Norman Garden: Right now, a severe storm likely to be the first significant east coast low in three years is developing off the coast of New South Wales. It’s expected to intensify today before approaching the coastline on Tuesday. Huge waves, sustained heavy rains and very strong winds are likely. At this stage, it’s expected to linger offshore south of Coffs Harbour – the same area hit hard by unprecedented floods on the Mid-North Coast last month. Residents on the coast or in low-lying areas have been asked to prepare.
There’s nothing new about east coast lows, intense winter storms which can hit coastlines anywhere from southern Queensland to Tasmania. But what is new are the historically warm seas. Just like a tropical cyclone, east coast lows feed on ocean heat. And just like a tropical cyclone, they can intensify rapidly if the conditions are right.
The storm looming this week has been intensifying very fast, to the point it could be classified as a “weather bomb” – a storm undergoing explosive cyclogenesis.
If the storm shapes up as predicted, we can expect to see damage to houses and trees as well as significant beach erosion – especially in heavily populated areas exposed to the storm’s southern flank.
It’s too early to say just how bad this storm will be. Much depends on how intense it becomes and how close it tracks to the coast. Earlier storms have caused flooding of businesses and properties and significant disruptions to transport networks and electricity supplies.
The Bureau of Meteorology is forecasting strong to damaging winds and moderate to heavy rain for this deepening weather system from Tuesday onwards, and hazardous surf conditions for much of the week. Sea surface temperatures are 1 to 2.5 degrees Celsius above average off most of the NSW coast. This ocean heat will act as fuel for the storm, boosting the chance of even stronger winds and heavy rain if the centre moves closer to the coast and slows down.
Why do winter storms need their own title? East coast lows are quite distinct. They’re most common in autumn and winter, but they can occur any time.agencies