Heavy rain over the interior has eventuated over the last 24 hours, with the Red Centre seeing its best rain over a year. Watarrka, best known for its proximity to Kings Canyon west of Alice Springs, picked up a massive 77mm - the highest daily rain since February, 2000. For November, it is the wettest day in at least 18 years. Alice Springs recorded 39mm overnight, in persistent heavy showers which dumped 3 to 5mm per 10 minutes for large chunks of the night. It is the inland city's best rain since January, 2007. A trough arcing across the interior of the country and dragging tropical moisture from the oceans to the north and up, over the MacDonnell Ranges is responsible for the rain. With thick cloud and instability persisting over the Centre, more falls of similar magnitude are expected over the next few days as the trough shifts only very slowly north. Storms will also become more widespread over the Top End as the trough shifts north early in the week.