau of Meterology, a thunderstorm is associated with a very tall cloud mass called a cumulonimbus cloud. A good proportion of thunderstorms develop when warm, humid air near the ground is forced upwards due to converging surface winds and rises rapidly in an unstable atmosphere.
Snaking through stormy skies, lightning is one of nature’s most spectacular displays—but it can also be spectacularly dangerous.
So what causes this high-voltage show and how can you track where it’s happening? Well, the Bureau of Meterology says it begins within a developing thunder cloud.
“Within [the cloud] there are millions of tiny ice crystals and super-cooled water droplets rubbing up against each other as they move up and down,” it said.
“This causes a positive charge to develop at the top of the cloud and a negative charge at the bottom. The negative charge at the bottom of the cloud moves closer to the ground through a faint, negatively charged channel in a series of steps called ‘leaders’, while coming up from the ground are a series of positively charged channels known as ‘streamers’.”
When one of the positive steps connects with the negative streamer, a powerful electrical current races from the cloud to the ground, and this is when we see the lightning bolt.
Lightning heats the air around it to a temperature of approximately 30,000 °C, which is hotter than the surface of the sun. This rapid heating makes the air expand extremely quickly in a shock wave that we hear as thunder.