The weather phenomenon that has summoned an enormous amount of rain to northern NSW and unleashed unprecedented floods is an unusually stagnant coastal trough that parked over the coast on Monday and refused to budge.
Troughs are regions of low-pressure that bring in storm clouds and rain, and this one is feeding off moist winds blowing in from the ocean.
As a result, some rain gauges have clocked 600mm of rain – about four months’ worth – since Monday.
The weird weather system has summoned unprecedented floods and brought about record-breaking rainfall to some areas.Credit: BOM
“The air that’s getting drawn into the east coast is very, very humid. There’s a lot of moisture in that air available to rain,” senior meteorologist from the Bureau of Meteorology Angus Hines said.
“Secondly, [the trough] just has not moved. Since about Monday, it’s been sat in the same place, which means it has rained day after day, after day this week. If it had only been one day and then it had gone, we would’ve seen some minor or moderate flooding but it wouldn’t have been too bad.
“But four days in a row of this amount of rainfall and we see this significant, extensive, widespread and major flood event happening in of front of our eyes.”
Read the full article here
