Howdy Pabloako, yes 100% they are mammatus. The word mammatus Comes from a Latin word meaning mamma or udder ( like on a cow. ). I had an old bushy mate when I was growing up, an ex- soldier, ex tracker who taught me survival and weather. But he never called the clouds by their right names. He said when you see the egg shell clouds ( mammatus) know that it is very turbulent up their and a bad storm is coming, and in the 70’s and early 80’s they were nasty.

He was a great family friend and mate even though he was so much older than me.

Great photo.

Cloud over the Northside but nothing eggciting. No lightning, thunder or spots of rain as at 16:21. Everything is going the way the models suggested and the NSW border and Goldie are getting the best of it, but at the same time a lot of lightning and if it is dry, possible fire ignition points.