The tropical cyclone alert for the Northern Territory has been cancelled but residents have been urged to prepare for heavy rain and damaging winds. Forecasters had warned that a tropical low brewing north of Darwin over Christmas could intensify into a category one Boxing Day cyclone. But the Bureau of Meteorology downgraded the alert late on Saturday, saying the weather system would remain a tropical low. It crossed the coast about about 150 kilometres southwest of Darwin overnight and is currently moving slowly southeast across the Daly region. The bureau said parts of the Top End have been hit by heavy rain and squalls. A severe weather warning has been issued for people in Daly, Tiwi, Arnhem, and Carpentaria regions. Heavy rainfall that could lead to flash flooding is expected to continue throughout Sunday across the Arnhem, Daly, Tiwi and northwest Carpentaria districts. Rainfall of 150 to 250mm and isolated falls to …