A low is deepening over the Tasman Sea. An associated band of heavy rain, preceded by a strong, north to northeast flow, should move across the upper North Island Saturday afternoon and rapidly down the east coast of the North Island on Sunday. By Sunday evening it is expected to lie off the Marlborough coast with a strong east to southeast flow directing rain into eastern Otago, Canterbury and possibly southern parts of the Kaikoura Coast.

This watch is for a period of heavy rain in southern Northland, Auckland, Waikato, Coromandel Peninsula, Bay of Plenty and northern Gisborne from later Saturday to noon Sunday and in western Nelson through much of Sunday. A warning will likely be issued for Bay of Plenty Saturday morning, but for the other areas, rainfall accumulations would appear to fall short of warning criteria.

In the east of the South Island, the watch is for a period of heavy rainfall for eastern Otago, Canterbury and Marlborough from Sunday afternoon through to Monday night or Tuesday morning.

In many of these areas, the ground is already very sodden and further rainfall will likely cause significant problems, especially in Bay of Plenty, Canterbury and eastern Otago.